Selection principle of positive die structure in precision metal stamping dies

Whether the structure of the cold stamping die design is reasonable or not plays a key role in the success of the production of precision hardware. Even a group of simple die parts consists of dozens of types, so their precision cannot be underestimated when designing.

At the beginning of the design,

1. what kind of mold structure should be selected?
2. Is it a front mold structure (ie, the female mold is installed on the lower mold base)?
3. Or is it an inverted (reverse) mold structure (ie, the punch installed on the lower mold base)?
4. Or choose Single process mold construction? Or should I opt for composite mold construction?

This is a topic well worth in-depth discussion before each of our molders, and this is a great article.

When to choose a positive mold structure

Structural characteristics of front loading mold

The structural feature of the front mold is that the concave mold is installed on the lower mold base. As a result, workpieces or scrap can easily fall into the scrap holes on the punch table, whether for workpiece drop, punching, or other processes.

Therefore, the flow of workpiece or scrap does not have to be considered when designing the master mold. This results in a very simple and practical tool structure.

The advantages of positive assembly mold structure

1. (1) Due to the simple structure of the mold, the mold manufacturing cycle can be shortened, which is conducive to the development of new products.
2. (2) It is more convenient to use and maintain.
3. (3) It is easier to install and adjust the gap of the convex and concave die (compared with the reverse die).
4. (4) The mold manufacturing cost is low, which is conducive to improving the economic benefits of the enterprise.
5. (5) Since the crimping force always exists throughout the stretching process, it is suitable for stretching non-rotating body parts.

Disadvantages of positive mold structure

• (1) Due to the accumulation of workpieces or scraps in the die hole, the group lift force in the die hole increases. Therefore, the concave surface must increase the wall thickness to increase its strength.
• (2) Since the workpiece or waste is accumulated in the die hole, the die edge must be machined with the drop slope, and in some cases, the reverse hole (discharge hole) of the die edge must be machined, which prolongs the cycle time of the die And increase the processing cost of the mold.

Selection principle of positive die structure

In summary, we can see that the design principle we should follow when designing stamping dies is to give priority to the positive die structure. Only when the technical requirements of the workpiece can be met under the front-loading mold structure, other forms of mold structure can be considered.