Grinding Shop Steps Up To CNC Machining

When Absolute Grinding shifted gears to CNC machining, the company saved a significant amount of time. The new machines were capable of performing many tasks simultaneously, making the shop more efficient.

Case Study From: 4/20/2004 Modern Machine Shop

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5 minutes to write these programs

Mr. Murnyack says his employees switch from an ID operation to an OD operation on a different part in 1 hour with the S31. It takes him only 5 minutes to write these programs.

Rob Murnyack had been turning his professional life upside down in a quest to use CNC machining at his shop. He'd been working for his father for more than 20 years in what had become a successful grinding operation. However, Mr. Murnyack wanted to take the company to the next level—using CNC machining.

"We couldn't gather a powerful enough argument to nudge my father over the line," Mr. Murnyack says. "I can't blame him. He's 65 and has built a solid business around manual operations, and for him to invest $150,000 to $200,000 to move in a new direction was a tough sell."

Mr. Murnyack worked out a deal with his father, setting up a kind of "beta site" operation. He took several of his father's employees, a number of established customers and four manual grinding machines and began Absolute Grinding (Mentor, Ohio) in May 1994. Then, 4 months later, he found himself in Chicago, Illinois at the International Manufacturing Technology Show (IMTS).

"I wasn't making a salary at this point," he says. "Here I was looking at machines that cost $200,000 and more. I thought I was nuts. But at the same time, I realized I needed to make the investment if I wanted to shift gears to CNC."

Obviously, a lot rode on his first plunge into CNC machining. He chose a Studer S35cnc universal cylindrical grinding machine from United Grinding Technologies (Miamisburg, Ohio). It had a choice of a straight or angular infeed with the grinding wheel mounted left or right; wheel dressing and profiling with continuous path control; automatic grinding and dressing cycles; automatic change-over from external to internal grinding; and an automatic swiveling wheelhead. It also allows the use of up to three grinding wheels in a single workpiece program, as well as a special workhead with a C axis that permits form and thread grinding.

Mr. Murnyack notes that none of his employees were familiar with CNC, so in that respect, the new machine had to be easy to learn. "We literally self-taught ourselves," he says. "The programming was that easy."

Three years after he entered the CNC arena, Mr. Murnyack added an S36cnc, a universal cylindrical grinding machine for medium-sized workpieces. His objective was to find a quality machine that could do internal and external grinding for less than $250,000.

One of the bonuses of the grinding machine, according to Mr. Murnyack, was that it allowed the company to do random wheel shapes and more intricate configurations of the grinding wheel and of the grinding cycle. In general, it gave Absolute the ability to tackle complicated projects.

The latest addition to the company's fleet of Studers is the S31cnc purchased in 2001. Mr. Murnyack thought he should investigate the new generation of CNC machines, which are more flexible than their predecessors and would allow the company to handle a wider variety of parts with a reduction in setup time. The S31 took care of this, with a drive-spindle power of 10 hp, grinding wheels with a maximum diameter of 20 inches, a width of 3.15 inches and an infinite B axis. It permits grinding ID, OD and tapered ID's on one machine.
"We do four or five setups a day," he explains. "This is a job shop. We can't spend 4 hours on a setup. My guys can switch from an ID operation to an OD operation on a different part in an hour with the S31. With other machines, I hear from people in the field that they might spend 4 hours just writing the program. It takes us just 5 minutes to write these programs on the CNC machines."

Because of the significant time savings the company has discovered when using CNC machines, Mr. Murnyack and his shop employees understand what a difference they can make in a shop's efficiency. Not only are these machines easy to operate, but they also provide quality machining to complicated projects. They also allow one machine to perform many tasks, rather than wasting time using several machines.

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