钻模与夹具外文文献翻译、中英文翻译

1、JIGS AND FIXTURESINTRLDUCTIONIt has already been stated that the workpiece must be located relative to the cutting tool , and be secured in that position .After the workpiece has been markec out ,it is still necessary to position it with respect to the machine morement,and to clamp it in that posito

2、n before machining is started.When several identical sorkpieces are to prlduced the need to mark out each part is eliminatde by the use of jigs and fixtures,but if a casting or forging is involved ,a trial oorkpiece is markec out ,to ensure that the workpiece can be produced from it ,and to ensure t

3、hat ribs, cores, etc. have not become misplaced.Jigs amd fixtures are alike in that they both incorporate devices to ensure that the workpiece is correctly bocated amd clamped, but they differ in that jigs incorpoorate means of tool guiding during the actual cutting operationj, and fixture do not .

4、In practice, the only cutting tools that can be guided while actually cutting are drills, reamers, and similar cutters; and to figs are associated with drilling operations, and fixtures with all other operations. Fixtures may incorporate means of setting the cutting tools relative to the location sy

5、stem.The advantage of jigs and fixtures can be summarized as follows:1) marking out and other measuring and setting out methods are eliminated;2) unskilled worked may proceed confidently and quickly in the knowledge that the workpiece can be positionde correctly, and the tools guided or set;3) The a

6、ssembly of parts is facilitated,since all components will be identical within small limits , and reyingand filling of work is eliminated;4) the parts will be intrechangeable ,and if the product is sold over a wide area, the problem of spare parts will be simplified;Bolt holes often have 1.5mm of eve

7、n 3.0mm clearance for the bolt , and the reader may doubt the necessity of making precision jigs for such work. It must be rememgered that the jigs, once made, will be used on many components, and the estra cost of an accurately made jig is spread orer a large output, Furthermore,it is surprising ho

8、w small errors accumulate in s mechanism during its assembly, When a clearance is specified, it is beteer to ensure its observance, rather than to allow careless marking our and machining to encroach upon it.1) The location of workpeece.Fig,10.1 represents a body that is completely freeing space, in

9、 this condition it has six degrees of freedon. Consider these freedons with respect to the three mutually perpendicular axes XX, YY, and ZZ. The body can move along any of these axes; it therefore has three freedoms of translation. It can also rotate about any of the three axes; it bherefore has thr

10、ee freedoms of rotation. The total number of freedoms is six. When work is located, as many of these freedoms as possible must be eliminated ,to ensure that the operation is performed with the required accuracy. Accuracy is ensured by machining suitable location features as early as possible, and us

11、ing them for all location unless other considerations mean that other location features must be used. If it is necessary, the new location features must be machined as a result of lication from the former location features.2）The clampoing of the workpiece, The clamping system must be such that the w

12、orkpiece is held against the cutting forces, and the clamping forces must not be so great as to cause the workpiece to become distorted or damaged. The workpiece must be supported beneath the point of clamping, to ensure that the forces are taken by the main frame of the fig or fixture, and on to th

13、e machine table andbed. When jigs and fixtures are designed, the claming system is designed to ensure that the correct clamping force is applied, and that the clamps can be oprated quickly but with asfety.DEFINTION OF A DRILL JIG A drill jig is a device for ensuring that a hole to be drilled, tapped

14、, or reamed in a workpiece will be machined in the proper place, Basically it consists of clamping device to hold the part in position under hardened-steel bushings through which the drill passes during the drilling operation、The drill is guided by the bushings. If the workpiece is held by the jig,

15、and the jig is arranged so that the workpiece can be quickly inserted and as quickly removed after the machining ooperation is performed.Jigs make it possible to drill, ream, and tap holes at much greater speeds and with greater accuracy than when the boles are produced by conventional hand methods.

16、 Another advantage is that skilled workers are not required when jigs are used. Responsibility for the accturacy of hole location is taken from the operator and given to the jig The term jig should be used only for devices employed while drilling, reaming, tapping holes, It is not fastened to machin

17、e on which it is used and my be moved around on the table of the drilling machine to bring each bushing directly under the drill. Jigs physically limit and control the path of the cutting tool.If the operation includes machining operations like millling, planning, shaping, turning, etc.the term fixt

18、ure should be used, A fixture holds the work during machining operations but dses not contain special arrangements for guiding the cutting tool, as drill figs do.TYPICAL JIGS AND FIXTRRESTypical drill jig, Figure 10.2 illustrates a drilling jig for drilling jig for drilling four holes in the flange

19、of a workpiece that has been completed escept for the four holes. The workpiece has an accurately machined bore, and is located form the bore and the end face, from a cylindrical post. There is no need to control the rotational position bout the axis of the bore, because up to the tine when the hole

20、s are drilled, it is symmetrical about that axis The four bushes used to control the drill are held in the drill plate, which, with the hand nut, is used to clamp the workpiece against the base of the fixture, Typical milling fixture, figure 10.3 illustrates a simple milling fixture for milling the

21、slot in the otherwise completed workpiece shown, The workpiece is located from two lf the four hole in its base, and from the underside of the base, The workpiece is clamped in position, and cutter is located against the setting block, which provides setting or cutter position and depth of cut. The

22、fixture must be positioned relative to the machine table, this is done by engaging the two tenons at be bottom of the foxture in the slot in the machine table. The fixture is secured to the machine table with T-bolts. Also engaging in the slots in the table.中文翻译：钻模与夹具介绍工件必须位于相对于刀具安全的位置上。然后在工件上必须划线，移

23、动到需要加工的位置上，并且在加工前夹紧在这个位置。当许多特殊的工件进行加工前，需要通过钻模和夹具对每部分进行划线，但如果是铸件，为了保证工件能被加工出来，必须对工件做出划线，以保证加强肋、型芯不发生变形或错位。钻模和夹具要结合起来才能保证工件正确的定位和夹紧。钻模是意味着加工过程中刀轨不同，夹具就不是这样。在实际中，只是刀具是钻头，绞刀和类似刀具才能进行导向。因此，钻模用于钻加工，夹具用于所有其它加工操作中。夹具用于刀具装置相对于定位的结合。钻模和夹具的优点能分成以下几方面：a) 减少和消除了一些测量和安装的工序。b) 非专业人员也可以准确快速的掌握刀具安装。c) 装配部分的工件更加方便，所有工件也很少拆装。d) 零件将实现互换，如果工件是固定在一个领域的话，零件将实现单一化。螺栓孔经常有1.5mm到3mm的均匀螺距，读者可能会怀疑用钻模加工它的精确性。必须记住钻模是一次制造而成，用于许多元件精确制造钻模的费用是额外大的，此外，令人惊奇的是小小的错误聚焦在它装配的时候。粗心的划线和机器碰它。1） 工件位置。表明了物体在空间的自由度，有三个自由度分别是XX、YY、ZZ物体能够沿着这些轴进行轴向移动；还有三个自由度是角度方向的。它们可以绕坐标轴转动。自由度的个数是六个。当工作固定后，它的自由度可能被消除，以保证工件正确操作的需要。要尽可能的