Eptam Plastics Makes Difficult Parts Look Easy
- Industry: Contract Manufacturing
- Process: Turning
- MGI Division: The Robert E. Morris Company
- Builder Tool: Okuma CAPTAIN-L370
- Outcome: The results have been dramatic: complete part cycle times were reduced from thirty-three minutes, excluding multiple set up times, to eighteen minutes.
EPTAM Plastics of Northfield, New Hampshire makes manufacturing of difficult-to-machine parts look easy. Founded in 1981 by Richard Dearborn, EPTAM started off as a small plastics distributor and contract manufacturer with only three employees and a utilitarian work environment. Today, EPTAM is a leading manufacturer of precision plastic components. "In the late 90's We saw easy work going away to Mexico, and other countries,” explains Jeff Hollinger, President of EPTAM Plastics. “Anything that was +/- .005 to 0.010 was most likely gone.” Taking a calculated risk, Hollinger and the EPTAM Plastics management team created a new business model centered around parts that would continue to be produced in the United States. “We wanted to machine parts that scare other people.”
One of the toughest manufacturing challenges that EPTAM Plastics faced as it moved forward involved a critical sub assembly cut from 2.00” Torlon bar and featuring more than 14 different OD geometries, extensive face milling work, and holes that run almost the entire length of the 5” part. An extremely abrasive material, Torlon® polyamide-imide (PAI) is a high strength plastic with the highest strength and stiffness of any thermoplastic up to 275°C (525°F). It has outstanding resistance to wear, creep, and chemicals— including strong acids and most organics—and is ideally suited for severe service environments.
In an attempt to resolve these issues, EPTAM decided to take the parts off the lathe after OD turning and transfer them to a machining center to drill the long holes: two of the holes are within .035” of the outside wall of the part. Later a probe was added to verify the absolute position of the piece and the location of the holes. While this succeeded in marginally reducing the scrape rate, it added a tremendous amount of “non value added” time to the process, increasing costs and negating any benefits. To machine the part profitably, EPTAM would need to produce the part complete on one machine.
A chance meeting between EPTAM Plastics Engineering Manager Tim Fay and Mike Berube of The Robert E. Morris Company opened the door to a single machine solution. “I felt that an Okuma Captain L370 MW, with live tools and a sub spindle, could be used to machine the part complete,” explained Berube. With no previous Okuma experience, Fay was skeptical until Berube promised EPTAM that a customized solution from The Robert E. Morris Company would produce the part to print complete.
The challenge seemed so daunting that EPTAM Plastics initially no quoted the part, before re-considering and submitting an aggressive quote. “We decided we needed to be able to make this part, or we shouldn’t be in business,” says Hollinger. First attempts to manufacture the part were less than ideal. “We were just bleeding red ink on this part,” explains Hollinger. “We began by trying to machine the part complete on a super precision CNC lathe that we had been using for some time”. While the lathe featured full C axis, needed to position and hold the part for face drilling operations, it lacked the positioning accuracy necessary to handle the five extremely deep holes running almost the entire length of the part; a 20% scrap rate resulted.
Jay Beck, an application engineer from the Robert E. Morris Company, arrived with the machine and worked with Fay to create the turnkey solution. One of the critical components of the turnkey was custom tooling that slashed part set up time from 3 - 4 days to 1.5 hours. “In an effort to be as lean as possible, we doubled up on all tool holders; this allows us to keep almost all of our tools resident,” says Hollinger. The results have been dramatic: complete part cycle times were reduced from thirty-three minutes, excluding multiple set up times, to eighteen minutes. As production levels increased, EPTAM Plastics added a high productivity Okuma LT200 Twin spindle Twin turret lathe to handle similar parts in the family; it was able to complete the part in eleven minutes.
Keywords: Torlon, plastic, turning, eptam, okuma, The Robert E. Morris Company