New Resin Targets Inserts

Design engineers are pushing for smaller and smaller electronic components, stretching materials' capabilities.

“The trend in the consumer electronics' market is for thinner and smaller devices, which can lead to extensive manufacturing challenges,” says Gerald DiBattista, a market segment leader at Bayer MaterialScience in Pittsburgh, PA. “Generally, as devices become thinner, they become less rigid. This has forced designers to either work with very expensive, light and strong metals like aluminum or magnesium, or to work with thinner plastic materials and deal with the loss in stiffness which can result in an inferior-looking product. Since plastics are still preferred because they offer better design freedom, are easier to make into complex shapes and cost less, the answer to this engineering challenge is a plastic-metal hybrid.”

One route to a hybrid is metal insert injection molding, in which metal components are positioned in a mold cavity prior to injection of the plastic resin.

CerBo Ltd. is a new design and manufacturing operation located in Sligo, Ireland, formed jointly by Phillips Plastics Corp. of Prescott, WI and Pro-Tek Medical Ltd., also of Sligo, Ireland. The creation of CerBo Ltd. will expand Phillips' global footprint. “CerBo Ltd. will offer customers increased global reach by providing design and manufacturing options for the production of medical devices in the USA and Ireland,” says Kevin Hosmer, Phillips' director of business development. “The partnership combines the strengths of both companies, allowing new and existing customers from Europe and North America access to combined technologies and global resources.” Pro-Tek Medical was established in 1995 to provide outsourcing to the orthopedic, cardiology, drug delivery, respiratory, endoscopy and vascular sectors. The company specializes in precision injection molding, finished devices assembly and fine wire forming and welding. An accomplished medical component producer, Phillips Plastics is a 43-year-old custom injection molder of plastic and metal with annual sales of more than $260 million.

Bayer MaterialScience developed the Makroblend® UT5205 resin to address the engineering expansion issues associated with metal insert molding. Plastic expands and contracts more than metal. As a result, a metal insert molding process adds stresses to the part as the plastic shrinks around the metal during cooling. Makroblend® UT5205 resin is said to reduce these stresses during the molding process, as well as in everyday heating and cooling cycles (such as when a device is left in a hot or frigid car). Chemical resistance is also improved. “This is particularly important when molding ultra-thin electronics like cell phones and MP3 players, which consumers expect to be able to take with them wherever they go,” says Nick Sunderland, a senior associate scientist at Bayer MaterialScience. Metal insert molding is also a simpler, more cost-effective manufacturing process than alternatives like die casting, which requires the use of costly metal and die-cast parts or glass-filled plastics, which are prone to fracturing and can result in poor surface finish.

A new antimicrobial agent targets medical applications. BIOSAFE meets ISO 10993-1 and USP bio-compatibility standards. In vivo and in vitro tests at independent laboratories included intracutaneous, systemic toxicity and cytotoxicity studies by the NATO Maintenance and Supply Agency (NAMSA). “Pre-qualifying BIOSAFE under these standards enables OEMs and polymer processors to reduce the risk of project failure and the resulting cost and loss of time,” says Donald J. Wagner II, BIOSAFE's vice president for business development. BIOSAFE costs less than conventional silver-based additives and forms a permanent bond with the base polymer. The bond prevents the antimicrobial from leaching, being washed away or being rubbed off. Tiny loadings of the BIOSAFE additive, ranging from 0.1 to 1.0 percent, are said to be sufficient to keep product surfaces clean and protected from the staining and degradation caused by bacteria, mold, mildew and fungi.