《外文翻译--提高级进模性能.doc》由会员分享，可在线阅读，更多相关《外文翻译--提高级进模性能.doc（11页珍藏版）》请在金锄头文库上搜索。
1、英文原文 Improving Performance of Progressive DiesProgressive die stamping is a cost-effective and safe method of producing components. Careful design and construction of dies will ensure optimum performance.A progressive die performs a series of fundamental sheet metal operations at two or more station
2、s in the die during each press stroke. These simultaneous operations produce a part from a strip of material that moves through the die. Each working station performs one or more die operations, but the strip must move from the first station through each succeeding station to produce a complete part
3、. Carriers, consisting of one or more strips of material left between the parts, provide movement of the parts from one die station to the next. These carrier strips are separated from the parts in the last die station.There are six elements that should be addressed when designing and building a pro
4、gressive die to maximize its performance: Interpreting the part print, Starting material into the die, Part lifters and part feeding, Flexible part carriers, Upper pressure pads, and Drawn shells.Interpreting the Part PrintThe first step in the proper design of a progressive die is to correctly anal
5、yze the part print. The tool designer must interpret the print to determine the function of the part by looking for such things as the type of material, critical surfaces, hole size and location, burr location, grain direction requirements, surface finish and other factors.The die designer must unde
6、rstand the part well, particularly if it has irregular shapes and contours. However, modern computer-drawn prints make this more difficult because computer-drawn part data can be downloaded directly to the die-design computer. As a result, the designer may not become thoroughly familiar with importa
7、nt part features.Also, many computer-drawn parts are more difficult to understand, because often, only one surface is shown and it may be the inside or outside surface. Computer drawings often show all lines, including hidden features, as solid lines instead of dotted lines. This leads to interpreta
8、tion errors, which in turn leads to errors in the building of the die.To better understand complex part shapes, it is helpful to build a sight model of the part using sheet wax, rubber skins or wood models. Dimensional accuracy is not critical for these models, as they are used primarily to visualiz
9、e the part. Rubber skins and sheet wax also can be used to develop preform shapes and to develop the best positions for the part as it passes through each die operation in the progressive die.Starting Material in the DieCare must be taken to ensure that the strip is started correctly into the die. I
10、mproper location of the lead end of the strip will do more damage to the die in the first 10 strokes of the press than the next 100,000 strokes. Lead-in gauges must have large leads and a ledge to support the lead end of the coil strip when it is inserted into the die. Large leads on the gauges are
11、important so that the die setup person does not have to reach into the die, as well as for minimizing the time required to start a new strip into the die. Also, one gauge should be adjustable to compensate for variation in strip width,.The position of the lead edge of the strip is critical for the f
12、irst press stroke, and must be determined for every die station to ensure that piercing punches do not cut partial holes in the lead edge. This could cause punch deflection or result in a partial cut with trimming punches, which can result in an unbalanced side load as the strip passes through the d
13、ie. Any of these conditions can result in a shift of the punch-to-die relationship that may cause shearing of the punches.Improper location of the lead edge of the strip also can result in an unbalanced forming or flanging condition that can shift the upper die in relation to the lower die. Heels sh
14、ould be required to absorb this side load, particularly when forming thick materials.A pitch notch and pitch stop can provide a physical point to locate and control the lead edge of the strip. Brass tags or marker grooves also can provide a visual location, but these are not as accurate or as effect
15、ive as a pitch notch stop. The press can be prevented from operating with either a short feed or over feed by mounting the pitch stop on a pivot and monitoring it with a limit switch.Part Lifters and Part FeedingProgressive dies often require the strip to be lifted from the normal die work level to
16、the feed level before strip feeding takes place. This can vary from a small amount-to clear trim and punching burrs-to several inches to allow part shapes to clear the die.Normally, all lifters should rise to the same height so that the strip is supported in a level plane during forward feed. The strip must not sag between lifters; otherwise parts will be pulled out of their correct station location spacing. Bar lifters provide
