| Possible causes | Suggested solution |
|---|
| Injection molding machine |
1. The last production of degradable plastics materials in the cylinder, screw, valve adapter maybe curing inside the aggregate hot runner pipe. |
Use cleaning compounds or high molecular weight PMMA material to clean the injection cylinder unit. |
2. Plastic material traps in the cylinder device's dead area or stagnant area, causing it to stay too long in the high temperature.
|
1. cylinder and screw should be removed and thoroughly clean the surfaces in contact with the polymer melt. |
| 2. Check whether the nozzle is located correctly in injection cylinder. |
| 3. Use open or direct type nozzle to replace opening and closing nozzle. |
| 4. Check the stop valve for cracks, etc. Change a new device if necessary. |
| 3. Plastic enters the mold cavity too fast causing excessive shear polymer. |
Reduce the injection speed. |
| 4. Melt temperature is too high. |
1. Reduce fire zone melt temperature in a feed tank. Check the flow rate if its sufficient for cooling the hopper locking device, adjust the flow rate if necessary. |
| 2. Reduce the cycle time to increase plastic that is passed by the cylinder device. |
| 5. Using the incorrect screw surface speed and back pressure, causing the molten plastic over cut. |
Use minimum back pressure and the correct use of the screw surface speed |
| 6. Use a correct type of screw design in the process of plastic. |
Use a lower rate of a extrusion screw. |
| Mold |
1. Grease or oil occur within the mold. |
Mold and nozzle should be removed and thoroughly cleaned. |
| 2. Gate is too small. |
Increase the gate size. |
| 3. Wall injection molded too thin, so that plastic flow is not sufficient to pass through, so it casuses no degradation. |
Check the correctness and consistency of wall thickness, if necessary, will be modified. |
| 4. Hot runner mold produces impurities. |
The hot runner mold aggregates tube completely remove and clean. |
|
|
1. PVC or other heat-sensitive plastic appear impurities. |
Check the source of impurities, especially with PVC manufacturing and conveying plastic pipe part. |
| 2. Excessive heating of the back using the previous materials. |
Strict inspection after the separation of impurities in materials. |
| 3. Due to the lack of room cleaning or plastic dry casues plastic blended with burnt particles. |
Dry cleaning and reuse of some materials. |
| 4. Poor plastic flow characteristics casued by Insufficient lubrication of plastic. |
Add a certain amount of external lubricant (such as Zeng 0.05% to 0.1% zinc stearate). |
