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The Reasons of the Demoulding Difficulty of Plastic Injection Mold

After the plastic part is injection molded, the plastic part is ejected from the mold cavity. Whether it is a single or multi-element ejection mechanism, the demolding work is generally completed at one time. But sometimes due to the special shape of the plastic part or the need of production automation, it can’t be finished at one time. There’s a situation that after a demolding work is completed, the plastic part is still difficult to be taken out from the cavity or cannot fall off automatically. At this time, another demoulding should be done to make the plastic part fall off. Demolding difficulty is mainly because the gate or the plastic part is compressed in the mold. The reasons for that are mainly as follows:

1. Equipment: insufficient ejector power.

2. Molds

(1) Unreasonable demoulding structure or improper position.

(2) The draft angle is insufficient.

(3) Mold temperature is too high or poor ventilation.

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

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


3. Process

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

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

4. Raw materials: insufficient lubricants

The traditional demoulding methods of plastic molded parts are roughly divided into four types: ejection, pushing, pulling, and spinning.

Now there is a newest demoulding technology that can easily solve the problem of plastic demoulding. In the plastic mold industry, there are many unsolvable problems, especially when a variety of resin compounds are used for highly complex designs and high-gloss finish processing.

Nano release coating can form a coating on the surface of the plastic mold, or even the insert of the plastic mold. It can significantly reduce the coefficient of friction of these surfaces. Besides, a highly glossy processing surface can be made without using traditional mold release agents. Even though the design and plastic compound make the machine/tool maintenance downtime longer, resulting in low production yield.

If the cost is limited, nano-release coating can also extend uninterrupted production time and significantly reduce machine/tool maintenance downtime. It maximizes the efficiency and role of plastic mold production and reduces waste. Nano release coating not only improves the smoothness and accuracy of the plastic mold surface, but also greatly improves the productivity of the plastic mold manufacturing industry!