What is Extrusion Blow Molding?
Extrusion Blow Molding (EBM) is a common blow molding technology used with many different types of plastics, including, but not limited to, PP (Polypropylene), HDPE (High-Density Polyethylene), PETG (Polyethylene Terephthalate Glycol) and PVC (Polyvinyl Chloride). It’s commonly used for containers requiring special barriers to oxygen and moisture to improve stability.
Process of extrusion blow molding
Extrusion blow molding is a simple process where plastic is melted and extruded into a hollow tube, or parison, which is then captured by a closing mold. Air is then injected to inflate the material until it fills the mold in the shape of a hollow bottle, container or part. After the plastic has cooled sufficiently, the mold is then opened, and the part is ejected.
One downfall of EBM is the scrap that is produced due to excess material formed around the mold. The excess must be trimmed either in mold, or with a secondary operation, where the scrap can be fed back into the extruder and used as regrind.
Advantages of Extrusion blow molding
Extrusion blow molding, when compared to other manufacturing processes, has lower mold costs and shorter lead times. This makes it a great choice in terms of logistics and cost benefits. EBM also has the capability to process multi-layer products, products with handles or angled necks, and allows for the use of In Mold Labeling (IML).
How Extrusion Blow Molding Differs from Injection Molding
The primary difference between these two methods is that extrusion blow molding is used to manufacture hollow parts such as water and liquid soap containers. EBM can also manufacture complex shapes, which is of tremendous value for product branding and identity.
However, injection molding is regularly used for the manufacturing of solid parts. Besides, injection molding can deliver huge volumes of quality parts at a high pace with accuracy.
