Page 23 - MetalForming July 2010

Richter customer K.S. of West Virginia boasts of a significant increase in die life using the Richter Titankote C2-SL process when deep drawing bushings and forming surface-critical hub-seal parts. Shown here: a bushing 80-mm dia. by 82 mm tall, and a hub seal
6 mm tall by 80-mm dia.
1000 highly oxidation-resistant layers and a coating hardness in excess of 3500 Vickers.
“We developed the C2-SL process early in 2009,” says Thompson, “for those applications where the toughness of a TD coating is required but where a low-temperature coating process is needed.”
Automotive-industry supplier K.S. of West Virginia Co. (KSWV), Ravens- wood, WV, is a believer in the C2-SL process, having approached Richter early in 2009 for help with a deep-draw dies used to stamp bushings.
Says KSWV quality manager Jeff Easter: “The draw dies generate a lot of heat forming the mild-steel (1.8 mm) bushings. The press runs at 18 to 22 strokes/min. and parts exit the die at around 120 F. Our TiCN PVD coatings were failing after 25,000 parts. We tried different coatings, fine-tuned the die radii and adjusted the clearances, and still struggled, finally turning to Richter for the Titankote C2-SL coating.
“Since September 2009, the Titankote C2-SL-coated die has run more than 150,000 parts,” Easter con-
tinues, “and we’re approaching 200,000 parts. And, in addition to the huge increase in run time, surface finish of the parts also has improved dramati- cally. Based on that success, we’ve used the coating for many other dies and generally experience triple the life compared to other TiCN coat-
ings, at about one-third the cost.”
Citing another example
where the new Titankote process
has helped, KSWV die-department manager Clayton Kerns describes a transfer die stamping hub-seal rings for antilock braking systems. Rings are of either 1008 carbon steel, 304 stainless, or (most recently, for a GM heavy-duty truck) 430 stainless (0.6 to 0.8 mm thick).
“Surface finish on these rings is crit- ical,” says Kerns, “to ensure the dura- bility of the seals. And it’s difficult to avoid scratches when drawing 430 stain- less. While a TD coating might be ideal for its durability, we tried the lower- temperature C2-SL process to help maintain the tight tolerances (0.01 mm) on the punch dimension that governs
the ID of the seal ring. The C2-SL-coat- ed punches have run more than 250,000 parts and continues to meet our surface- roughness tolerances Ra 0.8 microme- ter) and minimum scratch-depth requirements (6 to 8 micrometers).”
have in die prep—grinding and pol- ishing—to optimize the life of its coat- ings.
“It’s the elbow grease and the time we take to hand-work the die steels that optimizes coating performance in the stamping press,” says Mike Hamell, Teikuro vice president of sales and mar- keting. “We use proprietary techniques and specially engineered finishing tools developed here and in Japan to allow stampers to (often) get hundreds of thousands of hits before requiring the dies to be replated.
“We can turn around a chrome job in 24 to 48 hr.,” continues Hamell, “get- ting our customers’ presses back up and running during a planned weekend shutdown. A lot of times stampers can’t wait for the typical three to five days needed for a TRD coating.”
Expert Symptom Diagnosis
Leads to
the Optimum Treatment Plan
“We consider ourselves die experts first and foremost,” says John Emerich, plant manager at the Springfield, OH plant of die-coating companyTeikuroCorp.“Wecanlookat a die—worn either from tryout or from production runs—evaluate its wear conditions and identify specific issues we need to address during surface prepa-
ration, before applying the coating.”
Teikuro, a Japanese hard-coating company established in the United States in 1987 to support NUMMI oper- ations in California, specializes in chrome plating of large OEM automo- tive dies. In 2000 the firm added a ther- mo-reactive diffusion (TRD) coating to its resume to round out its offerings to the stamping industry. It’s most proud of the expertise its employees
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