Injection Blow Moulding
What is Injection blow moulding
Injection blow moulding is basically a series of processes involved in making hollowed plastic components and parts. The three major processes are;
(1) Injecting a parison or thermoplastic into a blow mold to create a pipe,
(2) Blowing the thermoplastic into a mold’s cavity to form a hollow object and
(3) Ejecting the final product. A wide range of hollowed products can be achieved through this method such as plastic bottles and pipes.
Raw thermoplastic materials are easily utilized within the blow-molding process
when they come in the form of small granules or pallets, which are melted first and molded into a hollow tube(parison). There is a wide range of thermoplastic materials that can be used but the ones that are easy to make
polyvinyl Chlorine (PVC)
Polythene Terephtalate (PET).
High and low density polyethylene (HDPE) and (LDPE) respectively.
Injection Blow Moulding Process.
There are 3 unique steps or processes involved during creating blow molded parts
, they include;
This process is purposely used to produce hollowed objects having bi-axial molecular orientation. This is important as the specific molecular orientation provides clarity, acts as a perfect gas barrier and provide enhanced physical properties needed in storing carbonated beverages or chemicals.
The process is further subdivide into two distinct molding techniques. The one stage process requires the preform to be injected into the mold having properly conditioned temperatures and blown into the required containers—all under one continuous process. This method is effective where large production is not a priority.
The two-stage process: The preform is injected into the mold, where it is left for about 1 to 4 days and thereafter blown into containers. A re-heat blow(RHB) is a machine is used in this case. Typically, this process is costly compared to the one process technique but it is the best in mass production, for example, carbonated-beverage bottles.
Injection blow molding
The hot thermoplastic material is indexed and blown into the mold while still on the pin. The bottle formed for instance is left to cool. It is then indexed and ejected at the next station. This stage or process allows neck finishing and threading at the mouth. The process is less concerned with the orientation enabling attaining more physical properties of the products.
This blow molding process
commences with the conservation of an extruded prison tube. The prison is extruded between 2 halves of opened blow molds. Once the right length is attained, the molds close, holding the neck-end wide open while the bottom end is pinched and closed. A rod of the right diameter is then inserted on the neck end, while the poison is still hot to form the necessary threads. The molded bottle is then removed and excess material is trimmed from the pinch off area at the bottom and neck areas.
This method is not only economical it is also popular because it is known to produce high-quality solid parts and products. If you want to produce rigid walled bottles or pipes, then this the method for you.
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