Medical Device Link.

Thermoset elastomers

Custom Molding of Thermoset Elastomers (Munich: Hanser Gardner, 2009) is designed to educate potential customers, explains author Bernie Stritzke, Vice President and General Manager of US-based custom moulder MedPlast. Medical product manufacturers typically have an excellent understanding of elastomers, he says, but they lack knowledge of materials processing. “I’m often asked: Why is one process preferred over another for my part? This book helps explain the logic behind the choice and helps our customers make the right decisions,” says Stritzke.

Stritzke comes from a mechanical engineering background and has been in the elastomers field for more than 25 years. While other books have been written about elastomers, they tend to come from a chemist’s perspective, he explains.

Custom Molding of Thermoset Elastomers concentrates on the processing of thermoset millable elastomers and liquid silicone rubber. Emphasis is placed on compression, transfer and injection moulding, as well as hybrid moulding techniques involving insulated delivery systems and flashless methods. The book will serve as an educational piece for those who already have a working knowledge of most moulding methods.

“Elastomer processing is often characterised as more difficult to understand than traditional plastic or liquid silicone injection moulding,” says Stritzke. “This is because it is usually necessary to develop custom elastomer formulations for certain applications. There are more variables and more design decisions to be made when working with elastomers, and it is critical that the compound formulation is appropriate for the processing technique being used,” adds Stritzke.
Medplast
Tempe, AZ, USA
www.medplastgroup.com

Industrial solutions selector

New literature from a supplier of joining technologies provides detailed information on the company’s line of adhesives, sealants, metal pretreatments, coatings, cleaners and metalworking fluids for a range of industrial assembly applications. The 84-page Industrial Solutions Selector Guide is broken down into 12 industrial application categories, including medical devices and equipment.

The literature also provides detailed information on 12 categories of products: surface preparation, cleaners and conversion coatings; autodeposition coatings; chemical specialties; metalworking fluids; hot-melt adhesives; structural adhesives; elastomeric adhesives; potting, moulding and encapsulating compounds; seam sealants; energy, NVH and fluid management; water-based adhesives; and integrated equipment solutions.
Henkel
Düsseldorf, Germany
www.henkel.de

Direct metal laser sintering

A manufacturer of laser sintering systems has published a white paper explaining the benefits of using direct metal laser-sintering (DMLS) to create tooling inserts. Optimised Mould Temperature Control Procedure Using DMLS combines descriptions of moulding innovations with documented field results—time, cost savings and quality increases—taken from injection-moulding projects that use DMLS-derived tooling. Laser-sintered mould inserts can drop cycle times in injection moulding by up to 60%, according to one user of the manufacturer’s laser sintering systems who is cited in the white paper. Another important benefit of DMLS in injection moulding is a significant reduction in scrap rates.

Cooling time can account for up to 70% of injection moulding cycle times. Traditional methods of creating heating and cooling channels in moulds involve straight-line drilling, which is limited in its ability to develop channels that reach critical hot spots. DMLS enables built-in, conformal cooling channels that can be optimised to draw off heat more rapidly and more evenly, dramatically reducing cycle time and increasing part quality by eliminating warpage and other defects.
EOS GmbH Electro Optical Systems
Krailling, Germany
www.eos.info

Cable particulation study

A white paper presents the results of a cable particulation study conducted by the Fraunhofer Institute for Manufacturing Engineering and Automation IPA at the behest of Gore. The study measured the particulation of four different cable systems for ISO cleanroom certification: two cable chains with flexible flat cables from Gore; one trackless cable, also from Gore; and a cable chain with round cables from an unnamed manufacturer. To identify the source of potential particulation for the two chains with flat cables, Gore selected two nonmetal cable chains to use in the test. One was a low-vibration cable chain while the other had a conventional chain design with links and pins.

Designing cable systems that reduce friction is the key to achieving low particulation from these components, according to Paul Warren, Gore’s Lead Design Engineer. “Because of the significance of particulation in cleanroom environments, we wanted to verify the relationship between friction and particulation in various types of cable systems,” says Warren. Using criteria set forth in Guideline VDI 2083 and ISO 14644-1, Fraunhofer calculated the amount of particles at three separate measuring points for each cable. The test registered zero particulates for both the trackless and flexible flat cables in the low-vibration chain. The conventional chain with flexible flat cables emitted particles at rates of 0.1 to 1.7 particles per cubic foot, depending on the velocity; the conventional chain with round cables was also affected by velocity, emitting 0.0 to 2.5 particles per cubic foot.
Gore
Newark, DE, USA
www.gore.com