Thomas Vacca

Director of Tooling and Design Engineering
Micro Stamping Corp.
Has a shop floor stamping or tool and die question stumped you? If so, send your questions to kateb@thefabricator.com to be answered by Thomas Vacca, director of tooling and design engineering at Micro Stamping Corp.

Ask the Stamping Expert: How can I form titanium successfully?

April 15, 2016

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Q: We are getting more and more inquiries for components made of titanium. We have never worked with this material. Any advice? A: Titanium can be cold- or hot-formed on standard equipment using techniques similar to those used on stainless steels, but you need to consider two main issues: The...

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Ask the Stamping Expert: How can we achieve fast punch changeout halfway through a run?

April 1, 2016

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Q: I’m a diemaker for a Detroit Three automaker. We have a job on which we have to change punches halfway through the run. Changing the punches is a lengthy operation and involves quite a bit of downtime. Does anyone in the industry make an automatic or semiautomatic punch removal system that we...

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Ask the Stamping Expert: Can I pierce material in a progressive die in the opposite direction?

March 31, 2016

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Q: Do you have much experience with piercing material in the opposite direction than usual in a progressive die? In other words, the slug goes through the punch shoe. A: Yes. This is very doable and not uncommon. I assume you need to do this because the piercing direction is a part-functional...

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Ask the Stamping Expert: How do I hold washers in the strip in a compound die?

March 30, 2016

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Q: Do you have suggestions for holding washers in the strip in a compound die? High-strength, low-alloy material properties change from heat to heat, periodically causing parts to drop out of the strip. For this reason, we blank up and use a knockout bar to eject the parts. A: Two significant...

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Ask the Stamping Expert: What do the various press styles have to offer?

March 11, 2016

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Q: I am having a problem stamping a shallow drawn cup about 0.75 in. deep from 0.045-in. 304 half-hard stainless steel. I’m using a mechanical press. What do other press technologies have to offer? A: Years ago I wrote a brief on the major differences between mechanical and hydraulic presses....

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Ask the Stamping Expert: The 10 Tooling Laws explained

March 11, 2016

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Q: In your last column you listed the 10 Tooling Laws. I had never seen these before. Can you please explain each law in more detail? A: I drafted these laws years ago out of necessity. After more than 35 years of experience in the stamping field - - many as a master toolmaker, then as a...

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Ask the Stamping Expert: When is a WEDM purchase justifiable?

March 11, 2016

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A stamper is getting pressure from customers to add WEDM to reduce costs. Thomas Vacca advises him on how to justify the purchase.

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Ask the Stamping Expert: How can we maximize our tooling’s hits per service?

March 10, 2016

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Q: We are running high-strength, low-alloy (HSLA) brackets for a large aerospace firm. We cannot get the hits per service we need from our tooling and are struggling to meet production requirements. Any advice? A: Regardless of how many hits per service you get off a tool, you always want to...

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Ask the Stamping Expert: Why does tooling fail during coining and forming operations?

March 10, 2016

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Q: In our stamping division, we do a lot of coining and forming of 300 and 400 series stainless steels from 0.030 to 0.090 in. thick. We coin up to a 30 percent reduction in thickness and form multiple bends with very tight radii. Our punches and form die inserts fail. They break, crack, chip, or...

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Ask the Stamping Expert: How do I calculate shear pressure when figuring stamping die tonnage?

March 9, 2016

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Q: I read the article “How can I reduce snap-through condition effects?” in the September/October 2012 STAMPING Journal®. If I understand the article correctly, you do not want to stagger the punches too much to prevent the stored energy from releasing before the next set of punches hit. If...

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Ask the Stamping Expert: Why does my tooling yield such big variation?

March 9, 2016

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Q: My company stamps right-side and left-side links for conveyor belts. The peanut-shaped parts, made in a changeover tool, are about 0.1 in. thick, 1.5 in. wide, and 3 in. long. Half of the part (lengthwise) is coined offset, one material thickness in depth. This is in addition to a number of...

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Ask the Stamping Expert: What's the best-in-class process for developing a progressive-stamping die?

March 8, 2016

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Q: What is the best-in-class process for developing a new progressive-stamping die? A: Many tool builders think the process of progressive-die development is undefined and difficult to predict, and therefore takes way too long. Development is costly. It ties up engineering, design, toolroom...

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Ask the Stamping Expert: What type of hydraulic clamps are best for quick-change setups?

March 8, 2016

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Q: What type of hydraulic clamps do you use in your stamping presses for quick-change setups? A: The type of clamp is insignificant; there are many suitable brands. How you use the clamp is the important thing. Before you get into a true lean die-change system, you need to do some homework....

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Ask the Stamping Expert: How do we solve problems with die springs in hinge stamping?

March 7, 2016

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Q: We stamp low-carbon steel hinges, anywhere from 0.045 in. thick low-carbon steel about 0.5 in. square with a 1/16-in.-dia. roll form on the end, up to 1/8-in. thick and 5 in. square with a 3/4 roll form on the end for the assembly pin. Our stampings have a lot of dimensional problems, which we...

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Ask the Stamping Expert: Should light curtains stop a press even if it is traveling up?

January 8, 2016

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Q: We have some manual presses set up in a single part load-and-stamp production mode. The press is equipped with light curtains. When the operator activates the press buttons, he has to wait until the tool runs through the entire press cycle before he can reach into the work area. If he tries to...

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