Wittmann Battenfeld targets LSR micromoulding

Kottingbrunn, Austria – Wittmann Battenfeld’s latest moulding technology developments include equipment that harnesses its expertise in liquid silicone processing and the production of micro parts.

In a recent release, the Austrian company highlighted an application for the technology in a 2C process for the manufacture of a micro support ring used in industrial metrology. 

The parts – in polycarbonate from Covestro and a self-adhesive LSR from Momentive – were manufactured in an eight-cavity mould constructed in cooperation with Nexus. 

With a diameter of about 6mm, a height of 1.8mm and a total part weight of just 23mg, a stand-out feature of the moulding is the silicone membrane – only 20µm thick and weighing no more than 120µg. 

This extremely thin membrane is designed to permit accurate transmission of even minute pressure differences between two different media. 

Optimal choice of materials meant that neither high operating temperatures of up to 150°C nor difficult media presented any problems, Wittmann Battenfeld stated.

The LSR was be fed from 1litre cartridges, with the material flows metered in microlitre quantities by a liquid-dosing unit. 

Simultaneously, measured material quality was recorded and transmitted to the machine’s B8 control system via an OPC UA interface (Euromap 82.3). 

AServomix X1liquid dosing unit for LSR supplied by Nexus was a part of the overall package, which met all requirements for the production of micro parts, the company said.

Minimal flow paths, it added, combined with “optimal process control in material loading as well as further processing in the two-step injection unit of the MicroPower from Wittmann Battenfeld, specially designed for microparts injection moulding. 

“All of this provides the best possible conditions for producing top-quality micro parts with utmost repeatability. ”

The machine used for this application was a MicroPower 15/10H/10H Combimould – a multi-component unit equipped with two horizontally mounted injection units and a rotary disk, and laid out for cleanroom injection moulding. 

The connections for heating, temperature sensors, water tempering, core pull pneumatics and sensors, as well as the blow through valve, are all placed near the encapsulated rotary disk. 

According to Wittmann Battenfeld, the resulting short connection lines to the mould enhance the machine’s user friendliness. 

Similar to the standard machine, the injection units of the MicroPower multi-component model also take the form of two-step screw-and-plunger aggregates with a shot volume of 4 cm³.

Minimal flow paths enable processing of thermally homogeneous melt and consequently producing parts of excellent quality, the machine maker concluded.