What is the reason for the difficulty of mold release in injection molding

What are the reasons and solutions for the difficult demolding of injection molds?

Difficulties in demolding often occur when the injection mold is tested for injection molding. Summarized as follows:

There are many reasons for the difficulty of mold release in the injection molding process of the injection mold:

1. Waterway design;

2. There are grooves inside the mold;

3. The demolding situation of the front and rear molds;

4. The mold finish is not high;

5. Insufficient draft angle;

6. Whether the setting of the inclined top and the thimble are consistent.

Insufficient draft angle is one of the important reasons for the difficulty of drafting. Therefore, when designing injection molds for processing products, the slope should be marked on the drawing, usually between 1-2 degrees, and more than 0.5 is allowed in special occasions. During operation, in order to smoothly release the plastic product from the mold, a release agent containing silicone oil is used, but only a little bit can be used. If the spray is too thick, it is very difficult to wipe off. At the same time, it will also cause the second processing of the printed mark to become poor. Once the release agent is applied to the mold, it will be attached to the plastic product and it is very difficult to wipe it off. It should be noted that the injection pressure should not be too high. If the plastic product is too tightly attached to the injection mold, demolding will become very difficult.

Difficulties in demolding plastic injection molded parts are often encountered in our injection molding production process. Poor demolding has a great impact on the quality of injection molded products. Mild poor demolding may cause scratches or patterns on the surface of the product; serious poor demolding will Lead to warping, deformation, or even cracking and damage of the product. Therefore, solving the problem of poor release of the injection molding process of the injection mold affects the quality of the final injection product.

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. However, sometimes due to the special shape of the plastic parts or the need for production automation, after a demolding work is completed, the plastic injection molded parts are still difficult to take out from the cavity or cannot fall off automatically. At this time, another demolding action must be added to make the plastic Pieces fall off. Difficulty in demolding is mainly because the gate or the plastic part is compressed in the mold.