The Main Reason For The Difficulty Of Demoulding After Plastic Injection Molding

- Sep 26, 2018-

After the injection molding of the plastic part, the plastic part is released from the mold cavity, and the ejection work is generally completed in one time, whether using a single or multi-element ejection mechanism.


However, sometimes due to the special shape of the plastic part or the need of production automation, after a demolding work is completed, the plastic part is still difficult to remove from the cavity or can not fall off automatically. At this time, it is necessary to add another demolding action to make the plastic part. Fall off. The difficulty in demolding is mainly due to the fact that the gate or plastic part is tightened in the mold. The reasons for this are as follows.


1. In terms of equipment, the ejection force is not enough.


2. Mold aspect

(1) The demoulding structure is unreasonable or improperly positioned.

(2) The draft is not sufficient.

(3) The mold temperature is too high or the ventilation is poor.

(4) The surface of the sprue wall or cavity is rough.

(5) The nozzle does not conform to the feed port of the mold or the diameter of the nozzle is larger than the diameter of the feed port.


3. Process aspects

(1) The barrel temperature is too high or the injection volume is too much.

(2) The injection pressure is too high or the pressure is maintained and the cooling time is long.


4. In terms of raw materials, the lubricant is insufficient.