JEC COMPOSITES MAGAZINE - Issue #66 - July/August 2011 - 36

thermoplastic
lightweight thermoplastic structures to other supporting structures, e.g. a supporting steel frame, to facilitate the transfer and transmission of the effective forces. State-of-the art formclosure joining technology was used to solve the issue of designing and integrating passive and active functional elements. This technology made the one-shot integrated manufacture of this component possible. The diagram also shows the aluminium insert used to transmit forces into the component, as described above. Using assembly injection moulding, ribs can be formed and the bond between the individual joining parts is created in compliance with the calculated compatibility principle specifications for optimum bond quality. Figure 6 shows the reference component. It clearly shows the ribs and the aluminium component joined using a form-closure bond. On the left, the hollow profiles are shown in magnified form. The evenness and accurate contours of the profile moulding can also be seen clearly. The FIT-Hybrid technology uses Fig. 5: Reference component design [source: NMF/LKT] process integration The diagram in Figure 5 illustrates the to shorten the process chain. This design of the reference component. results in shorter cycle times, thus Here, four custom-cut organic sheets allowing the manufacture of FRP are used. Two of them are used to components suitable for mass mould the hollow profile (FIT tubes I production. Combining different and II) according to the process component properties in one concept described above. The remaining two results in greater functional FRP preforms are used for torsional integration and optimal space stress absorption and as a cover layer. utilization. the FIT-Hybrid process results in greater lightweight construction potential. Furthermore, the use of thermoplastic-based FRPs improves recyclability.

Open structures / SpriForm
In the production of open structures using process combination and integration, the main focus is on the cost-efficient manufacture of thermoplastic-based FRPs suitable for mass production, as with the creation of hollow profiles. The process described here combines thermoplastic injection moulding and continuous fibre-reinforced thermoplastic thermoforming. SpriForm (from the German for injection moulding + thermoforming “Montagespritzgießen + Thermoformen”) combines the benefits of the individual processes in a single, robust process. Preheated textile preforms are pre-shaped using the closing movement of an injection moulding tool. In the same cycle, the products are further moulded using assembly injection, by applying a reinforcing structure – in this case ribs. The subsequent heat dissipation consolidates the component. The considerable design freedom provided by the injection moulding process makes it possible to integrate additional passive and active functional elements and modules. This process is described in more detail in Figure 8. A simple M-shaped bending beam made from an organic sheet with back-injection-moulded longitudinal ribs serves as a sample (see Figure 7).

jec composites magazine / No66 July - August 2011
Fig. 6: Technology transfer from sample to application, left: reference component with FIT hollow profile I and II, right: cross-section of FIT hollow profile I and II [source: NMF]

In principle, by combining lightweight structures (hollow profiles) with lightweight materials (FRP),

Fig. 7: Bending beam

JEC COMPOSITES MAGAZINE - Issue #66 - July/August 2011

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #66 - July/August 2011