Krauss-Maffei brings the Fiber-Form process up to speed
The Fiber-Form technique developed by Krauss-Maffei combines the thermoforming of organo sheets and injection moulding in a single process. The result is fibre-reinforced plastic components that are simultaneously extremely lightweight and very strong. They are used primarily in vehicle manufacture. According to Paul Caprio, President of the Krauss-Maffei Corporation, this enables fibre-reinforced lightweight components "to be produced cost effectively in large quantities and fast cycle times." At the NPE Plastics Show in Orlando, Krauss-Maffei was recently able to demonstrate how efficiently the Fiber-Form process can be combined with multi-component injection moulding.
There, a GXW 450-2000/1400 SpinForm with swivel platen technology produced a central armrest for a vehicle interior. A 1-mm-thick continuous fibre-reinforced organo sheet was first encapsulated in polypropylene (PP), then overpacked with thermoplastic elastomer (TPE). According to the company, this combination enables thermoplastic composites to be endowed with an entirely new look and feel in just one process. So thanks to the TPE component, the surfaces of functional and visible parts of the central armrest produced at the NPE are extremely soft and visually appealing, This increases comfort and visual aesthetics in the vehicle interior.
Combination of Fiber-Form and multi-component technology
The use of the organo sheet in turn enhances the rigidity and strength of the component. . As a result, the reinforcing ribs and component itself have thinner walls, which reduces their weight. Krauss-Maffei sees great potential for the combination of Fiber-Form and multi-component technology in applications such as vehicle manufacture, for semi-structural lightweight components in the interior or between the passenger compartment and the engine compartment.
High quantities are one of the strengths of Fiber-Form technology, which is why Krauss-Maffei consciously chose SpinForm swivel platen technology. It offers numerous advantages over other technologies such as the rotary table, indexing plate and sliding table. Using two mould parting lines provides twice the number of cavities with the same clamping force. This increases cost efficiency. Since rotation takes place between the pair of vertical bars, SpinForm technology offers a great deal of space, even for large moulds. This makes it ideal for producing large or multiple components. Furthermore, the technology allows for the integration of special processes such as stamping.
Cycle times of less than 60 seconds
In order to reduce the cycle times of the process, Krauss-Maffei combined swivel platen technology with an intelligent automation solution and heating technology that is ideally adapted to the injection moulding process. According to the company, this multi-component process achieves cycles of less than 60 seconds. The organo sheet is initially transferred to the production cell via a simple drawer system. Optical inspection of the organo sheet ensures positioning accuracy during transfer to the mould. This guarantees that only perfect semi-finished products are conveyed to the IR 600 R3000 K/S industrial robot, and picked up by it identically every time.
Next, the organo sheet is heated on both sides in the infrared heating station and transferred vertically to the mould system. The infrared heating station is located directly above the mould parting line. This reduces the transfer time even further and minimizes the overall cycle time. In the first cycle step, on one side of the swivel platen the basic components of the central armrest are now produced with the first injection moulding unit (top and bottom shell). The top shell is created by encapsulating the organo sheet with PP, while the bottom shell is primary-cast out of pure PP. For the second cycle step, the swivel platen rotates and the components are flow-coated with TPE with the second injection moulding unit.
While the top shell (visible and functional surface) is flow-coated with TPE, the bottom shell is flow-coated selectively. Component demoulding (top and bottom shell) is then performed by the second industrial robot, an IR 600 R2030 F/K. The heating of the organo sheets and component demoulding take place in parallel, so the individual process steps are asynchronous. This also saves valuable cycle time.