What is the difference between injection and blow molding? When it comes to custom plastic carrying cases, you have two options for manufacturing methods. Knowing the fundamental differences between the two will help you when narrowing down choices for case design. Both ways of molding plastic offer benefits, such as high-quality products and cost-effective prices.
When comparing blow and injection molding, the most notable difference is that injection molding creates solid plastic parts, whereas blow molding creates hollow pieces. When rigid walls are needed, consider injection molding. Blow molding is considered more versatile of the two manufacturing methods.
Injection molding works by melting resin into a hollow mold. Once the mold is completely filled, the injection mold is then held together using extreme pressure. The pressure is enough to force the resin into all areas of the mold.
Blow molding uses a plastic tube that is heated and filled with air until it becomes something akin to a balloon of hot plastic (parison). Molds are then clamped around the parison while air continues filling the parison to the shape of the part.
When building custom plastic carrying cases, it is common to see blow molding as the first choice for manufacturing. Blow molding takes less time than injection molding, and it is typically more affordable. Blow molding is lightweight because parts are hollow. Injection molding creates solid pieces.