IN THE LOOP: TRUE TO FORM

It's a fact: Manufacturers of rollform tooling that still use conventional grinders now risk being left behind by their competition.

For example, taking advantage of a rotary grinder for manufacturing rollform tooling holds several benefits over traditional methods, whether your business is a small shop or a large corporate enterprise.

Doug Witte, a certified rollform specialist at Shape Corporation (Grand Haven, MI), knows the advantages of using rotary grinders very well. Over the last 35 years, Shape Corporation has built a reputation of being an innovative trendsetter in automotive and industrial component rollforming, much of that coming from 'behind the scenes' with their use of rotary grinding. "Though a rotary grinder is not exactly needed to produce this tooling, it's simply much faster," says Witte. "And because this type of tooling is configured with a hole in the middle of it, that pattern is a perfect fit for the grinder we use because we have a bore inside our rolls."

Inside the tool room Witte uses a DCM IG 280 SD blanchard style industrial rotary surface grinder from DCM Tech Corporation (Winona, MN). This grinder removes stock quickly with a variable speed grinding spindle driven by a heavy-duty 20 hp spindle motor. "We're grinding hard steel with a CBN grinding wheel," notes Witte. "We figure it's about six times faster than a regular surface grinder." This machine, which has a 76 in x 64 in footprint, can grind parts one up on center, or multiple parts off center, for pass-through grinding under 12 in or 15 in diameter grinding wheels.

Beyond pure speed, rotary grinders meet other demands as well, including quality parameters, surface finish requirements, feed rates, and, in Witte's case, problems with parallel faces. "We have had problems with parallel faces with our conventional surface grinder and our automatic feed grinder," remarks Witte. "But with this rotary surface grinder, our faces are always parallel."

He's not alone. Roy Johnson, the president of River City Rollform (Muskegon, MI), also makes use of rotary grinding to do surface grinding up to 17 in diameter (432 mm) in his smaller operation. Johnson uses a rotary grinder because of its accuracy and speed. "We use a DCM IG 280 SD blanchard style rotary surface grinder to grind the face of the roll," he says. "This must be extremely accurate because in roll forming, exact geometry placement within each roll is an absolute must. The design will never work if the rolls do not accurately represent the designer's intent."

The quality achieved by rotary surface grinding was the difference for Johnson. "You get a much better grind out of this than a conventional grinder. We were able to get a much better surface finish and also consistency from roll to roll," adds Johnson. "With these rolls stacked together, they have to be fairly accurate. A conventional, manual grinder can make you guess on tolerances, but this servo drive grinder moves down to the exact desired position for grinding for a better finish and higher accuracy. The pieces stack up together."

And don't forget speed. "The other reason I use this equipment is because it's probably 10 to 15 percent faster than a conventional grinder," states Johnson. In passing, Johnson added that he initially preferred the DCM grinder because it is American-made. "Most, if not all, rotary surface grinders are currently made in Asia," he commented. "I personally like to buy American when I can. That's what started me looking at this unit in the first place, and the cost was very reasonable."

Investing in a good rotary surface grinder can bring many advantages to the shop floor and keep your business competitive. Compounded by these tough economic times, it's definitely something to consider.

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Kyndall Brown is the assistant editor of Fabricating & Metalworking magazine. Contact her at 866-832-8476 or kyndall.brown@cygnusb2b.com.

Shape Corporation, 1900 Hayes Street, Grand Haven, MI 49417, 616-846-8700, www.shapecorp.com.

DCM Tech Corporation, 4455 Theurer Boulevard, Winona, MN 55987, 507-452-4043, Fax: 507-452-7970, www.dcm-tech.com.