Georg Kaufmann Formenbau AG presents GK LIPfibre mould technology

Lightweight design, the future technology: Enormous response from automotive and aviation industries

At the K 2010, Georg Kaufmann Formenbau AG, Busslingen/Switzerland, made the public début of its newly developed moulding technology GK LIPfibre (Georg Kaufmann Lightweight Integrated Process fibre). This moulding system, which consists of a combined thermoforming and injection mould, produces lightweight structural components from glassfibre reinforced thermoplastic composites. Such parts are distinguished by their high strength and rigidity and are 25% lighter than comparable metal components. Enormous interest was shown in this innovative moulding and processing technology, especially by visitors from the automotive and aviation industries, but also for other applications throughout the plastic industry.

Demonstrated at K 2010 was the scrap-free production of a passenger car side impact protection component on an injection moulding machine from KraussMaffei. The entire project was realized in close collaboration with Audi AG, KraussMaffei Technologies GmbH, Lanxess Deutschland GmbH, Bond-Laminates GmbH, and Jacob Composite GmbH. For the production of this dynamic impact modifier, a flat pre-heated sheet of fabric and glassfibre reinforced thermoplastic is first thermoformed and remains in the now closed mould. Then in a second step, in the same mould, it is enhanced by adding reinforcement ribs, corners, and edges. The material for the ribs is a glassfibre filled polymer.

This innovative combination of thermoforming and injection moulding requires a production system in which the individual process steps are exactly coordinated and synchronized with each other, in order to guarantee the required product quality and process reliability. The first stage of the process - the thermoforming of the glassfibre-reinforced thermoplastic composite sheet - begins with a special cavity insert that presses the sheet onto the core and holds it in place. During the thermoforming the sheet may not develop any creases. Also important is the orientation of the fibres in the now formed sheet, which is predetermined according to the functionality of the part.

The mould remains in its closed position at the end of the thermoforming process. The melt for the overmolded ribs, consisting of a glass fibre reinforced polymer, is injected via a hot runner system and bonds completely with the thermoformed sheet. In addition the melt flow ensures that all sections of the part are fully formed and filled.

The research production mould was equipped with several sensors for pressure and temperature measurements. They monitored the various process stages, the shaping of the glassfibre reinforced sheet during thermoforming, the injection of the polymer melt, and the complete filling of all corners and edges of the part. The recording of the measurements during these operations will help to better understand the requirements for future applications. Future moulds of this type will be equipped likewise with considerably fewer sensors to monitor the different steps in the process. Detailed production documentations for safety relevant parts are then available.