May 2008 Edition

MACHINING CENTERS

Five Axes, One Setup, Endless Results

The one setup power of a 5-axis machine brought a machine shop into the future

Owens Industries, Oak Creek, WI, specializes in performance machining – delivering high-quality, high-tolerance components to the medical, computer, and telecom industries.

As business skyrocketed in the telecom industry, related parts comprised an increasing share of Owens’ business. But, with a reversal in trends, Mark Plesnik, a former employee, was called in to develop a new business model and return the company to profitability.

Because most of Owens’ work was in high-value raw materials – nickel alloys, molybdenum, titanium, and others – Plesnik and his team sought to reduce scrap and eliminate waste. One solution included maintaining multiple set-ups on machines to save time and ensure accuracy. Another involved performing different operations in a single setup.

"Every time a part is transferred from one machine or process to another, there is the risk going out of tolerance. As a result, we moved toward more 4- and 5-axis machining and the use of better tooling to perform multiple functions on the same machine."

Plesnik said this is the future of machining and the future of Owens Industries.

"I saw what outsourcing was doing to American shops producing high-volume commodity parts and realized that our future lay in a diversified base of small ultra-high precision parts requiring up to 7-axis machining in low to medium quantities," Plesnik said. "We needed to perform the jobs other shops wouldn’t, with perfect results."

Taking on the Challenge

A Texas-based engineering company that developed a
concept for an emergency shut-off mechanism for use in oil wells needed a shop that could deliver the precision the part needed.

"The device uses components that are both down-hole and above-hole, and crucial to the process is a flapper lid that cuts off the oxygen supply to any fire," Plesnik said. "The material was a high-nickel alloy, and the tolerances were 0.0015" on the inside radius. They were unable to find a shop willing to produce the parts in quantity – much less at a reasonable price – until they came to us."

The engineering company made it clear that if Owens could make the part, there would be follow-on business.

"Because the part was larger than what we normally handle, we had to purchase a fully-integrated 5-axis machining center with enough rigidity to hold the tolerances," Plesnik said.

After an extensive search, Owens chose a Hermle C 20 U from Hermle Machine Co., Franklin, WI.

"Besides meeting our expectations in terms of its capability, we were impressed by Hermle’s commitment to customer service," he said. "The company’s applications people worked closely with our team and, once the sale was made, its service group ensured that the installation was perfect and on time."

Machining the Part

The machine met the production requirements of the emergency shut-off mechanism.

"We begin by rough turning to the approximate shape, then transferred it to the Hermle," Plesnik said. "In one setup, we perform milling, both horizontal and vertical drilling, tapping, and profiling. Surface finish was critical, and the customer specified that to seal adequately, the sealing surfaces would have to be lapped. We were able to achieve an 8µ finish on the seal without lapping, eliminating multiple operations on separate machines," he said. "Machining time was 4.5 hours – a significant achievement on a part this complex. Without 5-axis machining, it could take more than twice as long and necessitate multiple setups."

The program was successful.

"When the part was vacuum tested, it held for over half an hour before they stopped the test. Prior to our part delivery, no other part had held longer than eight minutes," he said.

Success Brings Diversification

Owens’ customer list has grown and diversified and serves such industries as medical, tooling and appliances, avionics and aerospace, communications, high-tech commercial providers, R&D houses, and the oil industry.

The key is the care taken at every step of the manufacturing process. On high-value parts, adequate deburring is critical but, given the comparatively delicate nature of the components, it cannot be accomplished by just mechanical means. A special deburring room with individual workstations equipped with microscopes and measuring equipment is isolated from the rest of the facility. Here, experienced personnel ensure that excess material is removed without damage to the part.

Machining time was 4.5 hours – a significant achievement on a part this complex. Without 5-axis machining it could take twice as long and necessitate multiple setups.

Owens maintains an apprenticeship program led by its most skilled workers. It is one of the few shops where machinists can grind a tool under a microscope kept at the machining stations.

Equally important is the Owens quality assurance department. Because many of the part orders require 100 percent inspection, the QA department receives finished parts accompanied by both the blueprint or CAD drawing, as well as the original purchase order.

"We want to be sure that every requirement specified by the customer is met and nothing forgotten," Plesnik said.

When many shops are experiencing overseas competition, Owens Industries thrives. By upgrading its manufacturing capabilities, the company achieves ongoing growth, primarily through word of mouth.

"Machines and tools are important, but the most important thing is having the people who know how to use them. Our commitment to continuous personnel development and raising a new generation is the key to our success and to our future. Put the right tools in the hands of the right team and miracles will happen," Plesnik said. Hermle Machine Co.

Visit www.rsleads.com/805mn-204 for more information

What do you think?
Will the information in this article increase efficiency or save time, money, or effort? Let us know by e-mail from our website at www.ModernApplicationsNews.com or e-mail the editor at pnofel@nelsonpub.com.