WHAT IS METAL DIE STAMPING?
In the 15th century, Gabriel Biel said: “Pro tali numismate tales merces”
Translation? “You get what you pay for.”
The application of this maxim to the Metal Stamping business is this. Die designers need to have a clear understanding of the intended end use application as a critical aspect of tool design. Die design should not be a reflection of the limitations of the designer or the shop.
This helps to explain why there can be such wide variances in die costs and die performance.
Progressive Metal Die Stamping is a demanding method of working with metal that can encompass not just “stamping”, but punching, bending and several other ways of modifying various types and grades of metal raw material, combined with an automatic feeding system.
The progressive die is placed into a reciprocating stamping press. As the press moves up, the top die moves with it, which allows the material to feed. When the press moves down, the die closes and performs the stamping operation. With each stroke of the press, a completed part is removed from the die.
A feeding system pushes a strip of metal as it unrolls from a coil through all of the stations of a progressive stamping die. Each station performs one or more operations until a finished part is made. Additional work is done in each “station” of the die. The strip must be advanced very precisely so that it aligns within a few thousandths of an inch as it moves from station to station. Bullet shaped or conical “pilots” enter previously pierced round holes in the strip to assure this alignment since the feeding mechanism usually cannot provide the necessary precision in feed length.
The final station is a cutoff operation, which separates the finished part from the carrying web. The carrying web, along with metal that is punched away in previous operations are knocked down (or out of the dies) and then ejected from the die set. In mass production this scrap material is often transferred to scrap bins to be recycled.
The dies are made of tool steel to withstand the high shock loading involved, retain the necessary sharp cutting edge, and resist any abrasion forces involved.
The number of features determines what tooling will need to be used, which in turn determines the cost.
- Many companies advise keeping features as simple as possible to keep the cost of tooling to a minimum.
- This is not a practical approach as the part needed may have features that are close together
However, this is a problem for some die makers and stamping companies because it may not provide what they feel is enough clearance for the punch, which could result in another station. It can also be problematic to have narrow cuts and protrusions.
There are ways around such “problematic” situations that require the most exacting design of the die itself.
- ‘A master die maker “sees” the potential problem, but can also “see and think” about how to resolve it through masterful design to produce a part that meets the need’.
- Only time, training and experience in the designing of dies can supply this critical “forward thinking” necessary for a tool to be designed that is exact and meet the need
Die designers need to have a clear understanding of the intended end use application as a critical aspect of tool design. The design should not be a reflection of the limitations of the designer or the shop.
Bahrs Die & Stamping has been producing quality custom tooling and metal stampings for over 70 years. It is our goal to supply the finest quality tooling and metal stampings to at very competitive prices without sacrificing critical aspects of tool design and function. We design, build and maintain our own tooling and fixtures in house giving us control over all aspects of the manufacturing process.
- “You can’t make great parts without a great designer”
Our designers have over 60 years of experience custom designing stamping dies for a wide variety of complex applications.