Solutions to common problems in injection molding
1. Plastic is wavy
Reason: Due to the narrow gate or other parts, when the molten plastic pushes the solidified plastic part forward, the surface is corrugated.
Solution:
1. Increase the diameter of the injection
2. Increase the temperature of injection nozzle and mold
3. Increase the height of the barrel
4. Speed up injection molding
5. Slow down the injection speed
6. Change the mold cooling water inlet position to keep it away from the gate
7. Expand the gate.
2. The plastic parts are in the shape of silver streaks
Reason: Due to the water content of the plastic, the mixing is not uniform, the air is trapped during injection molding, and there are too many additives or mold release agents.
Solution:
1. Strengthen the back pressure
2. Slow down the injection rate
3. Clean the barrel
4. Increase mold temperature
5. Change the gate location
6. Expand the runner and gate
7. Baking
8. Install infrared light in the material door.
3. Poor plastic interface
Reason: The temperature of the plastic is too low to melt, or the two or more shunts are mixed due to insufficient gas discharge, resulting in hair-like thin lines or bubbles.
Solution:
1. Increase the temperature of the material
2. Increase the injection temperature
3. Increase the injection rate
4. Seam line peripheral cold material pool
5. Set the air outlet
6. Change the gate position or gate
7. Do not use mold release agents
8. Switch to easy-flowing low-viscosity raw materials.
Fourth, the plastic parts show voids
Reason: Because the surface of the plastic contacts the low temperature mold wall during the solidification of the melt, the shrinkage is concentrated in the thick-walled section, resulting in voids, or voids due to air inclusions.
Solution:
1. Increase injection pressure (and secondary pressure)
2. Extended betting time
3. Lower the barrel curing temperature
4. Reduce the thickness of the mold wall to less than 6mm, set up equal wall thickness guides if necessary, and remove the excess wall thickness
5. Expand the gate
6. Shorten the runner
7. Mix the mold temperature thoroughly
8. Change the gate position to eliminate air inclusion.
Five, lack of injection or lack of plastic parts
Reason: due to insufficient mechanical injection and plasticizing performance, poor material flow, too thin gate section, too thin mold wall or poor air leakage.
Solution:
1. Increase the injection rate, if it is still insufficient, you need to replace heavy machinery
2. Install leak-proof injection valve screw
3. Increase injection pressure
4. Improve barrel, nozzle curing and mold temperature
5. Check whether the heating wire is disconnected
6. Check whether the nozzle is blocked and increase the circulation speed
7. Improve mold outgassing ability
8. Increase the gate section
9. Increase product wall thickness
10. Add auxiliary lines and transform material flow
11. Select low viscosity raw materials
12. Add lubricant.
6. Extrusion of plastic at the side of the mold
Reason: due to high material temperature and injection pressure, or insufficient clamping force.
Solution:
1. Reduce injection pressure and barrel curing temperature
2. Shorten the betting time
3. Reduce the injection speed
4. Switch to high clamping force machine
5. Transform the clamping surface for tight fit and clean the clamping surface
6. Switch to low viscosity material.
Seven, the surface of the plastic part is dented
Reason: The surface of the plastic part is cooled due to time, and its surface is dented.
Solution:
1. Increase the injection rate
2. Increase the internal pressure of the die cavity (secondary pressure)
3. Reduce the curing temperature of the barrel material
4. Increase injection flow
5. Increase the injection rate
6. Extended betting time
7. Make the mold temperature uniform
8. Change gate location
9. Expand gate
10. Shorten the mold runner.
8. Plastic parts are twisted and deformed
Reason: The plastic parts are deformed and distorted due to the relaxation of the residual stress in the injection molding.
Solution:
1. Reduce injection pressure
2. Reduce the curing temperature of the barrel material
3. Extend the cooling time
4. Mixing the wall thickness of the material and mixing and demoulding lock action
5. Add a release lock
6. Change the gate position
7. Mix the mold temperature thoroughly.
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Solutions to common problems in injection molding
