Blow Molding vs. Injection MoldingBlow molding differs from injection molding in several key ways, and a better understanding of these differences helps avoid production problems.
- Injection molding makes solid parts, like a Frisbee®, while blow molding makes hollow parts, like a soap dispenser.
- Blow molding, by its nature, makes parts whose wall thickness will vary from place to place, based on how much the material has to stretch as it is being blown. An injection-molded part’s thickness is determined by the mold and core relationship.
- With injection molding, making the mold is 90% of the job. In blow molding, making the mold is only 50% of the job – a host of other variables must be managed closely, such as the type of plastic, the process temperature, the velocity or pressure of the blown air, and the mold close speed.