Maintenance of Moulding Machines

Control System on Injection Moulding Machines is like human brain, but there is no protection systems like human skull. So it is upto end user to take care of the Electronics of the Machine carefully.

Frequent power outages are the major culprit for Electronic Systems. So it is highly recommended that 1kVA on-line ups will solve such problems.

Proper Earthing is vital for the correct operation of Control System on the Injection Moulding Machine.

All the inductive loads like Solenoid coils, Contactors, Relays generate spikes in excess of 1000v when goes off and shall be suppressed properly. Otherwise the spikes will damage electronics of the control systems. For AC solenoids installing a snubber is mandatory.  Snubber consists of a capacitor of the value 0.1uF/400-800V in series with 50-100 ohm Resistor. snubber cables should be as short as possible.  If solenoid is a DC coil then free-wheeling Diode to be connected across the Coil in reverse polarity.i.e Anode of the Diode to be connected to negative terminal of Solenoid and Cathode of the Diode to be connected to positive terminal of Coil. Usually all the PLCs come with in built Diode. But to get the best result Diode to be placed right across the Coil Terminals.

Due to the Shortage of Power, now many Industries are installing Inverter (Drive)  for AC Motor of Injection Moulding Machines. These inverters produce lot of  harmonics on the supply line which are very much dangerous to the Electronic Systems. To suppress these harmonics suitable chokes to be used on both input and output side of the inverter. Again the distance between Inverter and Input choke is to be shorter. DO NOT EVER  install AC Drive  without input Choke.

Though these are very simple solutions, but are ignored by most of the Maintenance Engineers.

Haribabu