METHOD AND HEATING DEVICE FOR THERMOFORMING

摘要

The present invention relates to a method and a heating device for thermoforming thermoplastic semi-finished products. According to the method locally different thermoforming behaviour during shaping to give a three-dimensional moulded part is achieved by locally different heating of the semi-finished product (1). Two contact heating devices (2) are used for the heating of the semi-finished product (1) and are brought into contact with the semi-finished product (1) simultaneously from opposing sides. Each contact heating device (2) comprises an individual heating circuit (6) formed of a ceramic heating layer on a thermally-insulating support (7), the locally different heating being achieved by means of a locally differing geometrical design of the heating circuits (6) on the support (7). The method and the heating device permit selective control of the wall thickness distribution in the moulded part to be produced without the use of prestretching male moulds or radiant heaters.