Blow molding and injection molding are two common molding methods, but there are many differences between the two. Today, Kunshan Juxinchang editor will give you a clear understanding of injection molding and blow molding.

There are several important differences between the types of blow molding and injection molding, including: molding process, air utilization, and molded products.
1. Molding process:
Roughly speaking, blow molding is injection + blowing, and injection molding is injection + pressing.
1. Blow molding
Also known as hollow blow molding, a tubular plastic parison obtained by extrusion or injection molding of thermoplastic resin. It is placed in a split mold while hot (or heated to a softened state), and compressed air is immediately introduced into the parison after the mold is closed, so that the plastic parison is blown up and closely attached to the inner wall of the mold. After cooling and demolding, various hollow products are obtained.
2. Injection molding
It is thermoplastic injection molding. This method is to melt the plastic material and then inject it into the film cavity. Once the molten plastic enters the mold, it is cooled and molded into a certain shape according to the mold cavity, and the resulting shape is often the finished product. No other processing is required before installation or use as a finished product. Many details such as protrusions, ribs, and threads can be molded in one step of injection molding. The injection molding machine has two basic components: an injection device for melting and feeding the plastic into the mold and a clamping device.

2. Air utilization:
Air is the enemy of injection molding. If air is present during the manufacturing process, it will create air pockets or bubbles. These anomalies can create weak points in the product, leading to product defects and possible discarding.
But with the blowing method, air is very important. Blow molding revolves around the entry of air into the mold to push out and expand the product. The mold can hold a limited amount of air before separating and leaving holes in the molten product. But without air, blow molding is impossible.

3. Molded products
Although there are subtle differences between the types of blow molding and injection molding, there is also a particular major difference between these two types of plastic manufacturing.
Generally speaking, blow molding is done to create hollows. For example, bottles are commonly used in the food and beverage industry, the pharmaceutical industry, and countless other industries.
Injection molding is used to produce solid parts, such as plastic products. The blow molding process creates the shape of the plastic product, while the result of injection molding is the product itself. With injection molding, manufacturers only need to make the mold to ensure the success of the product. Any additional molds will be replicas of the original mold. However, with blow molding, manufacturers must pay special attention to production variables to ensure that each product has the same thickness.
The above are the differences between blow molding and injection molding. Do you understand? If you still don’t understand, you can communicate with Kunshan Juxinchang editor by leaving a message on QQ or WeChat or calling the hotline.