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啤酒桶清洗机的设计及PLC控制,啤酒,清洗,设计,PLC,控制
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附录:英译汉LATHES & MILLINGA shop that is equipped with a milling machine and an engine lathe can machine almost any type of product of suitable size.The basic machines that are designed primarily to do turning,facing and boring are called lathes. Very little turning is done on other types of machine tools,and none can do it with equal facility. Because lathe can do boring,facing,drilling,and reaming in addition to turning,their versatility permits several operations to be performed with a single setup of the workpiece. This accounts for the fact that lathes of various types are more widely used in manufacturing than any other machine tool. Lathes in various forms have existed for more than two thousand years. Modern lathes date from about 1797,when Henry Maudsley developed one with a leadscrew. It provided controlled,mechanical feed of the tool. This ingenious Englishman also developed a change gear system that could connect the motions of the spindle and leadscrew and thus enable threads to be cut. Lathe Construction. The essential components of a lathe are depicted in the block diagram of picture. These are the bed,headstock assembly,tailstock assembly,carriage assembly,quick-change gearbox,and the leadscrew and feed rod. The bed is the back bone of a lathe. It usually is made of well-normalized or aged gray or nodular cast iron and provides a heavy,rigid frame on which all the other basic components are mounted. Two sets of parallel,longitudinal ways,inner and outer,are contained on the bed,usually on the upper side. Some makers use an inverted V-shape for all four ways,whereas others utilize one inverted V and one flat way in one or both sets. Because several other components are mounted and/or move on the ways they must be made with precision to assure accuracy of alignment. Similarly,proper precaution should betaken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The ways on most modern lathes are surface hardened to offer greater resistance to wear and abrasion. The headstock is mounted in a fixed position on the inner ways at one end of the lathe bed. It provides a powered means of rotating the work at various speeds. It consists,essentially,of a hollow spindle,mounted in accurate bearings,and a set of transmission gearssimilar to a truck transmissionthrough which the spindle can be rotated at a number of speeds. Most lathes provide from eight to eighteen speeds,usually in a geometric ratio,and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle,it is of heavy construction and mounted in heavy bearings,usually preloaded tapered roller or ball types. A long- itudinal hole extends through the spindle so that long bar stock can be fed through it. The size of this hole is an important size dimension of a lathe because it determines the maximum size of bar stock that can be machined when the material must be fed through the spindle. The inner end of the spindle protrudes from the gear box and contains a means for mounting various types of chucks,face plates,and dog plates on it. Whereas small lathes often employ a threaded section to which the chucks are screwed,most large lathes utilize either cam-lock or key-drive taper noses. These provide a large-diameter taper that assures the accurate alignment of the chuck,and a mechanism that permits the chuck or face plate to be locked or unlocked in position without the necessity of having to rotate these heavy attachments.Power is supplied to the spindle by means of an electric motor through a V-belt or silent-chain drive. Most modern lathes have motors of from 5 to15 horsepower to provide adequate power for carbide and ceramic tools at their high cutting speeds.The tailstock assembly consists,essentially,of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon,with a means for clamping the entire assembly in any desired location. An upper casting fits on the lower one and can be moved transversely upon it on some type of keyed ways. This transverse motion permits aligning the tailstock and headstock spindles and provides a method of turning tapers. The third major component of the assembly is the tailstock quill. This is a hollow steel cylinder,usually about2 to3 inches in diameter,that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw. The open end of the quill hole terminates in a Morse taper in which a lathe center,or various tools such as drills,can be held. A graduated scale,several inches in length,usually is engraved on the outside of the quill to aid in controlling its motion in and out of the upper casting. A locking device permits clamping the quill in any desired position. The carriage assembly provides the means for mounting and moving cutting tools. The carriage is a relatively flat H-shaped casting that rests and moves on the outer set of ways on the bed. The transverse bar of the carriage contains ways on which the cross slide is mounted and can be moved by means of a feed screw that is controlled by a small hand wheel and a graduated dial. Through the cross slide a means is provided for moving the lathe tool in the direction normal to the axis of rotation of the work.On most lathes the tool post actually is mounted on a compound rest. This consists of abase,which is mounted on the cross slide so that it can be pivoted about a vertical axis,and an upper casting. The upper casting is mounted on ways on this base so that it can be moved back and forth and controlled by means of a short lead screw operated by a hand wheel and a calibrated dial. Manual and powered motion for the carriage,and powered motion for the cross slide,is provided by mechanisms within the apron,attached to the front of the carriage. Manual movement of the carriage along the bed is effected by turning a hand wheel on the front of the apron,which is geared to a pinion on the back side. This pinion engages a rack that is attached beneath the upper front edge of the bed in an inverted position.To impart powered movement to the carriage and cross slide,a rotating feed rod is provided. The feed rod,which contains a keyway through out most of its length,passes through the two reversing bevel pinions and is keyed to them . Either pinion cam be brought into mesh with a mating bevel gear by means of the reversing lever on the front of the apron and thus provide “forward” or “reverse” power to the carriage. Suitable clutches connect either the rack pinion or the cross-slide screw to provide longitudinal motion of the carriage or transverse motion of cross slide.For cutting threads,a second means of longitudinal drive is provided by a lead screw. Whereas motion of the carriage when driven by the feed-rod mechanism takes place through a friction clutch in which slippage is possible,motion through the lead screw is by a direct,mechanical connection between the apron and the lead screw. This is achieved by a split nut. By means of a clamping lever on the front of the apron,the split nut can be closed around the lead screw. With the split nut closed,the carriage is moved along the lead screw by direct drive without possibility of slippage.Modern lathes have a quick-change gear box. The input end of this gearbox is driven from the lathe spindle by means of suitable gearing. The out put end of the gear box is connected to the feed rod and lead screw. Thus,through this gear train,leading from the spindle to the quick-change gearbox,thence to the lead screw and feed rod,and then to the carriage,the cutting tool can be made to move a specific distance,either longitudinally or transversely,for each revolution of the spindle. A typical lathe provides,through the feed rod,forty-eight feeds ranging from 0.002 inch to0.118 inch per revolution of the spindle,and,through the lead screw,leads for cutting forty-eight different threads from 1.5 to 92perinch.On some older and some cheaper lathes,one or two gears in the gear train between the spindle and the change gear box must be changed in order to obtain a full range of threads and feeds.Milling is a basic machining process in which the surface is generated by the progressive formation and removal of chips of material from the workpiece as it is fed to a rotating cutter in a direction perpendicular to the axis of the cutter. .In some cases the workpiece is stationary and the cutter is fed to the work. In most instances a multiple-tooth cutter is used so that the metal removal rate is high,and frequently the desired surface is obtained in a single pass of the work.The tool used in milling is known as a milling cutter. It usually consists of a cylindrical body which rotates on its axis and contains equally spaced peripheral teeth that intermittently engage and cut the workpiece. In some cases the teeth extend part way across one or both ends of the cylinder. Because the milling principle provides rapid metal removal and can produce good surface finish,it is particularly well-suited for mass-production work,and excellent milling machines have been developed for this purpose. However,very accurate and versatile milling machines of a general-purpose nature also have been developed that are widely used in job-shop and tool and die work. A shop that is equipped with a milling machine and an engine lathe can machine almost any type of product of suitable size.Types of Milling Operations. Milling operations can be classified into two broad categories,each of which has several variations:1.In peripheral milling a surface is generated by teeth located in the periphery of the cutter body;the surface is parallel with the axis of rotation of the cutter. Both flat and formed surfaces can be produced by this method. The cross section of the resulting surface corresponds to the axial contour of the cutter. This procedure often is called slab milling.1. In face milling the generated flat surface is at right angles to the cutter axis and is the combined result of the actions of the portions of the teeth located on both the periphery and the with the face portions providing a finishing action.The basic concepts of peripheral and face milling are illustrated in Fig. Peripheral milling operations usually are performed on machines having horizontal spindles,whereas face milling is done on both horizontal-and vertical-spindle machines.Surface Generation in Milling. Surfaces can be generated in milling by two distinctly different methods depicted in Fig. Note that in up milling the cutter rotates against the direction of feed the workpiece,whereas in down milling the rotation is in the same direction as the feed .As shown in Fig., the method of chip formation is quite different in the two cases. In up milling the c hip is very thin at the beginning, where the tooth first contacts the work,and increases in thickness, be-coming a maximum where the tooth leaves the work. The cutter tends to push the work along and lift it upward from the table. This action tends to eliminate any effect of looseness in the feed screw and nut of the milling machine table and results in a smooth cut. However, the action also tends to loosen the work from the clamping device so that greater clamping forcers must be employed. In addition, the smoothness of the generated surface depends greatly on the sharpness of the cutting edges.In down milling,maximum chip thickness occurs close to the point at which the tooth contacts the work. Because the relative motion tends to pull the workpiece into the cutter,all possibility of looseness in the table feed screw must be eliminated if down milling is to be used. It should never be attempted on machines that are not designed for this type of milling. In as mush 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 consider able 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. 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. Profile-cutters 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 cam-relieved 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 straight-shank cutters are held in a chuck. Facing cutters usually are bolted to the end of a stub arbor.Types of Milling Cutters. Plain milling cutters are cylindrical or disk-shaped,having straight or helical teeth on the periphery. They are used for milling flat surfaces. This type of operation is called plain 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. Staggered-tooth 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 particularly effective in milling deep slots. Metal-slitting saws are thin,plain milling cutters,usually from 1/32 to 3/16 inch thick,which have their sides slightly“dished”to provide clearance and prevent binding. They usually have more teeth per inch of diameter than ordinary plain milling cutters and are used for milling deep,narrow slots and for cutting-off operations.汉译:车床和铣床车间里拥有一台车床和一台普通铣床就能加工出具有适合尺寸的各种产品。用于车外圆、端面和镗孔等加工的机床称作车床。车削很少在其他种类的机床上进行,因为其他机床都不能像车床那样方便地进行车削加工。由于车床除了用于车外圆外还能用于镗孔、车端面、钻孔和铰孔,车床的多功能性可以使工件在一次定位安装中完成多种加工。这就是在生产中普遍使用各种车床比其他种类的机床都要多的原因。两千多年前就已经有了车床。现代车床可以追溯到大约 1797年,那时亨利莫德斯利发明了一种具有丝杠的车床。这种车床可以控制工具的机械进给。这位聪明的英国人还发明了一种把主轴和丝杠相连接的变速装置,这样就可以切削螺纹。图中标出了车床的主要部件:床身、主轴箱组件、尾架组件、拖板组件、变速齿轮箱、丝杠和光杠。床身是车床的基础件。它通常是由经过充分正火或时效处理的灰铸铁或者球墨铸铁制成,它是一个坚固的刚性框架,所有其他主要部件都安装在床身上。通常在床身上面有内外两组平行的导轨。一些制造厂生产的四个条导轨都采用倒“V ”形,而另一些制造厂则将倒“ V ”形导轨和平面导轨相结合。由于其他的部件要安装在导轨上并(或)在导轨上移动,导轨要经过精密加工,以保证其装配精度。同样地,在操作中应该小心,以避免损伤导轨。导轨上的任何误差,常常会使整个机床的精度遭到破坏。大多数现代车床的导轨要进行表面淬火处理,以减小磨损和擦伤,具有更大的耐磨性。主轴箱安装在床身一端内导轨的固定位置上。它提供动力,使工件在各种速度下旋转。它基本上由一个安装在精密轴承中的空心主轴和一系列变速齿轮类似于卡车变速箱所组成,通过变速齿轮,主轴可以在许多种转速下旋转。大多数车床有 8-18种转速,一般按等比级数排列。在现代车床上只需扳动 2-4 个手柄,就能得到全部挡位的转速。目前发展的趋势是通过电气的或机械的装置进行无级变速。由于车床的精度在很大程度上取决于主轴,因此主轴的结构尺寸较大,通常安装在紧密配合的重型圆锥滚子轴承或球轴承中。主轴中有一个贯穿全长的通孔,长棒料可以通过该孔送料。主轴孔的大小是车床的一个重要尺寸,因为当工件必须通过主轴孔供料时,它确定了能够加工棒料毛坯的最大外径尺寸。主轴的内端从主轴箱中凸出,其上可以安装多种卡盘、花盘和挡块。而小型的车床常带有螺纹截面供安装卡盘之用。很多大车床使用偏心夹或键动圆锥轴头。这些附件组成了一个大直径的圆锥体,以保证对卡盘进行精确地装配,并且不用旋转这些笨重的附件就可以锁定或松开卡盘或花盘。主轴由电动机经 V 带或无声链装置提供动力。大多数现代车床都装有 5-15马力的电动机,为硬质合金和金属陶瓷合金刀具提供足够的动力,进行高速切削。尾座组件主要由三部分组成。底座与床身的内侧导轨配合,并可以在导轨上做纵向移动,底座上有一个可以使整个尾座组件夹紧在任意位置上的装置。尾座安装在底座上,可以沿键槽在底座上横向移动,使尾座与主轴箱中的主轴对中并为切削圆锥体提供方便。尾座组件的第三部分是尾座套筒,它是一个直径通常在2-3英寸之间的钢制空心圆柱轴。通过手轮和螺杆,尾座套筒可以在尾座体中纵向移入和移出几英寸。活动套筒的开口一端具有莫氏锥度,可以用于安装顶尖或诸如钻头之类的各种刀具。通常在活动套筒的外表面刻有几英寸长的刻度,以控制尾座的前后移动。锁定装置可以使套筒在所需要的位置上夹紧。拖板组件用于安装和移动切削工具。拖板是一个相对平滑的 H 形铸件,安装在床身外侧导轨上,并可在上面移动。大拖板上有横向导轨,使横向拖板可以安装在上面,并通过丝杠使其运动,丝杠由一个小手柄和刻度盘控制。横拖板可以带动刀具垂直于工件的旋转轴线切削。大多数车床的刀架安装在复式刀座上,刀座上有底座,底座安装在横拖板上,可绕垂直轴和上刀架转动。上刀架安装在底座上,可用手轮和刻度盘控制一个短丝杠使其前后移动。溜板箱装在大拖板前面,通过溜板箱内的机械装置可以手动和动力驱动大拖板以及动力驱动横拖板。通过转动溜板箱前的手轮,可以手动操作拖板沿床身移动。手轮的另一端与溜板箱背面的小齿轮连接,小齿轮与齿条啮合,齿条倒装在床身前上边缘的下面。利用光杠可以将动力传递给大拖板和横拖板。光杠上有一个几乎贯穿于整个光杠的键槽,光杠通过两个转向相反并用键连接的锥齿轮传递动力。通过溜板箱前的换向手柄可使啮合齿轮与其中的一个锥齿轮啮合,为大拖板提供“向前”或“向后”的动力。适当的离合器或者与齿条小齿轮连接或者与横拖板的螺杆连接,使拖板纵向移动或使横拖板横向移动。对于螺纹加工,丝杠提供了第二种纵向移动的方法。光杠通过摩擦离合器驱动拖板移动,离合器可能会产生打滑现象。而丝杠产生的运动是通过溜板箱与丝杠之间的直接机械连接来实现的,对开螺母可以实现这种连接。通过溜板箱前面的夹紧手柄可以使对开螺母紧紧包合丝杠。当对开螺母闭合时,可以沿丝杠直接驱动拖板,而不会出现打滑的可能性。现代车床有一个变速齿轮箱,齿轮箱的输入端由车床主轴通过合适的齿轮传动来驱动。齿轮箱的输出端与光杠和丝杠连接。主轴就是这样通过齿轮传动链驱动变速齿轮箱,再带动丝杠和光杠,然后带动拖板,刀具就可以按主轴的转数纵向地或横向地精确移动。一台典型的车床的主轴每旋转一圈,通过光杠可以获得从 0.002到 0.118英寸尺寸范围内的 48种进给量;而使用丝杠可以车削从 1.5到92牙 /英寸范围内的 48 种不同螺纹。一些老式的或价廉的车床为了能够得到所有的进给量和加工出所有螺纹,必须更换主轴和变速齿轮箱之间的齿轮系中的一个或两个齿轮。铣削是机械加工的一个基础方法。在这一加工过程中,当工件沿垂直于旋转刀具轴线方向进给时,在工件上形成并去除切屑从而逐渐地铣出表面。有时候,
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