Injection molding product release solution

In the injection molding process, it must be ensured that the molded product can be removed from the mold.

The biggest advantage of injection molding is that it can be processed in unmanned mass production, but if the molded product remains in the mold and must be removed manually, the molding machine must always be assigned staff, and unmanned processing cannot be performed, which will lead to personnel shortages. rising costs.

If the mold is closed with the molded product left in the mold, in the worst case, the cavity and core may be damaged, resulting in a major economic accident. If the mold is damaged, it cannot be easily repaired in most cases. Therefore, the mold must be adjusted to ensure that 100% of the molded product can be removed from the mold.

So why does the molded product remain in the mold? The phenomenon that the molded product remains in the mold is called poor mold release. The occurrence of poor mold release is the result of the combined action of the following factors.

(1) Shrinkage of molded products

(2) Thickness of the molded product

(3) The inner diameter of the molded product

(4) The smoothness of the molding material

(5) Surface roughness of cavity and core

(6) Draft angle of cavity and core

(7) The surface temperature of the molded product when the mold is opened

(8) Ejection speed

(9) Number and configuration of ejector pins

(10) The shape of the top corner of the molded product

(11) The vacuum state between the molded product, the cavity and the core

(12) Alignment of glass fibers, etc.

It is difficult to take relevant measures when the mold release failure has already occurred, so it is very important to fully consider this in the early stage of mold design. Specifically, the key point is that the shape and material of the molded product, the gate position, the draft angle, the height of the molded product, the configuration of the side core-pulling slider and the inclined guide column, the thickness of the molded product, etc. need to be checked. Fully explored to predict where demolding defects may occur. If you can't make predictions, you can't take action accordingly, so it is extremely important to fully understand the various samples of poor mold release and poor analysis reports in the past.

That is, an exhaustive set of bad records reports must be constructed. Defects such as poor mold release caused by the intertwining of many factors are difficult to find through analysis. Experienced designers can foresee the occurrence of bad demoulding through tacit knowledge, but it is difficult to do this without sufficient experience, so it is necessary to systematically accumulate data that accurately records bad phenomena.