Both injection Blow Molding and extrusion blow molding processes are integral in many manufacturing applications. These techniques are used to create many disposable and recyclable plastic parts, including products used in medical and research applications. Both processes feature unique functions to produce different results, which is why it’s important to understand each process to determine which is suitable for manufacturing a particular product. To help you better understand the differences between injection blow molding and extrusion blow molding, we’ll go over how each process works so that you can determine which is best for your needs.
To increase production efficiency in the 1930s, injection molding was developed. The process involves melting plastic and then injecting it into a predesigned mold. Primary advantages of injection molding include reduced waste, minimal finishing requirements, and recyclability. Unlike extrusion molding, the design capabilities of injection molding allow for the manufacturing of 3D components. The machines used for injection molding include two core components: the clamping unit and the injection unit. Injection blow molding, or IBM, is a specific type of injection molding process that involves the use of a metal shank or core rod. The process uses a parison that forms the basis for the finished product. The beginning of the IBM process entails transferring the parison/core rod into the blow molding unit of the machine, followed by inflating and cooling the pre-formed part. After cooling, the core rod is rotated to the ejection position, the mold is opened, and the product is removed. Throughout the process, three sets of core rods are used to facilitate mold injection, blow molding, and the ejection of the formed part.
Extrusion blow molding, or EBM, is similar to IBM, but instead of injecting melted plastic into a mold, the material is extruded or expelled into a hollow tube, known as a parison. A mold closes around the parison in order to shape the part while at the blow station. At the blow station, air is blown into the parison inflating it into the shape of the mold. Once the plastic has cooled, the mold is opened, and the part is extruded. Any excess material is trimmed from the completed part. Because of the EBM process, there is typically a high level of scrap produced.
There are three main areas in which injection blow molding and extrusion blow molding differ.
The principal difference between IBM and EBM is the type of products they create. IBM is typically used to form more solid parts, which can include medical parts, kitchen parts, and other solid components. Meanwhile, EBM is used for manufacturing more hollow parts like bottles and other containers. Extrusion Blow Molding can manufacture more complex shapes due to how the product is formed. However, injection molding is able to produce large volumes of quality parts quickly and accurately.
For IBM, there needs to be a high precision match between both halves of the mold to enable total control over the flow of resin. Most of the work involved in injection molding involves producing the mold. In EBM, there is a higher level of design flexibility between both mold halves since each half forms its own wall shape.
Extrusion blow molding is most commonly used to form products out of:
Injection blow molding is most commonly used to form products out of:
It is important to consider your product when determining whether injection blow molding or extrusion blow molding is right for your needs. At E2Global we can help determine which process is best suited for your application. With our extensive experience manufacturing a variety of bottles, tubes, and other consumables, we are here to help guide you with your packaging need from design to production. Contact us today.
With high quality products and considerate service, we will work together with you to enhance your business and improve the efficiency. Please don't hesitate to contact us to get more details of Plastic Blow Molding.