Warm Global Customers
With China Plastic Machinery
With China Plastic Machinery
Dimensional variation of injection molded parts refers to the change in weight and size during the injection molding process that exceeds the production capacity of the mold, injection molding machine, and plastic combination.
Possible causes of problems
(1) Uneven plastic input into the injection cylinder.
(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) Unstable injection pressure.
(5) Unstable screw reset.
(6) Changes in operating time and inconsistent solution viscosity.
(7) Unstable injection speed (flow control).
(8) Using a type of plastic that is not suitable for the mold.
(9) Consider the effects of mold temperature, injection pressure, speed, time, and holding pressure on the product.
Remedies
(1) Check whether there is sufficient cooling water flowing through the hopper throat to maintain the correct temperature.
(2) Check for inferior or loose thermocouples.
(3) Check if the thermocouple used with the temperature controller is of the correct type.
(4) Check the injection molding machine's injection volume and plasticizing capacity, and then compare it with the actual injection volume and the amount of injection material used per hour.
(5) Check if there is stable molten hot material in each operation.
(6) Check if the backflow prevention valve is leaking and replace it if necessary.
(7) Check for incorrect feed settings.
(8) Ensure that the screw return position is stable in each operation, that is, the change is no more than 0.4mm.
(9) Check for inconsistency in operation time.
(10) Use back pressure.
(11) Check if the hydraulic system is operating normally and whether the oil temperature is too high or too low (25-60oc).
(12) Select the type of plastic that is suitable for the mold (mainly considering the shrinkage rate and mechanical strength).
(13) Re-adjust the entire production process.
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