Solution to bubble phenomenon of the bucket mould during injection molding
According to the cause of the bubble in plastic bucket mould, the solution to the problem is as follows:
(1) When the wall thickness of the bucket is large, the outer surface is cooled faster than the center portion. Therefore, as the bucket moulding cooling progresses, the resin at the center portion is expanded toward the surface while being shrunk, so that the center portion is insufficiently filled. This condition is called a vacuum bubble. The main solutions are:
a) Determine the proper gate and runner size based on wall thickness. Generally, the height of the gate should be 50% to 60% of the wall thickness of the plastic bucket or pails.
b) A certain amount of supplementary injection material is left until the gate is sealed.
c) The injection time should be slightly longer than the gate sealing time.
d) reduce the injection speed and increase the injection pressure,
e) Use a material with a high melt viscosity rating.
(2) The bubbles of the bucket mould caused by the generation of volatile gases are mainly solved by:
a) Adequate pre-drying.
b) Lower the temperature of the resin to avoid decomposition gases.
(3) Bubbles caused by poor fluidity can be solved by increasing the temperature of the resin and the bucket mold and increasing the injection speed.
