Extrusion Blow Molding Vs Injection Blow Molding

The blow molding process and the injection molding process are both plastic production processes. If you observe carefully, you will find that there are obvious differences in principle between the two. This article will introduce you to the advantages, disadvantages and differences between the blow molding process and the injection molding process.

Article Directory

What is Extrusion Blow Molding?
What is Injection Blow Molding
The Difference Between Blow Molding and Injection Molding
Professional Blow Molding Machine Manufacturer

What is Extrusion Blow Molding

In extrusion blow molding, plastic is melted and extruded into a hollow tube (a parison). This parison is then captured by closing it into a cooled metal mold. Air is then blown into the parison, inflating it into the shape of the hollow bottle, container, or part. After the plastic has cooled sufficiently, the mold is opened and the part is ejected.

Advantages and disadvantages of extrusion blow molding


Advantages of extrusion blow molding	Disadvantages of extrusion blow molding
It can produce a variety of products. It comes with low costs It allows for multiple methods of production It promotes a higher level of productivity It offers the benefits of automation	It is highly dependent on petroleum. It creates a huge impact on the environment. It requires a lot of production methods. It comes with limited uses. It requires process and material precision that creates waste.

Common extrusion blow molding applications

Extrusion Blow Molding Products made by Extrusion Blow Molding Machines are milk or water bottles, shampoo bottles, automotive air ducts, jerry cans, and hollow industrial preform parts such as plastic drums or other plastic containers.

What is Injection Blow Molding

The process of injection blow molding (IBM) is used for the production of hollow glass and plastic objects in large quantities. In the IBM process, the polymer is injection molded onto a core pin; then the core pin is rotated to a blow molding station to be inflated and cooled. This is the least-used of the three blow molding processes and is typically used to make small medical and single-serve bottles. The process is divided into three steps: injection, blowing, and ejection.

Advantages and disadvantages of Injection blow molding


Advantages of Injection blow molding	Disadvantages of Injection blow molding
Accurate shaping of the neck. A high level of dimensional accuracy. Mini weight tolerance. The highest quality surface finish. Production is absolutely free from waste. Crystal clear containers for pharmaceutical application. Finished bottle without weld line and scrap. Secondary /finishing operations can be avoided. Multi-cavities can be operated.	The preform design generally establishes the core rod length & diameter. The process is more expensive than extrusion blow moulding. Compromise between preform wall thickness and blow-up ratio. The ratio of the maximum wall thickness to minimum wall thickness across a preform cross-section should be less than 1.5 to prevent weld lines. Preform thickness greater than 6 mm is unstable during blowing since the thick section cannot be properly conditioned. The technique is not suitable for manufacturing bottles with handles such as those used for detergent bottles. Since the injection moulds are required for each preform type of shape, the process is more expensive than the extrusion blow moulding.

Common Injection blow molding Applications

Blow molding can be used to create numerous types of parts. Parts produced from the blow molding process are generally plastic, hollow, and thin-walled. These types of products are regularly used and are available in a bevy of shapes and sizes. Some of these types of blow molded parts, include:

Water & soda bottles
Shampoo bottles
Oil jugs
Milk containers
Storage tanks
Plastic drums
Tubs
And more

The Difference Between Blow Molding and Injection Molding

Injection molding is currently suitable for almost all thermoplastics, and over the years, injection molding has also been successfully used to mold some thermosets. Injection molding has a short molding cycle, and the mass of molded products can range from several grams to tens of kilograms. It can form molded products with complex shapes, precise dimensions, and metal or non-metal inserts at one time. The method has strong adaptability and high production efficiency.

Blow molding is widely used. It uses gas pressure to inflate a hot parison closed in a mold into a hollow product or a method of inflating a tube parison without a mold to form a tube film. This method is mainly used for the manufacture of various packaging containers and tubular films. As long as the melt index is 0.04~1.12, it is a relatively good hollow blow molding material, such as polyethylene, polyvinyl chloride, polypropylene, polystyrene, thermoplastic polyester, polycarbonate, polyamide, cellulose acetate, and Polyacetal resin, etc., among which polyethylene is used more

Professional Blow Molding Machine Manufacturer

MEPER is a leading blow molding machine manufacturer in China. Since 1998, we have been selling blow molding machines for overseas markets such as USA, Australia, UK, Canada, etc.

After years of hard work, we have now become one of the best blow molding machine manufacturers in China. Our blow molding machines are cheap and good quality. When you need a blow molding machine, please feel free to contact us.