Injectieblow

Injectieblow, also known as injection blow molding, is a plastic forming process used to manufacture hollow parts such as bottles and containers by combining injection molding and blow molding. In the two-step variant, resin pellets are melted and injected into a mold to form a preform (parison) with the desired neck finish. The preform is then transferred to a second station where it is reheated and placed in a blow mold. Compressed air inflates the softened plastic, pushing it against the mold walls to create the final hollow part. A one-step variant integrates injection and blowing in a single machine, reducing handling but requiring more complex tooling.

Materials commonly used in injectieblow include PET, polypropylene, polyethylene terephthalate, polycarbonate and other thermoplastics suitable for forming hollow containers. The process is widely employed for producing consumer bottles, cosmetics containers, and pharmaceutical vials, especially where consistent wall thickness and clear, glossy surfaces are desired.

Advantages of injectieblow include high production rates for small to medium-sized parts, good control over wall thickness and neck finish, and compatibility with recycling streams when using PET. The method also enables relatively precise replication of complex shapes and thin walls, contributing to lightweight designs.

Limitations involve tooling complexity and cost, geometry constraints that favor certain bottle shapes over others, and less suitability for very large or highly irregular parts. Surface quality can depend on material and mold design, and post-molding finishing may be required for certain applications.

Historically, injection blow molding evolved as a two-step process alongside one-step variants, becoming a staple in beverage packaging and other hollow-part production. See also blow molding, extrusion blow molding, stretch blow molding, and one-stage ISBM.