DEVICE AND METHOD FOR WELDING OF THERMOPLASTIC MATERIALS Russian patent published in 1999 - IPC

FIELD: mechanical engineering. SUBSTANCE: this is intended for joining by welding of thermoplastic materials or materials with thermoplastic coating, preferably packaging materials. This is done by means of heating and compressing them together within zone of welding so as to fuse together surfaces of thermoplastic layers placed one upon other to produce continuous and mechanically strong and durable welded joint. This also relates to manufacture of device intended for realization of aforesaid method. Welding device is made in the form of welding clamp consisting of two welding jaws which are located so as to be movable relative to each other. Welding jaws are arranged so as to allow for placing of material between them intended for welding. At least one welding jaw is provided with layer of electrically insulating ceramic material and also with at least one continuous electrically conducting core. This continuous conducting core is made of electrically conducting ceramic material and is imbedded in electrically insulating ceramic material. Ends of continuous conducting core have points connected to source of electric current. According to method of manufacturing welding clamp, combined into single unit is insulating ceramic material and at least one electrically conducting continuous core. Before combining into single unit, insulating ceramic material and continuous core are shaped as required by pressing or moulding. Combined unit is subjected to heating at temperature of up to 1600-1900 C under pressure of higher than 100 MPa during at least 120 min. In result of this procedure, ceramic materials are fused together to create dense and poreless article of high hardness and resistance to abrasive wear. Application of aforesaid method and device allows to perform welding over curved welding lines to produce welded joints with adhesive force and strength which are different over length of joint. EFFECT: higher efficiency. 9 cl, 4 dwg