Wittmann showcase micro parts made of LIM and thermoplastic at Compamed

At Compamed, the international trade fair for medical suppliers and product developers being held in Düsseldorf, Wittmann Battenfeld is demonstrating its expertise in liquid silicone processing by manufacturing a membrane made of thermoplastic and liquid silicone for a micro loudspeaker.

The membrane is manufactured on a MicroPower15/10H/10H Combimould with a single-cavity mould supplied by Starlim Spritzguss, Austria. The machine is a MicroPower in multi-component version. It is equipped with a 2-step screw-and-plunger thermoplastic aggregate and a 2-step screw-and-plunger LSR aggregate as well as a rotary table integrated in the machine. The rotary table takes care of turning the part towards the second injection unit and back. The machine is also laid out for clean-room injection moulding. Its rotary table is completely encapsulated. All connections for heating aggregates, temperature sensors, water tempering, core pull pneumatics and sensors, as well as the blow-through valve, are installed close to the rotary disk. The resulting short connection lines to the mould enhance the machine’s user friendliness.

The choice of a single-cavity mould serves to demonstrate the high precision of the mould in combination with the machine, which is specially designed for the production of micro parts. It is often necessary to build costly multi-cavity moulds already at the prototyping stage for the sole purpose of reaching the necessary minimum throughput of the machine.

The LSR metering pump supplied by EMT Dosiertechnik, Germany, is a 1-litre cartridge system developed for extremely small metering volumes. Smooth, continuous emptying of the cartridges ensures highest precision together with consistent quality. Another advantage is the blending section reduced to a minimum, with the special benefit of rapid cleaning and minimal material loss with every material changeover.