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PET injection molding process common problems and solutions

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Release time:

2021-12-07

1. Presentation Problem: Plastic is in waves.

Reason: due to the narrow gate or other parts, when the molten plastic pushes the solidified plastic part forward, the surface produces ripples.

Solution: 1. Increase the injection diameter 2. Increase the injection nozzle and mold temperature 3. Increase the height of the barrel 4. Speed up the injection speed 5. Slow down the injection speed 6. Change the inlet position of mold cooling water to keep it away from the gate 7. Expand the gate.

2. presentation problem: plastic parts are silver-shaped.

Reason: due to plastic moisture, uneven mixing, injection molding gas, additives or release agent too much.

Solution: 1. Strengthen back pressure 2. Slow down the injection speed 3. Clean the barrel 4. Tall the mold temperature 5. Change the gate position 6. Expand the runner and gate 7. Baking material 8. Install infrared lamp in the material door.

3. presentation problem: bad plastic interface.

Reason: because the plastic temperature is too low, can not be melted, or due to insufficient gas excretion caused by more than two streams mixed hair-like thin lines or bubbles.

Solution: 1. Increase the material temperature 2. Increase the injection temperature 3. Increase the injection speed 4. Set the cold pool outside the joint line 5. Set the air vent 6. Change the gate position or gate 7. Do not use the release agent 8. Transfer the low-viscosity raw materials that are easy to flow.

4. presentation problem: plastic parts are empty.

Reason: because the plastic surface contact the low temperature mold wall during the melt solidification, the shrinkage is concentrated in the thick wall section and causes the cavity, or the cavity is made by the air.

Solution: 1. Increase the injection pressure (and secondary pressure) 2. Extend the injection time 3. Reduce the curing temperature of the barrel 4. Reduce the mold wall thickness to less than 6mm, set equal wall thickness auxiliary line if necessary, and remove excess wall thickness 5. Expand the gate 6. Shorten the runner 7. Smoothing the mold temperature 8. Change the gate position to eliminate air entrapment.

5. problems: plastic parts are under-injected or short of materials.

Reason: due to insufficient mechanical injection molding and plasticizing performance, poor material flow, too fine gate section, too thin mold wall or poor deflation.

Solution: 1. Increase the injection rate. If it is still insufficient, replace the heavy machinery. 2. Mount the leak-proof injection valve screw. 3. Increase the injection pressure. 4. Increase the material simplicity, injection nozzle curing and mold temperature. 5. Check whether the electric hotline is disconnected. 6. Check whether the injection nozzle is blocked, increase the circulation speed 7. Improve the venting capacity of the mold 8. Increase the gate section 9. Increase the wall thickness of the product 10. Add auxiliary lines and transform the material flow 11. Select low-viscosity raw materials 12. Add lubricants.

6. Presentation Problem: Mold Side Extrusion Plastic.

Reason: because the material temperature and injection pressure is too high, or the clamping force is insufficient.

Solution: 1. Reduce the injection pressure and simple curing temperature 2. Shorten the injection time 3. Reduce the injection speed 4. Switch to a high clamping force machine 5. Transform the clamping surface tight fit and clean the clamping surface 6. Switch to low-viscosity materials.

7. star problem: the surface of the plastic part is pitted.

Reason: due to the plastic surface cooling, due to its surface dents.

Solution: 1. Increase the injection rate 2. Increase the internal pressure of the mold groove "Secondary pressure> 3. Reduce the curing temperature of the barrel material 4. Increase the injection flow rate 5. Increase the injection speed 6. Extend the injection time 7. Make the mold temperature uniform 8. Change the gate position 9. Expand the pouring 10. Shorten the mold runner.

Description of medical plastic bottle

Common Problems and Solutions of PET Bottle Blow Molding Process

Description of medical plastic bottle

Common Problems and Solutions of PET Bottle Blow Molding Process