Page 24 - MetalForming July 2010

Tooling Technology
A Quick Plating Saves the Day
Case in point: Teikuro customer Elsa LLC, an Elwood, IN stamper of automotive parts including fuel tanks, exhaust pipes, mufflers and cross mem- bers. While most of Teikuro’s coating work for Elsa is TRD coating of prog- die form stations, in one recent case, expedited chrome plating saved the day.
“In early production runs stamping a catalytic converter shell from a par- ticularly tough stainless steel (18Cr- Cb, more oxidation- and creep-resist- ant than Type 409),” says Elsa production engineer Earl Land, “we quickly discovered that we needed to redesign a couple of the form dies and draw beads. Rather than delay pro- duction for a TRD coating, we sent the tools to Teikuro for a quick chrome application, and in just two days we got the die back in the press. That allowed us to run off a sufficient inventory of parts so we then could send the form dies back to Teikuro to strip off the chrome and apply the more durable TRD coating.”
Stripping chrome from worn dies is a carefully crafted process at Teikuro, as well. “What’s common in the indus-
try is reverse plating,” says Emerich, who manages the plant’s chrome-plat- ing operations. “This reverse-etching process, we feel, can harm the sub- strate die steel, particularly when a tool receives several chrome applica- tions during its lifetime. Instead, we strip with a solution that works slow- ly, over an hour or two in a dip tank. The chrome washes away and the acid is mild enough to not attack the sub- strate.”
Heavy Metal (Chrome)
Substrate condition is key to opti- mum coating performance, and for the most challenging applications Teikuro takes its chrome plating up a notch with a process it refers to as heavy metal chrome. Protective of its proprietary process, Hamell describes the heavy metal process as “not applying more chrome, but rather it’s how we do the surface preparation to allow the coated tooling to better handle tougher draws and particularly thick materials. The process gains favor primarily for struc- tural automotive parts,” he says. “We want the 100,000th hit to look like the first—ultimately, that’s the job of the coating, to enhance the workmanship of the diemaker.”
“Our success is based entirely on the skill level of our employees,” Emerich adds. “The majority of the operators in our die-finishing department have completed seven levels of competency testing over a 7- to 9-yr. period. Each level comprises 800 hr. of documented on-the-job training in grinding, finish- ing and welding skills.
“Once we strip the old chrome off of a tool, these highly skilled operators can gain valuable insight into how and why the tool has worn,” continues Emerich. “The customer doesn’t get to see that. For example, if a tool gets dinged and damaged and the customer
Our Teikuro tour took us by this huge double-door aperture die in the midst of polishing to prepare it for chrome plating. A team of trained die finishers were using a variety of air tools and custom inhouse—developed and manufactured polishing wheels on the die, which had last been chrome plated in 2006.
When Teikuro takes in a die for replating, it also evaluates a sample panel that the die recently produced. “We need to see the stamped part together with the
die to get the complete story,” says John Emerich, Teikuro’s plant manager. Here a Teikuro technician takes a diamond file to a stamped class-A part to get a better look at a low spot appearing on the surface.
22 METALFORMING / JULY 2010
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