Page 20 - MetalForming March 2010

New Coating
Prevents Punch Ends from Ripping Off
Longer punch life keeps the presses running at this Connecticut automotive-parts supplier.
In 1838, C. Cowles & Company opened to provide lanterns for the thriving carriage trade in New Haven, CT. Today, its subsidiary, Cowles Stamp- ing Inc., also in New Haven, carries the transportation torch as a Tier Two auto- motive supplier. In fact, it was one of this country’s original suppliers to the
OEM automotive industry; it also sup- plies complex metal stampings and sub- assemblies to the bearing, seals and shields industries as well as other nonautomotive businesses.
Early in 2008, the firm found that when stamping parts for one automo- tive customer, its punches were breaking after only a few thousand hits. The problem: the punches were getting caught in the material. The solution: a switch to a new punch coating, which brought significantly longer punch life and increased productivity.
Broken Punches Stalled Job Runs
In its 80,000-sq.-ft. manufacturing facility, Cowles employs mechanical presses from 35 to 250 tons to provide precision small- and medium-sized stampings from material 0.01 to 0.25 in. thick. Other inhouse capabilities include welding and assembly, tapping (in die and secondary-operation), plating, heat treating, powder coating and finishing. Up front, Cowles leverages its engi- neering and rapid-prototyping expert- ise to help customers with product development. It also staffs a full-service toolroom to build smaller dies and maintain dies in stock.
On a couple of jobs, including the automotive stamping referenced above, tool maintenance had become quite a burden.
“After 3000 pieces, the punches— coated with a titanium-nitride prod- uct—actually pulled apart,” explains Cowles engineering manager Whyn Pelkey, describing difficulties experi- enced on an automotive part stamped on a progressive die in a 250-ton press at 35 strokes/min.
A change in tool coatings at Cowles Stamping increased punch life from 3000 to 16,000 hits between sharpenings when stamping HSLA- steel automotive parts.
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METALFORMING / MARCH 2010
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