【正文】 tion is then reproduced numerous times as a result of the axial feed motion of the ：圓柱面車削是所有車床操作中最簡單也是最普通的。工件旋轉(zhuǎn)一整圈產(chǎn)生一個圓心落在車床主軸上的圓；由于刀具的軸向進給運動這種動作重復許多次。The resulting machining marks are, therefore, a helix having a very small pitch, which is equal to the , the machined surface is always ，由此產(chǎn)生的機加工痕跡是一條具有很小節(jié)距的螺旋線，該節(jié)距等于進給。因此機加工表面始終是圓柱形的。The axial feed is provided by the carriage or the pound rest, either manually or automatically, whereas the depth of cut is controlled by the cross ，然而切削深度則由橫向滑板控制。In roughing cuts, it is remended that large depths of cuts(up to 6mm, depending upon the workpiece material)and smaller feeds would be the other hand, very fine feeds, smaller depths of cut(less than , or ), and high cutting speeds are preferred for finishing ，推薦使用較大切削深度()和較小進給。另一方面，精車則最好采用很小的進給、較小的切削深度()和較高的切削速度。 result of a facing operation is a flat surface that is either the whole end surface of the workpiece or an annular intermediate surface like a a facing operation, feed is provided by the cross slide, whereas the depth of cut is controlled by the carriage or pound ：端面車削操作的結(jié)果是將工件整個端部表面或者像軸肩之類的中間環(huán)形表面加工平整。在端面車削操作中，進給由橫向滑板提供，而切削深度則通過大拖板或復式刀架控制。Facing can be carried out either from the periphery inward or from the center of the workpiece is obvious that the machining marks in both cases take the form of a 。很明顯在這兩種情況下機加工痕跡都是螺線形式。Usually, it is preferred to clamp the carriage during a facing operation, since the cutting force tends to push the tool(and, of course, the whole carriage)away from the most facing operations, the workpiece is held in a chuck or on a face ，這是因為切削力傾向于將刀具(當然包括整個大拖板)推離工件。在大多數(shù)端面車削作業(yè)中，工件被支撐在卡盤或花盤上。Groove cutoff and groovecutting operations, only cross feed of the tool is cutoff and grooving tools, which were previously discussed, are ：在切斷和開槽操作中，刀具只有橫向進給。要采用前面已經(jīng)討論過的切斷和開槽刀具。Boring and internal and internal turning are performed on the internal surfaces by a boring bar or suitable internal cutting the initial workpiece is solid, a drilling operation must be performed drilling tool is held in the tailstock, and the latter is then fed against the ：鏜孔和內(nèi)部車削通過鏜桿或合適的內(nèi)部切削刀具在內(nèi)表面進行。如果初始工件是實心的，則必須首先進行鉆孔作業(yè)。鉆孔刀具安裝在尾架上，然后對著工件進給。Taper turning is achieved by driving the tool in a direction that is not parallel to the lathe axis but inclined to it with an angle that is equal to the desired angle of the are the different methods used in taperturning practice:錐面車削：錐面車削通過沿著與車床主軸不平行而傾斜成一個等于錐面所需角度的方向進刀來實現(xiàn)。下面是在實際錐面車削中采用的不同方法：(1)Rotating the disc of the pound rest with an angle equal to half the apex angle of the is manually provided by cranking the handle of the pound method is remended for taper turning of external and internal surfaces when the taper angle is relatively large.(1)將復式刀架盤旋轉(zhuǎn)一個等于圓錐體頂角一半的角度。通過搖動復式刀架操縱柄手動提供進給。當錐角相對較大時切削外錐面和內(nèi)錐面推薦使用這種方法。(2)Employing special form tools for external, very short, conical width of the workpiece must be slightly smaller than that of the tool, and the workpiece is usually held in a chuck or clamped on a face this case, only the cross feed is used during the machining process and the carriage is clamped to the machine bed.(2)對很短的外錐面采用特殊的成型刀具。工件的寬度必須略小于刀具的寬度，并且工件通常由卡盤支撐或夾緊在花盤上。在這種情況下，機加工作業(yè)時只有橫向進給而大拖板則夾緊在床身上。(3)Offsetting the tailstock method is employed for external taper turning of long workpieces that are required to have small taper angles(less than 8176。).The workpiece is mounted between the two centers。then the tailstock center is shifted a distance S in the direction normal to the lathe axis.(3)偏移尾架頂尖。對需要較小錐角(小于8176。)的較長工件外錐面車削采用這種方法。工件安裝于兩頂尖之間；然后將尾架頂尖朝垂直于車床主軸方向移動一距離S。(4)Using the taperturning method is used for turning very long workpieces, when the length is larger than the whole stroke of the pound procedure followed insuch cases involves plete disengagement of the cross slide from the carriage, which is then guided by the taperturning attachment.(4)采用錐面車削附加裝置。這種方法用于車削很長的工件，其長度大于復式刀架的整個行程。在這種場合下要遵循的步驟是將橫向滑板完全脫離大拖板，然后通過錐面車削附加裝置進行引導。During this process, the automatic axial feed can be used as method is remended for very long workpieces with a small cone angle, ., 8176。through 10176。.在此作業(yè)中，能照常使用自動軸向進給。對具有較小錐角(即8176。到10176。)的很長工件推薦采用這種方法。Thread performing thread cutting, the axial feed must be kept at a constant rate, which is dependent upon the rotational speed(rpm)of the relationship between both is determined primarily by the desired pitch of the thread to be ：在螺紋切削作業(yè)時，軸向進給必須保持恒定速率，這取決于工件的轉(zhuǎn)速(rpm)。兩者之間的關(guān)系基本上由被切削螺紋所需的節(jié)距決定。As previously mentioned, the axial feed is automatically generated when cutting a thread by means of the lead screw, which drives the the lead screw rotates a single revolution, the carriage travels a distance equal to the pitch of the lead ，當依靠驅(qū)動大拖板的絲桿切削螺紋時軸向進給是自動產(chǎn)生的。絲桿旋轉(zhuǎn)一圈，大拖板就行進等于絲桿節(jié)距的一段距離。Consequently, if the rotational speed of the lead screw is equal to that of the spindle(., that of the workpiece), the pitch of the resulting cut thread is exactly equal to that of the lead (即工件的轉(zhuǎn)速)，生成切削螺紋的節(jié)距就正好等于絲桿的節(jié)距。The pitch of the resulting thread being cut therefore always depends upon the ratio of the rotational speeds of the lead screw and the spindle: Pitch of the lead screw/ Desired pitch of workpiece=rpm of the workpiece/rpm of lead screw=spindletocarriage gearing ：絲桿的節(jié)距/工件所需節(jié)距=工件轉(zhuǎn)速/絲桿轉(zhuǎn)速=心軸到大拖板的傳動比。This equation is useful in determining the kinematic linkage between the lathe spindle and the lead screw and enables proper selection of the gear train between ，并且提供了正確挑選它們之間輪系的方法。In thread cutting operations, the workpiece can either be held in the chuck or mounted between the two lathe centers for relatively long form of the tool used must exactly coincide with the profile of the thread to be cut, ., triangular tools must be used for triangular threads, and so ，工件既能支撐于卡盤中，對相對較長的工件也能安裝在兩個車床頂尖之間。使用的刀具外形必須正好與要切削螺紋的輪廓一致，即三角形刀具必須用于三角形螺紋等等。 is mainly a forming operation in which no chips are involves pressing two hardened rolls with rough filelike surfaces against the rotating