Better toolpaths help keep work onshore

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END USER: Bob's Design Engineering Inc., (503) 648-7418, www.bdeinc.com. CHALLENGE: Retain contract for electronics components against offshore competition. SOLUTION: High-performance toolpath generation engine. SOLUTION PROVIDER: Celeritive Technologies Inc., (888) 253-6701, www.celeritive.com.

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It was a big score for a medium-size shop like Bob’s Design Engineering Inc.: a lucrative contract machining components for a subassembly needed by a U.S.-based computer and printer manufacturer. Most of the components, including ballscrews, cradles and drive mechanisms, are aluminum, and some are stainless steel. The parts range in size from pieces that can fit in the palm of your hand to a plate requiring a 72 " milling capability.

Courtesy of Celeritive Technologies

Using VoluMill, Bob’s Design Engineering programmed this complex test piece in 30 minutes and milled it out of 304 stainless steel in less than 13 minutes at 530 sfm.

Founded by Bob Hole and based in Hillsboro, Ore., Bob’s Design made the parts for 18 months before the contract came up for rebid. The rebid process was complicated by the fact a former employee of the customer went to a competing supplier in Southeast Asia, and gave that shop inside knowledge of Bob’s production methods and costs.

“We already had a proven track record and benchmark machine, tooling and labor costs for manufacturing these parts,” said Jim O’Leary, Bob’s tool engineer. “We had to come up with a way to reduce costs and still remain profitable to make sure we could compete with the shop in Southeast Asia.”

When O’Leary and others began looking at productivity factors, they realized the shop had a lot of underutilized machining capacity, leading to higher-than-necessary unit costs. “We had excellent workholding capability and were using high-quality cutting tools, so we had to look elsewhere,” O’Leary said.

After some research, O’Leary discovered the VoluMill toolpath generation engine and realized that toolpaths were the weak link in the production process. Developed by Celeritive Technologies Inc., Cave Creek, Ariz., VoluMill can replace traditional roughing toolpath engines to significantly increase machine utilization when milling.

To test the impact toolpaths generated by the plug-in software might have, O’Leary asked a programmer to design the most difficult part he could devise. O’Leary invited some tool vendors to participate in the test as well. 

The part was programmed with both the high-speed machining toolpath engine of a popular CAD/CAM package and with VoluMill. Using the former, it took the programmer almost an hour to program the test part. “He had to create a lot of extra geometry to reduce material and eliminate a lot of air-cutting time,” O’Leary explained. “Having never used VoluMill before, the same programmer read the instructions and programmed the part in 30 minutes.”

The shop then cut 10 parts out of the 304 stainless steel on its oldest machine tool using the toolpaths created with VoluMill. Average cycle time for the 1 "×4 "×4 " part was less than 13 minutes at a cutting speed of 530 sfm. “The idea of using a 12-year-old machine that’s basically worn out to cut stainless at that rate while getting longer tool life was phenomenal,” O’Leary said.

VoluMill allowed Bob’s Design Engineering to cut costs by 35 percent. The company adjusted its rebid on the electronics contract accordingly and ultimately retained the work while keeping it profitable.

With new contact in hand, Bob’s is using VoluMill for every potential application. “It is reducing cycle time an average of 50 percent while increasing tool life,” O’Leary said. “It’s also decreasing programming time—what used to take 2 hours for geometry creation and trial toolpaths has now been reduced to 40 minutes.”