Phenomenon
cause
Treatment measures
Insufficient product
not filled
1. Insufficient injection speed. 2. Plastic shortage. 3. The screw does not leave any screw gasket at the end of the stroke. 4. The running time changes. 5. The temperature of the injection cylinder is too low. 6. Insufficient injection pressure. 7. The nozzle part is sealed. 8. The heater outside the nozzle or the injection cylinder cannot work. 9. The injection molding time is too short. 10. The plastic is pasted on the throat wall of the hopper. 11. The capacity of the injection molding machine is too small (ie injection weight or plasticizing capacity). 12. The mold temperature is too low. 13. The anti-rust oil of the mold has not been cleaned. 14. The stop ring is damaged, and the molten material has backflow.
2. Increase the injection speed. 2. Check the amount of plastic in the hopper. 3. Check whether the injection stroke is set correctly, and change it if necessary. 4. Check whether the check valve is worn or cracked. 5. Check whether the operation is stable. 6. Increase the melt temperature. 7. Increase back pressure. 8. Increase the injection speed. 9. Check the nozzle hole for foreign matter or unplasticized plastic. 10. Check all heater shells and use an ammeter to verify correct power output. 11. Increase the screw forward time. 12. Increase the throat area of the hopper or reduce the temperature in the rear area of the injection cylinder. 13. Use a larger injection molding machine. 14. Properly raise the mold temperature. 15. Clean up the anti-rust agent in the mold. 16. Check or replace the stop ring.
Size difference of injection molded parts
1. The plastic input into the injection cylinder is uneven. 2. The temperature or fluctuation range of the injection cylinder is too large. 3. The capacity of the injection molding machine is too small. 4. The injection pressure is unstable. 5. The reset of the screw is unstable. 6. Changes in operating time and inconsistencies in solution viscosity. 7. The injection speed (flow control) is unstable. 8. Plastic varieties that are not suitable for molds are used. 9. Consider the influence of mold temperature, injection pressure, speed, time, and holding pressure on the product.
2. Check that there is sufficient cooling water flowing through the hopper throat to maintain the correct temperature. 2. Check for inferior or loose thermocouples. 3. Check that the thermocouple used with the temperature controller is the correct type. 4. Check the injection volume and plasticizing capacity of the injection molding machine, and then compare it with the actual injection volume and the injection volume per hour. 5. Check whether there is a stable molten hot material for each operation. 6. Check whether the backflow prevention valve is leaking, and replace it if necessary. 7. Check whether the feed setting is wrong. 8. Ensure that the screw rod is stable in each return position, that is, the change is not more than 0.4mm. 9. Check for inconsistencies in operating hours. 10. Use backpressure. 11. Check whether the hydraulic system is operating normally and whether the oil temperature is too high or too low (25-60°C). 12. Choose the plastic variety suitable for the mold (mainly considering the shrinkage rate and mechanical strength). 13. Readjust the entire production process.
Shrink marks
1. The melting temperature is either too high or too low. 2. Insufficient plastic in the mold cavity. 3. During the cooling stage, the surface in contact with the plastic is overheated. 4. The runner is unreasonable and the gate cross section is too small. 5. Whether the mold temperature is compatible with the plastic properties. 6. The product structure is unreasonable (the reinforcement is too high, too thick, and the thickness is obviously different). 7. The cooling effect is not good, and the product continues to shrink after demoulding.
2. Adjust the temperature of the injection cylinder. 2. Adjust the screw speed to obtain the correct screw surface speed. 3. Increase the injection volume. 4. Make sure to use the correct gasket; increase the screw forward time; increase the injection pressure; increase the injection speed. 5. Check whether the stop valve is installed correctly, because abnormal operation will cause pressure loss. 6. Reduce the mold surface temperature. 7. Correct the flow channel to avoid excessive pressure loss; according to actual needs, appropriately expand the cross-sectional size. 8. Properly control the mold temperature according to the characteristics of the plastic used and the product structure. 9. Improve the product structure if allowed. 10. Try to let the product have enough cooling.
Post time: May-10-2023