Defects Name Characteristics of Injection Defects Possible Problems with Injection Molding Machines Recommended Remedies Differences in Size of Injection Moldings Changes in weight and size during the injection process exceed the capacity of the mold/injection molding machine/+plastic combination.
1. Insufficient plastic in the cartridge.
2. The range of temperature or fluctuation of the cartridge is too large.
3. Injection molding machine capacity is too small.
4. Unstable injection pressure.
5. The screw reset is unstable.
6. Changes in operating time, inconsistent solution viscosity. * Check if there is enough cooling water flowing through the hopper throat to maintain the correct temperature.
* Check for poor or loose thermocouples.
* Check that the thermocouple used with the temperature controller is the correct type.
* Check the injection molding machine's injection volume and plasticizing ability, and then compare it with the actual injection volume and the amount of plastic per hour.
* Check if there is a stable molten dunnage for each operation.
* Check if the backflow prevention valve leaks and replace it if necessary.
* Ensure that the screw is stable after each operation, ie no more than 0.4mm (0.016in) change.
* Check the operating time for inconsistencies and use back pressure. Insufficient filling of the filling process is incomplete because the cavity is not filled with plastic or the injection molding process lacks some details. 1. Injection molding machine speed is insufficient.
2. Plastic shortage.
3. The screw did not leave screw padding at the end of the stroke.
4. The operating time changes.
5. The temperature of the sol barrel is too low.
6. Insufficient injection speed.
7. The nozzle part is sealed.
8. The heater at the nozzle or sol tube cannot operate.
9. The injection time is too short.
10. Plastics are attached to the throat wall of the hopper.
11. Injection weight or plasticizing ability is too small. * Increase injection speed.
* Check the amount of plastic in the hopper.
* Check if the injection stroke is set correctly and change if necessary.
* Check the non-return valve for wear or cracks.
* Check if the operation is stable.
* Increase the sol temperature.
* Increase back pressure.
* Increase injection speed.
* Check if there is no foreign matter or unplasticized plastic in the nozzle hole.
* Check that all heaters have an ampere meter to verify that the energy output is correct.
* Increase the amount of cooling in the hopper throat area, or reduce the temperature in the rear zone of the melt cartridge.
* Use a larger injection molding machine. Color distribution deviation The color of injection molded parts is not uniform, ie there are shades of difference, colored stripes or patches. The mixing of the pigment in the sol barrel of the injection molding machine is not sufficient. * Increase back pressure.
* Lower the melt cartridge temperature for better plastic mixing.
