| Possible causes | Suggested solution |
|---|
| Injection molding machine |
Melt temperature is too low. |
Increase templerture in tank and injection mouth.
|
|
Reduce the speed of the screw or adjust the screw speed to get the correct surface speed
|
| The breakdown of the molecular structure of plastics casued by degradation in cylinder. |
In all regions to reduce injection cylinder temperature.
|
|
Reduced back pressure.
|
Mold filling is too slow.
|
Increase injection speed.
|
|
On the injection molding machine remains stable bedding.
|
| Mold |
Cold mold surface |
Increase mold temperature.
|
|
Limit the speed of cooling flows through the mold.
|
| Runner and the gate are too small, so the mold filling produced excessive shear rate. |
Use full-round runners and increase the size of runner and gate to provide acceptable mold filling phase shear rate.
|
| Plastic |
The pressure of injection molded parts without proper release or not be processed. |
Injection molded parts annealed, if nylon plastic products, which dipped in warm water.
|
| Injection molded parts is not sufficient for a particular plastic. |
If possible, design the product in order to improve the weak sections.
|
| Adding too much regrind. |
Reduced the mixture proportion of recycle materials with the new plastic materials.
|
| Heterogeneous plastic impurities. |
Check the plastics for impurities. |
| Thoroughly clean shot cylinder. |
| Hopper or filling machines to be removed and cleaned thoroughly. |
| Regrind may have poor quality. |
Double check the signs of impurities when recycle material being separated. |
| Ensure dust removing material. |
| Check for strict implementation of recycling programs. |
