Medical Industry is Magnet for High-Precision Custom Molders

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Plastics Injection Molding

Medical device manufacturers stand to benefit as a rising number of quality-driven contract manufacturers focus their talents on the fast-growing industry.

By Mark Shortt
Editorial Director, Design-2-Part Magazine

The ability to serve a diverse customer base is a strength that can help contract manufacturing companies soften the blow of an economic recession. While some industries have taken harder hits than others, one that remains healthy in today's economic climate--with prospects for significant future growth on the horizon--is medical product manufacturing. It's no wonder that a fair amount of quality-conscious contract manufacturers have, in recent months, ratcheted up their service to the medical industry by adding capabilities for clean room molding and assembly and, in some cases, by opening new business units dedicated to this intriguing market segment.

A quick check of industry news over the last few months shows a noticeable trend in which a rising number of custom molding companies, capable of high-precision manufacturing, are either expanding or initiating services to medical OEMs. Among the proactive companies that fit this description are Infinity Molding & Assembly (Mount Vernon, Indiana); Mack Molding Co., the Arlington, Vt., molder that recently launched a new medical products group, known as MackMedical; and Omega Plastics, a 25-year-old company in Clinton Township, Mich., that has created a new business unit named Omega Plastics Medical. Also in on the trend are Minneapolis-based Diversified Plastics, a high-precision injection molder that recently added a clean room facility; and MedPlast, a precision custom molder that has added clean rooms as part of expansions recently completed at facilities in Westfield, Pa., and Tempe, Arizona.

Infinity Molding & Assembly (, part of the IMA Group, is an established contract manufacturer and custom injection molder with 27 years of experience in serving OEMs. The company made news this summer when it launched a new ISO class 7 (10,000) clean room molding and manufacturing facility located adjacent to the Infinity Molding & Assembly facility in Mount Vernon, Indiana. The new 11,500-square foot facility began operations in June and is dedicated to serving current and prospective customers in the medical industry.

"The management team made a conscious decision three years ago to develop a more diversified customer base, with medical being a priority," stated Robert Carpenter, president and CEO of IMA Group. "We have realized modest success in working with new medical customers. However, in order to progress to the next level, we recognized the necessity for creating an entirely new culture that is focused on clean room manufacturing."

Infinity Molding & Assembly's specialties include the molding of parts with complex geometries that require multiple cam actions in the mold. Another capability is the manufacture of thin wall components that require specialized knowledge of tool design and processing. The company's experience also allows it to run difficult specialty materials, such as PEEK, PPS, PSU, and PVDF. Many of the thin-wall, fine-tolerance components manufactured by Infinity have nominal wall specifications of less than 0.5 mm, according to Randy Calvert, director of sales and marketing for Infinity CleanRoom Solutions. Small parts like these, he says, require engineering precision and in-depth understanding of the extended manufacturing chain to assure seamless and functional assembly.

"On the other end of the spectrum, we manufacture parts with glass-filled engineering materials with heavy wall sections capable of withstanding high-pressure leak testing," says Calvert. "Additionally, some of these heavy section components also require torque testing to 300 inch lbs. on threaded metal inserts molded in during processing."

Infinity is currently producing a number of components that are used in surgical devices and are required to be run in a clean room environment. Produced in custom multi-cavity molds, these parts have complex geometry and are processed in injection molding machines specifically for medical applications. They're required to be free of flash, a condition that the company controls through the use of a highly engineered mold and an injection molding machine capable of exerting enough tonnage to maintain the integrity of the clamp force.

The company also produces check strips for cardio meters that perform cholesterol tests, for example, to monitor key indicators for heart health. The check strips are manufactured for both home and professional medical meter models, and, like the complex-geometry parts for surgical devices, are produced through the injection molding process utilizing multi-cavity molds.

"The check strip program requires extremely flat parts to be processed on our customer's automation equipment," says Calvert. "Chemically treated media is assembled to the strip. After a blood sample is introduced to the assembled media, the meter performs a visual scan to determine certain cardio measurements. This requires a combination of good part design (proper wall section for the standing ribs and posts) and good tool design (critical cooling and ejection considerations) to satisfy customer requirements."

In addition to the check strips, Infinity manufactures the housings for the cardio meter product. Because these meter housings need to have a certain amount of aesthetic appeal as well as functionality, they require a processing window that balances both design considerations. For aesthetic reasons, the parts can't exhibit any heat sink conditions--caused by thick walls adjoining the secondary surface that produce noticeable dimpling in the exterior surface. Molded-in texture, achieved by controlling heat and pressure during the molding process, is necessary to exhibit crisp features. The parts must also be accurate enough to allow the assembly of the printed circuit board, optical components, silicone key pads, and viewing lens.

One of the more important services provided by Infinity CleanRoom Solutions is its design guidance for tool building and part manufacturing. The company strives to "coach" its customer into achieving a "design for manufacturability" that eliminates processing problems while maintaining the integrity of the design. Its diverse customer base all but guarantees that Infinity encounters a fresh set of design and engineering challenges with each new manufacturing program.

"Our customer base is made up of customers from different industries, and the engineering challenges we face many times exceed the normal mechanical engineering input that most companies can provide," he says. "In addition to a solid mechanical engineering group, Infinity also has electrical and chemical engineers on staff. This strength of engineering resources allows us to give expert direction to customers who are facing challenges that require them to weave diverse technologies into successful, integrated program solutions."

One particularly difficult application required Infinity to hermetically seal eight magnets in a stator that was to be used in a motor for food processing equipment. The magnets were to be encapsulated in an FDA grade Kynar (PDVF) material. According to Calvert, Infinity achieved the hermetic seal by placing cavity pressure transducers in the tool. "These transducers sensed when the molten material was almost knitting around the knockout pins and automatically pulled the pins back from the magnets, allowing material to totally seal the stator magnets in the molded component," he explained.

While Infinity's customers value its technical prowess, Calvert says, the company's biggest strength is its responsiveness to customer issues. "Many of our successful relationships began with a frantic call from customers who had tools at another source and couldn't achieve the results they required," he discloses. "We draw on a wealth of company talent and historical success over the company's 27-year history. Our customers choose to work with us because they know our experience in working with tough programs, our responsiveness to their timelines, and the trust we've built with them over a number of years and program launches."

Infinity's new clean room manufacturing facility, located on the same campus as its molding and assembly plant, currently houses two 110-ton, Tiebar-less, Engel eMotion all-electric injection molding machines. The machines, Calvert says, represent what the company believes is "a step up" for clean room molding. "They feature exhaust venting surrounding the injection barrel, which is the highest area of particulate contamination," says Calvert. "Additionally, we specified these machines with high torque motors and high-output heater bands in order to run high-heat materials, such as PEEK (polyetheretherketone)." PEEK, an organic polymer used in demanding engineering applications, is considered an advanced biomaterial for use in orthopedic implants, he adds.

Michigan Automotive Supplier Transitioning to Medical Manufacturing

Another company determined to stake its claim in the medical device market is Omega Plastics, an injection molding company headquartered in Clinton Township, Michigan. Since its founding in 1984, Omega Plastics has specialized in molding engineered plastic components mainly for the automotive industry. But in August, the company announced its creation of a new business unit, Omega Plastics Medical, focused on the tooling, development, and manufacturing of medical device parts (

The announcement came less than a year after Omega had engaged the services of CJPS Enterprises, of Troy, Mich., to develop the strategies needed to diversify from a mostly automotive business into medical devices. With the assistance of CJPS Enterprises, Omega was able to score a grant from the Michigan Economic Development Corporation (MEDC) designed to help automotive suppliers diversify into the medical device industry (

"At a time when we are challenged by the industry that we served, it is exciting to be able to continue to grow into the stable, exciting, and growing medical device market, while leveraging what we already do best," said Jeff Kaczperski, president of Omega Plastics, in a statement. "Our growth initiatives have only started, and we expect to create business growth and new jobs in Michigan thanks to the powerful help of the State of Michigan and CJPS Enterprises."

Minnesota Precision Molder Expands Services with New Clean Room

This summer, Diversified Plastics, Inc., a Minneapolis-based injection molder of high-precision, small- to medium-size plastic components, began offering value-added services that require a clean room environment. The company's new clean room facility allows Diversified Plastics to extend its reach into industries such as medical devices, filtration, and aerospace, where special assembly and packaging operations need to be performed in clean room conditions.

The Diversified Plastics clean room is certified to ISO 14644-1 class 8 standards, which means that the filtered air in the clean room contains no more than 100,000 particles larger than one-half (0.5) micron in size, per cubic foot of air (a micron is one millionth of a meter; a human hair averages about 75 microns in diameter). The room's positive pressure airflow forces contaminants outward when the clean room door is opened. Before entering the clean room environment, workers must enter a changing room to dress in special apparel such as smocks, shoe coverings, and hair nets. Before any production begins, all work surfaces are wiped down completely. To ensure that the strict level of cleanliness is maintained, Diversified Plastics continually monitors the room's particle count.

"Adding a clean room facility was in our long-term plans; however, a medical device industry customer had an immediate production need, therefore we accelerated our installation plans," says Annette Lund, vice president. Diversified Plastics is now equipped to assemble, sonic weld, and package parts all in a clean environment. The company will also inventory and deliver the customer's product as needed. "This gives us a big competitive advantage by offering these value-added services for our customers," says Joe Bourgeault, quality director. "Now our customers make only one stop to have their products molded, assembled, packaged, and inventoried."

Diversified Plastics ( is a full-service injection molder that provides design assistance and mold construction, as well as intricate molding and component assembly. The 32-year-old company is ISO 9001:2000 certified and UL registered.

Vermont-Based Firm Launches Medical Products Group

Also this summer, Mack Molding Co. ( announced the formation of its medical products group, MackMedical. Located at Mack's headquarters in Arlington, Vt., MackMedical is a focused group that includes product development, program management, quality, regulatory, document control, purchasing, sales, and production staff.

"We have been aggressively developing the medical manufacturing sector of our business for the past nine years by refining quality and supply management systems, hiring specialized staff, and adding new technology," says Jeff Somple, president of Mack Molding's Northern Division. "As a result, the medical market now represents a full 30 percent of our business, including several Class III medical devices, surgical equipment, and disposables for the orthopedic market. After this significant investment of time and resources, we now have all the markers in place to legitimately call ourselves MackMedical."

MackMedical manages all medical accounts, from upfront engineering through final manufacturing and distribution. "This is an engineering-intensive team with a medical manufacturing culture that understands the industry," explains Kevin Bradley, business unit director. "The customer doesn't have to spend time bringing us up to speed on the stringent requirements of this market."

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