Emerging techniques to make molded interconnect devices are gaining attention in automotive and electronics industries, but need improved resin formulas to reach the big time.
The devices are being embraced more quickly in the European market than in the United States, and Japanese firms make devices using generally higher-temperature resins than those employed for MIDs in Europe or the United States.
MIDs are selectively metalized, injection molded parts that combine structural and electronic functions. The industry surfaced in the mid-1980s. Core technologies arrived a few years later, but continue to be refined and are moving down the cost curve for new processes.
Currently, there are three principal manufacturing methods:
High-volume, two-shot molding for jobs with the most-complex, three-dimensional circuitry;
Defining circuits with photo imaging's light energy, and then etching away unwanted metal;
Attaching an injection molded plastic substrate to a flexible film.
The Molded Interconnect Device International Association estimates two-shot molding accounted for about 60 percent of the industry's worldwide 1998 volume of $44 million; photoimaging processes 39 percent; and film techniques 1 percent.
The North Haven, Conn.-based association has 28 member companies. The group projects MID sales of $68 million in 1999 and $100 million next year.
While the technology can cut costs by reducing parts and processing requirements, and making assembled products lighter, current limitations confine the devices to niche markets.
Users lose product flexibility by investing in a two-shot mold, and they are held to two layers with circuit photo imaging. More development is needed to produce multiple layers of circuitry.
``We're launching products now that will go into every cell phone and car,'' Michael Mettler, chief executive officer of Molded Interconnect Device LLC in Rochester, N.Y., said in a telephone interview. ``Granted, [industry's] total sales value is not great today, but the number of technologies is allowing for increased variety of product design.''
The firm, which adopted the technology's name as its own, employs 55, occupies 28,000 square feet and had 1998 sales of $6 million.
``We are growing as fast as we can add people and capacity,'' he said. ``We plan to do $15.5 million in 1999.''
In one recent application, MID LLC achieved success by two-shot molding catalyzed polyethersulfone and a blend of polystyrene, polycarbonate and ABS for a computer joystick mount. The company has delivered more than 2.5 million of the mounts, each with interconnections of eight switches and eight diodes over four circuit-board planes.
The firm used the same process and materials to make a laser scanner for use in grocery stores.
Plastics account for more than one-third of MID LLC's business. The company operates one 275-ton, two-material, rotary platen press, mostly for development work, but sold off 11 presses to a local joint venture. Upstate New York processors mold most of the firm's plastics.
New programs require a mix of press configurations, generating an ongoing internal debate about whether to outsource the whole molding portion, Mettler said. MID LLC was known from 1990-96 as Mitsui Pathtek Corp., and earlier was an Eastman Kodak Co. unit.
European companies, allied in a research association, have advanced and promoted the technology faster than firms in the United States. The group is affiliated with the University of Erlangen in Germany.
Members have developed automotive connectors and electronic components, said Roland Meier, coordinator for the 45-company group, Three Dimensional Electronic Assemblies in Erlangen.
``MID can solve problems to develop highly integrated modules,'' he said.
Different research groups meet frequently, and the assembly supports the marketing of new results, he added.
Both high-precision, two-shot molding and photo imaging are potential billion-dollar MID markets, according to Tishiaki Ichige, chief engineer with the electric wire and cable design department of Hitachi Cable Ltd.'s Takasago-works in Hitachi, Japan.
Hitachi uses both techniques in making mobile telephone and automotive and electronic devices.
``In Japan, most applications are aimed at miniaturization and packages for electronic devices'' using high-temperature liquid-crystal polymers, syndiotactic polystyrene and epoxy for platable applications and polyphenylene sulfide and syndiotactic PS in nonplatable situations, Ichige said. The devices include camcorders, cameras and sensors.
The U.S. and European MID markets are targeted at reduced-component products and those with electromagnetic interference shielding, Ichige said, noting that some Europeans use low-temperature engineering thermoplastics such as ABS, polyamide and polycarbonate.
Automotive industry users of MIDs include units of Ford Motor Co. in Dearborn, Mich.; Eaton Corp. in Milwaukee; and Siemens NV in Oostkamp, Belgium.
``Fundamentally, MID is an interesting technology combining plastics, electronics and electromechanical features,'' said Andrew Glovatsky, a manufacturing development engineer with Ford's Visteon Automotive Systems unit.
The devices have the ability to integrate many pieces into one or two parts ``and fulfill a lot of different applications from small modules to connectors to switches,'' Glovatsky said.
Motorola Inc. wants to team with a plastics processor and a resin company to make devices that can go through a reflow oven.
So far, resin makers have not developed suitable high-temperature plastics for that application, said Don Zito, technical planning manager with Motorola's automotive industrial electronics group in Northbrook, Ill.
UFE Inc. of Stillwater, Minn., anticipates releasing some new film-technology applications in mid-1999, said Chairman Orville Johnson. The uses will demonstrate nearly the full capability of MID technology, he said.
UFE's injection molding business unit fits a flexible circuit into a mold cavity and injects resin to fuse the circuit to a plastic part, Johnson said.
``We can expose it so you can surface-mount on the circuit.''
UFE acquired its film technology for MIDs in 1991 from Rockwell International Corp.'s automation unit, formerly Allen-Bradley Co.
UFE found it necessary to collocate electrical and mechanical designers to achieve MID solutions eliminating parts and reducing costs, Johnson said.
``For this technology to pay off, you need to design around the technology,'' he said.