B29C 65/1441

Joining {or sealing} of preformed parts {, e.g. welding of plastics materials}; Apparatus therefor by heating, with or without pressure using wave energy {, i.e. electromagnetic radiation,} or particle radiation {characterised by the way of heating the interface at least passing through one of the parts to be joined, i.e. transmission welding making use of a reflector on the opposite side, e.g. a polished mandrel or a mirror }