Method and apparatus for thermally joining thermoplastic fiber composite components, and cover for a pressurization device suitable for this purpose

An apparatus for thermally joining thermoplastic fiber composite components, the apparatus comprising:

• a pressurization arrangement for jointly covering, at least in a region of a joining zone, thermoplastic fiber composite components to be joined and applying pressure to the thermoplastic fiber composite components to press the thermoplastic fiber composite components against one another, at least in the joining zone, the pressurization arrangement being flexible, at least in some section or sections;
• and
• a welding device configured for welding the thermoplastic fiber composite components in the joining zone during pressurization;
• wherein the pressurization arrangement and the welding device are configured to weld the thermoplastic fiber composite components in a pressurized state in the joining zone;
• wherein the pressurization arrangement is a vacuum arrangement configured to maintain pressurization independently of the welding device by applying a vacuum until the thermoplastic fiber composite components in the joining zone solidify;
• wherein the welding device is a resistance welding device, and the vacuum arrangement has a cover for maintaining the vacuum on a top side and/or a bottom side of the thermoplastic fiber composite components, wherein the cover comprises a substantially flat and flexible directionally conductive diaphragm that is electrically conductive in a direction normal to a main surface of the cover and is electrically insulating in directions along the main surface of the cover, and wherein the cover is configured to transmit a welding current of the welding device into the joining zone while maintaining an airtight connection over the thermoplastic fiber composite components during the applying of the vacuum.