New Alloy Helps Shop Meet Target Price, Obtain More Work

The employees on the shop floor could hear the difference. When they cut regular stainless steel, they could hear the tools squeak and wear from the pressure. When they switched to a new alloy, the silence was noticeable.

Case Study From: 10/1/2003 Modern Machine Shop

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Project 70+ alloy

(Left) Carpenter Technology Project 70+ alloy bar is loaded for automatic feeding into a CNC Swiss screw machine at AccuRounds. (Below) AccuRounds uses Project 70+ alloy bar to produce mechanical components such as solvent filter fittings for use in medical testing machines.

The employees on the shop floor could hear the difference. When they cut regular stainless steel, they could hear the tools squeak and wear from the pressure. When they switched to a new alloy, the silence was noticeable. For AccuRounds (Avon, Massachusetts), it was golden.

Switching to the Project 70+ family of premium stainless machining alloys produced by Carpenter Technology Corporation has also helped this 40-employee shop meet its target price and obtain more work.

“We continually face marketplace demands to produce products better, faster and more competitively priced,” says Michael Tamasi, co-owner of AccuRounds. “The old stainless just wasn’t working. With Project 70+ stainless, we’ve gained the ability to drill micro-sized holes under 0.005 inch in diameter and hold tolerances to 0.000150.”

AccuRounds manufactures high precision, custom mechanical components for a variety of industries, including automotive, medical and printing. The shop consists of CNC Swiss screw machines with milling capabilities, plus centerless and cylindrical grinding equipment. It specializes in tight tolerance parts (to the millionths of an inch), such as shafts and pins. As a value-added service, AccuRounds can also manage assemblies. The company processes 350 to 400 jobs at any given time, and it produces millions of parts each year.

Founded in 1958 by Mr. Tamasi’s father, AccuRounds is family-owned and operated. The family has seen increased pressure from customers to squeeze costs from the machining process. When it won a job to machine a solvent filter fitting used in testing machines for the medical industry, AccuRounds was put to the test.

At first, the company tried to machine the part with a standard grade of stainless. AccuRounds began by machining the part complete on CNC Swiss mill/turn lathes with a subspindle to reduce cycle time. It produced a bushing with an extension on one end, a hole through the part and a flange—a job that required precision work. But the original material created issues with machinability and finish, not to mention the noise tools make when they wear.

To solve the problem and meet the customer’s target price, AccuRounds switched to Carpenter’s Project 70+ grade Type 316 stainless steel. The company saw immediate results. Machinability, tool life, tolerances and finishes improved with the new material, which in turn made the job run more efficiently. By using the best grade of material, then straightening and grinding it prior to putting it into a CNC Swiss machine, AccuRounds regained the ability to machine faster and better—and kept the client and owners happy.

The new stainless steel alloy allows AccuRounds to do ID work it couldn’t do before, such as drilling holes of less than 0.005 inch in diameter. Before Project 70+ stainless, the shop could only drill down to 0.008 inch in diameter consistently, because the material was too abrasive, and the drills would break. The new material has also improved concentricity. On some jobs, using Project 70+ stainless means the company does not have to add a post-op grind to the process.

In many cases, is that cycle times have improved by 20 percent and throughput has improved by 30 percent. The increase in tool life has been the most dramatic, from 50 percent to 100 percent, especially with drilling. There is now less downtime for machines and fewer repair jobs for engineers.

“Any opportunity to improve performance needs action,” says Mr. Tamasi of the switch to Project 70+ stainless. “In this case, we found material that has improved processing across the board. It is going to allow us to be more competitive.”

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