In the field of plastic injection molding, product cracking is an issue that cannot be ignored, encompassing various forms from minute cracks to complete fractures. Delving deeper, these cracking phenomena can be attributed to two major causes: mechanical cracking and chemical stress cracking.

1. Mechanical Cracking: A Contest Between Physical Force and Structural Support

When the physical force exerted on a plastic injection molded product exceeds the inherent material properties and the structural support that the product can provide, cracking occurs. This phenomenon undoubtedly imposes higher requirements on plastic product design. At the outset of design, we must not only carefully select the appropriate materials and models but also comprehensively consider the various external forces that the product may encounter during use. To enhance the structural support of the product, an effective design strategy is to appropriately increase the thickness of the plastic product, thereby ensuring its stability when faced with external force challenges.

2. Chemical Stress Cracking: The Invisible Threat of Chemical Substances

Compared to the straightforward nature of mechanical cracking, chemical stress cracking is more concealed and complex. It stems from the erosive effects of chemical substances on plastics, causing the plastic to expand and subsequently exacerbating internal stresses. Once these stresses exceed the bearing limit of the plastic product, cracking ensues. It is particularly noteworthy that during the assembly process of plastic injection molded products, the use of lubricants, release agents, and other chemical products often becomes the "culprit" that induces cracking. Therefore, to eliminate the occurrence of chemical stress cracking from the source, we must strictly screen and control the chemical products used in the production process, resolutely prohibiting the use of those that may induce cracking.