Why do cracks appear in the design of injection cover mold parts? How to solve it?

Under the premise of ensuring the normal output of the mold, the injection molding process should be as simple as possible and easy to release, and avoid or reduce all kinds of core-pulling structures around the mold as far as possible, which can greatly simplify the mold structure. it is convenient for mold injection molding and can improve production efficiency. 

When making the mold, in order to avoid the convergence of fillet stress as much as possible, inject the mold parts and improve the strength of the parts to ensure the stress convergence at the corner of the parts, and reduce the rupture that will occur when the product is subjected to force or impact, if the forming conditions are improper or the structure of the parts is unreasonable, great internal stress will occur, especially simple stress cracking. 

When the fillet radius at the convergence is less than 0.3 times of the wall thickness, the stress convergence increases sharply, and when it is greater than 0.8 times the wall thickness, the stress convergence becomes smaller obviously.

Only the use of fillets can be simple filling and demoulding, for some poor mobility of plastics or to participate in the filling of plastics, parts planning on a variety of fillets is particularly important, not only can improve the performance of filling, and can improve the performance of parts. 

The fillet is beneficial to the production of all kinds of moulds, the bottle preform mold manufacturers have planned all kinds of fillets in improving the strength of the mold, and the corresponding parts of the mold should also be filleted, which increases the firmness of the mold. The mold will not crack due to the convergence of stress during quenching or use, thus increasing the strength of the mold demoulding. 

In order to satisfy the different physical and mechanical properties of the machine. 

The primary requirements are dense products, firm welding, high strength and low internal stress. 

However, in our daily injection or mold testing process, even if the process parameters are adjusted, the products will often appear a variety of different phenomena, such as lack of filling, high internal stress, exterior streamline and so on. The primary reason is that there is a problem with the exhaust of the mold.