JEC COMPOSITES MAGAZINE - Issue #62 - January/February 2011 - 35

injection

Thermoforming and injection moulding in a single mould
Georg Kaufmann Formenbau AG, Busslingen, Switzerland, has just launched a combined thermoforming and injection mould. KraussMaffei Technologies GmbH demonstrated this “organo sheet mould” in fully automatic operation on a CX 300-1400 IMC.

he mould is used for the production of a lightweight structural component for a passenger car. The dynamically loaded component is made from a semi-finished glass-fibre-reinforced thermoplastic composite called organo sheet, and stiffened with moulded-on ribs. The organo sheet is thermoformed and then provided with the moulded-on stiffening ribs, all in the same mould.

Innovative combination
This innovative combination of thermoforming and injection moulding processes requires a production system where the individual process stages are exactly coordinated and synchronized with each other. This is where the organo sheet

mould plays an essential role in terms of both product quality and process reliability. For the first stage of the process – thermoforming of the organo sheet – the cut-to-size sheet, which has been preheated and is therefore very soft and unstable, must first be positioned in the mould with absolute, reproducible accuracy. The mould closing operation commences with the advance stroke of a female mould insert, which presses the organo sheet onto the male mould half and holds it there. The actual thermo-forming operation now takes place: the sheet is drawn over the male mould half and its peripheral edge is held in place by means of clamping strips that are shaped three-dimensionally so as to match the contours of the moulded part. These clamping strips must be set with extreme precision in order to allow the hot organo sheet to flow freely without sustaining any damage or deterioration.

Innovation through partnership
This project demonstrates quite impressively how a project involving many partners can be implemented quickly and successfully all the way through to series production. Other partners in this technology-bridging project besides KraussMaffei Technologies GmbH and Kaufmann were Jacob Composite GmbH, Audi AG, Lanxess Deutschland GmbH and Bond-Laminates GmbH. In addition, when it came to optimizing the processing sequences in the mould, gwk Gesellschaft Wärme Kältetechnik mbH contributed specific know-how in the field of temperature control; Incoe Europe, in hot runner technology; and Kistler Instrumente AG, in measuring technology.

No62 January - February 2011 / jec composites magazine

parts of the structural component that could not be filled during the thermoforming operation are now fully moulded to shape. As many as six companies and organizations were involved in this future-oriented, technology-bridging project. Despite the complexity of this involvement, the project was implemented within a very short period of only six months. Within three months of receiving the initial component specifications for designing the mould, Kaufmann was already commencing the mould trials in its own pilot facility.

Controlled pressure and temperature

Teamwork

The mould remains in its closed position at the end of the thermoforming process. The melt for the mouldedon stiffening ribs, consisting of a glass-fibrereinforced polymer, is injected via three injection nozzles and bonds completely with the organo sheet. In addition, the melt flowpaths ensure that those

This combined thermoforming and injection mould for organo sheet processing is equipped with more than a dozen sensors for pressure and temperature measurements. Not only do they monitor the flow of the organo sheet during the thermoforming operation, the injection of the polymer melt and the complete moulding to shape of the structural component, they are also necessary to make these operations better understandable for future applications. Further organo sheet moulds will also be equipped with sensors (although perhaps not as many), as they are absolutely indispensable when it comes to process monitoring and quality documentation in applications involving the production of safety-relevant parts. n
More information: www.gktool.ch

Feature automation

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JEC COMPOSITES MAGAZINE - Issue #62 - January/February 2011

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #62 - January/February 2011