1、 单位代码 学 号 分 类 号 密 级 毕业设计论文 卧式双面组合钻床前主轴箱设计 院（系）名 称： 工学院机械系 专 业 名 称： 机械设计制造及其自动化 学 生 姓 名： 陈 赛 指 导 教 师： 贾百合 年 月 日机械设计制造及自动化专业毕业设计（论文）译文0Drilling and Milling MachinesUpright drilling machines or drill presses are available in a variety of sizes and types, and are equipped with a sufficient range of apin
2、dle speeds and automatic feeds to fit the neds of most industries. Speed ranges on a typical machine are from 76 to 2025 rpm., with drill feed from 0.002 to 0.020 in.per revolution of the spindle.Radial drilling machines are used to drill workpieces that are too large or cumbersome to conveniently m
3、ove. The spindle with the speed and feed changing mechanism is mounted on the radial arm; by combining the movement of the radial arm around column and the movement of the spindle assembly along the arm, it is possible to align the spindle and the drill to any position within reach of the machine. F
4、or work that is too large to conveniently support on the base, the spindle assembly can be swung out over the floor and the workpiece set on the beside the machine. Plain radial drilling machines provide only for vertical movement of the spindle; universal machines allow the spindle to swivel about
5、an axis normal to the radial arm and the radial arm to rotate about a horizontal axis, thus permitting drilling at any angle.A multispindle drilling machine has one or more heads that drive the spindles through universal joints and telescoping splined shafts. All spindles are usually driven by the s
6、ame motor and fed simultaneously to drill the desired number of holes. In most machines each spindle is held in an adjustable plate so that it can be moved relative to the others. The area covered by adjacent spindles overlap so that the machine can be set to drill holes at any location within its r
7、ange.The milling operation involves metal removal with a rotating cutter. It includes removal of metal from the surface of a workspiece, enlarging holes, and form cutting, such as threads and gear teeth.Within an knee and column type of milling machine the column is the main supporting member for th
8、e other components, and includes the base containing the drive motor, the spindle, and the cutters. The cutter is mounted on an arbor held in the spindle, and supported on its outer extremity by a bearing in the overarm. The knee is held on the column in dovetail slots, the saddle is fastened to the
9、 knee in dovetail slots, and the table is attached to the saddle. Thus, the build-up the knee and column machine provides three motions relative to the cutter. A four motion may be provided by swiveling the table around a vertical axis provided on the saddle.机械设计制造及自动化专业毕业设计（论文）译文1Fixed-bed milling
10、machines are designed to provide more rigidity than the knee and column type. The table is mounted directly on the machine base, which provides the rigidity necessary for absorbing heavy cutting load, and allows only longitudinal motion to the table. Vertical motion is obtained by moving the entire
11、cutting head.Tracer milling is characterized by coordinated or synchronized movements of either the paths of the cutter and tracing elements, or the paths of the workpiece and model. In a typical tracer mill the tracing finger follow the shape of the master pattern, and the cutter heads duplicate th
12、e tracer motion.The following are general design considerations for milling:1. Wherever possible, the part should be designed so that a maximum number of surfaces can be milled from one setting.2. Design for the use of multiple cutters to mill several surfaces simultaneously.3. The largest flat surf
13、ace will be milled first, so that all dimensions are best referred to such surface.4. Square inside corners are not possible, since the cutter rotates.Grinding Machines and Special Metal-removal ProcessRandom point-cutting tools include abrasives in the shape of a wheel, bonded to a belt, a stick, o
14、r simply suspended in liquid. The grinding process is of extreme importance in production work for several reasons.1.It is most common method for cutting hardened tool steel or other heat-treated steel. Parts are first machined in the un-heat-treated condition, and then ground to the desired dimensi
15、ons and surface finish.2.It can provide surface finish to 0.5m without extreme cost.3.The grinding operation can assure accurate dimensions in a relatively short time, since machines are built to provide motions in increments of ten-thousandths of an inch, instead of thousandths as is common in othe
16、r machines. 4.Extremely small and thin parts can be finished by this method, since light pressure is used and the tendency for the part to deflect away from the cutter is minimized.On a cylindrical grinding machine the grinding wheel rotates between 5500 and 6500 rpm., while the work rotates between
17、 60 and 125 rpm. The depth of cut is controlled by moving the wheel head, which includes both the wheel and its drive motor. Coolants are provided to reduce heat distortion and to remove chips and abrasive dust.机械设计制造及自动化专业毕业设计（论文）译文2Material removal from ductile materials can be accomplished by usi
18、ng a tool which is harder than the workpiece. However during Word War the widespread use of materials which were as hard or harder than cutting tools created a demand for new material-removal methods. Since then a number of processes have been developed which, although relatively slow and costly, ca
19、n effectively remove excess material in a precise and repeatable fashion. There are two types of processes. The first type is based on electrical phenomena and is used primarily for hard materials; the second depends upon chemical dissolution. Chemical milling is controlled etching process using str
20、ong alkaline or acid etchants. Aluminum, titanium, magnesium, and steel are the principal metals processed by this method. The area to remain untouched by the etchant are masked with a protective coating. For example, the entire part may be dipped in the masking material and the mask removed from th
21、ose areas to be etched, or a chemically resistant prescribed time, after which the part is rinsed in cold water, the masking removed, the part inspected, and thoroughly cleaned.There are certain disadvantages to consider. Metal will erode equally in all directions, so that walls of the etched sectio
22、n will have a radius equal to the depth of etch. A second disadvantage is that a better finish is obtained on surfaces parallel to the direction of rolling of a sheet than on surface perpendicular to the direction of rolling. This can be compared to the surface obtained when working wood parallel to
23、, or across the grain. A third disadvantage, not unique with this process, is the warpage that will occur in thin, previously stressed sections etched on just one side.Chemical milling, however, has many advantages over conventional metal-removal methods. There is no warpage of heavy sections such a
24、s forgings or extrusions when the etchant is applied simultaneously to all sides for reduction of section thickness. In conventional milling only one side can be worked at a time, and frequent turning of a part is necessary to prevent warpage. Chemical milling can be applied to parts of irregular sh
25、ape where conventional milling may be very difficult. Light-weight construction can be obtained with chemical milling by the elimination of welding, riveting, and stiffeners; parts can be contoured to distribute the load in the most suitable manner. As an example of the potential savings of this pro
26、cess, as compared to machine milling, one company reports that the cost of removing aluminum by chem.-milling is $0.27 per pound as compared to $1.00 per pound by conventional milling. The rate of metal removal for chem.-milling is 0.001in. for aluminum.机械设计制造及自动化专业毕业设计（论文）译文3Electric-discharge mach
27、ining is a process in which an electrical potential is impressed between the workpiece and the tool, and the current, emanating from a point source on the workpoiece, flows to the tool in the form of a spark. The forces that accomplish the metal removal are within the workpiece proper and, as a resu
28、lt, it is not necessary to construct the unit to withstand the heavy pressures and loads prevalent with conventional machining methods.The frequency of the electrical discharge ranges from 20,00 cps (cycles per second) for rough machining, to 50,000 cps for finishing such items as hardened tools and
29、 dies. The current may vary from 50 amp, during rough machining, to as low as 0.5 amp, during finishing. The process is currently applied to the machining of single-point tools, form tools, milling cutters, broaches, and die cavities. It is also applicable to the removal of broken drills, taps, and
30、studs without damaging the workpiece in which the broken tool is imbedded. Other uses are the machining of oil holes in a hardened part, and the machining of small safety-wire holes in the heads of special alloy bolts, such as titanium.The ultrasonic machining process is applied to both conducting a
31、nd non-conducting material, and relies entirely upon abrasive action for metal removal. The workpiece is submerged in slurry of finely fivided abrasive particles in a vehicle such as water. The tool is coupled to an oscillator and vibrates at frequencies between 15,000 and 30,000 cps. The vibrating
32、tool cavitates the liquid, and the force drives the abrasive into the surface of the workpiece to remove metal chips which are carried away by the liquid. The acceleration given the abrasive grains is as much as 100,000 times the acceleration of gravity, providing a smooth and rapid cutting force.In
33、troduction of MachiningMachining as a shape-producing method is the most universally used and the most important of all manufacturing processes. Machining is a shape-producing process in which a power-driven device causes material to be removed in chip form. Most machining is done with equipment tha
34、t supports both the work piece and cutting tool although in some cases portable equipment is used with unsupported workpiece. Low setup cost for small quantities. Machining has tow applications in manufacturing. For casting, forging, and pressworking, each specific shape to be p5roduced, even one pa
35、rt, nearly always has a high tooling cost. The shapes that may be produced, even one part, nearly always has a high tooling cost. The shapes that may be produced by welding depend to a large degree on the shapes of raw material that are available. By making use of generally high cost equipment but w
36、ithout special 机械设计制造及自动化专业毕业设计（论文）译文4tooling, it is possible, bu machining, to start with nearly any form of any material, so long as the exterior dimensions are great enough, and produce any desired shape from any material. Therefore, machining is usually the preferred method for producing one or
37、a few parts, even when the design of the part would logically lead to casting, forging or pressworking if a high quantity were to be produced.Close accuracies, good finishes. The second application for machining is based on the high accuracies and surface finishes possible. Many of the parts machine
38、d in low quantities would be produced with lower but acceptable tolerances if produced in high quantities by some other process. On the other hand, many pars are given shapes by some high quantity deformation process and machined only on selected surfaces where high accuracies are needed. Internal t
39、hreads, for example, are seldom produced by any means other than machining and small holes in pressworked parts may be machined following the pressworking operations.机械设计制造及自动化专业毕业设计（论文）译文5钻床和铣削直式钻床或钻孔式印刷机可用于各种尺寸和种类，它能安装轴速度的足够范围和自动运转以适应大多工业的要求。一个典型机器的速度范围是 70 至2025rmp，以及钻孔的运转速度是 0.002 到 0.020 英尺。旋转钻
40、床用来钻那些太大或太笨重的而不能够移动的工件。通过将转臂绕立柱的转动和主轴组件沿转臂的移动组合，可使主轴钻头对准机床可达范围内的任何位置，由于运转太大而不方便建立在此基础上，主轴能够在垂直的地上方摇摆以及工件能固定在机器旁边的地上。普通的旋臂钻床只提供轴的垂直运动和径向转臂，通过平行轴来运转。因此允许钻头处于任何一个角度。一个多轴通过万能连接和可伸缩的花键轴来驱动的钻床有一个或多个头。通常所有的轴都是通过相同的发动机来驱动和同时运转，目的是钻出理想中洞的数量。很多钻床的每个轴容纳在一个可调整的盘里，以便与其他相关的部件移动。相邻的轴重叠部分的覆盖区域目的促使机器能够在它的范围的任何地方开始钻孔
41、。铣床操作与转动的切削金属和移动相关。它包括了一个工件的表面金属移动，洞的扩大和成型切削，比如线和齿轮。铣销机床的升降台式柱是其他部件的主要支持部分。包括了容量驱动机的基础，心轴切割工具。切割工具固定在容纳在主轴的刀杆上能过一个悬臂的轴承支撑在它的外部的末端。升降台通过燕尾槽滑动支撑立柱和立柱机器，提供一三种与切割工具相关的意向。另一种意向可能是工作台由提供的滑板围绕着轴旋转而得到的。固定的铣销机床的设计目的是比升降台或立柱提供更大的刚度。工作台直接固定在机窗的根部，它能为强大切割负荷提供强度的需要。而且允许对工作台径度的方向。垂直运动是通过移动整个切割工具才能达到。仿型铣床的特点是刀具和跟踪
42、元件的轨道运动的协调或同步，或者是工件或模型的轨迹运动的协调或同步典型的仿型铣床的仿型号像是遵照模型的形式，而且切割机头部分与仿行部分相同。下面是铣削的总体的设计目录：1. 如果可能的话，零件将被设计以便在一个工位上最大的平面能被铣削。2. 对选择性的切割工具的设计目的是同时铣削几个平面。3. 应当首先铣最大的平面，这样所有的尺寸都能很好的参照这个表面。4. 因为切割工具的转动，仿形里的各个角落是不可能的。刺耳的机器和特殊的金属移动程序随机点切削刀具包括构成轮子形状的，或粘结到带子或棍子上或直接悬浮在液体中的研磨材料。因为几个原因研磨进程在工件的生产中很重要。机械设计制造及自动化专业毕业设计（
43、论文）译文61. 对切削硬化的刀具钢材料或其他的热处理钢材来讲它是最普通的方法。零件在没有热处理条件下第一次机器切割，然后得到理想的尺度和表面光洁度。2. 它能在没有极限范畴时提供表面光洁度达 0.5 微米。3. 研磨操作在相对较短的时间内能确保精确的尺度，因为机器在作为其它机器的一般精度构造时提供的动态是每英尺增加了百分之一的精度，而不是千分之一。4. 尤其是小而细的零件能用这个方法完成，由于轻压力被使用和零件的柔韧性所折射出的切削值是最小的。研磨轮子在圆柱形的研磨机器上在 5500 和 6500rmp 之间转动，当工件在60 和 125rmp 之间转动时，切削的深度运动由木头控制，它包括了
44、轮子和它的驱动发动机。冷却液用来降低热扭曲和移动切削以及研磨材料时的灰尘。有韧性的材料的运动通过那些材质硬的刀具来完成，但是在二战期间材料的广泛传播使用，它比新材料运动方法的切削刀具的要求更高。因为大量的过程被改进，尽管相当慢且花费高，它能用精确接受的方式来移动过量的材料，这里有两种进程模式：第一种类型是建立在电子现象的基础上，它用于基本的原材料；第二种取决于化学溶解。化学物质的铣削用于控制那些用了很浓的碱性或酸性的腐蚀剂腐蚀进程。铝、钛、镁和钢是通过这种方式的主要原料进程。化学铣削开始于一个零件的传统的光洁，包括脱脂、脱酸和烘干，这个领域用以维持不与那些笼罩在制服外面的腐蚀剂接触。可以将整个
45、零件侵入遮盖材料，然后将遮盖层从将要被侵蚀的区域去除；也可以使用抗化学侵蚀的粘接带遮盖要保护的区域，遮盖之后要侵蚀一般指定的时间，然后要将零件在冷水中清洗，将遮盖层去除，检查零件，并彻底全面的清洗。还应该考虑到的缺点：第一缺点是金属在各个方面都是平等的侵蚀，以至于侵蚀的外部半径和侵蚀的深度相等；第二个缺点是在平行于钢板的方向上所得光洁度要比垂直于木纹的方向上工作所得的表面相比较；第三个缺点不是过程的唯一，而是发生在细的只腐蚀一边的压力段上的翘曲。而化学铣削在传统的金属移动方发中有很多的优点。这在很多部件没有翘曲例如当腐蚀被用来降低纵切面厚度的各个面上时的锻造和挤压，传统的铣削里一次只用一面来运
46、转，而且零件的频繁转变是阻止翘曲所必要的。化学铣削能用于不规则的部件，而那是传统铣削很难做到的。轻易的建筑物可通过焊接的清除，铆接和加强筋与铣削而获得零件可以被定形通过以适当的方式分配负荷和潜在的节省过程的例子一样，与机器切割铣床相比。一个文件报道了有关化学铣削移动铝的成本，是 0.27 美元每英镑，而传统铣削则是 1.00 美元每英镑。所以铣削铝金属移动的比率是 0.001 英尺每分钟。电子排放机器是一个电压作用于工件和刀具之间的过程，电流从金属工件的源头流出，以火花的形式流向刀具。完成金属移动的力量是金属工件本身。结果，对一般的传统机械手段而言，没有必要建设一个单元来抵制重压和重负荷。由于
47、排放器的范围大约从 2000cps 至 5000cps 用来精加工如此硬的刀具和模具。电流在粗加工期间是不断变化的。从 50amp 低到精加工期间的 0.5amp，机械设计制造及自动化专业毕业设计（论文）译文7这个过程应用了机械的单点刀具，成形刀具，铣削切割刀具，拉刀以及模具涡凹。它也能移动坏了的钻头，而丝锥和螺栓不损坏嵌入的工件。其他的使用方法是一个硬部件的油洞，小安全电线洞的机械是由大量特殊合金制造的，如钛。超声机械程序用于导体和半导体，而且完全依靠于金属移动的研磨行为，工件淹没在液下分数的研磨微粒如水。刀具连接着震荡器以及在 15000 至3000cps 之间频繁的震动，震动的刀具抽空液
48、体，冲力研磨材料进入工件的表面用来移动金属切削。它们能随着液体流动。研磨的纹密加速度是重力的 100000倍，以提供一个光滑而快速的切削冲力。关于机械加工作为一种成形方式的机械加工是广泛使用的也是所有机械制造进程中的最重要的部分。机械加工是通过切削形式使驱动装置引起材料运动产生形状的过程。尽管在某些场合，工作支持情况下，使用移动式装备实现加工，但是大多数的机械加工还是通过既支撑工件有支撑刀具的装备来完成。小批量生产低费用，机械加工在制造方面有两种用途：对浇筑，锻造，压力加工，即将生产的每个具体形状，甚至一个零件而言，几乎是一个高标准的刀具铸型。这些通过焊接可能产生的形状在很大程度上取决可利用的
49、原材料的形状。一般说来，通过利用高价设备而又无需特种加工条件下，几乎可以从任何种类原材料开始，借助机械加工把原材料加工成任意要求的结构形状，只要外部尺寸够大，那都是可能的。因此，机械加工是常用来生产少量零件，甚至在大量生产以及当零件的设计在逻辑上导致浇铸、锻造，压力加工的时候所推荐的方法。严密的精度，合适的平面粗糙度，对机械加工的第二个应用是建立在可行性的高精度和高表面粗糙度之上。很多用机械切割的少量部件会产生较小且能够接受的偏差是否能够通过其他的工艺流程生产大量的部件。另一方面，很多部件通过一些大量的变形过程和由机械切割所需要的高精度选择平面有了他们的一般形状，例如：内部的螺纹很少能通过其他的方式生产，除了机械加工和压力加工部件的小洞可能被机器切割成的压力加工过的操作。
