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Tough Coating Combats HSLA

Wednesday, March 1, 2017
 

Headquartered in the Cleveland, OH, suburb of Wickliffe, Universal Metal Products has leveraged its 50 years of experience to position itself as a leader in supplying precision metal parts via slideforming and stamping operations. A specialist in high-volume appliance, automotive and industrial metal stampings, the Tier Two manufacturer ships parts out of Cleveland, suburban Toledo, OH, and McAllen, TX.

Tooling for this steering stabilizer bracket, formed from HSLA steel, had to be refurbished after only 1000 to 2000 parts, according to Universal Metal Products officials. But with new tool coating, more than 80,000 parts are produced before the tooling requires repolishing and recoating.
With its inhouse capabilities and knowhow, few things can slow the company down in meeting customer needs. But one issue has proven challenging: forming high-strength low-alloy (HSLA) steels. Given the complex forms and tough part material, tooling for HSLA tasks takes a beating at Universal. To minimize the risk of worn and broken tooling shutting down a run, or quality issues drawing customer ire, the company has sought to protect its tooling with the best-performing coatings it could find.

Tougher Material for Auto and Appliance Parts

Much of Universal’s need for tough tool coating arises from operations at its stamping facility in Pemberville, south of Toledo. Here, mechanical presses in capacities to 600 tons churn out parts to the tune of 20 to 50,000 pieces per month spread across about 40 jobs. The parts are produced via progressive dies from material 0.118 to 0.187 in. thick. In Texas, too, the company stamps parts in similar volumes, also using progressive dies from material in similar thicknesses. Across Universal, HSLA has crept in, testing the tooling and the company’s efforts to keep that tooling in production. The strong material is found in stabilizer brackets for the auto/truck industry; refrigerator door hinges; and clutch discs, stack plates and spring covers, also for automotive.

“When we started to get into HSLA, we found that the coatings weren’t holding up,” explains Ken Bateman, vice president of manufacturing at Universal, who, along with Jim Harsa, senior tool designer, detailed the company’s tool challenges with MetalForming. “So, we began researching other coatings as well as the tool steel itself. Even with higher-quality steels, we still couldn’t overcome the tool wear when forming HSLA. For the clutch discs and related parts, a lot of shaving and extrusion is performed with the tooling to form pockets. For the door hinges, which shifted to stronger material in order to support heavier refrigerator doors while maintaining a low profile, we run higher volumes, to 100,000 pieces, and the HSLA was pretty abrasive against the tooling.”

Tool Coating Proves Effective

Back in 2004, Universal first identified a tool-coating process from Phygen Coatings Inc., Minneapolis, MN, as a possible remedy, after testing other coatings applied at both high and low temperatures.

“The first time we used it was for an emergency-brake bracket that necessitated vertical wiping, the forming of ribs and requirements for tight tolerances on a 190-deg. draw,” Bateman says. “Nothing would hold up until we identified the coating process from Phygen.”

A bottom stabilizer bracket, made from Grade 70 steel, requires side wiping, with corners experienced a large amount of compression and tension. “This tore up an old coating, but with the Phygen coating, tool life quadrupled at least,” says Jim Harsa, senior tool designer at Universal Metal Products. “We had been going through expensive forms after forming only 20,000 pieces. Now we may recoat after 6 months instead of after one day.”
How did the new coating work?

“We went from worn out forms and gouging after forming 10,000 pieces,” recalls Bateman, “to being able to produce as many as 200,000 pieces before recoating. The difference was night and day.”

Phygen applies its patented FortiPhy physical vapor deposition technology to create a thin and dense nanocrystalline coating structure onto any tool-steel substrate. Described by Phygen president Dave Bell, the process creates a high level of adhesion. And, it does so without pulling carbon from the tools.

Temperature also varies among the various tool-coating processes. Chemical-vapor-deposition coatings and thermal-diffusion coatings usually are applied at temperatures greater than 1800 F. Phygen’s coating requires significantly lower temperatures, claims Bell, lessening the chance of distortion that can play havoc with tolerances and minimizing tool-hardness concerns.

Bateman and Harsa laid out a host of applications where the coating has greatly extended tool life since then. (For related video, see this article online at www.metalformingmagazine.com.)

“A bottom stabilizer bracket, made from Grade 70 steel, requires side wiping,” explains Harsa, “and the corners experienced a lot of compression and tension. This tore up an old coating, but with the Phygen coating, tool life quadrupled at least. We had been going through expensive forms after forming only 20,000 pieces. Now we may recoat after 6 months instead of after one day.”

The coating also is applied on tooling responsible for forming spring plates.

“We use the coating when drawing forms on the pockets, because the pockets are very high-wear, with friction on the sides of the punch,” Bateman says. “We also use it with excellent results on the shape punches for that part.”

Savings on Material and Part Cleaning, Too

By employing this coating process, Universal also can save on the type of tool steel it uses.

“We have excellent results when using D2, properly heattreated for coating,” says Bateman. “Phygen provided us with a heattreat procedure for D2 and when followed, it has held up very well. D2 is not the most expensive tool steel, so we save some money when choosing these types of steels over some of the newer steels.”

When recoating is required, turnaround is only 2 to 2.5 days, reports Bateman, which assists greatly in keeping Universal’s presses humming.

Also, “as lubristic as these coatings are,” Bateman says, “we don’t have to use heavy drawing compounds that are hard to clean and that drive up finish costs on parts. Almost all of these parts are painted or plated, so we save on the cleaning because we can use less aggressive coolants.” MF

 

See also: Phygen Coatings, Inc.

Related Enterprise Zones: Materials/Coatings, Tool & Die


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