Abstract
Liquid packaging machine processes fast moving plastic film and produces liquid packaging bags continuously. The machines use rotary tools and coordinated velocity control of them. Two control schemes have been applied to produce arbitral size of bags. One is two-steps velocity control of the seal roll and second is a synchronous motion control of seal roll and cut roll. Previous machines employed programmed velocity pattern and the motion controller to achieve the pattern precisely. This paper proposes a simple control system, which switches the velocity command of the motor driver by using a positioning dog attached at a roll axis. The control system adjusts the high or low feed speed command according to the angles of feed roll based on the feedback control schemes. In order to examine the practical problems, a simple film processing machine was developed and experimental results using the machine shows that the proposed control system can be applied to actual machines.
