Generally speaking, if bubbles are found at the moment of mold opening, it is due to gas interference issues. The formation of vacuum bubbles is caused by insufficient plastic injection or low pressure. Under the rapid cooling of the mold, the fuel pull at the junction with the mold cavity results in volume loss.

Solution:

Increase injection energy: pressure, speed, time, and material volume, while enhancing back pressure for full and even molding.

(2) Improve material temperature flow. Reducing material temperature reduces shrinkage; appropriately increase mold temperature, particularly for the local mold temperature at the vacuum bubble forming area.

(3) Position the gate on the thicker part of the workpiece to improve the flow conditions of the nozzle, runner, and gate, thereby reducing pressure loss.

(4) Improved mold exhaust conditions.