Plastic to MIM: A natural evolution

By: Clare Goldsberry

Moving into MIM seemed a natural evolution for custom plastic injection molder Trenco Products Inc. (San Diego, CA). The process allows the company to broaden the services and capabilities it offers to its customers in the medical device, telecommunications, textile machinery, and hardware end markets.

"We're flexible in trying to meet customer requirements in any area they want us to, and we saw MIM as a real growth area," says Mark Jahn, director of marketing for Trenco.

Jahn explains that Trenco was sometimes frustrated trying to meet its customers' needs with only thermoplastic injection molding materials and processes. "Many times our customers needed better properties than plastics alone could offer, even though we were aware of the higher-performing engineering thermoplastics like PEEK," he says. "When we first found out about MIM we got very excited about it, and the board of directors made the decision to move in this direction. It allows us to offer more in the way of customer support across the breadth of manufacturing the product."

Complete Solutions

Trenco started in the custom injection molding business in San Diego in 1987. Since then, the company has added a second plant in the U.S. and two operations in Asia. It was at its Taiwan plant in 1996 that Trenco broke into metal injection molding. Last year, demand for MIM prompted the company to begin offering the process at its Los Angeles area facility.

Jahn is reluctant to specify the company's market niches because applications for MIM run the gamut of all industries. But, at the recent MD&M West trade show in Anaheim, Trenco displayed some of the many parts it has made, including barrels for firearms, golf putter heads, and a variety of components for industrial products such as the nail gun pictured at right. Jahn says people are often surprised at the large size of the components Trenco is capable of producing, such as the thick-walled pistol barrel.

"We do much larger parts and more complex parts than a lot of others," says Jahn. "People are amazed that you can mold parts as large as a gun barrel, finish it and blue it, and basically use it as molded with no subsequent machining, except for the rifling in the barrel."

Jahn says the forte of the company is its ability to manufacture and assemble complete products, which it does by offering a broad range of secondary operations. For one product—the aforementioned nail gun—Trenco molds the plastic housings and other plastic components, makes the MIM components, heat treats the anvil, does the secondary work, assembles the product (complete with the motor installation), tests the units, packages them, and ships them to the customer, finished.

"We're very vertically integrated in what we can do from design for manufacturability and moldmaking on the front end through to finished products at the back," says Jahn.

Customer Know-how

Marketing MIM is made somewhat difficult for Trenco because many of its customers consider the use of MIM in their products to be proprietary. "A lot of the parts we do for customers we're not allowed to show because people want to use us as their competitive advantage," Jahn explains. "That's why many people say they have never heard of us. We've been a well-kept secret, but that's because our customers didn't want us known."

However, it's getting harder to keep the secret. MIM is becoming more well known and accepted as a viable process for many applications across industries. "It used to be that I'd have to explain MIM to everyone, but we do a lot less of that now," he says. "About a third of the customers we come into contact with still need an education, but the vast majority know exactly what the process is all about, how to use it, and what it can do for them as far as eliminating costs to manufacture, particularly on complex components, over the cost to machine parts. The more complex the part, the more cost reduction the customer can expect to see."

Jahn adds, however, that "cost reduction for simple parts can be very cost-effective as well." In fact, the company regularly produces tooling and makes parts in quantities of just a few thousand.

About 40 percent of the company's MIM customer base is in the U.S., 25 percent in Europe, another 25 percent in Asia, and the balance from other regions. To Jahn, MIM appears to be more widely known and used in the U.S. "We have worldwide customers," he says. "It just seems there are more MIM-savvy designers and engineers here in the states, or a greater concentration of them, so most of our work comes out of the U.S."