Managing the switch from plastics to powders

Greg Howard is the president of a startup PIM molding company in Surrey, British Columbia called Columbia Powder Injection Molding Inc. The new company is a spinoff of Columbia Plastics, an established plastics custom molder. Howard admits that the PIM learning curve has been quite steep, but he believes the rewards for his company’s efforts eventually will be substantial.

Howard shared his experiences, both good and bad, with attendees of PM2TEC’99 in Vancouver earlier this year. Howard says that his company began investigating PIM in 1997. It was immediately apparent that a PIM enterprise would be both capital and intelligence intensive.

Still, Columbia decided to take the plunge and become a full-service supplier, offering design-for-manufacturability services to its customers as well as manufacturing. It partners with customers, just as it does in plastics molding, to identify opportunities that are mutually beneficial.

“Many plastics molders have tried to enter into PIM and have failed because they tried to bring over an unfocused, shoot-and-ship mentality, and because they simply did not do their homework,” says Howard.

The Gameplan
Columbia, on the other hand, did do its homework and came up with a detailed business plan for success that covered all of the different aspects of a PIM business:

Feedstocks. Howard says Columbia found that the daunting challenges of powder, binder, and additive selection, powder characterization and analysis, compounding, and pelletizing would be better left to the suppliers of precompounded feedstocks. Columbia already had long histories with AlliedSignal and BASF, which allowed the company to concentrate on the production of medium-to-large-size PIM parts, weighing between 110 and 150g. “We knew we would need help when it came to powder handling and compounding,” says Howard, “and we decided to concentrate on our own strengths, which include molding and molds.”Part design. Columbia has been ISO 9002 registered since 1992. Howard says little additional overhead would be required to fold processes like sintering into existing 9002 certification, but part design was another matter. Add-ing that capability would require recertification, so it is not offered.Moldmaking. “Vancouver is a relatively remote location, so we have always built our own molds,” Howard says. Columbia has CAD/CAM in place and is a CNC house. Its experience allows it to hit complex, tight-tolerance, high-performance specs right out of the gate. Howard says Columbia has found that steel-rich cores and cavities work well with PIM. But since PIM pressures are lower than those for thermoplastics, he believes aluminum tooling can be used when the parts are not too complex. Columbia has already used epoxy sampling tools to get comfortable with molding feedstocks.Molding. Columbia uses its standard, unmodified existing plastics molding presses for trials, determining which thermoplastics molding rules work for which feedstocks. Once all the correct process parameters are worked out, Milacron/Fanuc all-electric presses are used for PIM production.Debinding/sintering. “Molders know heat treating for molds, but they don’t know sintering. There is a big difference between the two,” Howard confesses. He says Columbia had planned to job out work to toll sintering houses, but because the Vancouver area is too remote, this proved impossible. So, Columbia purchased a 4.5-cu-ft batch debinding/sintering furnace from Elnik.The Rewards
When it comes to customers, Howard says Columbia has been fortunate enough to find progressive and open-minded ones who realize that his company is developing its PIM molding skills, and is willing to work with it. Yet Columbia’s PIM enterprise has already worked a few wonders.For example, Columbia has successfully molded sophisticated aerospace engine parts, some of which are usually five-axis machined, in a powder—AlliedSignal PowderFlo feedstock containing Hastelloy X—that has never before been MIM molded. PowderFlo is a nickel-based superalloy powder that has superior oxidation resistance at service temperatures up to 1600F.Columbia used a 110-ton, 4.3-oz Fanuc press running a low-compression screw. Critical tolerances on one part are to within ±.006 inch; Cpk is less than 1.5. Even as a newcomer, Columbia hit all the critical dimensions on the first shot. Some of the finished MIM parts were machined in a secondary step to eliminate a center-gate vestige, but that was all. Obviously, the the company really did do its homework.Contact information
Columbia Powder Injection Molding Inc.
Surrey, BC
Greg Howard
Phone: (604) 530-9990
Fax: (604) 530-7306