I receive many questions on how to improve high-speed progressive die hits per service, otherwise known as tooling life. How can I get more parts per service? How can I run tooling longer? Faster?
The most immediate answer is to add a coating to your tools. But first, you have to make sure your stamping process is predictable and repeatable with perfect part quality, and that starts with a robust tool design.
Fix Tool Design First
If your tool design is lacking, investing in coatings will be throwing good money after bad. Here are the most common design shortcomings I have seen:
- Die shoes that are too thin and sitting over a large opening in the bolster without proper support. They flex during stamping, which not only affects part quality by causing increased dimensional variation but also causes the cutting edges on the tooling to break down faster because of increased vibration.
- Guide pins and ball cages that are too small for the application. Again, they will flex, causing vibration during cutting and forming, which will lead to premature degradation.
- Poor, spotty, and inconsistent lubrication of the base material during stamping. I have seen felt pads with clothespins holding them in place and oil being dripped only on the top of the strip, leading to inconsistent lube spread. Your strip must be evenly coated top and bottom with just the right amount of lube. Too much can be as bad as too little.
- Designs that do not include proper slug retention, part ejection, and sensors to prevent tool damage. I would confidently state that more than half of stampers’ inefficiency and maintenance expenses are due to these issues.
Once you achieve a consistent and predictable stamping process—your tooling service life is repeatable to +/-10%—you can take service life to the next level with tooling coatings. If your tooling service life repeatability is a higher number historically, you need to figure out what is going on. If you get 100,000 hits per service today and only 50,000 hits per service tomorrow, tool coatings will not help you.