Injection blow molding and extrusion blast molding are integral to many manufacturing processes. These methods are used to produce many disposable and recyclable plastic parts. They also include products for medical and research purposes. Each process produces different results. It is important to know their differences to choose which is best for your product. We’ll explain the different processes so you can choose which one is right for you.

What is Injection Blow Molding?

Injection molding was invented to increase productivity in the 1930s. Injection molding involves melting plastic, then injecting it into a predesigned mold. Injection molding has several advantages, including reduced waste, minimal finishing requirements, and the possibility of recycling. Injection molding’s design capabilities allow for the manufacture of 3D components, which is not possible with extrusion molding. Two core components are required for injection molding: clamping and injection units. Injection blow molding (or IBM) is a particular type of injection molding that uses a core rod or metal shank. A parison is used to create the base for the final product. The IBM process begins with the transfer of the core rod/parison into the blow molding unit. Next, inflate and cool the pre-formed part. After cooling, the core rod is turned to the ejection position, and the mold is opened. The product is then removed. Three core rods will be used throughout the process to allow mold injection, blow molding, and ejection.

What is Extrusion Blow Molding (EBM)?

EBM (extrusion blow molding) is similar to IBM. However, instead of injecting melted material into a mold, the material is extruded into a hollow tube known as a parison. A mold is placed around the parison to shape the part at the blow station. The blow station inflates the parison into the mold shape by blowing air into it. After the plastic cools, the mold can be opened, and the part extruded. The part is then trimmed off any excess material. The EBM process produces a lot of scraps.

What are the Key Differences between Injection and Extrusion Molding?

Injection blow molding and extrusion molding are different in three key areas.

Products

EBM and IBM have different products. That is their main difference. IBM is used for the creation of more substantial parts. That includes kitchen and medical components. EBM can be used to make hollow parts such as bottles and other containers. Because of the way that the product is made, Extrusion Blow Molding allows for more complex shapes to be manufactured. Injection molding can produce high volumes of quality parts in a short time and with great accuracy.

Molds

To ensure total control of resin flow, IBM requires a precise match between the mold’s two halves. The mold is the most important part of injection molding. EBM allows for greater design flexibility because each mold half has its wall shape.

Different types of materials

Most commonly, extrusion blow molding is used to create products from:

  • HDPE is high-density polyethylene
  • Polypropylene (PP)
  • Polyethylene Terephthalate (PET).

Most commonly, injection blow molding is used to create products from:

  • Acrylic
  • Polycarbonate
  • Polyoxymethylene (POM).
  • Polyethylene (PE).

Partner with GS Machinery

GS Machinery is a distinguished Manufacturer, Exporter, and Supplier of a wide assortment of high-performance HDPE blow molding machines, injection machines, and plastic molds. Incorporated in the year 2009, the company is located in Zhangjiagang city, China.

GS Machinery continues to bring the latest state-of-art technological improvement through the regular analysis of critical aspects of the manufacturing process with the approach of quality improvement. The manufacturing is supported by the latest fully automatic blow molding machines.