Vacuum forming of thermoplastics is a cheap, rapid and clean technique for the production of a.o. large-scale panels and structures. Due to the large deformations the material has to undergo, the technique so far has been limited to unreinforced thermoplastics.

A similar technique, however, is also suitable for the forming of continuous- (CFRPs), long- (LFTs/GMTs) and short fibre (SFRPs) reinforced thermoplastics. This will open vacuum forming as a production method for semistructural and structural parts due to the high material stiffness and strength associated with fibre reinforced thermoplastics. Furthermore, vacuum forming has some additional advantages over the traditional forming methods of composite materials:

All of the above can add to a significant cost reduction over traditional forming methods of thermoset and thermoplastic composites whilst maintaining their elevated properties.

Due to the inherent advantages of the technique, vacuum forming of thermoplastic composites is a promising new technique for the rapid and low-cost production of large-scale panels and structures for application in the automotive and other industries, as an alternative for the current, costly techniques. However, in order to make optimum use of the potential this technique offers, a more thorough knowledge of the production process and the resulting properties of the final products is needed.

Application of earlier research into the production and processing of continuous fibre reinforced thermoplastics to vacuum forming of these materials within CLS has led to a prototype process, as schematically depicted in the following figures.

The thermoplastic composite material is first put under vacuum in between elastomeric diaphragms (fig. a). While the vacuum is maintained, the package is heated to the forming temperature in an infrared oven or between hot plates (fig. b). The heated package is then transferred over the mould where vacuum is applied between the mould and the package and the product is formed (fig. c). If required, additional pressure can be applied on top of the package. After cooling down, the vacuum between the diaphragms is removed and the product can be taken out (fig. d). A suitcase shell produced following this technique on our prototype production line, is shown in the above pictures.

We propose a joint project aiming at acquiring and transferring expertise on the vacuum forming process for thermoplastic composites, application of the process to a final product and further development of the process to an industrial level. The project will focus on the following items:

The current project is planned to cover further development and up-scaling to an industrial level of the vacuum forming process and determination of opportunities the different thermoplastic composites offer. During the project, the following topics are envisaged:

We seek partners covering the complete path from raw materials to final product: