Common problems of injection molding machines and its solution
Time：2020-08-27 10:00:33 / Popularity： / Source：
First, common problems of injection molding machine
1, Mold-unlocking
1. Check safety door front stroke switch and repair it.
2. Check 24V/5A power supply in electric box, replace fuse and power supply box.
3. Check if spool is stuck and clean valve plug.
4. Check if I/O board has output and whether solenoid valve is energized.
5. Check if hydraulic safety switch is pressed and mechanical lock lever is open.
2. Check 24V/5A power supply in electric box, replace fuse and power supply box.
3. Check if spool is stuck and clean valve plug.
4. Check if I/O board has output and whether solenoid valve is energized.
5. Check if hydraulic safety switch is pressed and mechanical lock lever is open.
2, Die closing machine squeaking
1. Check if lubricating oil pipe is disconnected. If it is, oil pipe must be reconnected.
2, Amount of lubricating oil is small, increase amount of lubricating oil, it is recommended to oil every 50 molds or manually add enough lubricant.
3, Clamping force is large, check whether mold requires large clamping force, reduce clamping force.
4. Current of amplifier board is disordered. Check whether current parameters meet acceptance criteria and re-adjust current value.
5, Parallelism is out of tolerance, use dial gauge to check whether parallelism of the first two plates is greater than acceptance criteria and adjust parallelism.
2, Amount of lubricating oil is small, increase amount of lubricating oil, it is recommended to oil every 50 molds or manually add enough lubricant.
3, Clamping force is large, check whether mold requires large clamping force, reduce clamping force.
4. Current of amplifier board is disordered. Check whether current parameters meet acceptance criteria and re-adjust current value.
5, Parallelism is out of tolerance, use dial gauge to check whether parallelism of the first two plates is greater than acceptance criteria and adjust parallelism.
3, Wait a few seconds to open mold
1. Starting speed is slow. Check if screw damping is too large and adjust screw damping hole.
2. Middle hole of damping screw is too large. Check if damping of Y hole screw is too large, and change damping pin of center hole.
2. Middle hole of damping screw is too large. Check if damping of Y hole screw is too large, and change damping pin of center hole.
4, Unlocking mode creeping
1. Two-plate guide rail and Corinth column are worn out. Check two-plate guide rail and Golin column, replace two-plate copper sleeve and Colin column, add lubricant.
2. Pressure of unlocking mold is not properly adjusted. Set flow rate 20. When pressure is 99, two plates should not crawl. Adjust flow proportional valve hole or pilot valve hole to adjust linear current value of proportional valve.
3. There is air in the pipeline and cylinder, should be exhausted.
2. Pressure of unlocking mold is not properly adjusted. Set flow rate 20. When pressure is 99, two plates should not crawl. Adjust flow proportional valve hole or pilot valve hole to adjust linear current value of proportional valve.
3. There is air in the pipeline and cylinder, should be exhausted.
5, Mold cant be opened
1. Increase speed of opening mold, pressure flow is too small, adjust speed of mold, check whether pressure is appropriate, and increase pressure and speed of mold.
2. Clamping electronic scale is changed to zero position. Check whether clamping die straightening machine is terminated at zero position and re-adjust electronic ruler zero position.
3. Check if hinge is reversed.
2. Clamping electronic scale is changed to zero position. Check whether clamping die straightening machine is terminated at zero position and re-adjust electronic ruler zero position.
3. Check if hinge is reversed.
6, In automatic production, mold adjustment will become tighter or looser.
1. Adjust internal leakage of solenoid valve, check whether solenoid valve is “O” type, replace solenoid valve.
2. Whether there is mold adjustment action when manually playing other actions, and see if valve is stuck.
2. Whether there is mold adjustment action when manually playing other actions, and see if valve is stuck.
7, When other movements are working after clamping, mold is slowly opened automatically.
1. Oil board leaks, check or replace extra quick lock valve, and replace oil board.
2. Mold opening valve leaks, oil pump is started and mold clamping is terminated. According to shooting stage or injection glue action, whether second board moves backwards or not, mold opening oil valve is replaced. Normally, does not move when mold opening.
2. Mold opening valve leaks, oil pump is started and mold clamping is terminated. According to shooting stage or injection glue action, whether second board moves backwards or not, mold opening oil valve is replaced. Normally, does not move when mold opening.
8. Only mold opening action when clamping
1. Connect wrong line, check if there is 24VDC to valve, check wiring.
2, Card valve or wrong valve core, check whether valve core is installed incorrectly or blocked, reinstall valve plug or clean. Under normal circumstances, does not move when mold opening.
2, Card valve or wrong valve core, check whether valve core is installed incorrectly or blocked, reinstall valve plug or clean. Under normal circumstances, does not move when mold opening.
9, Poor mold locking
1. A and B holes are not properly adjusted. Set system flow rate 20. When pressure is 99, observe whether mold clamping action is crawling, re-adjust or change valve.
2. There is air in oil circuit. Listen to sound of air in oil circuit. Check for bubbles in oil and exhaust.
3. Magnifying plate is adjusted improperly by ramping up and down. Observe current value of ammeter is proportional to change of lift or speed, adjust magnifying plate.
2. There is air in oil circuit. Listen to sound of air in oil circuit. Check for bubbles in oil and exhaust.
3. Magnifying plate is adjusted improperly by ramping up and down. Observe current value of ammeter is proportional to change of lift or speed, adjust magnifying plate.
10, Lock can not afford high pressure, beyond stroke
1. Limit switch exceeds limit, check whether mold adjustment is appropriate, adjust appropriate mold thickness; check whether motor is in a normal state.
2. If hydraulic limit exceeds stroke, whether position of electronic ruler is suitable, check whether mold adjustment is appropriate, and adjust mold forward.
2. If hydraulic limit exceeds stroke, whether position of electronic ruler is suitable, check whether mold adjustment is appropriate, and adjust mold forward.
11, Manual with termination of die opening, semi-automatic without
1. Mold opening valve leaks, and action is taken after manually shooting stage. Observe whether two plates are retreating and replace mold opening valve.
2. Check maximum stroke and pressure flow of electronic ruler.
2. Check maximum stroke and pressure flow of electronic ruler.
12, No thimble action
1. Thimble limit switch is broken. Check if 24V proximity switch is lit with a multimeter. Replace thimble limit switch.
2, Card valve, whether hex key ejector valve spool can move, clean pressure valve.
3. Thimble limit rod is broken. After stopping, remove limit rod by hand and replace limit rod.
4. Thimble switch is short-circuited. Check voltage of ejector switch to ground with a multimeter and replace ejector switch.
5. Position of electronic ruler is not set properly.
2, Card valve, whether hex key ejector valve spool can move, clean pressure valve.
3. Thimble limit rod is broken. After stopping, remove limit rod by hand and replace limit rod.
4. Thimble switch is short-circuited. Check voltage of ejector switch to ground with a multimeter and replace ejector switch.
5. Position of electronic ruler is not set properly.
13, Semi-automatic thimble out of control
1. Thimble board is broken, check whether circut is normal, and normal voltage is DV24V. Repair ejector plate.
2. Wire break, comprehensively check switch connection line and I/O board connection line. Check wiring and rewire.
3. Check if mold is in position.
4. Is piston rod seal of cylinder damaged?
2. Wire break, comprehensively check switch connection line and I/O board connection line. Check wiring and rewire.
3. Check if mold is in position.
4. Is piston rod seal of cylinder damaged?
14, Loud when opening mold
1. Proportional linearity difference, poor pressure and flow regulation at the time of opening and closing mold, check ramp up and down in parameters and adjust it.
2. Hinge of clamping machine is poorly lubricated, check Corinthian column, second board sliding foot, machine hinge lubrication condition, increase lubrication, increase number of oiling.
3. Mold clamping force is too large, check clamping force when mold is stressed, and reduce clamping force depending on product. Check if time position is appropriate.
4. Parallelism deviation of first two plates and check parallelism of second plates. Adjust second board and head plate parallel error.
5, Setting position of low speed to open mold is too small, speed is too fast. Check if setting position of low speed to open mold is appropriate and slow mold opening speed is too fast. Lengthen slow mold opening position and reduce speed of slow mold opening.
2. Hinge of clamping machine is poorly lubricated, check Corinthian column, second board sliding foot, machine hinge lubrication condition, increase lubrication, increase number of oiling.
3. Mold clamping force is too large, check clamping force when mold is stressed, and reduce clamping force depending on product. Check if time position is appropriate.
4. Parallelism deviation of first two plates and check parallelism of second plates. Adjust second board and head plate parallel error.
5, Setting position of low speed to open mold is too small, speed is too fast. Check if setting position of low speed to open mold is appropriate and slow mold opening speed is too fast. Lengthen slow mold opening position and reduce speed of slow mold opening.
15, Semi-automatic 2 times clamping action
1. Mold-locking spool is not completely reset. Check whether next action is too continuous after mold-locking operation is completed. Increase delay time of next action.
Second, problem of mold adjustment and its treatment
1, Can not adjust mold
1. Mechanical level and parallelism are out of tolerance. Check with level square. Adjust parallelism and level. (For large models, small models have little effect)
2. Gap between pressure plate and mold adjustment is too small. Measure with a feeler gauge. Adjust clearance between pressure plate and nut, adjust clearance between nut and pressure plate (gap ≤0.05m m ).
3. Burning nut: Check if nut can rotate and heat, see if there is iron powder. Replace nut.
4. Adjust upper and lower support plates. Remove expense board, check lock nut. Adjust adjusting nut.
5. I/O board is broken. Check output point for a signal on computer page. Repair electronic board.
6. Mold valve plug is stuck. Remove valve check and clean valve.
7. Modification motor is bad: check oil motor. Replace or repair oil motor.
2. Gap between pressure plate and mold adjustment is too small. Measure with a feeler gauge. Adjust clearance between pressure plate and nut, adjust clearance between nut and pressure plate (gap ≤0.05m m ).
3. Burning nut: Check if nut can rotate and heat, see if there is iron powder. Replace nut.
4. Adjust upper and lower support plates. Remove expense board, check lock nut. Adjust adjusting nut.
5. I/O board is broken. Check output point for a signal on computer page. Repair electronic board.
6. Mold valve plug is stuck. Remove valve check and clean valve.
7. Modification motor is bad: check oil motor. Replace or repair oil motor.
Third, Problem of injection and its treatment
1, Can not shooting
1. There is a foreign body blockage in nozzle. Check if nozzle is clogged. Clean or replace nozzle.
2, Glue is broken. Unpack flange to check if rubber nozzle is broken. Replace dispensing nozzle.
3. Injection direction valve is stuck. Check if directional valve has 24V voltage and coil resistance is 15-20 ohms. If it is normal, valve is blocked. Clean valve or replace directional valve.
4, Injection rubber piston rod is broken. Loosen rubber piston rod and check if piston rod is broken. Replace piston rod.
5. Barrel temperature is too low. Check that actual temperature reaches melting point temperature required for material. Reset barrel temperature.
6. Rubber seal piston seal is damaged. Check if piston seal is broken. Replace oil seal.
2, Glue is broken. Unpack flange to check if rubber nozzle is broken. Replace dispensing nozzle.
3. Injection direction valve is stuck. Check if directional valve has 24V voltage and coil resistance is 15-20 ohms. If it is normal, valve is blocked. Clean valve or replace directional valve.
4, Injection rubber piston rod is broken. Loosen rubber piston rod and check if piston rod is broken. Replace piston rod.
5. Barrel temperature is too low. Check that actual temperature reaches melting point temperature required for material. Reset barrel temperature.
6. Rubber seal piston seal is damaged. Check if piston seal is broken. Replace oil seal.
2, Glue starts to sound loud
1. Glue injection speed starts too fast. Observe change of injection speed when shooting starts. Adjust flow rate and speed of injection.
2. There is air in oil circuit. Observe whether there is vibration in each action.
3. Sound is loud when glue is terminated.
2. There is air in oil circuit. Observe whether there is vibration in each action.
3. Sound is loud when glue is terminated.
3, Action conversion speed is too fast when shooting glue.
Check if injection glue has increased pressure. Increase pressure holding, adjust number of shots, and add glue delay.
4, Amount of shot is unstable
1. Oil seal of cylinder is worn. Observe pressure maintenance of pressure gauge. Replace oil seal.
2, Rubber nozzle, rubber ring wear. Check with 2 shots. Replace three-piece dispensing nozzle.
3. Barrel is worn. It was detected with 2 nozzles, and material was checked for wear. Replace melter cartridge.
2, Rubber nozzle, rubber ring wear. Check with 2 shots. Replace three-piece dispensing nozzle.
3. Barrel is worn. It was detected with 2 nozzles, and material was checked for wear. Replace melter cartridge.
5, Semi-automatic non-adhesive action
1. Advancement of shooting platform has not been terminated. Check that front of stage or mold lock switch is normal. Check wire and travel switch.
2. Broken wire. Check wire and rewire.
3. Mode locking is reset to zero. Position when machine hinge is straightened is 0. Re-adjust electronic ruler to zero position.
2. Broken wire. Check wire and rewire.
3. Mode locking is reset to zero. Position when machine hinge is straightened is 0. Re-adjust electronic ruler to zero position.
6, Half / fully automatic work, barrel temperature gradually exceeds set value
1. Melt speed is too fast. Use a tachometer to test if screw speed is too fast. Reduce melt speed.
2. Back pressure is too large. Observe back pressure gauge of product to minimize back pressure.
3. Screw and barrel are rubbed. Remove screw and barrel, check wear. Replace barrel or screw.
4. Temperature setting is improper. Check if actual temperature is too low. Reset temperature.
5. Shear heat of plastic is too large. Check front section and middle section. Reduce melt speed, back pressure.
2. Back pressure is too large. Observe back pressure gauge of product to minimize back pressure.
3. Screw and barrel are rubbed. Remove screw and barrel, check wear. Replace barrel or screw.
4. Temperature setting is improper. Check if actual temperature is too low. Reset temperature.
5. Shear heat of plastic is too large. Check front section and middle section. Reduce melt speed, back pressure.
7, Screw ring when melting
1. Drive shaft is not properly installed. Separate screw rotation to check if there is any sound, if any, remove flat bearing. Reassemble.
2. Flat bearing is broken. Separate screw to check that there is a sound in rotating part. Then replace flat bearing.
3. Screw is bent. Remove screw check and replace screw.
4. Screw has iron filings. Disassemble screw check and clean screw.
5. Check coaxiality of adjusting screw with a dial indicator. Beating around 0.05mm is normal.
2. Flat bearing is broken. Separate screw to check that there is a sound in rotating part. Then replace flat bearing.
3. Screw is bent. Remove screw check and replace screw.
4. Screw has iron filings. Disassemble screw check and clean screw.
5. Check coaxiality of adjusting screw with a dial indicator. Beating around 0.05mm is normal.
8, Can not melt
1. Bearing or drive shaft bursts. Separate screw and re-melt glue and observe sound. Replace bearing.
2. Screw has iron filings. Separate screw from barrel and check if screw has iron filings. Remove screw to clean it.
3. Melt valve is blocked. Use a hex key top to see if it moves. Clean solenoid valve.
4. Melter motor is damaged. Separate glue motor, when glue does not turn, replace or repair melter motor.
5. Burn out heating ring. Check if it is normal with a multimeter. Replace heating ring.
6, Plug is loose. Check if melted oil plug is in poor contact. Close plug and check if there is 24 power.
2. Screw has iron filings. Separate screw from barrel and check if screw has iron filings. Remove screw to clean it.
3. Melt valve is blocked. Use a hex key top to see if it moves. Clean solenoid valve.
4. Melter motor is damaged. Separate glue motor, when glue does not turn, replace or repair melter motor.
5. Burn out heating ring. Check if it is normal with a multimeter. Replace heating ring.
6, Plug is loose. Check if melted oil plug is in poor contact. Close plug and check if there is 24 power.
9, Back pressure can not be adjusted when melting
1. Back pressure valve is broken. Unloading increases back pressure. Check if screw is back. Clean back pressure valve.
10, Product has black spots
1. Screw has carbon deposits. Check and clean screw, barrel.
2. Barrel has carbon deposits and auxiliary machine is not clean. Check loader for dust. Polish barrel and clean auxiliary machine.
3. Rubber nozzle assembly is corroded. Check dispensing nozzle. Replace dispensing nozzle assembly.
4, Flange, nozzle has carbon deposits. Clean up and replace.
5, Raw materials are not clean, check raw materials. Replace raw materials.
6, Temperature is too high, melt back pressure is too large. Check temperature of each section. Cool down and reduce back pressure.
2. Barrel has carbon deposits and auxiliary machine is not clean. Check loader for dust. Polish barrel and clean auxiliary machine.
3. Rubber nozzle assembly is corroded. Check dispensing nozzle. Replace dispensing nozzle assembly.
4, Flange, nozzle has carbon deposits. Clean up and replace.
5, Raw materials are not clean, check raw materials. Replace raw materials.
6, Temperature is too high, melt back pressure is too large. Check temperature of each section. Cool down and reduce back pressure.
11, Poor screw mixed color
1. Material problems. Check toner quality and replace material.
2. Temperature is too low. Check actual temperature and required temperature of material. Increase temperature.
3, Back pressure is too low, check back pressure and increase back pressure.
4. Mixing time is short. Lengthen mixing time or replace it with a mixing head.
5. Speed is too low. Check screw speed and increase screw speed.
2. Temperature is too low. Check actual temperature and required temperature of material. Increase temperature.
3, Back pressure is too low, check back pressure and increase back pressure.
4. Mixing time is short. Lengthen mixing time or replace it with a mixing head.
5. Speed is too low. Check screw speed and increase screw speed.
12, No pumping action
1. Back pressure is large. Check speed of nozzle spray when melt manually. Reduce back pressure.
2. Broken wire. Pumping valve is broken.
3. Directional valve spool is not flexible. Use a hex wrench to press valve plug to check for free movement and clean valve plug.
2. Broken wire. Pumping valve is broken.
3. Directional valve spool is not flexible. Use a hex wrench to press valve plug to check for free movement and clean valve plug.
13, Motor is tailed when melt.
1. Bearing is broken. Observe strangeness when melt. Replace bearing.
2. Slanted bead bearing is improperly adjusted. Observe drive shaft for oscillation. Readjust gap.
3. Screw deformation. Separate screw to observe rotation of drive shaft. Replace screw.
2. Slanted bead bearing is improperly adjusted. Observe drive shaft for oscillation. Readjust gap.
3. Screw deformation. Separate screw to observe rotation of drive shaft. Replace screw.
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