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▶ ラップマスター ヴォルターズ ゲーエムベーハーの特許一覧
(19)【発行国】日本国特許庁(JP)
(12)【公報種別】公開特許公報(A)
(11)【公開番号】P2022125969
(43)【公開日】2022-08-29
(54)【発明の名称】両面または片面工作機械
(51)【国際特許分類】
B24B 37/08 20120101AFI20220822BHJP
B23Q 11/10 20060101ALI20220822BHJP
B24B 37/10 20120101ALI20220822BHJP
B24B 37/015 20120101ALI20220822BHJP
B24B 37/005 20120101ALI20220822BHJP
B24B 45/00 20060101ALI20220822BHJP
B24B 7/17 20060101ALI20220822BHJP
【ＦＩ】
B24B37/08
B23Q11/10 A
B24B37/10
B24B37/015
B24B37/005 B
B24B45/00 Z
B24B7/17 Z
【審査請求】有
【請求項の数】14
【出願形態】ＯＬ
【外国語出願】
(21)【出願番号】P 2022008879
(22)【出願日】2022-01-24
(31)【優先権主張番号】10 2021 103 709.3
(32)【優先日】2021-02-17
(33)【優先権主張国・地域又は機関】DE
【公序良俗違反の表示】
（特許庁注：以下のものは登録商標）
１．テフロン
(71)【出願人】
【識別番号】517033148
【氏名又は名称】ラップマスター ヴォルターズ ゲーエムベーハー
(74)【代理人】
【識別番号】100080182
【弁理士】
【氏名又は名称】渡辺 三彦
(74)【代理人】
【識別番号】100142572
【弁理士】
【氏名又は名称】水内 龍介
(72)【発明者】
【氏名】ボラー ハンスペーター
(72)【発明者】
【氏名】ヌーバー インゴ
【テーマコード（参考）】
3C011
3C034
3C043
3C158
【Ｆターム（参考）】
3C011EE01
3C034AA07
3C034BB06
3C034BB51
3C034BB75
3C034CB04
3C034DD10
3C043CC04
3C043CC11
3C043DD02
3C043DD05
3C043EE02
3C158AA04
3C158AA14
3C158AA16
3C158AA18
3C158AB04
3C158BA02
3C158BA08
3C158BB02
3C158CB01
3C158DA06
3C158DA09
3C158DA18
3C158EA01
(57)【要約】 （修正有）
【課題】熱の影響による、ワークピースを機械加工するための作業ギャップの形状の局所的または全体的な変化を最小化するタイプの両面または片面工作機械を提供する。
【解決手段】第１の支持ディスク１００に固定された環状の第１の作業ディスク１４０と、カウンターベアリング要素とを備える両面または片面工作機械であって、第１の作業ディスクおよびカウンターベアリング要素は、少なくとも１つの駆動シャフトによって互いに相対的に回転するように駆動可能であり、作業ギャップ１８０は、平坦なワークピースの両面または片面を機械加工するために、第１の作業ディスクとカウンターベアリング要素との間に形成され、第１のクランプ手段は、第１の作業ディスクと対向する第１の支持ディスクのクランプ面に対して、作業ギャップから離間する方向に向くクランプ面で第１の作業ディスクをクランプするために設けられる。
【選択図】図１
【解決手段】第１の支持ディスク１００に固定された環状の第１の作業ディスク１４０と、カウンターベアリング要素とを備える両面または片面工作機械であって、第１の作業ディスクおよびカウンターベアリング要素は、少なくとも１つの駆動シャフトによって互いに相対的に回転するように駆動可能であり、作業ギャップ１８０は、平坦なワークピースの両面または片面を機械加工するために、第１の作業ディスクとカウンターベアリング要素との間に形成され、第１のクランプ手段は、第１の作業ディスクと対向する第１の支持ディスクのクランプ面に対して、作業ギャップから離間する方向に向くクランプ面で第１の作業ディスクをクランプするために設けられる。
【選択図】図１
【特許請求の範囲】
【請求項1】
第１の支持ディスク（１０、１００）に固定された好ましくは環状の第１の作業ディスク（１４、１４０）と、カウンターベアリング要素とを備える両面または片面工作機械であって、前記第１の作業ディスク（１４、１４０）および前記カウンターベアリング要素は、少なくとも１つの駆動シャフトによって互いに相対的に回転するように駆動可能であり、作業ギャップ（１８、１８０）は、平坦なワークピースの両面または片面を機械加工するために、前記第１の作業ディスク（１４、１４０）と前記カウンターベアリング要素との間に形成され、第１のクランプ手段（２０）は、前記第１の作業ディスク（１４、１４０）と対向する前記第１の支持ディスク（１０、１００）のクランプ面（２４）に対して、前記作業ギャップ（１８、１８０）から離間する方向に向くクランプ面（２６）で前記第１の作業ディスク（１４、１４０）をクランプするために設けられる、両面または片面工作機械。
【請求項2】
デカップリング手段は、前記第１の作業ディスク（１４、１４０）および前記第１の支持ディスク（１０、１００）の前記クランプ面（２４、２６）の間に配置される少なくとも１つの軸受（３２）を備えることを特徴とする、請求項１に記載の両面または片面工作機械。
【請求項3】
前記少なくとも１つの軸受（３２）は、少なくとも１つの転がり軸受（３２）を備えることを特徴とする、請求項２に記載の両面または片面工作機械。
【請求項4】
前記デカップリング手段は、前記第１のクランプ手段（２０）を弾性的にプレストレスするための弾性プレストレス手段（３０）を備えることを特徴とする、請求項１から３のいずれか一項に記載の両面または片面工作機械。
【請求項5】
前記第１のクランプ手段（２０）は、前記第１の支持ディスク（１０、１００）を、前記第１の作業ディスク（１４、１４０）の前記クランプ面（２６）に対してそのクランプ面（２４）でクランプするクランプねじ（２０）を備えることを特徴とする、請求項１から４のいずれか一項に記載の両面または片面工作機械。
【請求項6】
前記弾性プレストレス手段（３０）は、前記クランプねじ（２０）のねじ頭（２２）と前記第１の作業ディスク（１４、１４０）から離間した方向に向く前記第１の支持ディスク（１０、１００）の表面（２８）との間に各々配置される弾性ばね座金（３０）を備えることを特徴とする、請求項４および５に記載の両面または片面工作機械。
【請求項7】
前記デカップリング手段は、前記第１の作業ディスク（１４、１４０）と前記第１の支持ディスク（１０、１００）との間にデカップリング中間層、特に摺動中間層または熱的分離のための中間層を含むことを特徴とする、請求項１から６のいずれか一項に記載の両面または片面工作機械。
【請求項8】
前記第１の作業ディスク（１４、１４０）の材料は、前記第１の支持ディスク（１０、１００）の材料よりも低い熱膨張係数を有することを特徴とする、請求項１から７のいずれか一項に記載の両面または片面工作機械。
【請求項9】
前記カウンターベアリング要素は、好ましくは環状の第２の作業ディスク（１６、１６０）によって形成され、前記第１および第２の作業ディスク（１６、１６０）は、互いに相対的に同軸上に配置され、前記作業ギャップ（１８、１８０）は、平坦なワークピースの両面または片面を機械加工するために、前記第１および第２の作業ディスク（１４、１４０、１６、１６０）の間に形成されることを特徴とする、請求項１から８のいずれか一項に記載の両面または片面工作機械。
【請求項10】
前記第２の作業ディスク（１６、１６０）は、第２の支持ディスク（１２、１２０）に固定され、第２のクランプ手段は、前記第２の作業ディスク（１６、１６０）に対向する前記第２の支持ディスク（１２、１２０）のクランプ面に対して、前記作業ギャップ（１８、１８０）から離間する方向に向くクランプ面で前記第２の作業ディスク（１６、１６０）をクランプするために設けられ、デカップリング手段はまた、前記第２の作業ディスク（１６、１６０）を前記第２の支持ディスク（１２、１２０）から少なくとも部分的に分離するために設けられることを特徴とする、請求項１から９のいずれか一項に記載の両面または片面工作機械。
【請求項11】
圧力容積部（３００）は、前記第１の支持ディスク（１０、１００）と前記第１の作業ディスク（１４、１４０）との間に配置され、該圧力容積部が、圧力が前記圧力容積部（３００）に蓄積され、前記第１の作業ディスク（１４，１４０）に所定の局所変形を生成するような方法で作動可能な圧力流体供給部に接続されることを特徴とする、請求項１から１０のいずれか一項に記載の両面または片面工作機械。
【請求項12】
温度制御チャネル（２２０、２８０）は、前記第１の作業ディスク（１４、１４０）の温度を制御するために設けられ、温度制御流体供給部に接続されることを特徴とする、請求項１から１１のいずれか一項に記載の両面または片面工作機械。
【請求項13】
前記温度制御チャネル（２２０、２８０）は、前記第１の作業ディスク（１４、１４０）内に配置され、前記温度制御チャネル（２２０、２８０）が前記圧力容積部（３００）よりも前記作業ギャップ（１８、１８０）の近くに配置され、前記温度制御チャネル（２２０、２８０）が前記圧力容積部（３００）に接続されないようにすることを特徴とする、請求項１１または１２のいずれか一項に記載の両面または片面工作機械。
【請求項14】
前記第１の作業ディスク（１４，１４０）は、互いに接続される２つの好ましくは環状ディスクから形成され、かつその間に前記温度制御チャネル（２２０、２８０）が形成され、一方の前記ディスクは前記作業ギャップ（１８、１８０）に隣接し、他方の前記ディスクは前記第１の支持ディスク（１０、１００）の前記クランプ面に対してクランプするための前記クランプ面を有することを特徴とする、請求項１２および１３のいずれか一項に記載の両面または片面工作機械。
【発明の詳細な説明】
【技術分野】
【0001】
本発明は、第１の支持ディスクに固定された好ましくは環状の第１の作業ディスクと、カウンターベアリング要素とを備える両面または片面工作機械であって、第１の作業ディスクおよびカウンターベアリング要素は、少なくとも１つの駆動シャフトによって互いに相対的に回転するように駆動可能であり、作業ギャップは、平坦なワークピースの両面または片面を機械加工するために、第１の作業ディスクとカウンターベアリング要素との間に形成され、第１のクランプ手段は、第１の作業ディスクと対向する第１の支持ディスクのクランプ面に対して、作業ギャップから離間する方向に向くクランプ面で第１の作業ディスクをクランプするために設けられる両面または片面工作機械に関する。
【背景技術】
【0002】
例えば、ウエハなどの平坦なワークピースは、両面工作機械において、両面同時に機械加工される。そのため、両面工作機械は、上部作業ディスクと下部作業ディスクとを有し、これらの間に作業ギャップが形成され、加工の間、この作業ギャップに機械加工対象のワークピースが案内される。上部作業ディスクは上部支持ディスクに固定され、下部作業ディスクは下部支持ディスクに固定される。機械加工の間、少なくとも１つの作業ディスクがその支持ディスクと共に回転駆動することによって、作業ディスクの間に相対回転が生じる。両面工作機械では、いわゆるロータディスクを誘導する両面工作機械が知られている。ロータディスクは一般に、機械加工されるワークピースを浮いた状態で円形開口部に収納する。また、適切な運動学によって、ロータディスクは、作業ディスクの相対回転中に作業ギャップ内で確実に回転する。その結果、ワークピースは、作業ギャップ内でサイクロイド軌道に沿って移動する。これにより、特に均一な表面機械加工が達成される。
【0003】
ここで問題となるような工作機械では、機械加工中に生じるプロセス熱に起因して、作業ディスクの間の作業ギャップに変化が生じる。具体的には、作業ディスクの熱に関連した変形が生じ、したがってギャップ形状に規定された形状からの偏差が生じる。この偏差は、加工の結果に悪影響を及ぼす。これは、特にいわゆるプライムウエハの非常に高い加工要件に当てはまる。
【0004】
特に半導体ウエハを機械加工するための二ディスク型研磨機が、ドイツ特許第１０００７３９０号（特許文献１）から知られている。この場合、冷却チャネルが、研磨ディスクを支持する支持ディスク内、または支持ディスク内および研磨ディスク内に形成され、この冷却チャネルによって冷却が行われることにより、作業ギャップの形状への望ましくない影響が防止される。さらに、ベース支持体と支持ディスクとの間で相対的な半径方向の移動が可能であり、これによりベース支持体と支持ディスクとの温度が異なるとき、変形が低減される。
【0005】
作業ディスクの温度を制御することによって、発生するプロセス熱による悪影響を弱めることが、ドイツ特許第１０２００４０４０４２９号（特許文献２）から知られている。チャネルが支持ディスクに形成され、そこに冷却水などの対応する温度制御流体が流される。
【0006】
さらに、上部支持ディスクと、上部支持ディスクと共にそこに取り付けられた上部作業ディスクとを機械的に変形させる装置が、ドイツ特許第１０２００６０３７４９０号（特許文献３）から知られている。この装置では、最初は平坦である上部作業ディスクの作業面をわずかに凹状の面に変更できる。反対に、最初はわずかに凸状である上部作業ディスクの作業面を平坦、またはそれぞれ凹状の作業面に変更できる。
【0007】
特に、例えば水のような圧力媒体を作業ディスクに作用する圧力チャンバに導入することによって、作業ディスクの少なくとも一方を局所的に変形させる手段を備えた両面または片面工作機械が、ドイツ特許出願公開第１０２０１６１０２２２３号（特許文献４）から知られている。この手段では、例えば作業ディスクに作用する局所的な凹状または複雑な変形を生成することが可能である。さらに、冷却チャネルが冷却用の作業ディスクの支持ディスクに形成されている。また、ドイツ特許第１０２００６０３７４９０号（特許文献３）に記載のように、全体的な変形を生成するための手段を設けることができる。
【0008】
周知のシステムに関する問題は、作業ギャップに直接隣接する作業ディスクが作業ディスクを支持する支持ディスクよりも動作中により高温の熱を帯びる可能性があることである。その結果、作業ディスクと支持ディスクとの間に応力が生じる可能性がある。したがって、作業ギャップが確実に、制御可能な手段による影響を受けることができなくなる。また、温度差に応じて、支持ディスクと作業ディスクとの間の相互的なずれが生じる可能性がある。動作後の後続の冷却の間、例えばねじ接続から、ディスクは、移動に対抗する摩擦力に起因して、完全に元の位置に戻らない。したがって、完全な冷却の後、摩擦力の２倍の量の力偏差がディスクの間に残る可能性がある。これにより、次に異なる局所形状が生じる可能性がある。さらに、支持ディスクと作業ディスクとの間のブレースの変化により、作業ディスクの全体的な形状が変化する可能性がある。また、動作中に、作業ギャップに隣接する作業ディスクの面と作業ディスクの反対側との間で大きな温度差が生じる可能性がある。これらにより、２つの面に異なる熱膨張が生じる可能性があり、これによって作業ディスクに膨張が生じ、したがって局所形状にも変化が生じる可能性がある。
【0009】
熱に関連した形状の変化は、例えばインバーとして知られる、鉄－ニッケル特殊合金のように、熱膨張係数が非常に低い材料を使用することによって相殺することができる。ただし、このような材料は、高価で、加工、特に鋳造または機械加工が難しい。このような材料を使用することは、比較的薄い作業ディスクに対してのみ経済的に実行可能である。しかしながら、より熱膨張係数の大きい材料で作られた支持ディスクでこのような作業ディスクを支持することにより、バイメタルが形成され、比較的小さな温度変化の場合でも、形状の変化とそれに対応した大きなブレース力が発生することになる。したがって、国際出願第２０２０／２０８９６８号（特許文献５）は、熱膨張係数の低い作業ディスク材料を使用するとき、作業ディスクを支持ディスクで支持するのではなく、マウントを介して作業ディスクを支持ディスクに吊り下げるのみにすることを提案している。その結果、作業ディスクと支持ディスクとの間の接触は、最小化される。しかしながら、支持ディスクと作業ディスクとの間にブレースがないため、加工結果が損なわれる。
【先行技術文献】
【特許文献】
【0010】
【特許文献1】ドイツ特許第１０００７３９０号
【特許文献2】ドイツ特許第１０２００４０４０４２９号
【特許文献3】ドイツ特許第１０２００６０３７４９０号
【特許文献4】ドイツ特許出願公開第１０２０１６１０２２２３号
【特許文献5】国際出願第２０２０／２０８９６８号
【発明の概要】
【発明が解決しようとする課題】
【0011】
上述の従来技術から進めて、本発明の目的は、熱の影響による、ワークピースを機械加工するための作業ギャップの形状の局所的または全体的な変化を最小化するタイプの両面または片面工作機械を提供することである。
【課題を解決するための手段】
【0012】
本発明は、請求項１に記載の両面または片面工作機械によって、この目的を達成する。有利な実施形態は、従属請求項、明細書および図面にて開示される。
【0013】
問題となっているタイプの両面または片面工作機械に対して、本発明は、第１の作業ディスクを第１の支持ディスクから少なくとも部分的に分離するためのデカップリング手段が設けられている点で目的を達成している。
【0014】
工作機械は、例えば、研磨機、ラップ盤、または研削機とすることができる。片面工作機械では、第１の作業ディスクと単純重量または圧力シリンダなどのカウンターベアリング要素との間に作業ギャップが形成され、もしくはウエハなどの機械加工されるワークピースの両面または片面を機械加工する、両面工作機械で第２の作業ディスクとの間に作業ギャップが形成される。工作機械は、両面工作機械または片面工作機械とすることができる。両面工作機械では、ワークピースの底面および上面は、好ましくは作業ギャップ内で同時に機械加工され得る。それに対応して、両方の作業ディスクは、ワークピース表面を機械加工する作業面を有することができる。対照的に、片面工作機械では、片面のワークピースのみ機械加工される。例えば、下部作業ディスクによって底面のみが機械加工される。この場合、１つの作業ディスクのみが、ワークピース表面を機械加工する作業面を有する。この場合、カウンターベアリング要素は、作業ディスクによって機械加工するために対応するカウンターベアリングのみを形成するように機能する。
【0015】
ワークピースは、機械加工のために作業ギャップ内に配置されたロータディスクの開口部に周知の方法で浮遊するように収容可能である。第１の作業ディスクおよびカウンターベアリング要素は、動作中に、例えば第１および／または第２の駆動シャフトならびに少なくとも１つの駆動モータによって、互いに相対的に回転するように駆動する。カウンターベアリング要素ならびに第１の作業ディスクの両方は、例えば反対方向に回転するように駆動可能である。ただし、カウンターベアリング要素または第１の作業ディスクのいずれか一方のみを回転駆動することが可能である。例えば、両面工作機械では、ロータディスクは、適切な運動学によって移動して、この相対回転中に作業ギャップを通って回転し、ロータディスク内に配置されたワークピースが作業ギャップ内でサイクロイド軌道を描くようにすることができる。例えば、ロータディスクは、その外縁部および／または内縁部に、例えば第１の作業ディスクに連携する歯に係合する歯を有してもよい。このようないわゆる遊星運動学による機械は、周知である。
【0016】
第１の作業ディスクは、環状に設計され得る。また、カウンターベアリング要素、またはそれぞれ第２の作業ディスクは、環状に設計され得る。そして、第１の作業ディスクおよび第２の作業ディスクなどのカウンターベアリング要素は、対向する環状の作業面を有し、その間に環状の作業ギャップが形成される。作業面は、研磨布などの作業用カバーで覆われることが可能である。また、作業ディスクを保持する任意の支持ディスクは、環状に設計可能であるか、もしくは作業ディスクを固定する少なくとも環状の支持部分を有する。また、１つの作業ディスクにつき複数の支持ディスクを設けることができる。第１の作業ディスクおよび／またはカウンターベアリング要素は、１つまたは複数の層で形成可能である。第１の作業ディスクまたはカウンターベアリング要素を支持する支持ディスクにも同じことが当てはまる。
【0017】
本発明によれば、デカップリング手段は、第１の支持ディスクから第１の作業ディスクを少なくとも部分的に、例えば、完全に分離するため、具体的には機械的に分離するために設けられる。デカップリング手段によってもたらされる少なくとも部分的な分離により、デカップリング手段がない場合と比較して、第１の作業ディスクおよび第１の支持ディスクは、より容易に、すなわち低減された摩擦力の下で、互いに相対的に移動できるようになる。したがって、作業ディスクおよび任意選択で支持ディスクの実質的な自由膨張が可能である。具体的には、第１の作業ディスクおよび第１の支持ディスクの相互に対向するクランプ面の間で、第１のクランプ手段によってもたらされる、摩擦力が低減される。このため、デカップリング手段は、第１のクランプ手段に作用することができる。
【0018】
従来技術では、冷却または機械的な変形などの付加的な手段によって熱膨張を相殺する、特に可能な限り熱膨張を抑制するように試みられてきた。本発明は、別のアプローチを提供する。サイズの熱的変化は基本的に許容されるが、デカップリング手段は、サイズの熱的変化が作業ギャップに悪影響を与えず、したがって加工結果にも影響を与えないという効果を有する。第１の作業ディスクおよび支持ディスクのクランプ面の間の摩擦力が減少するため、例えば、動作中に作業ディスクのサイズの熱的変化による作業ギャップの形状の変化に関する冒頭で説明した問題は生じない。既述のように、第１の作業ディスクおよび第１の支持ディスクは、例えば動作中に第１の作業ディスクが加熱されると、対応する接合面を形成するそれらのクランプ面に沿って、互いに相対的に変位する。また、既述のように、第１のクランプ手段によってもたらされる摩擦力のために、後続の冷却では、出発位置への完全な復帰運動が生じない。したがって、ある程度のヒステリシスがある。デカップリング手段は、例えば、加熱後に行う冷却中に出発位置への完全な復帰動作が行われるような方法で、第１のクランプ手段によってもたらされる摩擦力を低減する。これにより、持続的な応力および局所的または全体的な形状の変化を最小化できる。同時に、支持ディスクと作業ディスクとの間で広範囲のブレースが実現され、特に第１の作業ディスクおよび／または第１の支持ディスクの表面全体または半径方向の拡張部全体にわたって実質的にブレースが実現される。したがって、このようなブレースがない上述した従来技術とは対照的に、加工結果は損なわれない。
【0019】
デカップリング手段は、第１の作業ディスクおよび第１の支持ディスクのクランプ面の間に配置され得る。したがって、第１の作業ディスクおよび第１の支持ディスクのクランプ面が直接接触せず、デカップリング手段を介した間接的な接触のみが可能である。同時に、作業ディスクおよび支持ディスクを、例えば、半径方向の異なる位置に設けられたクランプねじを介して、それらの表面全体、特に半径方向の拡張部全体にわたって、互いに固定することができる。また、デカップリング手段は、第１のクランプ手段自体にも作用することができる。その場合、第１の作業ディスクが第１の支持ディスクのクランプ面に対して直接そのクランプ面を支持するが、第１のクランプ手段は、例えば、低減された摩擦力で第１の作業ディスクと第１の支持ディスクとの間の相対的な移動がクランプ面の上で可能な方法で、プレストレスされることが可能である。
【0020】
本発明によれば、特に第１の作業ディスクのクランプ面は、第１の支持ディスクのクランプ面に対して直接支持することが可能であり、これらのクランプ面の間に中間層または中間要素が設けられていない。デカップリング手段が第１の作業ディスクおよび第１の支持ディスクのクランプ面の間に配置されている場合、デカップリング手段を除いて、クランプ面の間に中間層またはさらなる中間要素が存在しないことが可能である。
【0021】
特に実用的な実施形態によれば、デカップリング手段は、第１の作業ディスクおよび第１の支持ディスクのクランプ面の間に配置される、少なくとも１つの軸受、特に複数のこのような軸受を備えることができる。クランプ面の間に配置された軸受は、機械的な分離を実現することによって、かなり低減された摩擦力で第１の作業ディスクと第１の支持ディスクとの間で相対的な移動を可能にする。転がり軸受、例えば、ころ軸受は、特に適した軸受である。このような軸受は、例えば、特にクランプ手段、例えばクランプねじの周囲に配置され得る。
【0022】
さらなる実施形態によれば、デカップリング手段は、第１のクランプ手段を弾性的にプレストレスするための弾性プレストレス手段を備えてもよい。このような弾性プレストレス手段は、代替的または追加的に、クランプ面の間に配置される、軸受などのデカップリング手段のために設けられることができる。弾性プレストレス手段は、第１の作業ディスクおよび第１の支持ディスクのクランプ面を互いにクランプするような方法で、第１のクランプ手段を弾性的にプレストレスする。この弾性プレストレスに抗して、クランプ面がサイズの熱的変化の過程で相対的に変位したとき、クランプ面の間の摩擦力が低減される。既述のように、弾性プレストレス手段は、クランプ手段面の間のデカップリング手段、例えば、クランプ面の間の少なくとも１つの軸受に追加して設けられることができる。この場合、弾性プレストレス手段は、少なくとも１つの軸受、例えば、少なくとも１つの転がり軸受をプレストレスできる。そして、弾性プレストレス手段の弾性変形により、第１の作業ディスクおよび第１の支持ディスクのクランプ面の間で移動の自由度を高めることができる。
【0023】
さらなる特に実用的な実施形態によれば、第１のクランプ手段は、第１の支持ディスクを、第１の作業ディスクのクランプ面に対してそのクランプ面でクランプするクランプねじを備えることができる。このようなクランプねじは、作業ギャップから離間する方向に向く側面から、第１の支持ディスクおよび第１の作業ディスクの対応するねじ受容部に挿入可能である。このため、クランプねじを、第１の支持ディスクを通って案内し、第１の作業ディスクにねじ込むことができる。少なくとも第１の作業ディスクでは、ねじ受容部は、対応するねじ山を有することができる。クランプねじのねじ頭は、第１の作業ディスクから離間する方向に向く第１の支持ディスクの側面を支持することができる。固定するために、複数のクランプねじを設けることができる。例えば、環状の第１の作業ディスクの場合、クランプねじの第１のグループは、第１の作業ディスクまたは第１の支持ディスクの半径方向外側の部分円に沿って配置され、クランプねじの第２のグループは、第１の作業ディスクまたは第１の支持ディスクの半径方向内側の部分円に沿って配置される。部分円は各々、第１の作業ディスクまたは第１の支持ディスクの半径方向外側または半径方向内側の端部近くに配置され得る。
【0024】
これに関するさらなる実施形態によれば、弾性プレストレス手段は、弾性ばね座金を備えることができ、これらのばね座金は各々、クランプねじのねじ頭と第１の作業ディスクから離間した方向に向く第１の支持ディスクの表面との間に配置される。ばね座金は、ねじ頭と支持ディスクの対向する面との間でクランプされ、これによって弾性的に圧縮され、したがって、プレストレスされ得る。このプレストレスに対して、第１の作業ディスクおよび第１の支持ディスクのクランプ面の間の摩擦力を低減できる。
【0025】
さらなる実施形態によれば、デカップリング手段は、第１の作業ディスクと第１の支持ディスクとの間にデカップリング中間層を含むことができる。これは、例えば、特にテフロンなどの摺動材料の、摺動中間層であってもよい。ただし、デカップリング中間層は、熱的分離のための中間層であってもよく、したがって、低い熱伝導率を有する。したがって、デカップリング手段はまた、熱的デカップリング手段とすることができる。
【0026】
さらなる実施形態によれば、第１の作業ディスクの材料は、第１の支持ディスクの材料よりも低い熱膨張係数を有することができる。具体的には、第１の作業ディスクの熱膨張係数は、第１の支持ディスクの熱膨張係数よりも実質的に小さくすることができ、例えば、５分の１、好ましくは１０分の１まで低くすることができる。冒頭で説明したように、第１の支持ディスクと第１の作業ディスクとに熱膨張係数が大きく異なる材料を使用すると、バイメタルが発生し、サイズが熱的に変化した場合、これによって形状の変化が生じる。第１の作業ディスクと第１の支持ディスクとの間の本発明による少なくとも部分的な分離により、第１の作業ディスクと第１の支持ディスクとの熱膨張係数が大きく異なる場合でも、第１の作業ディスクと第１の支持ディスクとの間で大きな応力が発生しない。その結果、バイメタルに関して冒頭で説明した問題を回避できる。したがって、特に第１の作業ディスクに対してのみ、非常に低い熱膨張係数を有する材料、例えばインバーのような鉄－ニッケル合金を使用することが可能であり、一方で、より高い熱膨張係数を有する従来の材料、例えば鋳鉄を第１の支持ディスクに同時に使用可能である。そして、プロセス熱に大きく依存しない形状が生成される。同時に、熱膨張係数が非常に低い材料を作業ディスクに使用すると、作業ディスクの形状安定性、ひいては作業ギャップの形状安定性に関して有利である。
【0027】
さらなる実施形態によれば、カウンターベアリング要素は、好ましくは環状の第２の作業ディスクによって形成可能であり、第１および第２の作業ディスクは、互いに同軸上に配置され、作業ギャップは、平坦なワークピースの両面または片面を機械加工するために、第１および第２の作業ディスクの間に形成される。第２の作業ディスクは、第２の支持ディスクに固定可能であり、第２のクランプ手段は、第２の作業ディスクに対向する第２の支持ディスクのクランプ面に対して、作業ギャップから離間する方向に向くクランプ面で第２の作業ディスクをクランプするために設けられ、また、デカップリング手段は、第２の作業ディスクを第２の支持ディスクから少なくとも部分的に分離するために設けられる。第２のクランプ手段は、例えば、第１のクランプ手段として設計され得る。また、第２の作業ディスクおよび／または第２の支持ディスクは、第１の作業ディスクまたは第１の支持ディスクと同様に設計され得る。また、第２の作業ディスクを第２の支持ディスクから分離するためのデカップリング手段は、第１の作業ディスクを第１の支持ディスクから分離するためのデカップリング手段と同様に設計され得る。この点で、この文脈で説明した例示的な実施形態はすべて、第２のクランプ手段およびそれらのデカップリング手段を備えた第２の作業ディスクおよび第２の支持ディスクに転換可能である。
【0028】
さらなる実施形態によれば、好ましくは環状の圧力容積部を、第１の支持ディスクと第１の作業ディスクとの間に形成することができる。圧力容積部は、第１の作業ディスクに所定の局所変形を生成する圧力が圧力容積部に蓄積されるように作動可能な圧力流体供給部に接続される。本出願では、流体という用語が使用される限り、それは液体ならびに気体を指すことができる。圧力流体は、液体、具体的には水とすることができる。圧力容積部に圧力流体を導入することによって、支持ディスクと比較して薄い作業ディスクに圧力をかけることができ、当該圧力は作業ディスクの変形をもたらす。具体的には、これによって作業ディスクは、圧力容積部の圧力を低く設定することによって局所的に凹んだ形状に、中程度の圧力を設定することによって局所的に平坦な形状に、高い圧力を設定することによって局所的に凸形状に変化可能である。局所的に凸状の変形、またはそれぞれ凹状の変形、またはそれぞれ形状は、環状の第１の作業ディスクの内縁部と外縁部との間、特に半径方向にある。圧力容積部は、変化可能な圧力容積部である。第１の作業ディスクは、異なる圧力によって生じる圧力容積部の体積に応じて変形する膜を形成する。
【0029】
圧力流体供給部は、圧力容積部に接続された少なくとも１つの圧力ラインに接続される圧力流体リザーバを備える。ポンプおよび制御弁は、圧力ラインに配置可能であり、これらは、例えば、制御および／または調節装置によって、圧力容積部内に所望の圧力を蓄積するように作動することができる。さらに、圧力流体供給部は、圧力容積部内の圧力を直接または間接的に測定する圧力測定装置を備えることができ、また測定値を制御および／または調節装置に送ることができる。圧力容積部内の圧力流体供給部を適切に作動させることにより、所望の作業ギャップ形状に必要な圧力をこれに基づいて調整できる。例えば、半径方向の拡張部の上で作業ディスク間の距離が変化しないことが望ましい。所望のギャップ形状は、静的動作および／または動的動作において、すなわちワークピースの機械加工中に調整可能である。
【0030】
圧力容積部では、設置条件、形状および材料の境界条件によって決定される最大凹形状から最大凸形状の間で、第１の作業ディスクの局所形状をスムーズに調整することが基本的に可能である。第１の作業ディスクは、原則として任意の厚さを有することができる。ディスク形状の所望の調整範囲に応じて、作業ディスクは、その表面積、具体的にはそのリング幅、またはそれぞれその回転半径に応じて利用可能な圧力で変形できるように、適切な厚さを有する。ドイツ特許出願公開第１０２０１６１０２２２３号にて説明されるように、第１の作業ディスクの局所形状を半径方向に調整する可能性により、機械加工中の温度の影響によるギャップの変化を補償することができる。
【0031】
さらなる実施形態によれば、第１の作業ディスクの温度を制御するために温度制御チャネルを設けることが可能であり、温度制御チャネルは温度制御流体供給部に接続される。温度制御チャネルは、温度制御流体を流すように設計されている。温度制御チャネルは、例えばラビリンス状に設計され得る。温度制御流体、例えば水などの温度制御液体は、機械が動作している間、温度を制御するために、特に作業ディスクを冷却するために、温度制御チャネルを通って案内され得る。作業ディスクの熱に関連する変形は、温度制御チャネルによってある程度相殺され得る。
【0032】
さらなる実施形態によれば、温度制御チャネルは第１の作業ディスク内に配置され、温度制御チャネルが圧力容積部よりも作業ギャップの近くに配置され、温度制御チャネルが圧力容積部に接続されないようにすることが可能である。第１の作業ディスク内、具体的には第１の作業ディスク内に排他的に温度制御チャネルが配置されることにより、温度制御チャネルは、圧力容積部よりも作業ギャップの近くに配置され得る。特に、温度制御流体用の供給ラインおよび排出ラインは、温度制御流体供給部に接続される支持ディスク内を１本のみ貫通することができる。作業ギャップのより近くに配置された温度制御チャネルによって、第１の作業ディスクの冷却は、より効果的になり、特に作業ディスクが支持ディスクよりも強く加熱され、作業ギャップに隣接する作業ディスクの側面がより強く加熱されるという上述の問題を最小化できる。また、第１の作業ディスクと第１の支持ディスクとの間の対応する応力ならびに第１の作業ディスクの望ましくない変形を最小化できる。実際、温度制御チャネルは、作業ギャップに隣接する作業ディスクの表面に可能な限り近くに配置されることにより、作業ディスクを通るプロセス熱の支持ディスクへの浸透を防止できる。第１の作業ディスクと第１の支持ディスクとの間の熱の伝達をさらに最小化するために、第１の支持ディスクおよび／または第１の作業ディスクを、ディスク間の接触面が最小化されるようにそれらの接触の領域にバーまたは他の隆起物を備えて提供することが可能である。
【0033】
さらに、本発明では、温度制御チャネルと圧力容積部とが互いに接続され、かつ共通の回路を形成する従来技術とは異なり、温度制御チャネルは、圧力容積部に接続されない。したがって、一方では温度制御チャネル用に、他方では圧力容積部用に、別個の流体システム（回路）が設けられる。これにより、温度制御チャネル内の圧力とは無関係に、圧力容積部内の圧力をより柔軟に調整することが可能になる。さらに、局所形状を調整するための圧力容積部内の有用な圧力は、従来技術とは対照的に、温度制御チャネル内の圧力によって制限されない。
【0034】
別の実施形態によれば、第１の作業ディスクを、互いに接続される２つの好ましくは環状ディスクから形成することができ、かつその間に温度制御チャネルが形成され、一方のディスクは作業ギャップに隣接し、他方のディスクは第１の支持ディスクのクランプ面に対してクランプするためのクランプ面を備える。したがって、第１の作業ディスクは、２つの部品で構成され、第１の作業ディスクは、サンドウィッチ構造に類似した２つの部分的ディスクの間に温度制御チャネルを形成する。この設計により、第１の作業ディスク内に温度制御チャネルを排他的に形成することが、構造の観点から非常に容易になる。特に実用的な実施形態によれば、２つのディスクは、互いにねじ止めされ得る。ただし、他のタイプの固定ももちろん想定される。
【0035】
別の実施形態によれば、第１の作業ディスクを、その外縁部の領域および内縁部の領域においてのみ、第１の支持ディスクに固定することができる。上述したように、作業ディスクは、特に環状とすることができる。次に、好ましくは環状の圧力容積部は、第１の作業ディスクと第１の支持ディスクとの間に形成される。前述の実施形態では、第１の作業ディスクは、作業面に隣接するその半径方向外縁部および半径方向内縁部の領域においてのみ、第１の支持ディスクに固定され、例えばクランプ手段としてクランプねじを使用して部分円に沿ってねじ留めされる。対照的に、これらの縁部領域の間で、作業ディスクは、支持ディスクに固定されない。具体的には、圧力容積部は、この領域内に形成され得る。このように、圧力容積部内に適切な圧力を蓄積することによって、所望の方法で変形するために、作業ディスクは、必要な可動性を有する。支持ディスクへの作業ディスクの取り付けは、可能であれば作業ディスクの表面全体にわたって特定の変形を得るために、内縁部および外縁部上の接触面が可能な限り狭く保たれるように選択される。
【0036】
本発明の例示的な実施形態は、図面に基づいて下記により詳細に説明されている。
【図面の簡単な説明】
【0037】
【図1】両面工作機械の一部の断面図を示す。
【図2】第１の例示的な実施形態による両面工作機械の第１の作業ディスクと第１の支持ディスクの断面図を示す。
【図3】第２の例示的な実施形態による両面工作機械の第１の作業ディスクと第１の支持ディスクの断面図を示す。
【図4】さらなる例による両面工作機械の第１の作業ディスクと第１の支持ディスクの断面図を示す。
【0038】
特に明記しない限り、同一の参照番号は、図中の同一の対象を示す。
【発明を実施するための形態】
【0039】
図１にて単なる例として示された両面工作機械は、環状の第１の下部支持ディスク１００および同様に環状である第２の上部支持ディスク１２０を有する。環状の第１の下部作業ディスク１４０は下部支持ディスク１００に固定され、同様に環状である第２の上部作業ディスク１６０は上部支持ディスク１２０に固定される。環状作業ディスク１４０、１６０の間に、環状作業ギャップ１８０は形成され、この作業ギャップ１８０に、ウエハなどの平坦なワークピースが動作中に両面加工される。両面工作機械は、例えば研磨機、ラップ盤、または研削機とすることができる。
【0040】
上部支持ディスク１２０と、それと共に上部作業ディスク１６０、および／または下部支持ディスク１００とそれと共に下部作業ディスク１４０は、例えば上部駆動シャフト、および／または下部駆動シャフト、ならびに少なくとも１つの駆動モータを備える適切な駆動装置によって互いに相対的に回転駆動可能である。駆動装置自体は周知であり、明確性の理由からさらに説明されない。また、これ自体周知の方法では、機械加工されるワークピースは、作業ギャップ１８０内のロータディスクに浮遊するように保持され得る。適切な運動学、例えば遊星運動学によって、ロータディスクはまた、支持ディスク１００、１２０、またはそれぞれ作業ディスク１４０、１６０の相対回転中に作業ギャップ１８０を介して確実に回転することができる。制御および／または調整装置２００は、両面工作機械の動作を制御、またはそれぞれ調整する。
【0041】
図１に示す例では、ラビリンス状の温度制御チャネル２２０は、下部作業ディスク１４０内に設けられる。温度制御チャネル２２０は、例えば下部支持ディスク１００と下部作業ディスク１４０を駆動する駆動シャフトを介して、供給部２４０および排出部２６０によって、温度制御流体供給部に接続される。制御および／または調整装置２００を使用して、例えば温度制御チャネルの入口および／または出口で温度制御流体の所定の温度値に調整可能であり、もしくは温度制御流体の温度を相応に調整することによって、温度制御チャネルの入口で示される温度と出口で示される温度との間の所定の温度差を調整できる。また、図示された例では、ラビリンス状の温度制御チャネル２８０は、上部作業ディスク１６０内に形成され、また供給部および排出部（図示せず）を介して温度制御流体供給部に接続される。また、この温度制御流体供給部は、制御および／または調整装置２００によって制御される。温度制御チャネル２２０、またはそれぞれ２８０に温度制御流体、例えば水などの冷却剤を供給することによって、作業ディスク１４０、１６０の加熱および支持ディスク１００、１２０への熱の伝達は、効果的に相殺可能であることにより、対応する形状の変化が低減される。
【0042】
さらに、図示された例では、環状の圧力容積部３００は、下部支持ディスク１００と下部作業ディスク１４０との間に形成され、供給部３２０を介して、また例えば下部支持ディスク１００と下部作業ディスク１４０を駆動する駆動シャフトを介して、圧力流体供給部に接続される。また、圧力流体供給部は、制御および／または調整装置２００によって作動する。圧力流体を圧力容積部３００内に相応に導入することによって、下部作業ディスク１４０の局所的変形、具体的にはドイツ特許出願公開第１０２０１６１０２２２３号にて原則として説明されるような局所的な凹状または凸状の変形が生成される可能性がある。
【0043】
図１にて参照できるように、温度制御チャネル２２０は、圧力容積部３００よりも作業ギャップ１８０の近くに配置される。さらに、圧力容積部３００および温度制御チャネル２２０のダクトシステムは互いに接続されていないが、代わりに別々に制御可能であるか、もしくはそれぞれ調節可能である。
【0044】
図２から４は、図１に示す両面工作機械に使用可能な第１の支持ディスクと第１の作業ディスクを示す。説明の都合上、図２から４は、関連する供給部および排出ラインを含む、温度制御チャネル２２０および圧力容積部３００を示していない。また、図２から４に示す作業ディスクと支持ディスクが、供給部および排出ラインを含む、対応する温度制御チャネルおよび圧力容積部を有することは言うまでもない。さらに、図２から４は、例として第１の支持ディスクと第１の作業ディスクのみを示している。追加で提供される、第２の支持ディスクと第２の作業ディスクは、適宜設計され得る。
【0045】
図２は、例えば図１にて示す両面工作機械に使用可能な第１の下部支持ディスク１０および第１の下部作業ディスク１４の第１の例示的な実施形態を示す。図示された例示的な実施形態では、複数のクランプねじ２０が設けられ、このクランプねじ２０は作業ギャップ１８から離間する方向に向く側面から第１の支持ディスク１０を通って挿入され、かつ第１の作業ディスク１４の対応するねじ付ボアにねじ込まれる。クランプねじは、環状の支持ディスクおよび作業ディスク１０、１４を介して２つの部分円、すなわち半径方向外側の部分円および半径方向内側の部分円に沿って配置される。クランプねじ２０は、各々ねじ頭２２を有する。第１の支持ディスク１０は第１の作業ディスク１４に対向するクランプ面２４を有し、第１の作業ディスク１４は第１の支持ディスク１０に対向するクランプ面２６を有する。クランプねじ２０をねじ込む間、第１の支持ディスク１０と第１の作業ディスク１４は、互いに固定される。図２による図示された例示的な実施形態では、クランプ面２４、２６は、固定された状態で互いに直接横たわっており、互いに固定されている。
【0046】
図２による例示的な実施形態では、クランプねじ２０のねじ頭２２と第１の作業ディスク１４から離間する方向に向く第１の支持ディスク１０の表面２８との間に、弾性ばね座金３０が配置され、ばね座金はクランプねじ２０がねじ込まれた状態で弾性的に圧縮され、したがって、クランプ手段２０を弾性的にプレストレスする。その結果、クランプ面２４、２６の上の第１の支持ディスク１０と第１の作業ディスク１４との間における熱に起因する相対移動の場合、クランプ手段２０によって提供される摩擦力は低減されることにより、例えば、第１の作業ディスク１４の熱膨張およびこれによって第１の支持ディスク１０に対して引き起こされる相対移動の後に、第１の作業ディスク１４がその元の位置に完全に戻るようになる。
【0047】
図３は、図２による例示的な実施形態にほぼ対応するさらなる例示的な実施形態を示す。図３による例示的な実施形態では、弾性ばね座金３０に加えて、クランプねじ２０の周囲に配置された転がり軸受３２が、第１の支持ディスク１０と第１の作業ディスク１４のクランプ面２４、２６の間に設けられる。これらの転がり軸受３２によって、第１の支持ディスク１０と第１の作業ディスク１４、具体的にはそれらのクランプ面２４、２６は、互いに機械的に分離される。したがって、クランプねじ２０によって生じる第１の支持ディスク１０と第１の作業ディスク１４との間の摩擦力は、さらに低減される。
【0048】
図４は、上述したサイズの熱的変化の影響を回避するためのさらなる例を示す。図４による例は、一方では、弾性ばね座金３０の形態でデカップリング手段が設けられていない点で、図２による例示的な実施形態とは異なる。他方では、第１の支持ディスク１０‘と第１の作業ディスク１４‘におけるクランプねじ２０の周囲に逃げ溝３４、３６が形成されている点で異なる。このような逃げ溝３４，３６によって、上述したサイズの熱的変化による不利な影響を相殺する試みが行われてきた。しかしながら、この手段では、図２および３によるデカップリング手段に関連する成功をもたらさないことがわかっている。
【符号の説明】
【0049】
１０、１０‘、１００ 下部支持ディスク
１２、１２０ 上部支持ディスク
１４、１４‘、１４０ 下部作業ディスク
１６、１６０ 上部作業ディスク
１８、１８０ 作業ギャップ
２０ クランプ手段、クランプねじ
２２ ねじ頭
２４ クランプ面
２６ クランプ面
２８ 表面
３０ ばね座金
３２ 転がり軸受
３４ 逃げ溝
３６ 逃げ溝
２００ 制御および／または調整装置
２２０ 温度制御チャネル
２４０ 供給部
２６０ 排出部
２８０ 温度制御チャネル
３００ 圧力容積部
３２０ 供給部
１２、１２０ 上部支持ディスク
１４、１４‘、１４０ 下部作業ディスク
１６、１６０ 上部作業ディスク
１８、１８０ 作業ギャップ
２０ クランプ手段、クランプねじ
２２ ねじ頭
２４ クランプ面
２６ クランプ面
２８ 表面
３０ ばね座金
３２ 転がり軸受
３４ 逃げ溝
３６ 逃げ溝
２００ 制御および／または調整装置
２２０ 温度制御チャネル
２４０ 供給部
２６０ 排出部
２８０ 温度制御チャネル
３００ 圧力容積部
３２０ 供給部
【図1】
【図2】
【図3】
【図4】
【外国語明細書】
Double-Side or One-Side Machine Tool
The invention relates to a double-side or one-side machine tool comprising a preferably annular first working disk which is fastened to a first support disk, and comprising a counter bearing element, wherein the first working disk and the counter bearing element can be driven to rotate relative to each other by at least one drive shaft, wherein a working gap is formed between the first working disk and the counter bearing element to machine both sides or one side of flat workpieces, and wherein first clamping means are provided to clamp the first working disk with a clamping surface facing away from the working gap against a clamping surface of the first support disk facing the first working disk.
For example, flat workpieces such as wafers are simultaneously machined on both sides in double-sided machine tools. For this purpose, double-sided machine tools have a top working disk and a bottom working disk between which a working gap is formed in which the workpieces to be machined are guided during processing. The top working disk is fastened to a top support disk, and the bottom working disk is fastened to a bottom support disk. For machining, a relative rotation between the working disks is produced by rotatably driving at least one of the working disks together with its support disk. Double-sided machine tools are known in which so-called rotor disks are guided. The rotor disks generally accommodate workpieces to be machined in circular openings in a floating manner. By suitable kinematics, it is ensured that the rotor disks also rotate within the working gap during the relative rotation of the working disks. As a result, the workpieces move along cycloid paths within the working gap. Particularly consistent surface machining is hereby achieved.
With machine tools of the kind at issue here, a change in the working gap arises between the working disks due to the process heat which arises during machining. In particular, a heat-related deformation of the working disks occurs and hence a deviation in the gap geometry from the stipulated shape. This negatively influences the result of machining. This applies in particular to the very high machining requirements of so-called prime wafers.
A two-disk polishing machine is known from DE 100 07 390 B4, in particular for machining semiconductor wafers. In this case, cooling channels are formed in a support disk bearing a polishing disk, or in the support disk and in the polishing disk, by which cooling takes place to prevent undesirable influences on the geometry of the working gap. Moreover, a relative radial movement is permitted between a base support and the support disk, whereby a deformation is reduced when temperatures of the base support and support disk differ.
It is known from DE 10 2004 040 429 B4 to counteract negative effects from the arising process heat by controlling the temperature of the working disks. Channels are formed in the support disks through which corresponding temperature-controlling fluid such as cooling water is conducted.
Furthermore, an apparatus for mechanically deforming the top support disk, and with it the top working disk attached thereto, is known from DE 10 2006 037 490 B4. With this apparatus, an initially flat working surface of the top working disk can be changed to a slightly concave surface. Conversely, an initially slightly convex working surface of the top working disk can be changed into a flat, or respectively concave working surface.
A double-side or one-side machine tool is known from DE 10 2016 102 223 A1 with means for the local deformation of at least one of the working disks, in particular by introducing a pressure medium such as for example water into a pressure chamber acting on the working disk. In this manner, for example a local concave or complex deformation of the working disk can be created. Moreover, cooling channels are formed in a support disk of the working disk for cooling. In addition, means can be provided for creating a global deformation as described in DE 10 2006 037 490 B4.
A problem with known systems is that the working disk directly bordering the working gap can heat up more during operation than the support disk bearing it. As a result, stresses can occur between the working disk and the support disk and thus the working gap can no longer be influenced in a reliably controllable manner. Depending on the temperature difference, a mutual displacement between the support disk and the working disk can also occur. During subsequent cooling after operation, the disks do not completely return to their previous position due to a frictional force counteracting the movement, for example from a screwed connection. A force differential can therefore remain between the disks to the amount of twice the frictional force after complete cooling. This can in turn yield different local geometries. Moreover, the global geometry of the working disk can also be changed by the changed bracing between the support disk and working disk. Significant temperature differences can also occur during operation between a side of the working disk bordering the working gap and an opposite side of the working disk. These can lead to different thermal expansions of the two sides, which can cause a bulge in the working disk and therefore also a change in the local geometry.
A heat-related change in geometry could be counteracted by using a material with a very low coefficient of thermal expansion, such as special iron-nickel alloys, for example known as Invar. However, such materials are expensive and difficult to process, in particular cast or machine. The use of such a material would be economically viable only for comparatively thin working disks. A bracing of such a working disk with a support disk made of a material with a greater coefficient of thermal expansion would, however, form a bimetal, such that changes in geometry and correspondingly large bracing forces would occur even in the case of relatively small temperature changes. WO 2020/208968 A1 therefore proposes, when using a working disk material with a low coefficient of thermal expansion, not to brace the working disk with the support disk, but rather only to suspend it on the support disk via a mount. As a result, the contact between the working disk and the support disk is to be minimized. However, the resulting lack of bracing between the support disk and the working disk impairs the machining result.
Proceeding from the explained prior art, the object of the invention is to provide a double-side or one-side machine tool of the type in question which minimizes local or global changes in geometry of the working gap for machining workpieces due to thermal effects.
The invention achieves this object by a double-side or one-side machine tool according to claim 1. Advantageous embodiments are disclosed in the dependent claims, the description and the figures.
For a double-side or one-side machine tool of the type in question, the invention achieves the object in that decoupling means are provided for at least partially decoupling the first working disk from the first support disk.
The machine tool can for example be a polishing machine, lapping machine, or a grinding machine. A working gap is formed between the first working disk and a counter bearing element such as a simple weight or pressure cylinder with one-side machine tools, or a second working disk with double-side machine tools, in which workpieces to be machined such as wafers are machined on both sides or one side. The machine tool can be a double-side or a one-side machine tool. With a double-side machine tool, the bottom side and top side of workpieces can be preferably machined simultaneously in the working gap. Correspondingly, both working disks can have a working surface that machines the workpiece surface. With a one-side machine tool, only one workpiece side is contrastingly machined; for example, the bottom side by the bottom working disk. In this case, only one working disk has a working surface that machines the workpiece surface. The counter bearing element in this case only serves to form a corresponding counter bearing for machining by the working disk.
The workpieces can be accommodated for machining to float in a known manner in openings in rotor disks arranged in the working gap. The first working disk and the counter bearing element are driven to rotate relative to each other during operation, for example by a first and/or second drive shaft and at least one drive motor. Both the counter bearing element as well as the first working disk can be driven to rotate, for example in the opposite direction. It is, however, possible to only rotatably drive either the counter bearing element or first working disk. For example, with a double-side machine tool, rotor disks can be moved by suitable kinematics to rotate during this relative rotation through the working gap so that workpieces arranged in the rotor disks describe cycloid paths in the working gap. For example, the rotor disks can have teeth on their outer edge and/or on their inner edge that engage in associated teeth, for example of the first working disk. Such machines with so-called planetary kinematics are well-known.
The first working disk can be designed annular. The counter bearing element, or respectively the second working disk, can also be designed annular. The first working disk and the counter bearing element such as the second working disk then possess facing annular working surfaces between which the annular working gap is formed. The working surfaces can be covered with a working covering such as polishing cloths. Any support disks that hold the working disks can also be designed annular, or at least possess annular support sections to which the working disks are fastened. More than one support disk per working disk can also be provided. The first working disk and/or the counter bearing element can be formed in one or more layers. The same applies to a support disk bearing the first working disk or the counter bearing element.
According to the invention, the decoupling means are provided for at least partial, for example complete, decoupling, in particular mechanical decoupling, of the first working disk from the first support disk. The at least partial decoupling caused by the decoupling means is such that the first working disk and the first support disk can move relative to one another more easily, i.e. under reduced frictional force, than without the decoupling means. A virtually free expansion of the working disk and optionally of the support disk is thus possible. In particular, the frictional force, brought about by the first clamping means, between the mutually facing clamping surfaces of the first working disk and the first support disk is reduced. For this purpose, the decoupling means can act on the first clamping means.
In the prior art, attempts have been made to counteract a thermal expansion by means of additional measures, such as cooling or mechanical deformation, in particular to suppress thermal expansion as far as possible. The present invention provides another approach. A thermal change in size is basically permitted, but the decoupling means have the effect that the thermal change in size does not adversely affect the working gap and thus the machining result. Owing to the reduction in the frictional force between the clamping surfaces of the first working disk and the support disk, a thermal change in size of the working disk, for example, during operation therefore does not lead to the problems explained at the outset with respect to a change in geometry of the working gap. As explained, the first working disk and the first support disk are displaced relative to one another, for example when the first working disk is heated during operation, along their clamping surfaces which form corresponding joining surfaces. As also explained, owing to the frictional force caused by the first clamping means, subsequent cooling does not result in a complete return movement to the starting position. There is thus some degree of hysteresis. The decoupling means reduce the frictional force brought about by the first clamping means in such a way that, for example, a complete return movement to the starting position takes place during the cooling that occurs after heating. Corresponding lasting stresses and local or global changes in geometry caused thereby can thus be minimized. At the same time, extensive bracing is realized between the support disk and the working disk, in particular a bracing substantially over the entire surface or the entire radial extension of the first working disk and/or the first support disk. In contrast to such bracing that is lacking in the prior art discussed above, the machining result is therefore not impaired.
The decoupling means can be arranged between the clamping surfaces of the first working disk and the first support disk. Therefore, it is possible for there to be no direct contact between the clamping surfaces of the first working disk and the first support disk, but rather only indirect contact via the decoupling means. At the same time, working and support disks can be braced against one another over their entire surface, in particular their entire radial extension, for example via clamping screws provided in different radial positions. The decoupling means can also act on the first clamping means itself. It is then possible that although the first working disk bears with its clamping surface directly against the clamping surface of the first support disk, the first clamping means are prestressed, for example, in such a way that a relative movement between the first working disk and the first support disk is possible over the clamping surfaces with a reduced frictional force.
According to the invention, it is in particular possible for the clamping surface of the first working disk to bear directly against the clamping surface of the first support disk, without an intermediate layer or an intermediate element being provided between the clamping surfaces. If the decoupling means are arranged between the clamping surfaces of the first working disk and the first support disk, it is possible, apart from the decoupling means, for there to be no intermediate layer or no further intermediate element between the clamping surfaces.
According to a particularly practical embodiment, the decoupling means can comprise at least one bearing, in particular a plurality of such bearings, arranged between the clamping surfaces of the first working disk and of the first support disk. Bearings arranged between the clamping surfaces permit a relative movement between the first working disk and the first support disk with a considerably reduced frictional force by realizing a mechanical decoupling. Rolling bearings, for example roller bearings, are particularly suitable bearings. Such bearings can be arranged, for example, in particular around the clamping means, for example the clamping screws.
According to a further embodiment, the decoupling means may comprise elastic prestressing means for the elastic prestressing of the first clamping means. Such elastic prestressing means can alternatively or additionally be provided for decoupling means, such as bearings, arranged between the clamping surfaces. The elastic prestressing means elastically prestress the first clamping means in such a way that they clamp the clamping surfaces of the first working disk and the first support disk against each other. Against this elastic prestress, the frictional force between the clamping surfaces is reduced when the clamping surfaces are displaced relative to one another in the course of a thermal change in size. As explained, the elastic prestressing means can be provided in addition to decoupling means between the clamping means surfaces, for example at least one bearing between the clamping surfaces. In this case, the elastic prestressing means can prestress the at least one bearing, for example the at least one rolling bearing. An increased freedom of movement between the clamping surfaces of the first working disk and the first support disk can then be provided with elastic deformation of the elastic prestressing means.
According to a further particularly practical embodiment, the first clamping means can comprise clamping screws with which the first support disk is clamped with its clamping surface against the clamping surface of the first working disk. Such clamping screws can be inserted from the side facing away from the working gap into corresponding screw receptacles of the first support disk and of the first working disk. For this purpose, the clamping screws can be guided through the first support disk and screwed into the first working disk. At least in the first working disk, the screw receptacles can have a corresponding screw thread. The screw head of the clamping screws can bear against the side of the first support disk facing away from the first working disk. For bracing, a plurality of clamping screws can be provided. For example, in the case of an annular first working disk, a first group of clamping screws is arranged along a radially outer partial circle of the first working disk or the first support disk, and a second group of clamping screws is arranged along a radially inner partial circle of the first working disk or the first support disk. The partial circles can each be arranged close to the radially outer or radially inner end of the first working disk or the first support disk.
According to a further embodiment in this regard, the elastic prestressing means can comprise elastic spring washers, which are each arranged between a screw head of the clamping screws and a surface of the first support disk facing away from the first working disk. The spring washers can be clamped between the screw head and the facing side of the support disk and can thereby be elastically compressed and thus prestressed. Against this prestress, the frictional force between the clamping surfaces of the first working disk and the first support disk can be reduced.
According to a further embodiment, the decoupling means can comprise a decoupling intermediate layer between the first working disk and the first support disk. This may be, for example, a sliding intermediate layer, for example of a particularly sliding material, such as Teflon. However, it can also be an intermediate layer for thermal decoupling, which accordingly has a low thermal conductivity. The decoupling means can thus also be thermal decoupling means.
According to a further embodiment, the material of the first working disk can have a lower coefficient of thermal expansion than the material of the first support disk. The coefficient of thermal expansion of the first working disk can in particular be substantially less than the coefficient of thermal expansion of the first support disk, for example lower by a factor of 5, preferably lower by a factor of 10. As explained at the outset, the use of materials with greatly different coefficients of thermal expansion for the first support disk and the first working disk leads to a bimetal and changes in geometry caused thereby in the event of a thermal change in size. Owing to the at least partial decoupling according to the invention between the first working disk and the first support disk, there are no significant stresses between the first working disk and the first support disk even in the case of greatly different coefficients of thermal expansion of the first working disk and the first support disk. As a result, the problems explained at the beginning with regard to a bimetal can be avoided. It is thus possible, in particular only for the first working disk, to use a material with a very low coefficient of thermal expansion, for example an iron-nickel alloy, such as Invar, while a conventional material having a higher coefficient of thermal expansion, for example cast iron, is used simultaneously for the first support disk. A geometry which is largely independent of the process heat can then be generated. At the same time, the use of a material with a very low coefficient of thermal expansion for the working disk is advantageous with regard to the geometrical stability of the working disk and thus of the working gap.
According to a further embodiment, the counter bearing element can be formed by a preferably annular second working disk, wherein the first and second working disks are arranged coaxially with respect to one another, and wherein the working gap is formed between the first working disk and the second working disk for machining both sides or one side of flat workpieces. The second working disk can be fastened to a second support disk, wherein second clamping means are provided for clamping the second working disk with a clamping surface facing away from the working gap against a clamping surface of the second support disk facing the second working disk, and wherein decoupling means are also provided for at least partially decoupling the second working disk from the second support disk. The second clamping means can be designed, for example, as the first clamping means. The second working disk and/or the second support disk can be designed like the first working disk or the first support disk. The decoupling means for decoupling the second work disk from the second support disk can also be designed like the decoupling means for decoupling the first working disk from the first support disk. In this respect, all of the exemplary embodiments explained in this context can be transferred to the second working disk and the second support disk with the second clamping means and their decoupling means.
According to a further embodiment, a preferably annular pressure volume can be formed between the first support disk and the first working disk. The pressure volume is connected to a pressure fluid supply that is actuable such that a pressure is built up in the pressure volume that generates a predetermined local deformation of the first working disk. To the extent that the term fluid is used in this application, it can designate both a gas as well as a liquid. The pressure fluid can be a liquid, in particular water. By introducing the pressure fluid into the pressure volume, pressure can be exerted on the working disk, which is thin compared to the support disk, said pressuring leading to a deformation of the working disk. In particular, the working disk can be thereby changed to a locally concave shape by setting a low pressure in the pressure volume, to a locally flat shape by setting a medium pressure, and to a locally convex shape by setting a high pressure. The locally convex, or respectively concave deformation, or respectively shape, lies between the inner and outer edge of the annular first working disk, in particular in the radial direction. The pressure volume is a changeable pressure volume. The first working disk forms a membrane that deforms depending on the volume of the pressure volume produced by the different pressure.
The pressure fluid supply comprises a pressure fluid reservoir to which is connected at least one pressure line that is connected to the pressure volume. A pump and a control valve can be arranged in the pressure line that can be actuated to build up the desired pressure within the pressure volume, for example by a control and/or regulation apparatus. In addition, the pressure fluid supply can comprise a pressure measuring apparatus that directly or indirectly measures the pressure in the pressure volume and can also send the measurements to the control and/or regulation apparatus. By suitably actuating the pressure fluid supply in the pressure volume, the required pressure for the desired working gap geometry can be adjusted on this basis. An unchanging distance between the working disks over the entire radial extension is for example desirable. The desired gap geometry can be adjusted in static operation and/or in dynamic operation, i.e., while machining a workpiece.
With the pressure volume, a smooth adjustment of the local shape of the first working disk between a maximum concave to maximum convex shape determined by the installation, geometric and material boundary conditions is basically possible. The first working disk can in principle have any thickness. Depending on the desired adjustment range of the disk geometry, the working disk possesses a suitable thickness so that it can be deformed with the available pressure depending on its surface area in particular its ring width, or respectively its turning radius. As explained in DE 10 2016 102 223 A1, the possibility of adjusting the local geometry of the first working disk in a radial direction can compensate for a change in the gap from the influence of temperature during machining.
According to a further embodiment, it is possible for temperature-controlling channels to be provided for controlling the temperature of the first working disk, which temperature-controlling channels are connected to a temperature-controlling fluid supply. The temperature-controlling channels are designed to conduct a temperature-controlling fluid. They can for example be designed like a labyrinth. A temperature-controlling fluid, for example a temperature-controlling liquid such as water can be guided through the temperature-controlling channels while the machine is operating to control the temperature, in particular to cool the working disk. A heat-related deformation of the working disk can be counteracted to a certain extent by the temperature-controlling channels.
According to a further embodiment, it is possible for the temperature-controlling channels to be arranged within the first working disk, such that the temperature-controlling channels are arranged closer to the working gap than the pressure volume, and that the temperature-controlling channels are not connected to the pressure volume. Owing to the arrangement of the temperature-controlling channels within the first working disk, in particular exclusively within the first working disk, the temperature-controlling channels can be arranged closer to the working gap than the pressure volume. In particular, only one feed and discharge line for the temperature-controlling fluid can run through the support disk that are connected to the temperature-controlling fluid supply. Owing to the temperature-controlling channels arranged closer to the working gap, the cooling of the first working disk is more effective, so particularly the above-explained problems of stronger heating of the working disk than the support disk and stronger heating of a side of the working disk bordering the working gap can be minimized. Corresponding stresses between the first working disk and the first support disk as well as undesired deformations of the first working disk can also be minimized. In fact, the temperature-controlling channels are disposed as close as possible to the surface of the working disk bordering the working gap so that penetration of the process heat through the working disk into the support disk can be prevented. In order to further minimize the transfer of heat between the first working disk and first support disk, it is possible to provide the first support disk and/or the first working disk in the region of their contact with bars or other elevations so that the contact surface between the disks is minimized.
In addition, in this embodiment, the temperature-controlling channels are not connected to the pressure volume, also unlike in the prior art, in which they are connected to one another and form a common circuit. Separate fluid systems (circuits) for the temperature-controlling channels on the one hand and for the pressure volume on the other hand are thus provided. This enables a more flexible adjustment of the pressure in the pressure volume independent of the pressure in the temperature-controlling channels. In addition, the useful pressure in the pressure volume for adjusting the local geometry is not limited by the pressure in the temperature-controlling channels in contrast to the prior art.
According to another embodiment, it is possible for the first working disk to be formed from two preferably annular disks that are connected to each other, between which the temperature-controlling channels are formed, wherein one of the disks borders the working gap and the other of the disks comprises the clamping surface for clamping against the clamping surface of the first support disk. The first working disk is therefore constructed in two parts, wherein it forms the temperature-controlling channels between the two partial disks similar to a sandwich construction. This design makes the formation of the temperature-controlling channels exclusively within the first working disk very easy in terms of construction. According to a particularly practical embodiment, the two disks can be screwed to each other. However, other types of fastening are of course also conceivable.
According to another embodiment, it is possible for the first working disk to be fastened only in the region of its outer edge and in the region of its inner edge to the first support disk. As already explained, the working disks can particularly be annular. The preferably annular pressure volume is then formed between the first working disk and the first support disk. In the aforementioned embodiment, the first working disk is only fastened to the first support disk in the region of its radially outer edge and radially inner edge bordering the working surface, for example screwed along a partial circle using clamping screws as clamping means. Between these edge regions, the working disk is contrastingly not fastened to the support disk. In particular, the pressure volume can be formed within this region. In this manner, the working disk possesses the required mobility in order to be deformed in the desired manner by building up a suitable pressure in the pressure volume. The attachment of the working disk to the support disk is selected so that the contact surface on the inner and outer edge is kept as narrow as possible in order to achieve a specific deformation over the entire surface of the working disk if possible.
Exemplary embodiments of the invention are explained in greater detail below based on figures. Schematically:
Figure 1 shows a sectional view of a part of a double-side machine tool;
Figure 2 shows a sectional view of a first working disk and a first support disk of a double-side machine tool according to a first exemplary embodiment;
Figure 3 shows a sectional view of a first working disk and a first support disk of a double-side machine tool according to a second exemplary embodiment;
Figure 4 shows a sectional view of a first working disk and a first support disk of a double-side machine tool according to a further example.
The same reference signs refer to the same objects in the figures unless indicated otherwise.
The double-side machine tool depicted merely as an example in Fig. 1 has an annular first, bottom support disk 100 and a second, top support disk 120 that is also annular. An annular first, bottom working disk 140 is fastened to the bottom support disk 100, and a second, top working disk 160 that is also annular is fastened to the top support disk 120. Between the annular working disks 140, 160, an annular working gap 180 is formed in which flat workpieces such as wafers are machined on both sides during operation. The double-side machine tool can for example be a polishing machine, lapping machine, or a grinding machine.
The top support disk 120, and with it the top working disk 160, and/or the bottom support disk 100 and with it the bottom working disk 140, can be rotatably driven relative to each other by a suitable drive apparatus comprising for example a top drive shaft, and/or a bottom drive shaft, as well as at least one drive motor. The drive apparatus is known per se and will not be described further for reasons of clarity. In a manner which is also known per se, the workpieces to be machined can be held to float in rotor disks in the working gap 180. By suitable kinematics, for example planetary kinematics, it can be ensured that the rotor disks also rotate through the working gap 180 during the relative rotation of the support disks 100, 120, or respectively working disks 140, 160. A control and/or regulation apparatus 200 controls, or respectively regulates the operation of the double-side machine tool.
In the example shown in Fig. 1, labyrinth-like temperature-controlling channels 220 are provided within the bottom working disk 140. The temperature-controlling channels 220 are connected by a feed 240 and a discharge 260, for example via a drive shaft driving the bottom support disk 100 and the bottom working disk 140, to a temperature-controlling fluid supply. The control and/or regulation apparatus 200 can be used, for example, to regulate to a predetermined temperature value of the temperature-controlling fluid at the inlet and/or at the outlet of the temperature-controlling channels or to a predetermined temperature difference between the temperature present at the inlet and the temperature present at the outlet of the temperature-controlling channels by correspondingly adjusting the temperature of the temperature-controlling fluid. In the shown example, labyrinthine temperature-controlling channels 280 are also formed in the top working disk 160 that are also connected to a temperature-controlling fluid supply via a feed and discharge (not shown). This temperature-controlling fluid supply is also controlled by the control and/or regulation apparatus 200. By supplying the temperature-controlling channels 220, or respectively 280 with a temperature-controlling fluid, for example a coolant such as water, heating of the working disks 140, 160 and transfer of heat into the support disks 100, 120 can be effectively counteracted so that corresponding changes in geometry are reduced.
Moreover, a pressure volume 300 that is annular in the example shown is formed between the bottom support disk 120 and the bottom working disk 160 and is connected via a feed 320, for example also via a drive shaft driving the bottom support disk 100 and the bottom working disk 140, to a pressure fluid supply. The pressure fluid supply is also actuated by the control and/or regulation apparatus 200. By correspondingly introducing pressure fluid into the pressure volume 300, a local deformation of the bottom working disk 140 can be created, in particular a local concave or convex deformation as described in principle in DE 10 2016 102 223 A1.
As can be seen in Fig. 1, the temperature-controlling channels 220 are arranged closer to the working gap 180 than the pressure volume 300. Moreover, the duct systems of the pressure volume 300 and the temperature-controlling channels 220 are not connected to each other, but are instead separately controllable, or respectively regulatable.
Figures 2 to 4 each show a first support disk and a first working disk which can be used in the double-side machine tool shown in figure 1. For reasons of illustration, figures 2 to 4 do not show the temperature-controlling channels 220 and the pressure volume 300, including the associated feed and discharge lines. It goes without saying that the working disks and support disks shown in figures 2 to 4 can also have corresponding temperature-controlling channels and pressure volumes, including the feed and discharge lines. In addition, figures 2 to 4 show only a first support disk and a first working disk for the sake of illustration. The second support disks and second working disks, which are provided in addition, can be designed accordingly.
Figure 2 shows a first exemplary embodiment of a first, bottom support disk 10 and a first, bottom working disk 14, which can be used, for example, in the double-side machine tool shown in figure 1. In the exemplary embodiment shown, a plurality of clamping screws 20 is provided, which are inserted through the first support disk 10 from a side facing away from the working gap 18 and are screwed into a corresponding threaded bore in the first working disk 14. The clamping screws are arranged along two partial circles via the annular support and working disks 10, 14, namely a radially outer partial circle and a radially inner partial circle. The clamping screws 20 each have a screw head 22. The first support disk 10 has a clamping surface 24 facing the first working disk 14 and the first working disk 14 has a clamping surface 26 facing the first support disk 10. During the screwing-in of the clamping screws 20, the first support disk 10 and the first working disk 14 are braced against one another. In the illustrated exemplary embodiment according to figure 2, the clamping surfaces 24, 26 lie directly against one another in the braced state and are braced against one another.
In the exemplary embodiment according to figure 2, elastic spring washers 30 are disposed between the screw heads 22 of the clamping screws 20 and a surface 28 of the first support disk 10 facing away from the first working disk 14, which spring washers are elastically compressed in the screwed-in state of the clamping screws 20 and thus elastically prestress the clamping means 20. As a result, in the case of a thermally induced relative movement between the first support disk 10 and the first working disk 14 over the clamping surfaces 24, 26, the frictional force provided by the clamping means 20 is reduced, such that, for example, after a thermal expansion of the first working disk 14 and a relative movement caused thereby with respect to the first support disk 10, the first working disk 14 moves back completely into its original position.
Figure 3 shows a further exemplary embodiment which largely corresponds to the exemplary embodiment according to figure 2. In addition to the elastic spring washers 30, in the exemplary embodiment according to figure 3, rolling bearings 32 arranged around the clamping screws 20 are provided between the clamping surfaces 24, 26 of the first support disk 10 and the first working disk 14. By means of these rolling bearings 32, the first support disk 10 and the first working disk 14, in particular their clamping surfaces 24, 26, are mechanically decoupled from one another. Accordingly, the frictional force between the first support disk 10 and the first working disk 14 which is caused by the clamping screws 20 is further reduced.
Figure 4 shows a further example for seeking to avoid the effects of thermal changes in size explained above. The example according to figure 4 differs from the exemplary embodiment according to figure 2 on the one hand in that no decoupling means are provided in the form of the elastic spring washers 30. On the other hand, it differs in that relief grooves 34, 36 are formed around the clamping screws 20 in the first support disk 10‘ and the first working disk 14‘. Attempts have been made to counteract the disadvantageous effects of the thermal change in size explained above by means of such relief grooves 34, 36. However, it has been found that this measure does not yield the success associated with the decoupling means according to figures 2 and 3.
List of Reference Signs
10, 10‘, 100 Bottom support disk
12, 120 Top support disk
14, 14‘, 140 Bottom working disk
16, 160 Top working disk
18, 180 Working gap
20 Clamping screw
22 Screw head
24 Clamping surface
26 Clamping surface
28 Surface
30 Spring washer
32 Rolling bearing
34 Relief grooves
36 Relief grooves
200 Control and/or regulation apparatus
220 Temperature-controlling channels
240 Feed
260 Discharge
280 Temperature-controlling channels
300 Pressure volume
320 Feed
The invention relates to a double-side or one-side machine tool comprising a preferably annular first working disk which is fastened to a first support disk, and comprising a counter bearing element, wherein the first working disk and the counter bearing element can be driven to rotate relative to each other by at least one drive shaft, wherein a working gap is formed between the first working disk and the counter bearing element to machine both sides or one side of flat workpieces, and wherein first clamping means are provided to clamp the first working disk with a clamping surface facing away from the working gap against a clamping surface of the first support disk facing the first working disk.
For example, flat workpieces such as wafers are simultaneously machined on both sides in double-sided machine tools. For this purpose, double-sided machine tools have a top working disk and a bottom working disk between which a working gap is formed in which the workpieces to be machined are guided during processing. The top working disk is fastened to a top support disk, and the bottom working disk is fastened to a bottom support disk. For machining, a relative rotation between the working disks is produced by rotatably driving at least one of the working disks together with its support disk. Double-sided machine tools are known in which so-called rotor disks are guided. The rotor disks generally accommodate workpieces to be machined in circular openings in a floating manner. By suitable kinematics, it is ensured that the rotor disks also rotate within the working gap during the relative rotation of the working disks. As a result, the workpieces move along cycloid paths within the working gap. Particularly consistent surface machining is hereby achieved.
With machine tools of the kind at issue here, a change in the working gap arises between the working disks due to the process heat which arises during machining. In particular, a heat-related deformation of the working disks occurs and hence a deviation in the gap geometry from the stipulated shape. This negatively influences the result of machining. This applies in particular to the very high machining requirements of so-called prime wafers.
A two-disk polishing machine is known from DE 100 07 390 B4, in particular for machining semiconductor wafers. In this case, cooling channels are formed in a support disk bearing a polishing disk, or in the support disk and in the polishing disk, by which cooling takes place to prevent undesirable influences on the geometry of the working gap. Moreover, a relative radial movement is permitted between a base support and the support disk, whereby a deformation is reduced when temperatures of the base support and support disk differ.
It is known from DE 10 2004 040 429 B4 to counteract negative effects from the arising process heat by controlling the temperature of the working disks. Channels are formed in the support disks through which corresponding temperature-controlling fluid such as cooling water is conducted.
Furthermore, an apparatus for mechanically deforming the top support disk, and with it the top working disk attached thereto, is known from DE 10 2006 037 490 B4. With this apparatus, an initially flat working surface of the top working disk can be changed to a slightly concave surface. Conversely, an initially slightly convex working surface of the top working disk can be changed into a flat, or respectively concave working surface.
A double-side or one-side machine tool is known from DE 10 2016 102 223 A1 with means for the local deformation of at least one of the working disks, in particular by introducing a pressure medium such as for example water into a pressure chamber acting on the working disk. In this manner, for example a local concave or complex deformation of the working disk can be created. Moreover, cooling channels are formed in a support disk of the working disk for cooling. In addition, means can be provided for creating a global deformation as described in DE 10 2006 037 490 B4.
A problem with known systems is that the working disk directly bordering the working gap can heat up more during operation than the support disk bearing it. As a result, stresses can occur between the working disk and the support disk and thus the working gap can no longer be influenced in a reliably controllable manner. Depending on the temperature difference, a mutual displacement between the support disk and the working disk can also occur. During subsequent cooling after operation, the disks do not completely return to their previous position due to a frictional force counteracting the movement, for example from a screwed connection. A force differential can therefore remain between the disks to the amount of twice the frictional force after complete cooling. This can in turn yield different local geometries. Moreover, the global geometry of the working disk can also be changed by the changed bracing between the support disk and working disk. Significant temperature differences can also occur during operation between a side of the working disk bordering the working gap and an opposite side of the working disk. These can lead to different thermal expansions of the two sides, which can cause a bulge in the working disk and therefore also a change in the local geometry.
A heat-related change in geometry could be counteracted by using a material with a very low coefficient of thermal expansion, such as special iron-nickel alloys, for example known as Invar. However, such materials are expensive and difficult to process, in particular cast or machine. The use of such a material would be economically viable only for comparatively thin working disks. A bracing of such a working disk with a support disk made of a material with a greater coefficient of thermal expansion would, however, form a bimetal, such that changes in geometry and correspondingly large bracing forces would occur even in the case of relatively small temperature changes. WO 2020/208968 A1 therefore proposes, when using a working disk material with a low coefficient of thermal expansion, not to brace the working disk with the support disk, but rather only to suspend it on the support disk via a mount. As a result, the contact between the working disk and the support disk is to be minimized. However, the resulting lack of bracing between the support disk and the working disk impairs the machining result.
Proceeding from the explained prior art, the object of the invention is to provide a double-side or one-side machine tool of the type in question which minimizes local or global changes in geometry of the working gap for machining workpieces due to thermal effects.
The invention achieves this object by a double-side or one-side machine tool according to claim 1. Advantageous embodiments are disclosed in the dependent claims, the description and the figures.
For a double-side or one-side machine tool of the type in question, the invention achieves the object in that decoupling means are provided for at least partially decoupling the first working disk from the first support disk.
The machine tool can for example be a polishing machine, lapping machine, or a grinding machine. A working gap is formed between the first working disk and a counter bearing element such as a simple weight or pressure cylinder with one-side machine tools, or a second working disk with double-side machine tools, in which workpieces to be machined such as wafers are machined on both sides or one side. The machine tool can be a double-side or a one-side machine tool. With a double-side machine tool, the bottom side and top side of workpieces can be preferably machined simultaneously in the working gap. Correspondingly, both working disks can have a working surface that machines the workpiece surface. With a one-side machine tool, only one workpiece side is contrastingly machined; for example, the bottom side by the bottom working disk. In this case, only one working disk has a working surface that machines the workpiece surface. The counter bearing element in this case only serves to form a corresponding counter bearing for machining by the working disk.
The workpieces can be accommodated for machining to float in a known manner in openings in rotor disks arranged in the working gap. The first working disk and the counter bearing element are driven to rotate relative to each other during operation, for example by a first and/or second drive shaft and at least one drive motor. Both the counter bearing element as well as the first working disk can be driven to rotate, for example in the opposite direction. It is, however, possible to only rotatably drive either the counter bearing element or first working disk. For example, with a double-side machine tool, rotor disks can be moved by suitable kinematics to rotate during this relative rotation through the working gap so that workpieces arranged in the rotor disks describe cycloid paths in the working gap. For example, the rotor disks can have teeth on their outer edge and/or on their inner edge that engage in associated teeth, for example of the first working disk. Such machines with so-called planetary kinematics are well-known.
The first working disk can be designed annular. The counter bearing element, or respectively the second working disk, can also be designed annular. The first working disk and the counter bearing element such as the second working disk then possess facing annular working surfaces between which the annular working gap is formed. The working surfaces can be covered with a working covering such as polishing cloths. Any support disks that hold the working disks can also be designed annular, or at least possess annular support sections to which the working disks are fastened. More than one support disk per working disk can also be provided. The first working disk and/or the counter bearing element can be formed in one or more layers. The same applies to a support disk bearing the first working disk or the counter bearing element.
According to the invention, the decoupling means are provided for at least partial, for example complete, decoupling, in particular mechanical decoupling, of the first working disk from the first support disk. The at least partial decoupling caused by the decoupling means is such that the first working disk and the first support disk can move relative to one another more easily, i.e. under reduced frictional force, than without the decoupling means. A virtually free expansion of the working disk and optionally of the support disk is thus possible. In particular, the frictional force, brought about by the first clamping means, between the mutually facing clamping surfaces of the first working disk and the first support disk is reduced. For this purpose, the decoupling means can act on the first clamping means.
In the prior art, attempts have been made to counteract a thermal expansion by means of additional measures, such as cooling or mechanical deformation, in particular to suppress thermal expansion as far as possible. The present invention provides another approach. A thermal change in size is basically permitted, but the decoupling means have the effect that the thermal change in size does not adversely affect the working gap and thus the machining result. Owing to the reduction in the frictional force between the clamping surfaces of the first working disk and the support disk, a thermal change in size of the working disk, for example, during operation therefore does not lead to the problems explained at the outset with respect to a change in geometry of the working gap. As explained, the first working disk and the first support disk are displaced relative to one another, for example when the first working disk is heated during operation, along their clamping surfaces which form corresponding joining surfaces. As also explained, owing to the frictional force caused by the first clamping means, subsequent cooling does not result in a complete return movement to the starting position. There is thus some degree of hysteresis. The decoupling means reduce the frictional force brought about by the first clamping means in such a way that, for example, a complete return movement to the starting position takes place during the cooling that occurs after heating. Corresponding lasting stresses and local or global changes in geometry caused thereby can thus be minimized. At the same time, extensive bracing is realized between the support disk and the working disk, in particular a bracing substantially over the entire surface or the entire radial extension of the first working disk and/or the first support disk. In contrast to such bracing that is lacking in the prior art discussed above, the machining result is therefore not impaired.
The decoupling means can be arranged between the clamping surfaces of the first working disk and the first support disk. Therefore, it is possible for there to be no direct contact between the clamping surfaces of the first working disk and the first support disk, but rather only indirect contact via the decoupling means. At the same time, working and support disks can be braced against one another over their entire surface, in particular their entire radial extension, for example via clamping screws provided in different radial positions. The decoupling means can also act on the first clamping means itself. It is then possible that although the first working disk bears with its clamping surface directly against the clamping surface of the first support disk, the first clamping means are prestressed, for example, in such a way that a relative movement between the first working disk and the first support disk is possible over the clamping surfaces with a reduced frictional force.
According to the invention, it is in particular possible for the clamping surface of the first working disk to bear directly against the clamping surface of the first support disk, without an intermediate layer or an intermediate element being provided between the clamping surfaces. If the decoupling means are arranged between the clamping surfaces of the first working disk and the first support disk, it is possible, apart from the decoupling means, for there to be no intermediate layer or no further intermediate element between the clamping surfaces.
According to a particularly practical embodiment, the decoupling means can comprise at least one bearing, in particular a plurality of such bearings, arranged between the clamping surfaces of the first working disk and of the first support disk. Bearings arranged between the clamping surfaces permit a relative movement between the first working disk and the first support disk with a considerably reduced frictional force by realizing a mechanical decoupling. Rolling bearings, for example roller bearings, are particularly suitable bearings. Such bearings can be arranged, for example, in particular around the clamping means, for example the clamping screws.
According to a further embodiment, the decoupling means may comprise elastic prestressing means for the elastic prestressing of the first clamping means. Such elastic prestressing means can alternatively or additionally be provided for decoupling means, such as bearings, arranged between the clamping surfaces. The elastic prestressing means elastically prestress the first clamping means in such a way that they clamp the clamping surfaces of the first working disk and the first support disk against each other. Against this elastic prestress, the frictional force between the clamping surfaces is reduced when the clamping surfaces are displaced relative to one another in the course of a thermal change in size. As explained, the elastic prestressing means can be provided in addition to decoupling means between the clamping means surfaces, for example at least one bearing between the clamping surfaces. In this case, the elastic prestressing means can prestress the at least one bearing, for example the at least one rolling bearing. An increased freedom of movement between the clamping surfaces of the first working disk and the first support disk can then be provided with elastic deformation of the elastic prestressing means.
According to a further particularly practical embodiment, the first clamping means can comprise clamping screws with which the first support disk is clamped with its clamping surface against the clamping surface of the first working disk. Such clamping screws can be inserted from the side facing away from the working gap into corresponding screw receptacles of the first support disk and of the first working disk. For this purpose, the clamping screws can be guided through the first support disk and screwed into the first working disk. At least in the first working disk, the screw receptacles can have a corresponding screw thread. The screw head of the clamping screws can bear against the side of the first support disk facing away from the first working disk. For bracing, a plurality of clamping screws can be provided. For example, in the case of an annular first working disk, a first group of clamping screws is arranged along a radially outer partial circle of the first working disk or the first support disk, and a second group of clamping screws is arranged along a radially inner partial circle of the first working disk or the first support disk. The partial circles can each be arranged close to the radially outer or radially inner end of the first working disk or the first support disk.
According to a further embodiment in this regard, the elastic prestressing means can comprise elastic spring washers, which are each arranged between a screw head of the clamping screws and a surface of the first support disk facing away from the first working disk. The spring washers can be clamped between the screw head and the facing side of the support disk and can thereby be elastically compressed and thus prestressed. Against this prestress, the frictional force between the clamping surfaces of the first working disk and the first support disk can be reduced.
According to a further embodiment, the decoupling means can comprise a decoupling intermediate layer between the first working disk and the first support disk. This may be, for example, a sliding intermediate layer, for example of a particularly sliding material, such as Teflon. However, it can also be an intermediate layer for thermal decoupling, which accordingly has a low thermal conductivity. The decoupling means can thus also be thermal decoupling means.
According to a further embodiment, the material of the first working disk can have a lower coefficient of thermal expansion than the material of the first support disk. The coefficient of thermal expansion of the first working disk can in particular be substantially less than the coefficient of thermal expansion of the first support disk, for example lower by a factor of 5, preferably lower by a factor of 10. As explained at the outset, the use of materials with greatly different coefficients of thermal expansion for the first support disk and the first working disk leads to a bimetal and changes in geometry caused thereby in the event of a thermal change in size. Owing to the at least partial decoupling according to the invention between the first working disk and the first support disk, there are no significant stresses between the first working disk and the first support disk even in the case of greatly different coefficients of thermal expansion of the first working disk and the first support disk. As a result, the problems explained at the beginning with regard to a bimetal can be avoided. It is thus possible, in particular only for the first working disk, to use a material with a very low coefficient of thermal expansion, for example an iron-nickel alloy, such as Invar, while a conventional material having a higher coefficient of thermal expansion, for example cast iron, is used simultaneously for the first support disk. A geometry which is largely independent of the process heat can then be generated. At the same time, the use of a material with a very low coefficient of thermal expansion for the working disk is advantageous with regard to the geometrical stability of the working disk and thus of the working gap.
According to a further embodiment, the counter bearing element can be formed by a preferably annular second working disk, wherein the first and second working disks are arranged coaxially with respect to one another, and wherein the working gap is formed between the first working disk and the second working disk for machining both sides or one side of flat workpieces. The second working disk can be fastened to a second support disk, wherein second clamping means are provided for clamping the second working disk with a clamping surface facing away from the working gap against a clamping surface of the second support disk facing the second working disk, and wherein decoupling means are also provided for at least partially decoupling the second working disk from the second support disk. The second clamping means can be designed, for example, as the first clamping means. The second working disk and/or the second support disk can be designed like the first working disk or the first support disk. The decoupling means for decoupling the second work disk from the second support disk can also be designed like the decoupling means for decoupling the first working disk from the first support disk. In this respect, all of the exemplary embodiments explained in this context can be transferred to the second working disk and the second support disk with the second clamping means and their decoupling means.
According to a further embodiment, a preferably annular pressure volume can be formed between the first support disk and the first working disk. The pressure volume is connected to a pressure fluid supply that is actuable such that a pressure is built up in the pressure volume that generates a predetermined local deformation of the first working disk. To the extent that the term fluid is used in this application, it can designate both a gas as well as a liquid. The pressure fluid can be a liquid, in particular water. By introducing the pressure fluid into the pressure volume, pressure can be exerted on the working disk, which is thin compared to the support disk, said pressuring leading to a deformation of the working disk. In particular, the working disk can be thereby changed to a locally concave shape by setting a low pressure in the pressure volume, to a locally flat shape by setting a medium pressure, and to a locally convex shape by setting a high pressure. The locally convex, or respectively concave deformation, or respectively shape, lies between the inner and outer edge of the annular first working disk, in particular in the radial direction. The pressure volume is a changeable pressure volume. The first working disk forms a membrane that deforms depending on the volume of the pressure volume produced by the different pressure.
The pressure fluid supply comprises a pressure fluid reservoir to which is connected at least one pressure line that is connected to the pressure volume. A pump and a control valve can be arranged in the pressure line that can be actuated to build up the desired pressure within the pressure volume, for example by a control and/or regulation apparatus. In addition, the pressure fluid supply can comprise a pressure measuring apparatus that directly or indirectly measures the pressure in the pressure volume and can also send the measurements to the control and/or regulation apparatus. By suitably actuating the pressure fluid supply in the pressure volume, the required pressure for the desired working gap geometry can be adjusted on this basis. An unchanging distance between the working disks over the entire radial extension is for example desirable. The desired gap geometry can be adjusted in static operation and/or in dynamic operation, i.e., while machining a workpiece.
With the pressure volume, a smooth adjustment of the local shape of the first working disk between a maximum concave to maximum convex shape determined by the installation, geometric and material boundary conditions is basically possible. The first working disk can in principle have any thickness. Depending on the desired adjustment range of the disk geometry, the working disk possesses a suitable thickness so that it can be deformed with the available pressure depending on its surface area in particular its ring width, or respectively its turning radius. As explained in DE 10 2016 102 223 A1, the possibility of adjusting the local geometry of the first working disk in a radial direction can compensate for a change in the gap from the influence of temperature during machining.
According to a further embodiment, it is possible for temperature-controlling channels to be provided for controlling the temperature of the first working disk, which temperature-controlling channels are connected to a temperature-controlling fluid supply. The temperature-controlling channels are designed to conduct a temperature-controlling fluid. They can for example be designed like a labyrinth. A temperature-controlling fluid, for example a temperature-controlling liquid such as water can be guided through the temperature-controlling channels while the machine is operating to control the temperature, in particular to cool the working disk. A heat-related deformation of the working disk can be counteracted to a certain extent by the temperature-controlling channels.
According to a further embodiment, it is possible for the temperature-controlling channels to be arranged within the first working disk, such that the temperature-controlling channels are arranged closer to the working gap than the pressure volume, and that the temperature-controlling channels are not connected to the pressure volume. Owing to the arrangement of the temperature-controlling channels within the first working disk, in particular exclusively within the first working disk, the temperature-controlling channels can be arranged closer to the working gap than the pressure volume. In particular, only one feed and discharge line for the temperature-controlling fluid can run through the support disk that are connected to the temperature-controlling fluid supply. Owing to the temperature-controlling channels arranged closer to the working gap, the cooling of the first working disk is more effective, so particularly the above-explained problems of stronger heating of the working disk than the support disk and stronger heating of a side of the working disk bordering the working gap can be minimized. Corresponding stresses between the first working disk and the first support disk as well as undesired deformations of the first working disk can also be minimized. In fact, the temperature-controlling channels are disposed as close as possible to the surface of the working disk bordering the working gap so that penetration of the process heat through the working disk into the support disk can be prevented. In order to further minimize the transfer of heat between the first working disk and first support disk, it is possible to provide the first support disk and/or the first working disk in the region of their contact with bars or other elevations so that the contact surface between the disks is minimized.
In addition, in this embodiment, the temperature-controlling channels are not connected to the pressure volume, also unlike in the prior art, in which they are connected to one another and form a common circuit. Separate fluid systems (circuits) for the temperature-controlling channels on the one hand and for the pressure volume on the other hand are thus provided. This enables a more flexible adjustment of the pressure in the pressure volume independent of the pressure in the temperature-controlling channels. In addition, the useful pressure in the pressure volume for adjusting the local geometry is not limited by the pressure in the temperature-controlling channels in contrast to the prior art.
According to another embodiment, it is possible for the first working disk to be formed from two preferably annular disks that are connected to each other, between which the temperature-controlling channels are formed, wherein one of the disks borders the working gap and the other of the disks comprises the clamping surface for clamping against the clamping surface of the first support disk. The first working disk is therefore constructed in two parts, wherein it forms the temperature-controlling channels between the two partial disks similar to a sandwich construction. This design makes the formation of the temperature-controlling channels exclusively within the first working disk very easy in terms of construction. According to a particularly practical embodiment, the two disks can be screwed to each other. However, other types of fastening are of course also conceivable.
According to another embodiment, it is possible for the first working disk to be fastened only in the region of its outer edge and in the region of its inner edge to the first support disk. As already explained, the working disks can particularly be annular. The preferably annular pressure volume is then formed between the first working disk and the first support disk. In the aforementioned embodiment, the first working disk is only fastened to the first support disk in the region of its radially outer edge and radially inner edge bordering the working surface, for example screwed along a partial circle using clamping screws as clamping means. Between these edge regions, the working disk is contrastingly not fastened to the support disk. In particular, the pressure volume can be formed within this region. In this manner, the working disk possesses the required mobility in order to be deformed in the desired manner by building up a suitable pressure in the pressure volume. The attachment of the working disk to the support disk is selected so that the contact surface on the inner and outer edge is kept as narrow as possible in order to achieve a specific deformation over the entire surface of the working disk if possible.
Exemplary embodiments of the invention are explained in greater detail below based on figures. Schematically:
Figure 1 shows a sectional view of a part of a double-side machine tool;
Figure 2 shows a sectional view of a first working disk and a first support disk of a double-side machine tool according to a first exemplary embodiment;
Figure 3 shows a sectional view of a first working disk and a first support disk of a double-side machine tool according to a second exemplary embodiment;
Figure 4 shows a sectional view of a first working disk and a first support disk of a double-side machine tool according to a further example.
The same reference signs refer to the same objects in the figures unless indicated otherwise.
The double-side machine tool depicted merely as an example in Fig. 1 has an annular first, bottom support disk 100 and a second, top support disk 120 that is also annular. An annular first, bottom working disk 140 is fastened to the bottom support disk 100, and a second, top working disk 160 that is also annular is fastened to the top support disk 120. Between the annular working disks 140, 160, an annular working gap 180 is formed in which flat workpieces such as wafers are machined on both sides during operation. The double-side machine tool can for example be a polishing machine, lapping machine, or a grinding machine.
The top support disk 120, and with it the top working disk 160, and/or the bottom support disk 100 and with it the bottom working disk 140, can be rotatably driven relative to each other by a suitable drive apparatus comprising for example a top drive shaft, and/or a bottom drive shaft, as well as at least one drive motor. The drive apparatus is known per se and will not be described further for reasons of clarity. In a manner which is also known per se, the workpieces to be machined can be held to float in rotor disks in the working gap 180. By suitable kinematics, for example planetary kinematics, it can be ensured that the rotor disks also rotate through the working gap 180 during the relative rotation of the support disks 100, 120, or respectively working disks 140, 160. A control and/or regulation apparatus 200 controls, or respectively regulates the operation of the double-side machine tool.
In the example shown in Fig. 1, labyrinth-like temperature-controlling channels 220 are provided within the bottom working disk 140. The temperature-controlling channels 220 are connected by a feed 240 and a discharge 260, for example via a drive shaft driving the bottom support disk 100 and the bottom working disk 140, to a temperature-controlling fluid supply. The control and/or regulation apparatus 200 can be used, for example, to regulate to a predetermined temperature value of the temperature-controlling fluid at the inlet and/or at the outlet of the temperature-controlling channels or to a predetermined temperature difference between the temperature present at the inlet and the temperature present at the outlet of the temperature-controlling channels by correspondingly adjusting the temperature of the temperature-controlling fluid. In the shown example, labyrinthine temperature-controlling channels 280 are also formed in the top working disk 160 that are also connected to a temperature-controlling fluid supply via a feed and discharge (not shown). This temperature-controlling fluid supply is also controlled by the control and/or regulation apparatus 200. By supplying the temperature-controlling channels 220, or respectively 280 with a temperature-controlling fluid, for example a coolant such as water, heating of the working disks 140, 160 and transfer of heat into the support disks 100, 120 can be effectively counteracted so that corresponding changes in geometry are reduced.
Moreover, a pressure volume 300 that is annular in the example shown is formed between the bottom support disk 120 and the bottom working disk 160 and is connected via a feed 320, for example also via a drive shaft driving the bottom support disk 100 and the bottom working disk 140, to a pressure fluid supply. The pressure fluid supply is also actuated by the control and/or regulation apparatus 200. By correspondingly introducing pressure fluid into the pressure volume 300, a local deformation of the bottom working disk 140 can be created, in particular a local concave or convex deformation as described in principle in DE 10 2016 102 223 A1.
As can be seen in Fig. 1, the temperature-controlling channels 220 are arranged closer to the working gap 180 than the pressure volume 300. Moreover, the duct systems of the pressure volume 300 and the temperature-controlling channels 220 are not connected to each other, but are instead separately controllable, or respectively regulatable.
Figures 2 to 4 each show a first support disk and a first working disk which can be used in the double-side machine tool shown in figure 1. For reasons of illustration, figures 2 to 4 do not show the temperature-controlling channels 220 and the pressure volume 300, including the associated feed and discharge lines. It goes without saying that the working disks and support disks shown in figures 2 to 4 can also have corresponding temperature-controlling channels and pressure volumes, including the feed and discharge lines. In addition, figures 2 to 4 show only a first support disk and a first working disk for the sake of illustration. The second support disks and second working disks, which are provided in addition, can be designed accordingly.
Figure 2 shows a first exemplary embodiment of a first, bottom support disk 10 and a first, bottom working disk 14, which can be used, for example, in the double-side machine tool shown in figure 1. In the exemplary embodiment shown, a plurality of clamping screws 20 is provided, which are inserted through the first support disk 10 from a side facing away from the working gap 18 and are screwed into a corresponding threaded bore in the first working disk 14. The clamping screws are arranged along two partial circles via the annular support and working disks 10, 14, namely a radially outer partial circle and a radially inner partial circle. The clamping screws 20 each have a screw head 22. The first support disk 10 has a clamping surface 24 facing the first working disk 14 and the first working disk 14 has a clamping surface 26 facing the first support disk 10. During the screwing-in of the clamping screws 20, the first support disk 10 and the first working disk 14 are braced against one another. In the illustrated exemplary embodiment according to figure 2, the clamping surfaces 24, 26 lie directly against one another in the braced state and are braced against one another.
In the exemplary embodiment according to figure 2, elastic spring washers 30 are disposed between the screw heads 22 of the clamping screws 20 and a surface 28 of the first support disk 10 facing away from the first working disk 14, which spring washers are elastically compressed in the screwed-in state of the clamping screws 20 and thus elastically prestress the clamping means 20. As a result, in the case of a thermally induced relative movement between the first support disk 10 and the first working disk 14 over the clamping surfaces 24, 26, the frictional force provided by the clamping means 20 is reduced, such that, for example, after a thermal expansion of the first working disk 14 and a relative movement caused thereby with respect to the first support disk 10, the first working disk 14 moves back completely into its original position.
Figure 3 shows a further exemplary embodiment which largely corresponds to the exemplary embodiment according to figure 2. In addition to the elastic spring washers 30, in the exemplary embodiment according to figure 3, rolling bearings 32 arranged around the clamping screws 20 are provided between the clamping surfaces 24, 26 of the first support disk 10 and the first working disk 14. By means of these rolling bearings 32, the first support disk 10 and the first working disk 14, in particular their clamping surfaces 24, 26, are mechanically decoupled from one another. Accordingly, the frictional force between the first support disk 10 and the first working disk 14 which is caused by the clamping screws 20 is further reduced.
Figure 4 shows a further example for seeking to avoid the effects of thermal changes in size explained above. The example according to figure 4 differs from the exemplary embodiment according to figure 2 on the one hand in that no decoupling means are provided in the form of the elastic spring washers 30. On the other hand, it differs in that relief grooves 34, 36 are formed around the clamping screws 20 in the first support disk 10‘ and the first working disk 14‘. Attempts have been made to counteract the disadvantageous effects of the thermal change in size explained above by means of such relief grooves 34, 36. However, it has been found that this measure does not yield the success associated with the decoupling means according to figures 2 and 3.
List of Reference Signs
10, 10‘, 100 Bottom support disk
12, 120 Top support disk
14, 14‘, 140 Bottom working disk
16, 160 Top working disk
18, 180 Working gap
20 Clamping screw
22 Screw head
24 Clamping surface
26 Clamping surface
28 Surface
30 Spring washer
32 Rolling bearing
34 Relief grooves
36 Relief grooves
200 Control and/or regulation apparatus
220 Temperature-controlling channels
240 Feed
260 Discharge
280 Temperature-controlling channels
300 Pressure volume
320 Feed
Claims
1. A double-side or one-side machine tool comprising a preferably annular first working disk (14, 140) which is fastened to a first support disk (10, 100), and comprising a counter bearing element, wherein the first working disk (14, 140) and the counter bearing element can be driven to rotate relative to each other by at least one drive shaft, wherein a working gap (18, 180) is formed between the first working disk (14, 140) and the counter bearing element to machine both sides or one side of flat workpieces, and wherein first clamping means (20) are provided to clamp the first working disk (14, 140) with a clamping surface (26) facing away from the working gap (18, 180) against a clamping surface (24) of the first support disk (10, 100) facing the first working disk (14, 140), characterized in that decoupling means are provided for at least partially decoupling the first working disk (14, 140) from the first support disk (10, 100).
2. The double-side or one-side machine tool according to claim 1, characterized in that the decoupling means comprise at least one bearing (32) arranged between the clamping surfaces (24, 26) of the first working disk (14, 140) and the first support disk (10, 100).
3. The double-side or one-side machine tool according to claim 2, characterized in that the at least one bearing (32) comprises at least one rolling bearing (32).
4. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the decoupling means comprise elastic prestressing means (30) for elastically prestressing the first clamping means (20).
5. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the first clamping means (20) comprise clamping screws (20) with which the first support disk (10, 100) is clamped with its clamping surface (24) against the clamping surface (26) of the first working disk (14, 140).
6. The double-side or one-side machine tool according to claims 4 and 5, characterized in that the elastic prestressing means (30) comprise elastic spring washers (30) which are each arranged between a screw head (22) of the clamping screws (20) and a surface (28) of the first support disk (10, 100) facing away from the first working disk (14, 140).
7. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the decoupling means comprise a decoupling intermediate layer between the first working disk (14, 140) and the first support disk (10, 100), in particular a sliding intermediate layer or an intermediate layer for thermal decoupling.
8. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the material of the first working disk (14, 140) has a lower coefficient of thermal expansion than the material of the first support disk (10, 100).
9. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the counter bearing element is formed by a preferably annular second working disk (16, 160), wherein the first and second working disk (16, 160) are arranged coaxially relative to each other, wherein the working gap (18, 180) is formed between the first and second working disk (14, 140, 16, 160) to machine both sides or one side of flat workpieces.
10. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the second working disk (16, 160) is fastened to a second support disk (12, 120), in that second clamping means are provided for clamping the second working disk (16, 160) with a clamping surface facing away from the working gap (18, 180) against a clamping surface of the second support disk (12, 120) facing the second working disk (16, 160), and in that decoupling means are also provided for at least partially decoupling the second working disk (16, 160) from the second support disk (12, 120).
11. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that a pressure volume (300) is arranged between the first support disk (10, 100) and the first working disk (14, 140), said pressure volume being connected to a pressure fluid supply which is actuable in such a way that a pressure is built up in the pressure volume (300), which generates a predetermined deformation of the first working disk (14, 140).
12. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that temperature-controlling channels (220, 280) are provided for controlling the temperature of the first working disk (14, 140), which are connected to a temperature-controlling fluid supply.
13. The double-side or one-side machine tool according to any one of claims 11 or 12, characterized in that the temperature-controlling channels (220, 280) are arranged within the first working disk (14, 140), such that the temperature-controlling channels (220, 280) are arranged closer to the working gap (18, 180) than the pressure volume (300), and that the temperature-controlling channels (220, 280) are not connected to the pressure volume (300).
14. The double-side or one-side machine tool according to any one of either of claims 12 and 13, characterized in that the first working disk (14, 140) is formed from two preferably annular disks which are connected to one another and between which the temperature-controlling channels (220, 280) are formed, wherein one of the disks borders the working gap (18, 180) and the other of the disks has the clamping surface for clamping against the clamping surface of the first support disk (10, 100).
1. A double-side or one-side machine tool comprising a preferably annular first working disk (14, 140) which is fastened to a first support disk (10, 100), and comprising a counter bearing element, wherein the first working disk (14, 140) and the counter bearing element can be driven to rotate relative to each other by at least one drive shaft, wherein a working gap (18, 180) is formed between the first working disk (14, 140) and the counter bearing element to machine both sides or one side of flat workpieces, and wherein first clamping means (20) are provided to clamp the first working disk (14, 140) with a clamping surface (26) facing away from the working gap (18, 180) against a clamping surface (24) of the first support disk (10, 100) facing the first working disk (14, 140), characterized in that decoupling means are provided for at least partially decoupling the first working disk (14, 140) from the first support disk (10, 100).
2. The double-side or one-side machine tool according to claim 1, characterized in that the decoupling means comprise at least one bearing (32) arranged between the clamping surfaces (24, 26) of the first working disk (14, 140) and the first support disk (10, 100).
3. The double-side or one-side machine tool according to claim 2, characterized in that the at least one bearing (32) comprises at least one rolling bearing (32).
4. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the decoupling means comprise elastic prestressing means (30) for elastically prestressing the first clamping means (20).
5. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the first clamping means (20) comprise clamping screws (20) with which the first support disk (10, 100) is clamped with its clamping surface (24) against the clamping surface (26) of the first working disk (14, 140).
6. The double-side or one-side machine tool according to claims 4 and 5, characterized in that the elastic prestressing means (30) comprise elastic spring washers (30) which are each arranged between a screw head (22) of the clamping screws (20) and a surface (28) of the first support disk (10, 100) facing away from the first working disk (14, 140).
7. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the decoupling means comprise a decoupling intermediate layer between the first working disk (14, 140) and the first support disk (10, 100), in particular a sliding intermediate layer or an intermediate layer for thermal decoupling.
8. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the material of the first working disk (14, 140) has a lower coefficient of thermal expansion than the material of the first support disk (10, 100).
9. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the counter bearing element is formed by a preferably annular second working disk (16, 160), wherein the first and second working disk (16, 160) are arranged coaxially relative to each other, wherein the working gap (18, 180) is formed between the first and second working disk (14, 140, 16, 160) to machine both sides or one side of flat workpieces.
10. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that the second working disk (16, 160) is fastened to a second support disk (12, 120), in that second clamping means are provided for clamping the second working disk (16, 160) with a clamping surface facing away from the working gap (18, 180) against a clamping surface of the second support disk (12, 120) facing the second working disk (16, 160), and in that decoupling means are also provided for at least partially decoupling the second working disk (16, 160) from the second support disk (12, 120).
11. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that a pressure volume (300) is arranged between the first support disk (10, 100) and the first working disk (14, 140), said pressure volume being connected to a pressure fluid supply which is actuable in such a way that a pressure is built up in the pressure volume (300), which generates a predetermined deformation of the first working disk (14, 140).
12. The double-side or one-side machine tool according to any one of the preceding claims, characterized in that temperature-controlling channels (220, 280) are provided for controlling the temperature of the first working disk (14, 140), which are connected to a temperature-controlling fluid supply.
13. The double-side or one-side machine tool according to any one of claims 11 or 12, characterized in that the temperature-controlling channels (220, 280) are arranged within the first working disk (14, 140), such that the temperature-controlling channels (220, 280) are arranged closer to the working gap (18, 180) than the pressure volume (300), and that the temperature-controlling channels (220, 280) are not connected to the pressure volume (300).
14. The double-side or one-side machine tool according to any one of either of claims 12 and 13, characterized in that the first working disk (14, 140) is formed from two preferably annular disks which are connected to one another and between which the temperature-controlling channels (220, 280) are formed, wherein one of the disks borders the working gap (18, 180) and the other of the disks has the clamping surface for clamping against the clamping surface of the first support disk (10, 100).
Abstract
The invention relates to a double-side or one-side machine tool comprising a preferably annular first working disk which is fastened to a first support disk, and comprising a counter bearing element, wherein the first working disk and the counter bearing element can be driven to rotate relative to each other by at least one drive shaft, wherein a working gap is formed between the first working disk and the counter bearing element to machine both sides or one side of flat workpieces, and wherein first clamping means are provided to clamp the first working disk with a clamping surface facing away from the working gap against a clamping surface of the first support disk facing the first working disk, wherein decoupling means are provided for at least partially decoupling the first working disk from the first support disk.
The invention relates to a double-side or one-side machine tool comprising a preferably annular first working disk which is fastened to a first support disk, and comprising a counter bearing element, wherein the first working disk and the counter bearing element can be driven to rotate relative to each other by at least one drive shaft, wherein a working gap is formed between the first working disk and the counter bearing element to machine both sides or one side of flat workpieces, and wherein first clamping means are provided to clamp the first working disk with a clamping surface facing away from the working gap against a clamping surface of the first support disk facing the first working disk, wherein decoupling means are provided for at least partially decoupling the first working disk from the first support disk.