In the plastics industry, everyone will hear the term of blow molding. What is blow molding? Do you really know? Today, I will take you to know more about it.

What is blow molding?

Blow molding is a method of forming hollow products by means of gas pressure to blow and swell hot melt embryos closed in the mould. The hollow blow molding is to extrude from the extruder and put the tubular thermoplastic blank which is still in the softening state into the molding mould.Then through the compressed air, using the air pressure to deform the blank along the die cavity, thus blowing into a short neck hollow products.

Hollow blow molding is the most important forming technology for producing hollow plastic products. Almost all thermoplastics can be used for hollow blow molding, such as polyethylene, PVC, polypropylene, polystyrene, linear polyester, polycarbonate, polyamide, cellulose acetate and poly acid formaldehyde resin, etc.

With this molding technology, it can not only produce small volume bottles of several milliliters, but also can produce thousands of liters of large-volume barrels and storage water tanks, as well as floating balls, automobile fuel tanks and kayaks.

bottle blowing process

What characteristics should blow molding products have?

1.Environmental stress cracking resistance: as a container, it has the ability to prevent cracking when it comes into contact with surfactant;

2.Air tightness (permeability resistance) : refers to the characteristics that prevent the outward diffusion of oxygen, carbon dioxide, nitrogen and water vapor.

3.Shock resistance: in order to protect the goods in the container, the products should have impact resistance that cannot be broken down from one meter height.

4.In addition, there are drug resistance, static resistance, toughness and extrusion resistance.

What are the advantages of blow molding?

1.Hollow, double-walled structure can absorb and eliminate impact energy;

2.Flexible design, with high functionality and low production cost;

3.The processing technology can change the thickness of the embryo;

4.During processing, the thickness of the product can be changed at will without improvement of the mold;

5.Low pressure molding (the internal stress of the mold is much smaller than that of the injection molding), so as to improve dimensional stability, chemical corrosion resistance and high temperature performance;

6.Assembly diversity: self-tapping screw, die insert, rivet expansion fastener;

7.Simple mould, low cost and short processing cycle;

8.The sample mould with low price can be produced quickly.

Blow molding is a manufacturing process by which hollow plastic parts are formed: It is also used for forming glass bottles. In general, there are three main types of blow molding: extrusion blow molding, injection blow molding, and injection stretch blow molding.


.Stable performance with advanced PLC.

.Conveying preforms automatically with conveyor.

.Strong penetrability and good and swift distribution of the heat by letting the bottles rotate by itself and revolute in the rails simultaneously in the infrared preheater.

.High adjustability to enable the preheater to preheat preforms in shapes by adjusting the light tube and the length of the reflecting board in the preheating area, and eternal temperature in the preheater with an automatic thermostatic apparatus.

.High safetieswith security automatic-locking apparatus in each mechanical action, which will make the procedures turn into a state of safety in case of a breakdown in certain procedure.

Basically blow moulding is a making hollow plastic part and make container joining these part. It is available in many shapes and sizes. Blow moulding and injection moulding are one of the highly utilized techniques and commonly used with this technique we produce high quality plastic parts in minimum cost so this is great cost effective way. Blow moulding is an old technique used to create hollow objects. In Blow moulding many factors are involved such as “type of a plastic, velocity, speed, temperature. Air is one of the important factors and plays a vital role in blow moulding. Air pushed into the mould to expand it and give it the desired shape. Blow moulding process is very easy, highly utilized and includes low cost machines, manufacturing plastic bottles using this process is much cheaper as compared to injection moulding. In blow moulding moulds isn’t required for making high precision mould.

Blow molding – is a very specific manufacturing process by which hollow plastic parts are formed and can be joined together.

It is also used for forming glass bottles or any other hollow shapes.

In general, there are three main types of blow molding:

  • Extrusion blow molding
  • Injection blow molding
  • Injection stretch blow molding.

blow molding machine is widely used in commercial beverage production. The blow molding machine creates a plastic bottle according to a recipe, for example specifying the capacity of the bottle to be made. The machine consists of molds, a programmable logic controller, and mechanical and electronic instruments.