When discussing the PET preform mold, material selection is crucial, as it directly determines mold lifespan and the quality of PET preforms. Simply looking at mold lifespan, production cycle parameters, etc., isn't enough; factors such as wear resistance, corrosion resistance, etc, also need to be considered. For different function templates, component materials of preform mold are like choosing clothes-it's not just about one item looking good, but about overall harmony.
Let's start with wear resistance; it's extremely important. During preform production, the molten plastic doesn't flow gently, especially with materials like PET. It's like a high-pressure flow of water, constantly scouring and rubbing against the cavity/core surface. Under prolonged high-pressure "scouring," even the hardest steel can develop wear marks. If dimensions shift or the surface becomes damaged, the mold is essentially unusable. For core components such as the mold core and cavity, as a manufacturer, we prioritize recommending high hardness, wear resistant alloy tool steels, such as S136 or AISI 422. If handled properly, a hardness of HRC 52–56 can be achieved, making it much more resistant to everyday wear and tear. If the customer has special requirements, chrome plating or nitriding treatments can be applied to the mold surface, essentially giving the mold an "armor" and extending its lifespan.
The mold template, threaded parts, etc are actually quite "wronged", as they are subjected to impacts during each operation. If they are too brittle, they can easily chip or crack. In the case, strength and toughness must be considered together. The purity of the material itself, its grain size, and the microstructure resulting from the final heat treatment all affect its ability to achieve a balance of rigidity and flexibility. For large structural components like mold frames, pre-hardened materials such as P20, 4Cr13, etc, are now commonly used. This eliminates the need for further heat treatment after machining, saving time and preventing deformation. For neck parts, high-toughness materials such as 4Cr13 and S136 are often chosen to prevent brittle fracture.
If you're committed to the PET preform market or have any questions about the PET preform mold, we hope to have more exchanges with you.Our team of experts is always available to provide you with the information and support you need to make an informed decision.
We look forward to working with you! In the next issue, we will continue our discussion in detail other factors in selecting the materials of PET preform mold.