Cause analysis of bubbles in injection molded products

(vacuum bubble) the gas is very thin and belongs to vacuum bubble. Generally speaking, if bubbles are found at the moment of mold opening, it is a gas interference problem. The formation of vacuum bubble is due to insufficient filling of plastic or low pressure. Under the rapid cooling of the die, the fuel at the corner with the cavity is pulled, resulting in volume loss.

terms of settlement:

(1) Increase the injection energy: pressure, speed, time and material quantity, and increase the back pressure to make the mold full.

(2) Increase material temperature and smooth flow. Reduce the material temperature, reduce the shrinkage, and appropriately increase the mold temperature, especially the local mold temperature at the part where the vacuum bubble is formed.

(3) The gate is set at the thick part of the workpiece to improve the flow condition of nozzle, runner and gate and reduce the consumption of pressure.

(4) Improve mold exhaust condition.