| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To obtain a control method capable of conducting stable dielectric heating in a high-frequency dielectric heating device, particularly, welding in a stable welding state in a high-frequency welder. <P>SOLUTION: The high-frequency dielectric heating device is used for catching a heating object 5 of a sheet material made of a thermoplastic synthetic resin such as a polyvinyl chloride resin or a polypropylene resin of a dielectric material by a pair of high-frequency electrodes 4 to weld or heat the heating object by high-frequency dielectric heating between the high-frequency electrodes 4 (41 and 42). The impedance of the heating object is changed in response to a heating temperature, and stabilized in a molten state. Then, the rate of change of a high-frequency current supplied to the high-frequency electrode 4 or the rate of change of a phase difference between a high-frequency voltage and a current detected by an automatic matching circuit 3 is detected, and when the rate of change reaches a stable region of zero or below a certain value, it is determined that the heating of the heating object 5 is completed and the high-frequency current is cut off. Thereby, the heating object 5 is completely welded or welded under an optimum condition without being overheated. <P>COPYRIGHT: (C)2005,JPO&NCIPI</p> |
