Midwest Composite Technolo-gies Inc. and DTM Corp. are feuding in federal court over the legitimacy of a patent DTM holds for laser-sinterable nylon 11 powders used to make three-dimensional prototypes. In a patent-infringement suit filed Oct. 24, DTM claimed that Midwest knowingly used DTM's patented powder in a selective laser sintering process without permission.
But in a countersuit launched last month, Midwest charged that DTM's right to the patent is dubious, and that DTM and its majority owner, BFGoodrich Co. of Bath, Ohio, are using the patent to monopolize the niche market for SLS nylon 11 powders, ``a readily available commodity,'' according to a Midwest news release.
Now a Milwaukee federal court must decide whether Midwest of Hart, Wis., is infringing on the patent by buying nylon 11 powders on the open market and using them in a Sinterstation 2000 Selective Laser Sintering ma-chine, manufactured by DTM of Austin, Texas. Midwest said it purchased the Sinterstation from DTM in June 1994 for $255,000.
Since 1993, DTM has been manufacturing and selling its Sinter-station 2000 machines, which use SLS to make rapid prototypes and tooling from a variety of materials, including nylon and metal powders. Nylon is favored in SLS prototype applications that re-quire durability, thermal stability and good chemical resistance, according to Midwest's suit.
In DTM's SLS process, also patented, a roller deposits a material, such as nylon powder, in layers onto a cylinder bed, and an overhead infrared laser beam traces cross-sections of the part into the powder, layer by layer, to create a functional prototype.
Mike Ervin, DTM's vice president of engineering and development, said DTM's powder patent, issued Aug. 30, 1994, covers only those nylon 11 powders used in SLS.
Midwest's lawyer, Peter N. Jans-son, identified those patented powders as Rilsan D-50 and D-80, manufactured by Elf Atochem SA or the Paris firm's North American arm in Philadelphia.
Jansson said Midwest was being sued because it bought Rilsan D-50 and D-80 directly from a company other than DTM, and used the powders on DTM's SLS machine to make prototype parts. Midwest contends that DTM packages and resells the powders at greatly inflated prices, whereas the powders are available from other commercial sources at a much lower cost.
Ryan Koester, project engineer for Compression Inc., a design and engineering firm in Indiana-polis, said the DTM Sinterstations can make prototypes using nylon 11, glass-filled nylon or fine nylon. Compression owns nine DTM Sinterstation 2000 machines and buys all its powder from DTM, he said.
Although Elf Atochem manufactures the powders, DTM is the firm's exclusive U.S. distributor of them, Ervin said. He added that DTM spent several years doing research and development on various powders supplied by Elf Atochem, studying such properties as molecular weight, temperature, particle size and distribution, before identifying the types of nylon 11 that worked well with its patented SLS process.
``This is a very specific material we spent time on to develop,'' Ervin said. ``We're not trying to lock people out of this business at all. There's a broad range of nylon powders out there that are not covered by this [patent]. We would welcome other companies coming in with other materials for our machines.''
He noted that several DTM customers have received permission to develop other materials to be used with the Sinterstation.
But Midwest's June 17 countersuit questions the validity of DTM's patent on the nylon 11 powders, since the knowledge that nylon 11 can be used in the SLS process predates both DTM's Sinterstation and its patent, Jansson said by telephone from his office in Racine, Wis. That knowledge has been a matter of public record since 1989, according to the suit.
Midwest also alleges that when it stopped buying the SLS nylon 11 powders from DTM and began buying them elsewhere, DTM threatened to cut off parts and service for its Sinterstation. The lawsuit calls that act coercive, since, as Jansson put it, Midwest was forced ``to knuckle under'' and resume buying powders from DTM to keep its business intact.
Midwest is asking for treble damages under violations of federal and state antitrust laws.
Tom Lee, DTM vice president of marketing, called the countersuit ``fairly typical.''
``We don't feel that there's any basis for the claims that they've made in their countersuit,'' he said.
At its Hart plant, Midwest does rapid tooling and prototyping and low-volume production, mainly of reaction injection molded housings for medical equipment, said President Helmut Keidl. The firm, which operated for more than 15 years as Midwest Fiberglass & Tooling Inc., recently changed its name to Midwest Composite.
Though RIM tools are Mid-west's primary business, it also builds tooling for other processes, including vacuum forming, he said. The company employs 40. Keidl would not disclose sales.