The blow Molding can be described as a process that allows for the mass production of hollow plastic containers. As regards the processes involved in blow molding, injection blow molding and extrusion blow molding are the two most commonly used methods and each is appropriate for particular applications. Their differences can help manufacturers choose the technology that is best suited for their production process. Below is a detailed comparison of both methods in terms of process, applications, and advantages.

How They Are Different From Each Other

Injection Blow Molding:

Injection moulding comprises two cycles. First, an injection is made wherein, molten plastic is injected over a preform within a mold. This preform is then moved onto a blow mold where it’s inserted above a neck of a container with a shoulder and compressed air fills the container Further, this method enables a high accuracy and uniformity in wall thickness to be achieved.

extrusion blow moulding:

The process of extrusion blow molding utilizes a plastic extrusion process where molten plastic is forced into a hollow cylindrical shape known as parison. The parison is melted and inserted into a mold. The process is more simplistic and is predominantly used for larger and simpler hollow items than Injection moulding.

Differences In The Material And Products

Materials Used:

It's worth noting that both IBM and EBM utilize thermoplastic resins, however the Feed stock for IBM tends to differe and may include High Density Polyethylene (HDPE) and polyethylene terephthalate (PET) which are ideal for small and accurate manufacturing parts. Flexible designs in EBM are generally developed using PVC or PP. 

Products Produced:

High precision, small, Injection Blow Molding is an alternative in cosmetic container manufacture, medical bottle manufacture and pharmaceutical packaging. Conversely, Extrusion Blow Molding is preferred for large container items such as milk bottles, fuel tanks and drums. 

Key Advantages:

Injection Blow Molding Advantages:

The ability to produce high levels of precision in products with uniform wall thickness

Minimum amount of wastage due to raw materials during the process 

Provision of small size, high quality and aesthetically appealing containers

Extrusion Blow Molding Advantages:

Achieve larger, thicker, more complex shapes

Lower tooling cost in addition to faster production speeds than injection blow moulding 

Able to produce items with handles and a range of geometries 

Limitations of Each Process

Injection Blow Molding:

Higher costs in equipment, tooling 

It can only be used to produce small sized items 

Not recommended for good manufacturing of large containers 

Extrusion Blow Molding:

And Injection Blow Moulding lower accuracy erects intrusion into Extrusion molds 

Considerable wall thickness for seams may occur with uneven wall thickness for some areas.

Certain cases posses excessive material waste 

Choosing the Right Machine

For any product type, precision requirements, production needs, and budgets may determine which attributes of extrusion blow molding and injection blow molding are ideal for the production of said product. In the case of high-precision containers, IBM is a suitable choice. EBM is more effective and economical for larger, less intricate products.

The utilization of injection blow molding as well as extrusion blow molding machines is vital in the plastic manufacturing industry. Injection blow molding performs very well in terms of manufacturing precision and quality, whereas extrusion blow molding is better suited for mass production of larger objects. These two processes offer varying capabilities that give its users better chances of selecting the most appropriate process for production.