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.
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