How long will a die last?
A common question for new customers to stamping is how long will a tool last? The short answer is “a lot”. The more exact answer is, unfortunately, a lot more complicated.
While it would be great if we could know exactly how many parts can be made on a tool it is nearly impossible. There are several factors that determine the life of a tool, including the material type and thickness, forming functions within the die set, maintenance, and general operation of the tooling.
The greatest factor itself is determining what function the tooling is performing. Some operations are much tougher on the tooling, (cutting, punching, etc) than others (weld impressions, bending). Most tools are performing many operations at once, punching holes, bending edges, shearing sides, lancing tabs, etc.
For standard maintenance, the punches and die will be sharpened using a surface grinder. Tooling is sharpened by removing a very thin layer of material from each surface to bring the edges back to square (and sharp). Assuming there is no damage to any of the cutting surfaces, a typical sharpening will remove anywhere from 0.001″ to 0.005″ or more. If the die section has 0.500″ of cutting surface available prior to relief, then you could reasonably assume you would get 100 to 500 sharpenings with that particular tooling. If you can run 40,000 parts per sharpening, then you’d get 4,000,000 to 20,000,000 parts out of a tool. This is assuming no damage where more has to be removed to make it sharp again.
Usually, the tooling can be replaced without starting over. Today’s die makers utilize wire EDM for making complex shapes quickly, and this also gives them the power to make custom inserts in a tooling or reconstruct punches with extreme accuracy. Where new tooling may cost tens of thousands of dollars, a replacement section or punch may only be in the hundreds or thousands, significantly reducing the cost or eliminating a complete “re-tooling” of a part.