Common plastic injection molding problems: Sticking of the gate to the gate bushing

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In the precision plastic injection molding process, we often encounter a difficult problem - the gate sticking to the gate bushing. Today we will look in detail at the causes of this phenomenon and explore effective solutions.

Causes of the bolt sticking to the bolt bushing

  1. Deviation from calibration: Improper calibration between the plastic molded gate bushing and the nozzle is often the primary cause of sticking.
  2. Overflow: Excessive filling of the plastic inside the bolt sleeve increases the risk of sticking.
  3. Unsuitable temperature: The low nozzle temperature affects the flowability and dismantling of the plastic.
  4. Incomplete solidification: Especially in larger diameter closures, if the plastic is not fully cured inside the closure, this can also lead to sticking.
  5. Poor fit: If the arcing surfaces of the gate sleeve and nozzle do not align properly, a "mushroom-like" channel may form, increasing the likelihood of sticking.
  6. Insufficient exhaust angle: Improperly designed duct exhaust angle also aggravates the sticking problem.

Solutions

  1. Precise calibration: Recalibrate the nozzle and gate sleeve to ensure accurate alignment.
  2. Decrease in pressure: Reduce casting pressure to reduce overflow in the gate sleeve.
  3. Optimization of auger control: Reduce the time for the auger to advance by controlling the amount of plastic injected.
  4. Temperature rise: Increase the nozzle temperature or use a separate temperature controller to heat the nozzle to increase the flowability of the plastic.
  5. Increased cooling time: Increase the cooling time of the plastic mold, but replacing the gate bushing with a smaller gate bushing is preferable.
  6. Landing adjustments: Accurately adjust the mating surfaces of the gate sleeve and nozzle to ensure perfect compatibility.
  7. Adjusting the angle of extraction: Appropriately increase the channel draft angle to reduce resistance during disassembly.

With these detailed analyses and precise solutions, we can effectively solve the problem of the gate sticking to the gate sleeve in the plastic injection molding process, thereby improving productivity and product quality.

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