Injection Molds and Blow Molds
I. Injection Molds
Injection molding is a process in which plastic material is melted and then injected into a mold cavity. Once inside the mold, the plastic cools and takes on the desired shape-which corresponds to the final appearance of the product-eliminating the need for further processing. Additionally, the injection molding process allows for excellent control over details; features such as protrusions, ribs, and threads can be formed in a single step.
II. Blow Molds
Blow molding-also known as hollow blow molding-is a rapidly developing plastic processing method. The process works as follows: a thermoplastic resin or tubular plastic preform (parison) is placed into a mold; once the mold closes, compressed air is injected to inflate the plastic against the mold's inner walls; finally, the part is cooled and demolded to yield the desired hollow product.
It is worth noting that while the manufacturing of blown film is conceptually similar to the blow molding of hollow products, it does not utilize a mold, making it fundamentally different from injection molding. Based on the method of producing the preform, blow molding can be categorized into extrusion blow molding and injection blow molding; emerging trends in the field include multilayer blow molding and stretch blow molding.