Research Partners establish project for lightweight design

Editor: Eric Culp

A group of eight plastics and automation industry organisations has joined forces to create lightweight fibre-composite products for serial production.

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Project partners have developed a specially designed flexible manufacturing cell.
Project partners have developed a specially designed flexible manufacturing cell.
(Source: Georg Kaufmann)

Swiss mould maker Georg Kaufmann, Busslingen, has announced that it is co-operating with a range of companies in a project to develop the combined forming and back-injecting of organic sheets for the production of fibre-reinforced lightweight components with a thermoplastic matrix to the point of series production readiness.

The complexity of the project creates a need for teamwork

The shop said the Lightweight Integrated Process Application project, or LIPA, will be developed at its in-house tech centre. The company explained that the primary goal of the project is to develop and validate the manufacturing process for large-scale production by focusing on structural components and process control. “Decisive is, among others, integration of the different sub-processes as well as full process control and monitoring.”

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The host company said the steps required to produce a process that is ready for the factory floor cross many fields. “Due to the inherent complex correlations and interdependencies, there still exists a significant need for development work, which would typically be difficult for one company alone to handle. What promises to be successful, however, is an interdisciplinary co-operation that allows for a universal view of all the processes involved.”

From the drawing board to the shop floor

In order to provide the general framework for basic analyses, test series and component development, the shop said it and the partners have constructed a specially designed flexible manufacturing cell in Busslingen. In addition to an injection moulding machine with larger mounting plates (1920 x 1980 mm) and a clamping force of 4,200kN, its core equipment comprises an infrared heating station (1500 x 1250 mm) as well as a 6-axis robot with a weight capacity of 90 kg. The company noted that, depending on the respective development project, the manufacturing cell can be modified and expanded as needed, for example by means of a component-specific gripper system. Other equipment includes extensive sensor technology to keep track of all the parameters relevant to the process.

Market forces drive decision to start project

The main factor for setting up an independent lightweight construction development centre is the growing demand for highly stressable lightweight components with a thermoplastic matrix, the mould maker said, noting that the range for potential application is quite diverse. The company pointed out that demand is being reported in virtually all business sectors. “First and foremost by the automobile and transportation as well as the aerospace industry.” But numerous other companies such as manufacturers of household and consumer goods, sports articles and healthcare systems are said to be also showing increasing interest. The company explained that as a non-industry specific facility, the LIPA Development Center is available to interested processors, users and material manufacturers for testing – even with their own tools – as well as for development projects.

Plastic-fabric combinations outperform metals

Lightweight components made of thermoplastic semi-finished stitched and woven fabric-reinforced products excel versus comparable metal parts in terms of mechanical strength and reduced weight, which can be up to 25%. This is true for a wide range of fibre materials.

The production sequence, in short, is seen as follows: Defined preheated and thus soft and instable mats or organic sheets are placed and fixed accurately and reproducibly into the tool. When the tool closes, the reshaping process begins, whereby it is important that the hot organic sheet reforms as defined and without damage. When the reshaping process is finished, the tool closes and a regular injection process starts for integrating functional and stiffening elements into the organic sheet.

What has been problematic so far, however, is that the process is not suitable for high-volume-compatible production. In the combined process of reshaping and injection moulding, each step – primarily heating, handling, reshaping, injecting – must be perfectly co-ordinated with one another, with the tool and the handling system playing key roles. Here, development partners can benefit from more than 20 years of experience in back-injection/pressing of flexible materials such as textiles or thermoplastic sheets.

In the context of development partnerships, non-industry specific potential applications shall be investigated by considering the component design that is appropriate for the materials involved. This involves, among other things, the development of an optimal interface coordination with corresponding process control and process documentation. The latter is especially important, particularly with regard to serial production of structural components for the automobile industry.

Under the lead of GK Tech-Center AG, which is also responsible for process development and mould construction, the following Swiss co-operation partners currently participate in the LIPA project: Krelus AG, Oberentfelden, for IR systems; ASE Industrieautomation GmbH, Näfels, for automation and periphery; Kistler Instrumente AG, Winterthur, for manufacturing process control and sensor technology; and Quadrant Plastic Composites AG, Lenzburg, for organic sheet and material development. Furthermore, the project is supported by the German-based partners Krauss Maffei Technologies GmbH, Munich; Kuka Roboter GmbH, Augsburg; and the Institute of Lightweight Engineering and Polymer Technology (ILK) at Dresden University.