B29C 65/1438

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 focusing the wave energy or particle radiation on the interface}