Automation of an index cutting machine with NanoJ
The customer in question controlled the precision feed control of the punching knife in an index cutting machine with an SMCI47-S-2 and Nanopro. This solution was to be automated in such a way that a PLC integrated in the line could move to the individual punching positions. The teach-in for a new order continued to be carried out on a laptop. However, the function of the inputs and outputs was programmed in the SMCI47-S with NanoJ so that the program could be very simply configured on the superordinate PLC. For index cutting, it was necessary to move to up to 31 individual index positions, each with a separately adjustable length. These positions are saved by the machine setter in individual positioning records of the motor controllers via Nanopro. The precision feed control of the punch is controlled by the PLC over five digital inputs of the SMCI47-S and the home switch is connected to the sixth input of the controller:
|INPUT 1-||"Emergency off" 2-||"Next position" 3-||"Start reference run" 4-||"Move back to last position" 5-||"Reset to target position 1" 6-||Homing switch|
After the machine is switched on, the PLC uses Input 3 to first carry out homing to the home switch connected to Input 6. The machine is then moved to the next punching position by a signal on Input 2. If the operator notices that the punching is unprecise, the machine can be moved back one position each time via Input 4 and the punching is repeated. When all indexes of a book are punched, the counter is set back to the first index position again via Input 5. If the operator presses the emergency stop button on the machine, the motor is brought to a controlled stop via Input 1.
Safeguarded against scrap using encoder monitoring
The motor selected was an AP8918M6404-E with protection class IP65 that is not adversely affected by the dust that occurs during the punching process. The rotary encoder integrated in the motor is monitored by the SMCI47-S and ensures that the motor controller registers an error if there is any mechanical stiffness or blockage, for example, to prevent the index from being brought to the wrong position.