Process for thermoforming a sheet of thermoplastics and device for carrying out the process

摘要

The invention relates to a process for thermoforming a previously heated sheet of thermoplastics by means of a mould and a device for carrying out the process. In order to avoid undesired warping of the film at certain points on the sheet, e.g. at a separating line of a two-coloured plastic sheet, it is proposed to hold the sheet at these points by individual compliant needles. This can be carried out as early as during the heating by supporting the sheet using compressed air. The device for carrying out the process has a needle strip with individual height-adjustable needles, the weight of which is matched to the requirements. This needle strip is mounted on the movable tensioning frame. <IMAGE>