FILM WELDING BY MICROWAVE HEATING WITH LOCALIZED ADSORBER
Original Publication Date: 1994-Jun-30
Included in the Prior Art Database: 2004-Apr-07
Xerox Disclosure Journal
Disclosed is a process and apparatus where microwave energy is used to thermally weld two plastic film materials so that a continuous film surface, such as an endless belt, is formed. The plastic film materials are such that they can be melted by heating. The film materials are overlapped with a metal conductor located at the center of the overlapped region. The microwave energy is adsorbed by the metal conductor which is, in turn, heated to a temperature such that the surrounding plastic film material melts and combines to form a continuous plastic region. The molten plastic solidifies with cooling, after the removal of the microwave energy, to form an excellent mechanical bond between the two films with the metal conductor embedded at or near the center of the weld region. The advantages of this method for welding two plastic films are that the heat is applied directly at the interface of the two films and thus efficient heating occurs, and the surfaces of the film adjacent to the bond are not thermally distorted by the welding process. The bonding process for end sections of thin, flexible, multi-layered film, overlapping first and second ends of the film to be bonded; placing a metal conductor between the overlapping first and second film ends; clamping the metal conductor between the overlapping first and second film ends; and applying microwave energy from a microwave energy source to the overlapping first and second film ends, with the metal conductor disposed therebetween, to evenly heat the metal conductor causing the overlapping first and second film ends to melt and mix in the vicinity of the metal conductor, to form a mechanical bond after cooling and upon removal of the microwave energy.