Dimension difference of injection molded parts.
1. Features of defect of injection molding.
The change of weight in the injection process exceeds the production capacity of mold, injection molding machine and plastic combination.
2. Possible causes of problems.
(1). The plastic in the injection cylinder is not balanced.
(2) the range of temperature or fluctuation of the shooting cylinder is too large.
(3) the capacity of injection molding machine is too small.
(4). The injection pressure is unstable.
(5) screw reset instability.
(6) change of operating time and consistency of solution viscosity.
(7). Injection speed (flow control) is unstable.
(8) the plastic varieties that are not suitable for the mold are used.
(9). Consider the influence of mold temperature, injection pressure, speed, time and pressure protection on the product.
3. Remedies
(1). Check whether sufficient cooling water flows through the hopper throat to maintain the correct temperature.
(2) check whether the thermocouple is inferior or loose.
(3) check whether the thermocouple used with the temperature controller is the correct type.
(4). Check the injection molding capacity and plasticizing capacity of the injection molding machine, and then the actual injection quantity and the injection of each hour.
Compare the amount of plastic used.
(5) check whether there is a stable melting hot material in each operation.
(6) check the backflow prevention valve for leakage and replace it if necessary.
(7). Check for incorrect feeding Settings.
(8). Ensure that the screw rod is stable at each operation, i.e., no more than 0.4mm.
(9) check the inconsistency of operation time.
(10). Use back pressure.
(11). Check whether the hydraulic system is functioning properly and whether the oil temperature is too high or too low (25-60oc).
(12). Select suitable plastic varieties (mainly from shrinkage and mechanical strength).
(13). Re-adjust the whole production process.