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Polymechplast Machines Ltd
Leading Manufacturer & Exporter of Thermoplastic Injection & Blow Moulding Machines
An ISO 9001:2000 Certified Company
 
FAQ
Processing Tips
Injection Moulding Machine
PBM Blow Moulding Machine
 
 
 
 
 

FAQ_____________________________________________________________________

1) Injection Moulding Machine :

Que: Motor Does Not Start ?

Low Voltage.
Over-load relay trip.
Fuse of Motor Protection off.
Fuse of control voltage blown off.
Loose contract at motor ON push button.
Loose contact at contactor.
Loose contact at circuit connections.
Defective coil of contactor.
 
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Que: Motor starts but stops when push button released ?

Self holding circuit loose.
Check connections of self holding circuit.
Poor contact of contactor. Clean contacts of contactor.
 
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Que: Heater band failure ?
Heater band not fixed securely.
Fix the heater band in proper position.
Tighten the clamping screw of heater band.
Suddenly increase in voltage too high Check voltage (220 V 240V)
Any joints cuts with heater band. Check continuity. Join the joints
properly.
 
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Que: Mold does not close ?
Check out put signal of 'MOLD CLOSE' (in HAND operation)
Defect of loose connection of solenoid valve coil.
Check solenoid valve coil connection if loose, tightened it. Check continuity of solenoid valve coil if burnout replace it. Disconnect solenoid valve coil. Join the Connection.
Check the circuit according to the electrical circuit diagram.
Safety gate open (in semi/fully automatic operation)
Close the safety gate properly.
Defective cycle timer (in semi/fully automatic operation) Replace cycle timer.
Low hydraulic pressure. Increase to required level.
 
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Que: Mould does not open ?
Check out put signal of 'MOLD OPEN' (in HAND operation)
Defect of loose connection of solenoid valve coil.
Poor contact or loose connection of proxy switch.( in semi /fully automatic operation)
Join the connection properly. Replace if necessary.
Increase hydraulic pressure (in all operation)
Check hydraulic pressure if it is below the required pressure, increase the hydraulic pressure.
Defect or loose connection of solenoid valve coil. Defective coil of solenoid valve.
 
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Que: Injection not effected ?
Check out put signal of 'INJECTION' (in HAND operation)
Check circuit according to circuit diagram.
Defect or loose connection of solenoid valve coil. Defective coil
of solenoid valve.
Join the connection properly. If Coil is defective than replace.
Low temperature (In all operation) Check heater connection and
condition. Increase temperature as per requirement. Replace the
better heater band if necessary.
Defective torpido. Replace if necessary.
Injection pressure is too low (in all operation) Check injection pressure. Increase injection pressure as per requirement.
For PLC based control refer operator instructional manual.
 
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Que: Screw does not rotate or refilling is not effected ?
Check out put signal of 'REFILLING' (in HAND operation)
Check circuit according to circuit diagram.
Defect or loose connection of solenoid valve coil. Defective coil
of solenoid valve.
Join the connection properly. If Coil is defective than replace.
Low temperature (In all operation) Check heater connection and
condition. Increase temperature as per requirement.
Back pressure too high Decrease backpressure as per requirement.
Loose contact, connection or defective proxy/limit switch. Check
continuity. Join the connection properly. Adjust proxy/limit switch . Replace proxy/limit switch if required.
For PLC based controller refer the operator instructional manual.
 
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Que: Temperature control out of order ?
Reading of temperature value too high or too low than heated portion. Check loose connection of thermocouple. Join connection properly Thermocouple seats not proper. Fix thermocouple with proper spring tension. Thermocouple connection (negative and positive) are open or short. Join the connection of negative and positive properly. Defective thermocouple, replace with new thermocouple, if necessary.
Check the OUT PUT SIGNAL of heating.
Check the loose contact or connection of heating contactor. Replace the contact or contactor if necessary.
 
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2) PBM Blow Moulding Machine :

Que: Mould Does not close ?

  IN ALL OPERATION
 
Low pneumatic pressure
Blow pin is ‘IN' position
Poor connection or disconnected solenoid valves PY17.
Defective solenoid valve
Disconnected circuit
  IN HAND OPERATION
 
Loose or disconnected mold close out put
  IN FULY AUTOMATIC OPERATIONS
 
Loose or disconnected circuit
 
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Que: Mould Does not open ?

  IN ALL OPERATION
 
Low pneumatic pressure
Poor connection or disconnected solenoid valve PY26.
Defective solenoid vale or coil.
Disconnected circuit
  IN HAND OPERATION
 
Loose or disconnected circuit
  IN FULY AUTOMATIC OPERATIONS
 
Loose or disconnected circuit
 
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Que: Shooting 'IN' not effected ?
  IN ALL OPERATION
 
Low air pressure
Defective solenoid valve PY25
  IN HAND OPERATION
 
Loose connection or disconnected out put
  IN SEMI OR FULLY AUTOMATIC OPERATION
 
Loose or disconnected circuit
 
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Que: Blowing not effected ?
  IN ALL OPERATION
 
Low air pressure
Defective solenoid valve PY1
Defective solenoid valve coil
Loose connection or disconnected
Defective quick exhaust valve
  IN HAND OPERATION
 
Loose connection or disconnected circuit
  IN SEMI OR FULLY AUTOMATIC OPERATION
 
Loose or disconnected circuit
 
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Que: Shooting out not effected ?
  IN ALL OPERATION
 
Low air pressure
Solenoid valve defective PY4
  IN FULLY AUTOMATIC OPERATION
 
Loose or disconnected circuit
 
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Que: Overcoming operation hindrances ?
  DULL INTERNAL SURFACE
 
Increase processing temperature
Increase screw speed
Polish the core
Check the function of heating system
  DULL EXTERNAL SURFACE
 
Increase processing temperature
Increase die temperature
Polish the mouth piece or die
Increase blowing air pressure
Check the function of heating system
  MELT FRACTION
 
Increase processing temperature
Increase die temperature
Check the function of heating system
Decrease screw speed
Increase die gap
Improve material flow in the cross head
  LONGITUDINAL FLOW MARK
 
Clean and polish Die head
Polish the die and mouth piece
Improve material flow in the cross head and die head
Increase processing temperature
Increase cross head temperature
Decrease die head temperature
Check the function of heating system
  AIR BUBBLES
 
Decrease the processing temperature
Pre-dry the raw material
Increase feed zone temperature
Decrease cross head temperature
Decrease feed zone water cooling
Increase screw cooling air flow
  DUST PARTICLES
 
Clean the cross head and die head
Clean the polish the die head
Clean screw and barrel
  CHECK THE FUNCTION OF HEATING SYSTEM
 
Increase processing temperature
Increase cross head temperature
Increase or decrease die temperature
Decrease free zone temperature
Increase free zone water cooling flow
Decrease screw cooling air flow
Decrease screw speed
  DARK DISCOLORATION
 
Decrease processing temperature
Decrease cross head and die head temperature
Increase or decrease screw cooling air flow
Check the function of heating system
Check the thermocouple
Increase or decrease screw speed
Clean and polish the head, cross head, die head and die
  BURNT PARTICLES
 
Decrease processing temperature
Decrease die and head temperature
Increase screw cooling air flow
Increase feed zone cooling water flow
Check function of heating system
Check function of barrel cooling blower
Clean and polish cross head, die head, barrel, die and mouth piece.
 
 
 
 
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