B29C 65/7416

Joining {or sealing} of preformed parts {, e.g. welding of plastics materials}; Apparatus therefor by welding and severing {, or by joining and severing, the severing being performed in the area to be joined, next to the area to be joined, in the joint area or next to the joint area characterised by the relationships between the joining step and the severing step characterised by the pressure relationship between the joining step and the severing step the joining step and the severing step being performed at different pressures}