What is the blow molding process?

June 10, 2022 Plastic Drum blow molding machine

What is the blow molding process?

In simple terms, blow molding process is a method to produce plastic hollow products by blowing the plastic embryo in the molten state in the closed mold using gas pressure.


Classification of Blow Molding Process: Extrusion Blow Molding, Injection Blow Molding, Stretch Blow Molding

Extrusion blow molding is the process of extruding the mold head into the mold to complete the molding process.

Injection blow molding is the process of injecting the blanks into the mold to complete the molding process.

In stretch blow molding, the mold is first formed by extrusion or injection molding, and after the mold reaches the appropriate stretching temperature, the mold is stretched longitudinally by internal or external mechanical force, and gas is introduced into the mold while stretching to complete the production of plastic products.


Here, we will take the extrusion blow molding process as an example.


Blow molding process processing

The granular plastic raw materials are automatically added to the barrel by the blow molding machine, and after high temperature heating and mixing by the screw, the raw materials are mixed into a molten plastic mold. The blowing hole at the bottom of the blow molding machine blows gas into the inside of the mold, which makes the mold expand and stick to the inner wall of the mold, and the product is finished and enters the cooling stage. The mold is opened, the product is demolded, and the production is completed.


What raw materials are used in the blow molding process?

Almost all thermoplastic materials can be used as raw materials for blow molding, for example, high-density polyethylene (HDPE), polypropylene (PP), etc.

These two are recommended for everyone and are ideal for both material properties and others. Of course, there are other raw material options available for the blow molding process.


Advantages of the blow molding process

1. Fast molding process and stable product quality

2. Closed production process, no pollution

3. Low energy consumption in the process, energy saving

4. Small footprint of equipment

5. Wide range of production, one machine for multiple uses


What products can be produced by blow molding process?

The blow molding process can produce not only small-capacity plastic bottles of a few milliliters, but also large-capacity plastic water buckets and water storage tanks of thousands of liters. In addition to containers, the blow molding process can also produce floating balls, barricades, pallets, ton drums, double-ring drums and kayaks.


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