【導(dǎo)讀】用與車外圓、端面和鏜孔等加工的機(jī)床叫車床。中完成多種加工。杠和光杠床身是車床的基礎(chǔ)件。一些制造廠則將倒“V”形導(dǎo)軌和平面導(dǎo)軌相結(jié)合。應(yīng)該小心，以避免損傷導(dǎo)軌。導(dǎo)軌上的任何誤差，常常會(huì)使整個(gè)機(jī)床的精度破壞。發(fā)展的趨勢(shì)是通過電氣的或機(jī)械的裝置進(jìn)行無級(jí)變速。裝在緊密配合的重型圓錐滾子軸承或球軸承中。主軸由電動(dòng)機(jī)經(jīng)V帶或無聲鏈裝置提供動(dòng)力。尾座組件主要由三部分組成。尾座組件的第三部分是尾座套筒，它是一個(gè)直徑通常在2～3英寸之間的鋼制。通過手輪和螺桿，尾座套筒可以在尾座體中縱向移入和移出幾英寸。筒的外表面刻有幾英寸長(zhǎng)的刻度，以控制尾座的前后移動(dòng)。的，而刀具處于進(jìn)給狀態(tài)。這種加工過程常被稱為平面。夾緊裝置之間的松動(dòng)的趨勢(shì)，這時(shí)應(yīng)施加更大的夾緊力。順銑時(shí)，最大切屑厚度產(chǎn)生于靠近刀具與工件接觸點(diǎn)處。于不能用于順銑的銑床，應(yīng)不采用順銑方法。偏心后角的各面與切削刃平行，具有切削刃的相同形狀。

　　

【正文】 minated if down milling is to be used. It should never be attempted on machines that are not designed for this type of milling. Inasmush as the material yields in approximately a tangential direction at the end of the tooth engagement, there is much less tendency for the machined surface to show tooth marks than when up milling is used. Another considerable advantage of down milling is that the cutting force tends to hold the work against the machine table, permitting lower clamping force to be employed. 3 This is particularly advantageous when milling thin workpiece or when taking heavy cuts. Sometimes a disadvantage of down milling is that the cutter teeth strike against the surface of the work at the beginning of each chip. When the workpiece has a hard surface, such as castings do, this may cause the teeth to dull rapidly. Milling Cutters. Milling cutters can be classified several ways. One method is to group them into two broad classes, based on tooth relief, as follows: 1. Profilecutters have relief provided on each tooth by grinding a small land back of the cutting edge. The cutting edge may be straight or curved. 2. In form or camreheved cutters the cross section of each tooth is an eccentric curve behind the cutting edge, thus providing relief. All sections of the eccentric relief, parallel with the cutting edge, must have the same contour as the cutting edge. Cutters of this type are sharpened by grinding only the face of the teeth, with the contour of the cutting edge thus remaining unchanged. Another useful method of classification is according to the method of mounting the cutter. Arbor cutters are those that have a center hole so they can be mounted on an arbor. Shank cutters have either tapered or straight integral shank. Those with tapered shanks can be mounted directly in the milling machine spindle, whereas straightshank cutters are held in a chuck. Facing cutters usually are bolted to the end of a stub arbor. The mon types of milling cutters, classified by this system are as follows: Types of Milling Cutters. Hain milling cutters are cylindrical or diskshaped, having straight or helical teeth on the periphery. They are used for milling flat surfaces. This type of operation is called plai n or slab milling. Each tooth in a helical cutter engages the work gradually, and usually more than one tooth cuts at a given time. This reduces shock and chattering tendencies and promotes a smoother surface. Consequently, this type of cutter usually is preferred over one with straight teeth. Side milling cutters are similar to plain milling cutters except that the teeth extend radially part way across one or both ends of the cylinder toward the :center. The teeth may be either straight or helical. Frequently these cutters are relatively narrow, being disklike in shape. Two or more side milling cutters often are spaced on an arbor to make simultaneous, parallel cuts, in an operation called straddle milling. Interlocking slotting cutters consist of two cutters similar to side mills, but made to operate as a unit for milling slots. The two cutters are adjusted to the desired width by inserting shims between them. Staggeredtooth milling cutters are narrow cylindrical cutters having staggered teeth, and with alternate teeth having opposite helix angles. They are ground to cut only on the periphery, but each tooth also has chip clearance ground on the protruding side. These cutters have a free cutting action that makes them partilarly effective in milling deep slots.