(1) 1241931 九、發明說明 【發明所屬之技術領域】 本發明係例如關於使用於導光板成型用模具 加工的工作機械，特別是關於適合於如可就每一 傾斜角度一點一點地起變化的徐變溝槽加工的工 【先前技術】 第7圖係作爲施予該種徐變溝槽加工的工件 而顯示導光板成型用模具的透鏡溝槽的形狀之圖 行地延長的透鏡溝槽Lr〜L4的角度係在第7圖中 鏡溝槽那樣逐漸地成爲大的角度。 在第7圖中，符號1〇0是顯示切削刀具。在進 徐變溝槽加工之以往的工作機械，係具備用來改 具100的刀尖部之角度的切削刀具旋轉台。 第5圖、第6圖係顯示以往工作機械的切削刀 之例。在設置了切削刀具旋轉台的工作機械，係 左右方向水平移動的直線軸爲Y軸，向設置在鞍 台之前後方向水平移動的直線軸爲X軸，刀架之 的直線軸爲Z軸，這些爲共通的結構。 當說明關於第5圖的切削刀具旋轉台時，切 轉台1 1 0是被安裝在刀架1 1 1的下端部，形成裝言 刀具1 〇 〇。旋轉軸線1 1 4是以朝X軸平行的軸爲 號Π 5係以旋轉軸線n 4作爲轉動中心而驅動切肖|j 台Π 0的伺服馬達。 等超精密 條溝槽的 作機械。 W之例， 。各自平 左側的透 行如此的 變切削刀 具旋轉台 向鞍座的 座上的平 上下移動 削刀具旋 έ 1支切削 Α軸，符 刀具旋轉 (2) 1241931 在第5圖所示之具有以往的切削刀具旋轉台1 1 〇的工作 機械’在對成爲導光板成型用模具的工件 W刨床加工透 鏡溝槽L 1〜L4的情況，如第7圖所示，在使切削刀具1 0 〇 的切刀稜部1 0 1配合角度φ ，且傾斜的狀態下使切削刀具 1 〇 〇朝Ζ軸方向下降，且定位在預定的位置，以平台之X 軸的前後移動來加工面部f。 接著，持續對面部f的加工且爲了加工面部r係須要 如下的動作。 亦即，藉由使切削刀具1 00從工件W逃離且使切削刀 具旋轉台1 1 0旋轉來使切削刀具100的切刀稜部102配合於 面部r的傾斜（在第7圖以虛線所示）。但是因爲藉由切 削刀具旋轉台1 1 0的旋轉而切削刀具ί 0 0的刀尖部A的 Y 軸位置從透鏡溝槽的谷底頂點大幅偏離，所以進行Y軸移 動而不得不將切削刀具1 00的刀尖部配合於透鏡溝槽的谷 底的頂點。然後，使切削刀具1 00朝Z軸方向下降，且定 位在預定的位置，以平台的X軸的前後移動來加工面部r 〇 而且，在如以上的V字狀溝槽形狀的徐變溝槽加工中 ，因爲要進行良好的切削性，所以提案有在工具上下工夫 的切削裝置（例如，參照日本特開2002- 3 468 1 9號公報） 〇 可是，當改變切削刀具1 0 0的角度時，以旋轉軸線1 1 4 爲中心雖然使切削刀具100旋轉，但是當切削刀具100的刀 尖部的旋轉半徑R爲大時，大受分度精度的影響，且刀尖 (3) 1241931 部A的位置的誤差變大，因爲受到由於Y軸、Z軸的定位 精度的影響，所以切削刀具1 0 0的刀尖部的位置從作爲目 標的透鏡溝槽的谷底頂點偏離，其結果，具有所謂造成透 鏡溝槽的溝槽節距不良或深度不良的問題。 【發明內容】 於是，本發明的目的係解決上述先前技術之有的問題 點，在導光板成型用模具上徐變加工透鏡溝槽的情況，提 供有製作成藉由切削刀具的刀尖部位置之些微的移動而可 改變切削刀具的角度，且可進行高精度的徐變加工的工作 機械。 爲了達成上述的目的，本發明係具備：在床台上可朝 左右方向移動的鞍座、在上述鞍座之上設置成可朝前後方 向移動，且搭載工件的平台、設置在上述床台上的支柱、 可朝垂直方向移動並設置在上述支柱的刀架、及安裝在上 述刀架的下端部，且具有成爲切削刀具的旋.轉中心之傾斜 的旋轉軸，相對於上述旋轉軸的軸線而該切削刀具的刀尖 部的位置位在同一軸線或其下方偏位的位置之斜軸頭部爲 其特徵者。 根據本發明之較佳的情況，上述斜軸頭部係具備：藉 由軸承而可轉動地被支持，且相對於水平面而軸線爲傾斜 的旋轉軸、從上述旋轉軸的軸線傾斜而朝軸方向伸長的延 長軸、安裝在上述延長軸的前端部，且保持上述切削刀具 的切削刀具支撐架、及使上述旋轉軸轉動，且將切削刀具 -6- (4) 1241931 的旋轉角度分度的旋轉分度部。 根據本發明，在導光板成型用模具上徐 槽的情況，製作成藉由切削刀具的些微的刀 動’就可改變切削刀具的角度，而可進行高 工。 【實施方式】 [發明的實施型態] 以下，關於本發明的工作機械的一實施 照添附的圖面一面說明。 第1圖係顯示本發明的一實施型態的工 構成的正面圖，第2圖係顯示同工作機械的 弟1圖、弟2圖中，付號1〇係顯不床台’在床 設置有支柱1 2。 在支柱1 2係可朝上下方向移動地安裝有 架1 8係藉由均衡壓缸1 9而被支持。然後，安 下端部爲斜軸頭部2 0。在斜軸頭部2 0的前端 削刀具100。 另外’在弟1圖中’在床台10的上面係 移動地安裝有鞍座1 6。在該鞍座丨6上係可朝 地安裝有平台22。該平台22係具備固定工件 盤23。 而且，在平台22之上，爲了製作成可對 ’而藉由加工的種類也可設置以伺服馬達來 變加工透鏡溝 尖部位置的移 精度的徐變加 型態，一面參 作機械的全體 側面之圖。在 台1 〇的上面係 刀架18。該刀 裝在刀架1 8的 部係保持有切 可朝左右方向 前後方向移動 :W的真空吸 應於旋削加工 驅動的轉動平 (5)1241931 台。 在 使平台 珠螺桿 移動的 軸伺服 軸，驅 在 具旋轉 軸頭部 尖部的 而可改 於 5 〇是旋 面）。 〇 斜 5 0相對 43而被 4 4的軸 傾斜角 變化減 斜 保持切 弟1圖、第2圖中’本實施型態的工作機械的情況， 2 2朝水平方向移動的軸爲χ軸，驅動該X軸的滾 進L機構爲X軸伺服馬達2 7。使鞍座丨6朝水平方向 軸爲Y軸’驅動該γ軸的滾珠螺桿進給機構爲Y 馬達28力外’使刀架18朝上下方向移動的軸爲z 動該Z軸的滾珠螺桿進給機構爲Z軸伺服馬達2 9。 刀架1 8的下端部係取代第5圖所示之以往的切削刀 台1 1 〇 ’安裝有如第3圖所示的傾斜的旋轉軸4 4的斜 2 〇 ’藉由使用該斜軸頭部2 〇而在切削刀具！ 〇 〇的刀 附近設定旋轉中心，藉由些微的刀尖部位置的移動 變切削刀具1 0 0的切刀的角度。 是’在第3圖顯示斜軸頭部2 〇。在該第3圖中，符號 轉軸4 4的軸線。另外，符號5 2是顯示水平面（平台 α爲旋轉軸44的軸線50及平台面52所夾的傾斜角度 軸頭邰2 0係藉由托架4 2而被保持成旋轉軸4 4的軸線 於平台面5 2而夾成傾斜角度α ，並且藉由支持構件 堅固地支持。在該實施型態的斜軸頭部2 0，旋轉軸 線5 0的傾斜角度α係被設定成丨〇。。該旋轉軸4 4的 度α係爲了將切削刀具1 0 0的傾角（r a k e a η g 1 e )的 小，雖然越小越好，但是3 0。以內較佳。 軸頭部2 0係由頭部本體4 5、旋轉軸4 4、延長軸4 6、 削刀具1 〇 〇的切削刀具支撐架4 7、及將切削刀具丨〇 〇 (6) 1241931 的旋轉角度分度的旋轉分度部4 8所構成。而且，在頭部本 體4 5係盡其所能將與平台面5 2干涉的部分進行倒角，製作 成小的傾斜角度α。另外，延長軸4 6的平台面5 2側係施行 即使切削刀具1 0 0旋轉也不對平台面5 2干涉的倒角。 在旋轉軸44的前端係卡合有相對於軸線5〇而傾斜並延 長的延長軸4 6的基端部，該延長軸4 6係與平台面5 2朝大致 平行（水平）延長到前端側。然後，在延長軸46的前端係 安裝有切削刀具支撐架47。該切削刀具支撐架47係以垂直 的姿勢保持切削刀具1 0 0。在如此的延長軸4 6係因爲可維 持剛性’所以斜軸頭部2 0係成爲高剛性的構造。如第3圖 所示，切削刀具1 0 0的刀尖部Α在本實施型態係不在旋轉 軸4 4的軸線5 0上，從軸線5 0位於更下方的位置。亦即，在 該實施型態，切削刀具1 00的旋轉中心係較刀尖部A還位 在切削刀具支撐架4?側，刀尖部A係設定在從旋轉中心向 下方伸出2 Ο.ηιιπ左右的位置。可是，由於延長軸4 6，切削刀 具100的刀尖部 A也可位在旋轉軸44的軸線50上。在導光 板成型用模具的徐變溝槽加工的情況時，切削刀具1 〇 〇的 刀尖部從軸線5 0伸出的長度係〇〜3 0麵的範圍爲宜。 接著’旋轉分度部48係藉由伺服馬達54而被驅動。然 後藉由旋轉式編碼器56而取得位置反饋，藉由控制伺服馬 達5 4的轉動，以1 〇萬分之丨度的精度而成爲可分度旋轉軸 4 4的旋轉角度。如此的旋轉分度部4 8的控制軸爲A軸。 而且，在頭部本體4 5的內部，爲了使之對應於A軸的 分度精度，因此裝入有空氣軸承5 8來作爲可轉動自如地支 (7) 1241931 持旋轉軸4 4的軸承。 本實施型態的工作機械係如以上所構成，接著，作爲 如以上所構成的工作機械的加工例，而舉例說明在導光板 成型用模具上切削透鏡溝槽的徐變溝槽加工。 第4圖（a )乃至第4圖（c )係按照順序顯示在徐變溝 槽加工的切削刀具1 0 0的動作之圖。在工件W中個別平行 地並排的透鏡溝槽的角度係左側的透鏡溝槽逐漸地成爲大 的角度。在各透鏡溝槽，兩側的傾斜面的傾斜角度相等。 在本實施型態係加工成如以下的透鏡溝槽。 作爲加工前的準備，在斜軸頭部2 0係關於安裝在切削· 刀具支撐架47的切削刀具1〇〇，如第3圖所示，刀尖部A如 從旋轉軸44的軸線50伸出20圆左右，正確地配合於所·決定 的長度。 在第1圖中，切削透鏡溝槽的對象工件W係藉由真空 吸盤23而使之固定在平台22。 首先，藉由鞍座1 6的Y軸移動，使斜軸頭部2 0移動到 加工位置。如在第4圖（a )以2點鏈線所示，將切削刀具 1 0 0的Y軸位置配合於透鏡溝槽的面部Π的谷底頂點位置 。然後，藉由B軸伺服馬達5 4來驅動旋轉分度部4 8而使旋 轉軸44旋轉，切削刀具1〇〇的切刀稜部101的角度成爲與面 部Π的傾斜角度φ 1—致。 這樣，因爲將切削刀具1 〇〇的切刀稜部1 0 1的角度配合 於面部f 1的傾斜角φ 1，所以藉由Z軸移動而使切削刀具 1 〇 〇下降，在達到預定的位置時使平台2 2朝X軸移動，且 m -10- (8) 1241931 將切削刀具1 〇 〇的切刀稜部1 Ο 1轉謄於工件 W而創建面部 f 1。 在創建了面部π的時點，切削刀具1 〇 〇的刀尖部A係 位在透鏡溝槽的谷底頂點。相對於此，而在斜軸頭部2 0 ’ 切削刀具1 〇 〇的旋轉中心係在第4圖中切削刀具1 〇 〇的前端 部的B點。因此，切削刀具1 0 〇係因爲將刀尖部A配合於 透鏡溝槽的谷底頂點的那樣且不可旋轉，所以暫且如在第 4圖（b )以鏈線所示，藉由朝z軸移動來將切削刀具1 0 0 的刀尖部從透鏡溝槽逃離。 然後，爲了緊接著面部Π而加工面部r 1，藉由B軸 旋轉來使切削刀具100對旋轉中心B轉動而在第4圖（b ) 中朝反時鐘方向旋轉，可將切削刀具1 〇 〇的切刀稜部1 0 2配 合於面部r 1的傾斜角度（在第4圖（b )以2點鏈線所示） 。此時，切削刀具1 〇〇的刀尖部A的Y軸上的位置係僅只 從透鏡溝槽的谷底頂點偏離△ Y。因此，如在第4圖（c ) 以2點鏈線所示，藉，由Y軸移動來使切削刀具1 0 0僅只移動 A Y，可將切削刀具1 〇 〇的刀尖部A的 Y軸上的位置配合 於透鏡溝槽的谷底頂點。 接著，在第4圖（c )中，藉由Z軸移動而使切削刀具 下降，在達到預定的位置時使平台2 2朝X軸移動，且可將 切削刀具1 0 0的切刀稜部1 0 2轉謄於工件 W而創建面部r 1 〇 這樣若完成一條透鏡溝槽的加工，藉由Z軸移動來將 切削刀具1 0 0從透鏡溝槽逃離’藉由 Y軸移動來使切削刀 -11 - (9) 1241931 具1 00移動到旁邊的面部f2的透鏡溝槽的位置。然後，因 爲使切削刀具1 00的刀尖部A的Y軸上的位置配合於透鏡 溝槽的谷底頂點，所以藉由 B軸旋轉來使切削刀具1 00的 切刀稜部1 0 1的角度配合於面部f2的傾斜角φ 2，以下， 藉由反復與起初的透鏡溝槽的情況同樣的動作，而能連續 加工面部f2及面部r 2。此處，雖然從說明的方便上，說 明了使切削刀具1 0 0朝Z軸方向逃離，但是在實際加工中 ，因爲使切削刀具1 〇〇從工件W逃離至X軸方向的位置， 所以即使不朝Z軸方向逃離也可。 如以上，根據具有相對於旋轉軸4 4的軸線5 0而切削刀 具1 0 0的刀尖部A偏位的構造的斜軸頭部2 0，僅只稍微Y 軸的移動及藉由B軸的旋轉動作，就可使切削刀具1 〇 〇的 切刀的角度配合於面部f及面部r。其中，關於γ軸移動 ’與第5圖所示的以往刀架旋轉機構比較來看時，通常的 刀架的情況’即使短的切削刀具而旋轉半徑也要1 〇 〇隱左 右。相對於此，根據本實施型態的斜軸頭部2 0，因爲在切 削刀具1 0 0的前端部設定有旋轉中心，所以旋轉半徑係不 超過從旋轉軸4 4的軸線伸出的前端部的長度約2 〇眶。藉此 ，相較於第5圖的刀架旋轉機構，而在切削刀具丨〇〇旋轉時 所產生的刀尖部的位置的誤差沒有所謂起大的作用。另外 ，在加工面部f後可減小對面部r配合切刀的角度之際的 γ軸移動量。另外，延長軸46係從旋轉軸44使之傾斜，可 作爲高剛性的軸構造。 而且’在斜軸頭邰2 0 ’因爲使用傾斜的旋轉軸4 4而將 -12- (10) 1241931 旋轉位置設定在切削刀具1 〇 〇的前端部，所以雖然藉由方定 .轉而切削刀具1 〇 0的傾角變化，但是若旋轉軸4 4的傾斜角 度α爲1 0°左右’切削刀具1 ο 〇的傾角的變化之不良情況 是不成問題。 而且’傾斜的旋轉軸4 4係因爲以空氣軸承5 8來支持、 及以利用伺服馬達5 4來驅動的分度機構4 8作爲Α軸而藉由 數値控制來實現切削刀具1 〇 〇的旋轉運動，所以可得到高 精度的分度精度。 【圖式簡單說明】 第1圖係顯不本發明的一實施型態的工作機械的正面 圖。 第2圖係同實施型態的工作機械的側面圖。 第3圖係同實施型態的工作機械之具備的斜軸頭部的 側面圖。 第4圖係顯示在徐變溝槽的加工之切削刀具的刀尖部 的動作的說明圖。 第5圖係設置在以往的工作機械的切削刀具旋轉台之 例的說明圖。 第6圖係顯示從第5圖的X軸方向看到的切削刀具旋轉 台之圖， 第7圖係導光板成型用模具的透鏡溝槽的說明圖。 [主要元件符號說明】 -13- (11) (11)1241931 A···刀尖部 LI〜L4···透鏡溝槽 f、Π、f2···面部 r、r 1、r 2…面部 W·..工件 α…傾斜角度 φ 、 φ 1、 φ 2…傾斜角度 10…床台 1 2…支柱 1 6…鞍座 1 8…刀架 19··.均衡壓缸(balance cylinder 20…·斜軸頭部 22…平台 23…真空吸盤 2 7··. X軸伺月艮馬達 28…Y軸伺服馬達 29··· Z軸伺服馬達 42…托架 43…支持構件 4 4…旋轉軸 45…頭部本體 46…延長軸 47.··切肖ij刀具支撐架 -14 - (12) (12)1241931 48…旋轉分度部（分度機構 50…軸線 52···水平面（平台面） W,··伺月g馬達 5 6…編碼器 5 8…空氣軸承 1〇〇···切削刀具 101…切刀稜部 102···切刀稜部 1 10…切削刀具旋轉台 1 1 4…旋轉軸線 1 1 5…伺服馬達(1) 1241931 IX. Description of the invention [Technical field to which the invention belongs] The present invention relates to, for example, a work machine used for processing a light guide plate forming mold, and in particular, it is suitable for starting from a little by little for each tilt angle. Process of Changing Creep Groove Processing [Prior Art] FIG. 7 is a view showing a shape of a lens groove extending in the shape of a lens groove of a light guide plate forming mold as a workpiece to which the creep groove processing is applied. The angle of the grooves Lr to L4 gradually becomes a large angle like the mirror groove in FIG. 7. In Fig. 7, reference numeral 100 indicates a cutting tool. Conventional work machines for creep groove processing have a cutting tool rotary table for changing the angle of the tip of the tool 100. Figures 5 and 6 show examples of cutting tools of conventional working machines. For a working machine equipped with a cutting tool rotary table, the linear axis that moves horizontally in the left-right direction is the Y axis, the linear axis that moves horizontally before and after the saddle is the X axis, and the linear axis of the tool post is the Z axis. These are common structures. When the cutting tool rotary table of FIG. 5 is described, the cutting table 1 10 is mounted on the lower end portion of the tool post 1 1 1 to form a tool 10. The rotation axis 1 1 4 is an axis parallel to the X axis. The number 5 is a servo motor that drives the Chess | j stage Π 0 with the rotation axis n 4 as the rotation center. Such as ultra-precision grooved machinery. Example of W,. The left side of each plane penetrates such a variable cutting tool rotating table to move the cutting tool up and down on the seat of the saddle. One cutting A axis, and the cutting tool rotates (2) 1241931. When the working machine of the cutting tool rotating table 1 1 0 is used to process the lens grooves L 1 to L 4 on a workpiece W planer that is a mold for forming a light guide plate, as shown in FIG. 7, the cutting tool 1 0 0 is cut. The blade edge portion 101 is matched with an angle φ and the cutting tool 100 is lowered in the direction of the Z axis in an inclined state, and is positioned at a predetermined position, and the face f is processed by moving the X axis of the platform forward and backward. Next, the processing of the face f is continued, and the following operations are required to process the face r. That is, the cutting edge 100 of the cutting tool 100 is fitted to the inclination of the face r by causing the cutting tool 100 to escape from the workpiece W and rotating the cutting tool rotary table 1 10 (shown by a dotted line in FIG. 7). ). However, the Y-axis position of the tip A of the cutting tool ί 0 0 is greatly deviated from the vertex of the bottom of the lens groove by the rotation of the cutting tool rotating table 1 1 0. Therefore, the cutting tool 1 has to be moved to perform the Y-axis movement. The blade point of 00 is fitted to the vertex of the valley bottom of the lens groove. Then, the cutting tool 100 is lowered in the Z-axis direction and positioned at a predetermined position, and the surface r is processed by the X-axis movement of the platform back and forth, and the creep groove in the V-shaped groove shape as described above is processed. In order to achieve good machinability during machining, a cutting device that works on the tool is proposed (for example, refer to Japanese Patent Application Laid-Open No. 2002- 3 468 1 9). However, when the angle of the cutting tool 1 0 0 is changed Although the cutting tool 100 is rotated with the rotation axis 1 1 4 as the center, when the rotation radius R of the tip of the cutting tool 100 is large, it is greatly affected by the indexing accuracy, and the tip (3) 1241931 part A Due to the influence of the positioning accuracy of the Y-axis and Z-axis, the position of the cutting edge of the cutting tool 100 deviates from the vertex of the bottom of the target lens groove. As a result, there is a so-called This causes problems such as poor groove pitch or poor depth of the lens groove. SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the problems of the above-mentioned prior art, and in the case where a lens groove is creep-processed on a light guide plate forming mold, a position of a tip portion manufactured by a cutting tool is provided. It is a working machine that can change the angle of the cutting tool with a slight movement, and can perform high-precision creep processing. In order to achieve the above object, the present invention is provided with a saddle that can be moved in a left-right direction on a bed, a platform provided on the saddle that can be moved in a forward-backward direction, and a workpiece, and installed on the bed. A turret that can be moved in a vertical direction and is provided on the turret and a lower end portion of the turret that is installed at the lower end of the turret and has a rotating shaft that is a rotation center of the cutting tool and is inclined relative to the axis of the rotation shaft The oblique axis head of which the position of the cutting edge of the cutting tool is located at the same axis or a position deviated below is the characteristic. According to a preferred aspect of the present invention, the oblique shaft head is provided with a rotation shaft rotatably supported by a bearing and having an axis inclined with respect to a horizontal plane, and inclined from the axis of the rotation shaft toward the axial direction. An extended extension shaft, a cutting tool support bracket attached to the front end of the extension shaft, holding the cutting tool, and rotating the rotation shaft, and rotating the cutting tool by a rotation angle of 6- (4) 1241931 Indexing department. According to the present invention, in the case where a groove is formed in a light guide plate forming mold, the angle of the cutting tool can be changed by a slight movement of the cutting tool, and high-technologies can be performed. [Embodiment] [Embodiments of the invention] Hereinafter, an embodiment of a working machine according to the present invention will be described with reference to the attached drawings. Fig. 1 is a front view showing the working structure of an embodiment of the present invention, and Fig. 2 is a diagram showing the same working machine as Fig. 1 and Fig. 2. The drawing No. 10 indicates that the bed is not installed on the bed. There are pillars 1 2. Frames 18 and 8 are mounted on pillars 12 and 2 so that they can move up and down, and are supported by equalizing cylinders 19. Then, the lower end is the oblique shaft head 20. The tool 100 is cut at the front end of the inclined shaft head 20. A saddle 16 is mounted on the upper surface of the bed 10 "in the figure 1". A platform 22 is mounted on the saddle 6 to face down. The platform 22 is provided with a fixed work plate 23. In addition, on the platform 22, in order to produce a pairable ', the type of processing can also be provided with a servo motor to change the creep accuracy of the lens groove tip position movement accuracy, adding the whole machine Side view. A knife holder 18 is attached to the table 10. The knife is mounted on the part of the knife holder 18 and can be cut in the left and right direction. It can be moved in the left and right direction. The vacuum suction of W should be applied to the turning process. (5) 1241931. The axis servo shaft that moves the bead screw of the platform is driven at the tip of the head of the rotating shaft and can be changed to 50 (rotation surface). 〇Oblique 50 0 relative to 43 and 4 4 are changed by the inclination angle of the axis to reduce the slope to maintain the Chedi 1 diagram, the second diagram in the case of the working machine of this embodiment, 2 2 horizontal axis is the χ axis, The X-axis roll-in L mechanism is an X-axis servo motor 27. The saddle 丨 6 is set to the Y axis in the horizontal direction. The ball screw feed mechanism that drives the γ axis is driven by a Y motor 28. The axis that moves the tool post 18 in the up and down direction is z to move the ball screw in the Z axis. The feeding mechanism is a Z-axis servo motor 29. The lower end portion of the tool holder 18 replaces the conventional cutting tool table 1 1 0 ′ shown in FIG. 5, and an inclined 2 0 ′ having an inclined rotating shaft 4 4 as shown in FIG. 3 is attached. The inclined shaft head is used. Department 2 〇 And in the cutting tool! The rotation center is set near the blade of 〇 〇, and the angle of the cutting tool 100 is changed by a slight movement of the tip position. Yes' In Fig. 3, the oblique axis head 2 is shown. In this third figure, the axis of the rotating shaft 44 is designated. In addition, reference numeral 52 indicates a horizontal plane (the platform α is the axis 50 of the inclined axis sandwiched between the axis 50 of the rotation axis 44 and the platform surface 52. The axis 邰 20 is held by the bracket 4 2 as the axis of the rotation axis 44. The platform surface 52 is sandwiched at an inclination angle α and is firmly supported by the support member. In the inclined shaft head 20 of this embodiment, the inclination angle α of the rotation axis 50 is set to 丨 0. The degree α of the rotating shaft 44 is to reduce the inclination angle (rakea η g 1 e) of the cutting tool 100, although the smaller the better, it is preferably within 30. The shaft head 20 is the head. Main body 4 5. Rotating shaft 4 4. Extension shaft 4 6. Cutting tool support 4 for cutting tool 1 00. Rotary indexing section 4 8 for indexing the rotation angle of cutting tool 丨 〇 (6) 1241931 In addition, the head body 45 is chamfered as much as possible to interfere with the platform surface 52 to produce a small inclination angle α. In addition, the platform surface 52 side of the extension shaft 4 6 is A chamfer that does not interfere with the table surface 52 even if the cutting tool is rotated by 100 is performed. The front end of the rotation shaft 44 is engaged with The base end of the extension shaft 46 which is inclined and extended with the axis 50 is extended to the front end side substantially parallel (horizontally) to the platform surface 52. Then, the front end of the extension shaft 46 is attached Cutting tool support frame 47. This cutting tool support frame 47 holds the cutting tool 100 in a vertical posture. In such an extended shaft 4 and 6, the rigidity of the inclined shaft head 20 is a highly rigid structure because the rigidity can be maintained. As shown in FIG. 3, the cutting edge portion A of the cutting tool 100 is not located on the axis 50 of the rotating shaft 44 in the present embodiment, and is located further below the axis 50. That is, In the implementation mode, the rotation center of the cutting tool 100 is located at the cutting tool support 4 ° side of the cutting edge portion A, and the cutting edge portion A is set to protrude downward from the rotation center by about 20 mm. However, since the shaft 46 is extended, the tip A of the cutting tool 100 can also be positioned on the axis 50 of the rotating shaft 44. In the case of the creep groove processing of the light guide plate forming mold, the cutting tool 100 The length of the blade tip extending from the axis 50 is preferably in the range of 0 to 30 planes. The rotation indexing unit 48 is driven by a servo motor 54. Then, position feedback is obtained by a rotary encoder 56, and the rotation of the servo motor 54 is controlled to achieve an accuracy of 1 / 100,000 degree It becomes the rotation angle of the indexable rotation axis 44. The control axis of such a rotation indexing section 48 is the A axis. In addition, in the head body 45, in order to make it correspond to the index accuracy of the A axis Therefore, an air bearing 5 8 is installed as a bearing that can rotatably support (7) 1241931 and hold the rotating shaft 4 4. The working machine of this embodiment is constituted as described above. Next, as a processing example of the working machine constituted as described above, the creep groove processing for cutting the lens groove on the light guide plate forming mold is exemplified. Fig. 4 (a) to Fig. 4 (c) are diagrams showing the operation of the cutting tool 100 in the creep groove processing in order. In the workpiece W, the angles of the lens grooves arranged side by side in parallel are gradually larger angles. In each lens groove, the inclination angles of the inclined surfaces on both sides are equal. In this embodiment, the following lens grooves are processed. As a preparation before machining, the cutting head 100 attached to the cutting / tool support 47 is attached to the head 20 of the oblique shaft. As shown in FIG. 3, the cutting edge portion A extends from the axis 50 of the rotation shaft 44. Draw about 20 circles and fit the length you decided. In Fig. 1, a workpiece W to be cut into a lens groove is fixed to a stage 22 by a vacuum chuck 23. First, the Y axis of the saddle 16 is moved to move the oblique axis head 20 to the machining position. As shown in Fig. 4 (a) by a two-point chain line, the Y-axis position of the cutting tool 100 is matched with the bottom vertex position of the face Π of the lens groove. Then, the rotary indexing section 48 is driven by the B-axis servo motor 54 to rotate the rotary shaft 44, and the angle of the cutting edge section 101 of the cutting tool 100 is equal to the inclination angle φ 1 of the surface section Π. In this way, since the angle of the cutting edge portion 101 of the cutting tool 100 is matched with the inclination angle φ 1 of the face f 1, the cutting tool 100 is lowered by the Z-axis movement and reaches a predetermined position. At this time, the stage 22 is moved toward the X axis, and m -10- (8) 1241931 rotates the cutting edge 10 1 of the cutting tool 1 00 to the workpiece W to create a face f 1. At the time when the face π was created, the cutting edge A of the cutting tool 100 was located at the bottom vertex of the lens groove. On the other hand, the center of rotation of the cutting tool 1 00 at the oblique axis head 20 'is at the point B of the tip of the cutting tool 1 00 in Fig. 4. Therefore, the cutting tool 100 is not rotatable because the tip A is fitted to the vertex of the valley bottom of the lens groove. Therefore, as shown by the chain line in FIG. 4 (b), it is moved toward the z axis. To escape the tip of the cutting tool 100 from the lens groove. Then, in order to process the face r 1 immediately after the face Π, the cutting tool 100 is rotated to the rotation center B by B-axis rotation, and is rotated in the counterclockwise direction in FIG. 4 (b), and the cutting tool 1 can be rotated. The cutting edge 10 2 fits the inclination angle of the face r 1 (shown as a two-dot chain line in Fig. 4 (b)). At this time, the position on the Y axis of the cutting edge portion A of the cutting tool 100 is shifted from the vertex of the bottom of the lens groove only by ΔY. Therefore, as shown by the two-point chain line in FIG. 4 (c), by moving the Y-axis to move the cutting tool 100 by only AY, the Y-axis of the tip A of the cutting tool 100 can be moved. The upper position is fitted to the bottom vertex of the lens groove. Next, in FIG. 4 (c), the cutting tool is lowered by moving the Z axis, and when the predetermined position is reached, the table 22 is moved toward the X axis, and the cutting edge of the cutting tool 100 can be moved. 1 0 2 Turns to the workpiece W to create the face r 1 〇 In this way, if the processing of a lens groove is completed, the cutting tool 1 0 is escaped from the lens groove by Z-axis movement 'and the cutting is performed by Y-axis movement Knife-11-(9) 1241931 With 1 00 moved to the position of the lens groove of the side face f2. Then, since the position on the Y axis of the tip A of the cutting tool 100 is matched with the bottom vertex of the lens groove, the angle of the cutting edge portion 1 0 1 of the cutting tool 100 is rotated by the B axis. In accordance with the inclination angle φ 2 of the face f2, the face f2 and the face r 2 can be continuously processed by repeating the same operation as in the case of the original lens groove. Here, for convenience of explanation, it is explained that the cutting tool 100 is evacuated in the Z-axis direction. However, in actual processing, the cutting tool 100 is evacuated from the workpiece W to a position in the X-axis direction. It is not necessary to escape in the direction of the Z axis. As described above, according to the oblique shaft head 20 having a structure in which the cutting edge A of the cutting tool 100 is offset relative to the axis 50 of the rotation axis 44, only the Y-axis movement and the B-axis The rotation can match the angle of the cutting blade 100 to the face f and the face r. Among them, when the γ-axis movement is compared with the conventional tool post rotation mechanism shown in FIG. 5, the case of a normal tool post is 100 ° even with a short cutting tool. On the other hand, according to the oblique shaft head 20 of this embodiment, the rotation center is set at the front end portion of the cutting tool 100, so the rotation radius does not exceed the front end portion protruding from the axis of the rotation shaft 44. The length is about 〇 orbit. As a result, compared with the tool holder rotation mechanism of FIG. 5, the positional error of the tip portion generated when the cutting tool is rotated does not have a significant effect. In addition, after processing the face f, the amount of y-axis movement when the angle of the cutter with respect to the face r is reduced can be reduced. The extension shaft 46 is inclined from the rotation shaft 44 and can be used as a highly rigid shaft structure. In addition, because the inclined axis head 邰 2 0 is used, the -12- (10) 1241931 rotation position is set at the front end of the cutting tool 1 〇 because the inclined rotation axis 4 4 is used. The inclination angle of the tool 100 is changed, but if the inclination angle α of the rotary shaft 44 is about 10 °, the change in the inclination angle of the cutting tool 1 ο 〇 is not a problem. In addition, the 'inclined rotation axis 4 4 is supported by an air bearing 5 8 and the indexing mechanism 4 8 driven by a servo motor 54 is used as the A axis, and the cutting tool 1 is realized by numerical control. Rotary motion, so you can get high precision indexing accuracy. [Brief description of the drawings] Fig. 1 is a front view showing a working machine according to an embodiment of the present invention. Fig. 2 is a side view of a working machine in the same embodiment. Fig. 3 is a side view of an oblique shaft head provided in a working machine of the same embodiment. Fig. 4 is an explanatory view showing the operation of the tip portion of a cutting tool for machining a creep groove. Fig. 5 is an explanatory diagram of an example of a cutting tool rotary table provided in a conventional work machine. Fig. 6 is a view showing a rotary table of the cutting tool viewed from the X-axis direction of Fig. 5, and Fig. 7 is an explanatory view of a lens groove of a mold for forming a light guide plate. [Description of main component symbols] -13- (11) (11) 1241931 A ··· Blade tip LI ~ L4 ·· Lens grooves f, Π, f2 ·· face r, r 1, r 2 ... face W ... Workpiece α ... Tilt angles φ, φ1, φ2 ... Tilt angle 10 ... bed 1 2 ... pillar 1 6 ... saddle 1 8 ... tool post 19 ... balance cylinder 20 ... Inclined shaft head 22 ... platform 23 ... vacuum chuck 2 7 ... X axis servo motor 28 ... Y axis servo motor 29 ... Z axis servo motor 42 ... bracket 43 ... support member 4 4 ... rotation axis 45 … Head body 46… extension shaft 47. · Chesho ij tool support frame -14-(12) (12) 1241931 48… rotation indexing unit (indexing mechanism 50 ... axis 52 ... horizontal plane (platform surface) W ... Servo g motor 5 6 ... Encoder 5 8 ... Air bearing 100 ... Cutting tool 101 ... Cutting edge 102 ... Cutting edge 1 10 ... Cutting tool rotary table 1 1 4 … Rotation axis 1 1 5… servo motor