MicroPower will demonstrate molding of micro filter

Twelve MicroPower injection molding machines from Wittmann Battenfeld are now being used for medical applications, showing the increasing importance of micro molding in the medical market.

"Micro parts for the medical industry are medical clips, which are implanted and which are biodegradable, implantable sensor housings and micro bearings," Gabriele Hopf, marketing manager for Wittmann Battenfeld (Kottingbrunn, Austria) told Plastics Today.

At the Compamed in Düsseldorf, Germany (Nov. 14-16), Wittmann Battenfeld will produce a polyacetal filter with an 80µ grid and a part weight of 1.1 mg. The demonstration part could be used in acoustical engineering as well as in micro pumps or inhalators. It will be manufactured on a MicroPower 15/10 that has been specially developed for high-precision injection molding of nano and micro parts. The part will be produced in a two-cavity mold with a three-platen injection system.

The two-step injection unit consists of a screw and a plunger, and has a shot volume ranging from 0.05 to 4 cm³. Its auxiliary equipment being has been adapted to the production of micro parts.

The modular machine system consists of a basic platform that can be extended with a rotary disk, parts removal handling, quality monitoring and a clean-room module, extendable up to a complete production cell.

One of the benefits of the system is a thermally homogeneous melt, improving part repeatability and reducing cycle times. That's particularly important for medical molding given the high costs of plastics used in the market. Bioresorbable resins, for example, costs $1,200 to $3000/lb. Medical-grade PEEK used for implantable applications costs more than $1,000/lb.

Customers for the approximately dozen MicroPower units sold into medical applications could not be disclosed, Hopf said.

The first production model of Wittmann Battenfeld's new-generation MicroPower micromolding system, introduced at K 2010, was installed  at the RKT Centre for Polymer, Micro and Nano Technology in Bradford, UK.

At NPE2012 last April, an all-electric MicroPower produced a 28-pin micro connector with a weight of 3 mg from polyacetal with a 2-cavity tool. The parts were removed by a W8VS2 robot and checked by a camera system.