What is the reason for the cracking of plastic injection molding products?

Fractures of plastic injection molded products include cracks and micro-cracks. According to the cause, it can be divided into mechanical cracking and chemical stress cracking.

[1] mechanical rupture

When the physical force of the plastic molding product is greater than the inherent physical properties and structural support of the plastic, it will be broken due to unbearable. In order to prevent plastic injection molded products from cracking, care must be taken when designing plastic products. When designing plastic products, after selecting the materials and models used, other forces of the product should also be considered. In order to improve structural support, the thickness of plastic products can be increased in the design.

[2] Chemical stress cracking

Chemical stress cracking refers to the expansion of plastic under the action of chemical substances, which will increase the internal stress, resulting in a stress value higher than the carrying capacity of the plastic product. Chemical stress cracking usually occurs during the assembly of plastic molded products. When lubricants, mold release agents, etc. are used, the chemicals contained in them can cause the product to crack. In order to prevent cracks caused by chemical stress, the use of chemical products that can cause cracks should be prohibited.