Cylindrical Grinding Machine Provides Solutions To Accuracy And Production

Jeff and Gary Caron of Caron Precision, Inc. (Kalamazoo, Michigan) know grinding. They know grinding so well that their business is strictly grinding—no other machining at all. But not even the Carons ever thought they would invest in a cylindrical grinding machine to facilitate a single application.

They started their company in 1992 after both working at Studer for years. They planned to not have a typical job shop but to be a grinding outsource for other shops.

"We're not the typical shop that makes and sells parts," Jeff Caron says. "We're strictly a service company—a source for other shops who don't have the volume or the expertise to get into grinding."

Caron started out with a single Studer S40 cylindrical grinding machine for general grinding work. The company added about a machine a year, and today has four Studer S40s.

When it came time to select a new grinder, though, the Carons were after something different. While improving efficiency was a goal, the brothers also wanted to produce more accurate parts.

Caron Precision was asked to grind three different valve stops for fuel injectors. Two of the part numbers needed to hold a tolerance of one micron. In addition, all three valve stops needed to be ground in a production setting. These challenges necessitated a new grinding machine purchase for the shop.

They decided to purchase a Studer cylindrical grinding machine, available in North America from United Grinding Technologies (Miamisburg, Ohio).

The capabilities of the Studer S30leanPRO cylindrical grinding machine provided the needed solution. The machine features an automatic swivel wheelhead that makes possible internal, face, and external grinding operations in a single setup. It proved to be exactly what they needed for a large, ongoing production job.

"We have a large production job for a customer that makes fuel injectors. We grind a valve stop for them. It's something they could probably do in-house, but we've done a good job for them," Mr. Caron says.

The Carons saw the opportunity to greatly improve their efficiency with the new Studer S30leanPRO with the automatic swiveling wheelhead. The swivel range is -15 to +195 degrees, positioning every one degree. This would allow Mr. Caron to set the wheelhead at the 60-degree angle needed for the face grinding operation on the valve stop.

"Most conventional grinding wheels come in straight. With an angled head, you can get 30 or 45 degrees. But we don't know of another product with a 16-inch grinding wheel that would allow us to make these adjustments," Mr. Caron says.

As a result, the Studer S30leanPRO at Caron Precision is dedicated solely to grinding this valve stop.

A conventional precision cylindrical grinding machine, the S30leanPRO has all the advantages of a CNC unit. "Interactive" control technology allows the first workpiece to be manually ground and automatically generates the CNC program for each additional part. It includes three electronic handwheels: one for the lateral X axis, one for the longitudinal Z axis and one for special functions. The X axis has a 10.8-inch maximum travel, and the Z axis has a 41.4-inch maximum travel.

Studer's Pictogramming software interfaces with the Fanuc 16 control for an easy-to-use, interactive programming option. Pictogramming allows four basic grinding cycles: plunge grinding; traverse grinding; multi-plunge followed by traverse grinding; and length grinding followed by shoulder grinding. Nine automatic dressing cycles are also available using the Pictogramming software. In addition, special grinding wheel shapes can be manually programmed.

The S30leanPRO can be programmed using manual infeed with the handwheel or simple input from a keyboard, tape, disk or other programming system. The S30leanPRO has a center distance of 40 inches and a center height of 6.9 inches. The machine's stable four horsepower workhead is dimensioned to accommodate workpieces in chucks, up to 290 lbs, and can grind between centers. Its tailstock accommodates a 1.37-inch barrel travel and offers a 0.0016-inch adjustment for cylindricity corrections.