The difference between blow molding and injection molding

Blow molding and injection molding are two common molding methods. However, it is important to understand the difference between blow molding and injection molding before deciding. This article will give you a clear understanding of injection molding and blow molding in easy to understand sentences.

There are several important differences between the types of blow molding and injection molding. These differences include:

Molding process

Using air

Molding products

Next, let's expand on each of the above three points.

Molding process:

Purge and injection are also very different, roughly speaking, blow molding is injection + blowing, injection molding is injection + pressure.

Blow molding

Also known as hollow blow molding, thermoplastic resin by extrusion or injection molding obtained tubular plastic billet. When it is hot (or heated to the softening state), it is placed in the split mold. After closing the mold, compressed air is poured into the billet immediately to make the plastic billet blow and close to the inner wall of the mold. After cooling, it can get all kinds of hollow products.

Injection molding

Thermoplastic injection molding, which involves melting plastic material and injecting it into a membrane cavity. Once the molten plastic is in the mold, it is cooled and molded into a shape according to the cavity. The resulting shape is often the final product, requiring no additional processing before installation or use as a final product. Many details, such as bumps, ribs, and threads, can be molded in one step by injection molding. The injection molding machine has two basic parts: the injection device for melting and feeding the plastic into the mold and the mold closing device.

Air utilization:

Air is the worst enemy of injection molding. If air is present during the manufacturing process, pockets or bubbles will be created. These exceptions create weaknesses in the product, which eventually result in defects and can be discarded. With the blowing method, air is very important. 

Blow molding is surrounded by air entering the mold to launch and expand the product. The mold can hold a limited amount of air before separating and leaving holes in the molten product. But ultimately, without air, blow molding is impossible.

Product processing process:

Although there are subtle differences between blow molding and injection molding types, there is one major difference in particular between these two types of plastic manufacturing.

In general, blow molding is used to produce a hollow bottle, for example, are used in the food and beverage industry, the pharmaceutical industry, and countless other industries.

A wide variety of blow molding products. The same is true of the type of blow molding machine. MEPER has accumulated many years of experience in the blow molding industry and strives to adopt good blow molding process. In addition, MEPER has its own technical team. From product development to production can be completed independently. We produce different kinds of high quality blow molding machines.

Injection molding is used to produce solid parts, such as plastic products. The blow molding process ultimately creates the shape of the plastic product, while the result of injection molding is the product itself. With injection molding, the manufacturer only needs to make the mold to ensure the success of the product. Any additional molds will be replicas of the original molds. However, for blow molding, the manufacturer must pay special attention to the production variables to ensure that each product has the same thickness.

These are the differences between blow molding and injection molding, do you understand? MEPER MACHINE, focus on the design, production and sales of blow molding machine, especially multi-layer blow molding machine, if you have the need to buy blow molding machine, you can call our website at any time for consultation.