jzhvymetal
Member
I need some suggestion for calculations for an intermittent unwinder. The system consists of a servo controlled nip roller that moves film to a predetermined length and time. Then the nip roller delays for the remaining process on the machine. During the machine cycle the unwinder should continue to unwind if the machine gets consecutive machine cycles. Since the nip roller does not continuously index through the machine cycle I need a way to allow the unwind roll to slow down but not stop.
The film goes through a web with a dancer that has a senor to measure the position. The unwind roll diameter is being calculated via an ultrasonic sensor. Unlike a continuous unwind system I want the dancer to move up and down based on predetermined distance.
I would like to come up with equations that can calculate the speed required for VFD controlling the unwind roll. I know a PID loop is also required to compensate for error caused by slip, diameter error, and registration correction in the index.
I need some suggestions how to implement it.
I can calculate and have the following:
Nip Motion Profile: Triangular
Nip Index Time
Nip Index Length
Nip Expected Dwell
Machine Cycle Time= Nip Index Time + Nip Expected Dwell
Nip to Unwinder Ratio
Nip to Dancer movement Ratio
Dancer Movement Range Up/Down
Unwind Max Speed
Unwind Min Speed
Does anyone have experience in similar systems? [FONT="]Any suggestions are welcome.[/FONT]
Thanks
The film goes through a web with a dancer that has a senor to measure the position. The unwind roll diameter is being calculated via an ultrasonic sensor. Unlike a continuous unwind system I want the dancer to move up and down based on predetermined distance.
I would like to come up with equations that can calculate the speed required for VFD controlling the unwind roll. I know a PID loop is also required to compensate for error caused by slip, diameter error, and registration correction in the index.
I need some suggestions how to implement it.
I can calculate and have the following:
Nip Motion Profile: Triangular
Nip Index Time
Nip Index Length
Nip Expected Dwell
Machine Cycle Time= Nip Index Time + Nip Expected Dwell
Nip to Unwinder Ratio
Nip to Dancer movement Ratio
Dancer Movement Range Up/Down
Unwind Max Speed
Unwind Min Speed
Does anyone have experience in similar systems? [FONT="]Any suggestions are welcome.[/FONT]
Thanks