Explain design procedure of progressive dies.
Answers
This part was rotated in the strip to increase the consistency in critical tolerances.
The decision to produce a part progressively is usually determined by two factors: the volume of production and the complexity of the part. These two factors are instrumental in the design and construction of the tooling. It is important to address all factors that will contribute to the desired level of part quality, tool maintenance, and tooling life. Trade-offs will be necessary to reach most decisions, and all will affect tooling costs.
Part Orientation
The process begins with determining how the part will be run through the die. This is governed by the features of the part and the locations of the datums and critical tolerances. Then, the trade-offs begin.
Optimizing material usage may require rotating the part in the strip, which changes the grain direction of the steel in the part and thus can affect the strength of any forms in the part. Forming with the grain can cause cracking and fatiguing of the metal and make holding consistent form angles more difficult. Therefore, the form will be far more susceptible to problems associated with the chemical makeup of each coil that is run.
For example, Figure 1 shows a part for the computer industry that was rotated in the strip to guard against inconsistent form angles that could be caused by differences between coils. The part contained critical dimensions with 0.025-millimeter tolerances dependent on the forms. Rotating the strip to ensure more consistent forms was not the most efficient use of material. In this case, however, part tolerances won out over optimizing material usage.