What is the Difference Between Injection Molds and Blow Molds?

Injection molding and blow molding are two processing technologies for mold products, but they have different characteristics. In simple terms, injection molding molds use the "injection + pressure" mode, while blow molding molds use the "injection + blowing" mode, and injection molding produces solid products, while blow molding produces hollow products. In addition, the molds produced by injection molding process have gate sections, while the surface of the molds produced by blow molding process is uneven with blowholes.

Injection molding molds

Injection molding is the process of injecting thermoplastic plastic to form a shape. This method melts the plastic material and injects it into the mold cavity. Once the melted plastic enters the mold, it is cooled and shaped into the desired shape, often becoming the final product without further processing. In addition, injection molding can well control details, such as protrusions, ribs, threads, and other parts that can be formed in one step in the injection molding process.

Blow molding molds

Blow molding, also known as hollow blow molding, is a rapidly developing plastic processing method. Its processing principle is to place a thermoplastic resin or an injection-molded tubular plastic blank in a mold, and then inject compressed air after the mold is closed, causing the plastic blank to inflate and adhere to the inner wall of the mold. Then, after cooling and demolding, the desired hollow product is obtained.

It is worth mentioning that the manufacturing process of blow-molded film is similar in principle to that of blow-molded hollow products, but it does not use molds in production, which is completely different from manufacturing injection molding molds. From the perspective of plastic processing technology classification, the molding process of blow-molded film is usually included in the extrusion process. According to the manufacturing method of the blank, blow molding can be divided into extrusion blow molding and injection blow molding, and newly developed processes include multi-layer blow molding and stretch blow molding.

Differences between Injection molding molds and blow molding molds

Through the above introduction, we can have a certain understanding of these two processing technologies. In fact, the main difference between injection molding molds and blow molding molds lies in the products they produce. The products produced by injection molding have a thicker appearance and are relatively simple to manufacture, with relatively low requirements for raw materials. The blow molding process is different, with products produced thinner and more transparent, and any flaws are easily visible, which is why the blow molding molds have higher processing requirements and certain requirements for the toughness and stretchability of the raw materials.

Both injection molding molds and blow molding molds are widely used in daily life with their distinctive characteristics and advantages, and their processing technology is also improving year by year, with a good development prospect in the future.