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.

Stamping | Articles

Ask the Stamping Expert: How do we prevent buckling in thin material during strip feeding?

July 6, 2016 | By Thomas Vacca

Q: We are trying to stamp a drawn cup from 0.002-inch-thick by 0.500-in.-wide fully annealed stainless steel on a Bruderer BSTA 22e high-speed press with an aluminum ball bearing die set and a Bruderer 198/85 roll feed. There are six draws, and all of the draw die bushings are carbide with...

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Stamping | Articles

Ask the Stamping Expert: Five essential stamping rules for component designers

June 7, 2016 | By Thomas Vacca

Over the years I have received many requests from readers asking for suggestions and advice for particularly challenging stamping applications. Some of the issues can be addressed through creative tool design; some can’t. Some stampings by design make it virtually impossible to satisfy all the...

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Stamping | Articles

Ask the Stamping Expert: How can we form holes smaller than the material thickness?

May 31, 2016 | By Thomas Vacca

Q: We are using a progressive die to make a part that is 3.770 inch in diameter with 45 holes, each 0.172 in. in dimeter, on a 3.514-in. bcd [basic center diameter]. Our customer has asked us to change the material from 0.080-in. half-hard copper to 0.240-in. half-hard copper. Now the hole is...

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Stamping | Articles

Ask the Stamping Expert: How can I prevent slivers in blanking operations?

May 27, 2016 | By Thomas Vacca

Q: We are making shallow drawn cuts from 0.007-inch-thick aluminum base material with a thin polymer coating. The cups are assorted sizes from 0.375 to 0.75 in. and equal depths. We pierce the blank and use a balentine to carry it in the strip web through the draw operations, and finally we...

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Stamping | Articles

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

April 15, 2016 | By Thomas Vacca

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:...

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Stamping | Articles

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

April 1, 2016 | By Thomas Vacca

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...

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Stamping | Articles

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

March 31, 2016 | By Thomas Vacca

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...

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Stamping | Articles

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

March 30, 2016 | By Thomas Vacca

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...

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Stamping | Articles

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

March 11, 2016 | By Thomas Vacca

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...

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Stamping | Articles

Ask the Stamping Expert: The 10 Tooling Laws explained

March 11, 2016 | By Thomas Vacca

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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Stamping | Articles

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

March 11, 2016 | By Thomas Vacca

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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Stamping | Articles

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

March 10, 2016 | By Thomas Vacca

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...

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Stamping | Articles

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

March 10, 2016 | By Thomas Vacca

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,...

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Stamping | Articles

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

March 9, 2016 | By Thomas Vacca

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...

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Stamping | Articles

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

March 9, 2016 | By Thomas Vacca

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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