Faster wet compression moulding of lightweight structural materials

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The mass production of fibre-reinforced structural materials requires an efficient production method, such as that made possible by so-called wet compression moulding, or WCM. Hennecke has now further enhanced the WCM process. According to the company, what makes its WCM process different is that the reactive mixture is applied to the fibre fabric as a liquid film, without contact. The film is applied either by a robot-guided process in a separate workstation, or directly in the mould. In the separate workstation, the fibre fabric is guided under the WCM nozzle of the mixing head by one or more robots. 

At this stage, the reactive mixture is applied to the fibre fabric. The robot then places the impregnated fibre fabric precisely in the mould. The press and mould close together, ensuring the reactive plastic is distributed evenly. After curing, the finished component can be removed for trimming. Compared to HP-RTM technology, the WCM process places significantly fewer demands on production, particularly where the complexity of the mould is concerned. 

Producing complex geometries using the WCM process 

The use of WCM technology means that the material can also be applied directly in the lower mould if complex geometries or large components are involved. The lower mould is typically extended out of the press to ensure optimum accessibility. After the material has been applied, the mould moves into the press, whereupon it closes and the curing time also begins. 

The WCM nozzle developed by Hennecke differs from commercially available nozzles in that it has an improved wide slot, can be exchanged easily and also has various safety features. During the development of the WCM nozzle, the focus was on quick and easy maintenance. Consequently, a single operator can position the nozzle in a matter of seconds or replace it during maintenance.