Innovative developments in injection moulding for medical technology will be in focus at the upcoming K 2010 exhibition in Düsseldorf / Germany (www.k-online.de) held from 27 October to 3 November. Along with advances in process technology (co-injection, in-mould decoration, insert moulding, foam injection moulding, gas- and water-assisted injection moulding, combined processes, thin-wall technology and, increasingly, micro- and nanotechnology), the development of new types of materials is opening up additional fields of application, says fair organiser Messe Düsseldorf (www.messe-duesseldorf.de). Sterilisability, biocompatibility, antimicrobial finishes, special barrier properties, nano- and microsystems technology and biodegradable and absorbable materials are some of the catchwords.

For production of medical and pharmaceutical injection mouldings, cleanroom technology is a must, and manufacturers of injection moulding machines and cleanroom specialists are joining forces to offer a variety of custom-tailored solutions. These range from the simple and inexpensive mounting of a laminar-flow unit over the clamping plates for the injection mould to operation of the injection moulding machine in the cleanroom itself. Here, all-electric injection moulding machines are rapidly gaining ground. Compared to conventional hydraulic machines, these generate hardly any waste heat and as a result of their encapsulated drive units they are free of lubricants and other abrasive particles that might contaminate the injection mouldings.

Single-use medical articles are usually produced fully automatically and under strict quality control standards. For cost-effectiveness, every tenth of a second counts, and this is facilitated by slimmer removal systems with optimised drives. A cleanroom-compatible removal gripper launched by Hekuma (Eching / Germany; www.hekuma.com) at the end of 2009 is claimed to be the fastest removal system currently available for pipette tips, achieving linear axis acceleration rates of up to 10 g and travel speeds of up to 1,200 mm/s.

The injection moulds used for the mass production of medical technology items must be highly precise, cleanroom-compatible and at the same time economical. Along with the realisation of thin-walled products to save materials and cycle time, there is also a demand for multiple cavities and sophisticated cooling systems, says Messe Düsseldorf.

Injection moulding is now a preferred process for replacement of human body parts and components for use in inner organs. Russia’s Roscardioinvest (Moscow; www.roscardioinvest.ru/eng), for example, manufactures a new generation of tri-leaflet heart valves from a modified polyamide. The mechanical heart valve weighs only 0.25 grams. What is said to be the world’s first mould for the fully automatic, finishing-free injection moulding of such heart valve leaflets has been developed and is being produced by Köbelin Formenbau (Eichstetten / Germany; www.koebelin.com/). The trend towards miniaturisation in medical technology is also advancing apace.

High-precision components for use in minimally invasive surgery, increasingly being produced by advanced methods, are becoming steadily smaller, more complex and more precise, and as microtechnology plays an increasingly important role in diagnostics, plastics are gaining in importance. One good example is the “lab-on-a-chip”, a miniature analysis system with a network of intelligently interconnected microchannels produced far more cheaply from plastics than from glass or silicon.

Microscopically small surface structures also can be used in implant technology for the controlled growth of human cells. Researchers at the Fraunhofer Institute for Manufacturing Technology and Applied Materials Research (IFAM, Bremen / Germany; www.ifam.fraunhofer.de) are focusing on ultra-small implants. The application of micro metal injection moulding (µ-MIM) technology enables production of delicate heart valve rings made of biocompatible titanium. Even replicas of the tiniest human bone, the stirrup in the ear, can be produced in series as micro injection-mouldings made of titanium, biocompatible stainless steel or aluminium oxide, the institute says.