Maximum temperature control of welding blade heater band for heat impulse welding of thermoplastic films in which a sensor converts axial movement of a moving band into signals for control of current impulse

摘要

One end of the heater band(14) is fixed to a welding blade(10). The other end is under tension and has guided movement axially along (10). Movement of the guided end during a current impulse is converted by a sensor(40) into a path-dependent electrical signal controlling the current impulse during impulse duration so that a maximum extension, corresponding to a specific temperature of (14), is not exceeded. One end of the heater band(14) is fixed to a welding blade(10) and the other end is under tension and has guided movement axially along the blade. Movement of the guided end during a current impulse is converted by a sensor(40) into a path-dependent electrical signal. The signal controls the current impulse during impulse duration so that a specified maximum extension, corresponding to a specific temperature of the heating band, is not exceeded. The same method may be used in conjunction with a second heater band attached to the blade in the same way. The guided moving end of the heater band(14) is connected to a magnet(34) whose movement is converted into a path-dependent electrical signal by a Hall Effect sensor(40). An independent claim is included for a welding blade with a heating band used in the claimed process.