Integrated Gripping-system for Heating and Preforming of Thermoplastic Unidirectional Tape Laminates

Forming and overmolding of thermoplastic multi-layer UD-tape laminates has become increasingly important due to its potential for large-scale production. In the process the tape laminates have to be heated above melting temperature of the polymer in an infrared heater and then transported into the mold. To guarantee the formability of the laminate the temperature has to be maintained above the melting temperature during handling. To improve part quality a preforming of the tape laminate prior to overmolding is preferable. Integration of the preforming step in the handling process allows the shortening of the process route. In this work a gripping-system which allows further heating and preforming of the laminate during the handling process is presented. The temperature losses during transport have been modelled using the Stefan-Boltzmann law. By means of temperature measurements it is shown, that the integrated infrared-heaters allow a compensation of the cooling during handling, resulting in lower maximum heating temperature in the upstream infrared heating field and therefore a reduction of heating time and degradation of the polymer. ... mehrThe repeatability of the handling-integrated preforming has been evaluated using three-dimensional overlays of the resulting 3D-shaped laminates acquired by a laser scanning arm.