Patent ID: 8916241

Claim:
A method for controlling an actual spray duration time of a coating gun that sprays coating material onto a surface of a container during a coating operation, comprising the steps of: detecting rotational speed of the container to determine the number of revolutions of the a can during a time period, generating a trigger signal to the coating gun during the coating operation based on said detected rotational speed, said trigger signal having a trigger signal duration to turn the coating gun on to spray coating material from the coating gun onto the surface of a container and to turn the gun off to terminate the spraying of coating material from the coating gun; detecting changes in the pressure of the coating material supplied to the coating gun during the coating operation; generating a pressure signal that is a function of said detected pressure changes detected during the coating operation; determining an actual spray duration based on said detected pressure changes during the coating operation; comparing said actual spray duration with said trigger signal duration and if said actual spray duration is longer than said trigger signal duration then decreasing said trigger signal duration of a subsequent coating operation, and if said actual spray duration is shorter than said trigger signal duration then increasing said trigger signal duration of a subsequent coating operation.