Your Complete Guide to Blow Moulding

What is Blow Moulding?

Blow moulding refers to a manufacturing process used in making hollow plastic parts by inflating heated plastic preform inside a mould. This technique is employed for producing items like containers, bottles, and tanks for different applications.

Blow Moulding Types:

There are Three Primary Types of Blow Moulding:

• Extrusion Blow Moulding (EBM):

Here, extruded molten plastic from a “parison” (a hollow tube) is enclosed in a water-cooled mould, and air is blown into it. This inflates the plastic to conform to the shape of the mould. This method is used for making products like bottles and containers.

• Injection Blow Moulding (IBM):

Molten plastic is injected into a preform mould to create a solid preform. This preform is then transferred to a blow mould in which air is used to inflate it to the required shape. This method is ideal for producing high-quality jars and bottles with precise dimensions.

• Injection Stretch Blow Moulding (ISBM):

This method combines elements of both injection and blow moulding. An injection-moulded preform is reheated and stretched in both axial and radial directions during blow moulding. Here, the strength and clarity of the final product is improved, and is suited for items like PET bottles.

Blow Moulding Process:

The Blow Moulding Process has many Important Steps:

• Plasticizing:

Plastic material, often present as granules, is heated until it becomes molten.

• Forming the Preform or Parison:

According to the blow moulding method chosen, the molten plastic is extruded into a parison or injected into a preform mould.

• Moulding:

In this step, the preform/parison is placed into a mould.

• Inflation:

When air is blown into the preform/parison, it expands and assumes the shape of the mould.

• Cooling:

The mould is then cooled, and this solidifies the plastic into its required shape.

• Ejection:

The mould is opened, and the finished part is ejected out.

Extrusion Blow Moulding Process:

This method is widely used for creating simple hollow parts. A molten plastic tube (parison) is first formed and clamped inside a mould. When air is blown inside, it causes the plastic to expand and assume the mould’s shape. The mould is opened after cooling, and the final product is ejected. This method is used for manufacturing automotive parts, bottles, and industrial containers.

Injection Blow Moulding:

This method is highly precise in which plastic is first injected into a mould to make a preform. The preform is moved to a second mould, where it is then blown into its final shape. This method ensures uniform wall thickness and is suited for manufacturing pharmaceutical containers and cosmetic bottles. This highly efficient process allows for minimal material wastage.

Injection Stretch Blow Moulding:

This process improves the clarity and structural integrity of the plastic containers. Starting with injection moulding a preform, it is then reheated and stretched before being shaped into the required shape. This method (known for better strength and barrier properties) is employed in making PET bottles for beverages.

Blow Moulding Machine and Process:

A blow moulding machine plays a very important role in production automation. These machines come in various sizes and capabilities, depending on the type of blow moulding process that is being used. Use of a blow moulding machine allows for high-speed and efficient manufacturing process with consistency in quality.

Blow Moulding Machine and Process:

A blow moulding machine plays a very important role in production automation. These machines come in various sizes and capabilities, depending on the type of blow moulding process that is being used. Use of a blow moulding machine allows for high-speed and efficient manufacturing process with consistency in quality.

Injection Moulding Process vs. Blow Moulding:

Whereas the injection moulding process is used to produce solid plastic components, blow moulding helps to create hollow plastic parts. Both methods are required in plastic manufacturing. Injection moulding is the preferred method for creating precise intricate parts and blow moulding for larger, hollow assemblies.

Blow Moulding Machine Manufacturers in India:

India has a vibrant and growing industry for blow moulding machines and several manufacturers provide high-quality, efficient solutions for different industries. They offer machines for cost-effective, high-volume production of plastic bottles, containers, and automotive parts. They cater to both domestic and international markets.

Blow moulding, therefore, remains a key plastic manufacturing technology, offering efficiency, flexibility, and precision in producing a wide range of products.