Most mold companies are hot runners that make their own Pet Preform molds, which is not common in China. By making their own hot runners, they can also better control the quality and price of the hot runners. However, the stable operation of the hot runner requires a high degree of mindset and sophisticated equipment. Therefore, the company needs to make huge investments in mold equipment.
Internal threads are usually found in PET molds, but can also be designed in many technical products, such as plastic tube hardware. The planned manufacturing method (molding or post-molding processing) should be considered. If the lid is threaded after molding, the lid mold will be simpler (and less expensive) and the designer should understand the amount of production required. As we said before, achieving the lowest total cost product is more important than the most elegant manufacturing method. If a thread must be formed, we have two choices: how to remove the product from the core: by loosening or peeling.
Designers of plastic cover molds must consider whether the plastic cover can be peeled off from the threads. Peeling is the simplest (usually the lowest cost) solution for ejecting the top cover or closer to the top cover; however, the ease of peeling depends on many equally important factors.
The stripping theory is very simple. When the cover mold is opened, and after the cavity is removed from the side of the core, the demolding caused by the forward movement of the stripper begins. In this way, the plastic cover is pushed onto the ridge of the core; this causes the plastic to expand so that the portion of the core within the groove can slide out of the groove.
Choosing Jilian molds from China, we produce high quality Pet Bottle Preform, which can save you a lot of troubles.