二. Demold slope of plastic parts
Draft angle means that plastic parts should have a certain tilt angle in the direction of mold ejection, which is a necessary condition for normal mold ejection. When designing plastic parts, both the appearance and the inner structure must have a draft angle. The draft of the mold is related to the product appearance, material, product dimensions, and product functions. The design points of the draft of the mold mainly include the following aspects.
(1) For products with high requirements on product appearance, the demoulding slope should be small.
(2) For products with high product precision requirements, the demoulding slope should be small.
(3) For products with large dimensions, the draft must be small.
(4) If the plastic material contains lubricant, the demoulding angle should be small.
(5) The outer surface of the product is bright and the demoulding slope should be appropriately small.
(6) The product has a rough appearance and the demoulding angle needs to be increased.
(7) The shape of the product is complex, and the draft angle must be increased.
(8) When injecting plastics with poor fluidity or reinforced plastics, the demoulding angle should be increased.
(9) The product material is thick and the demoulding angle should be appropriately increased.
(10) Plastics with large shrinkage should use larger draft angles.
(11) The demoulding angle of plastic parts for transparent parts should be appropriately increased.
The method for determining the direction of the demoulding slope is as follows:
(1) The appearance of the product is based on the big end, and the slope is obtained from the small end using the glue-reducing draft method.
(2) The inner hole is based on the diameter of the small end, and the slope is obtained in the direction of expansion using the glue-reducing draft method.
(3) Under special circumstances, in order to ensure uniform material thickness and smooth mold ejection, one side needs to be reduced in glue and draft, and the other side needs to be added in glue and draft.
