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How to solve the problem of injection molding machine?

writer:LI SONG Share

Aiming at the problems and solutions that often occur in the injection molding process of the injection molding machine, here is a detailed introduction by the mechanical engineer of Lisong:

1. The solution to the inability to shoot glue:
1) The nozzle is blocked by foreign matter. Check whether the nozzle is blocked, clean or replace the nozzle.
2) The glue nozzle is broken. Disassemble the flange to check whether the glue nozzle is broken, and replace the glue nozzle.
3) The injection direction valve is stuck. Check whether the directional valve has 24V voltage and the coil resistance is 15-20 ohms. If normal, the valve is blocked. Clean the valve or replace the directional valve.
4) The rubber injection piston rod is broken. Loosen the rubber piston rod tightening nut, check whether the piston rod is broken, and replace the piston rod.
5) The temperature of the barrel is too low. Check whether the actual temperature reaches the required melting point temperature of the material, and reset the barrel temperature.
6) The oil seal of the rubber injection piston is damaged. Check whether the piston oil seal is broken and replace the oil seal.

2. The solution to the loud sound at the beginning of the glue injection:
1) The injection speed starts too fast. Observe the start speed change of the injection speed, and adjust the injection flow rate.
2) There is air in the oil circuit. Observe whether there is vibration in each movement.

LS330PET Injection Molding Machine
3. The solution to the loud sound when the glue is stopped and the glue is melted:
1) The movement conversion speed is too fast when shooting glue. Check whether the plastic injection has increased the holding pressure, increased the holding pressure, adjusted the number of injection levels, and delayed the addition of the melt.

4. Solution for unstable injection volume:
1) The oil seal of the oil cylinder is worn. Observe the pressure retention of the pressure gauge and replace the oil seal.
2) The rubber nozzle and rubber ring are worn out. Use 2 shots of glue to detect, replace the three-piece glue nozzle.
3) The barrel is worn. It is detected with 2 injection nozzles, and the material is dismantled to check the wear and tear, and the melt glue tube is replaced.

5. The solution for semi-automatic non-injection action:
1) The advancement of the firing station is not terminated. Check whether the travel switch before the injection station or the mold is normal, check the wiring and travel switch.
2) Disconnection. Check the wiring and rewire.
3) Return to zero when the mode is locked. When the machine hinge is straight, the position is 0, readjust the zero position of the electronic ruler.

6. The solution to the temperature of the barrel gradually exceeding the set value when working in semi/full-automatic mode:
1) The melting speed is too fast. Use a tachometer to test whether the screw speed is too fast, and reduce the melt speed.
2) Excessive back pressure. Observe the product, the back pressure gauge value, and reduce the back pressure as much as possible.
3) Friction between the screw and the barrel. Disassemble the screw and barrel, check the wear and tear, and replace the barrel or screw.
4) Improper temperature setting. Check whether the actual temperature is too low and reset the temperature.
5) The shear heat of the plastic is too large. Check the temperature rise in the front and middle sections, reduce the speed of the melt, and the back pressure.

7. The solution to the screw noise when melting glue:
1) Improper installation of the drive shaft. Separate the screw rotation to check if there is any noise, if there is any, remove the flat bearing and reassemble it.
2) The plane bearing is broken. Separate the screw and check that the rotating part has noise, then replace the flat bearing.
3) The screw is bent. Remove the screw for inspection and replace the screw.
4) The screw has iron filings. Disassemble the screw for inspection and clean the screw.
5) Use a dial indicator to check the coaxiality of the adjustment screw. The beating around 0.05mm is normal.

8. Solutions that can't melt glue:
1) Burning bearings or bursting of drive shafts. Separate the screw and melt the glue and observe the sound, replace the bearing.
2) The screw has iron filings. Separate the screw and the barrel, check the screw for iron filings, and remove the screw for cleaning.
3) The melt valve is blocked. Use the hexagon key to top the spool to see if it moves, and clean the solenoid valve.
4) The glue motor is damaged. Separate the melter motor. When the melter does not turn, replace or repair the melter motor.
5) Burn out the heating ring. Check whether it is normal with a multimeter and replace the heating coil.
6) The plug is loose. Check whether the molten glue oil plug is in poor contact, connect the plug tightly, and check whether there is a 24 power supply.

9. The solution to the problem that the back pressure cannot be adjusted when melting glue:
1) The back pressure valve is broken. Increase the back pressure when cutting the material, check whether the screw retreats, and clean the back pressure valve.

10. The solution to the product has black spots:
1) The screw has carbon deposits. Check the cleaning screw and barrel.
2) There is carbon deposit in the barrel and the auxiliary machine is not clean. Check the feeder for dust, polish the barrel and clean the auxiliary machine.
3) Corrosion of the glue nozzle components. Check the glue nozzle and replace the glue nozzle assembly.
4) Flange and nozzle have carbon deposits. Clean up and replace.
5) The raw materials are unclean. Check raw materials and replace raw materials.
6) The temperature is too high and the back pressure of the melt is too large. Check the temperature of each section, lower the temperature and reduce the back pressure.

11. Solutions to poor screw color mixing:
1) Material problems. Check the toner quality and replace the material.
2) The temperature is too low. Check the actual temperature and the required temperature of the material, and increase the temperature.
3) The back pressure is too low, check the back pressure and increase the back pressure.
4) Short mixing time. Extend the mixing time or replace it with a mixing head.
5) The speed is too low. Check the screw speed and increase the screw speed.

12. Solutions for no glue pulling action:
1) Large back pressure. Check the nozzle spraying speed when manually melting the glue to reduce the back pressure.
2) Disconnection. The pump valve is disconnected.
3) The spool of the directional valve is not flexible. Press the spool with an Allen wrench to check whether it is free to move, and clean the spool.

13. When melting glue, the solution of the motor tail swing:
1) The bearing is broken. Observe whether there is any abnormal sound when melting the glue, and replace the bearing.
2) Improper adjustment of the oblique ball bearing. Observe whether the drive shaft swings, and readjust the gap.
3) Deformation of the screw. Separate the screw to observe the rotation of the drive shaft, and replace the screw.
4) The copper sleeve of the rear plate of the shooting table is worn and the 2 guide rods are deformed or the fixing screws are loose. Observe whether copper powder is ground out of the second plate copper sleeve, and replace the copper sleeve.

14. Shoot glue twice
1) The nozzle aperture is too small, and the resistance is too large when shooting glue.
2) The nozzle heating ring is broken, check the heating ring or replace it.
3) Check whether the pressure and flow output is changed.

15. Reasons for screw breakage and solutions:
1) The shooting movement is not synchronized, adjust the shooting movement synchronization ±0.05
2) The injection cylinder is not synchronized, adjust the injection cylinder to synchronize ±0.05
3) The raw material and the screw performance of the injection molding machine do not match.
4) The temperature does not reach the melting point of the materials used.
5) Turn the screw until the temperature has just reached.
6) If the heating tube is burned out, it will not be heated. Check whether there is anti-cold function, and replace the heating tube.

16. The solution that cannot be adjusted:
1) The mechanical level and parallelism are out of tolerance. Check with a spirit level angle ruler to adjust the parallelism and level.
2) The gap between the pressure plate and the die-adjusting nut is too small. Measure with a feeler gauge to adjust the gap between the pressure plate and the nut, and adjust the gap between the die nut and the pressure plate (gap ≤ 0.05 mm).
3) Burn the nut to check whether the nut can be turned to generate heat and iron powder is coming out. Replace the nut.
4) Adjust the upper and lower support plates. Remove the lock nut of the expense board to check and adjust the adjusting nut.
5) The I/O board is broken. Check whether there is a signal at the output point on the computer page, and repair the electronic board.
6) The mold adjusting valve core is stuck. Remove the valve to check and clean the valve.
7) The mold adjusting motor is broken. Check the oil motor. Replace or repair the oil motor.

Regarding the problems and solutions that often occur in the injection molding machine during the injection process, here is so much for you. If you want to know more about the relevant knowledge, please pay attention to Lisong Machinery, and leave a message to us, we will answer you in detail!

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