Juan Carlos Cuevas • 8 de noviembre de 2022
But what is the Blow Injection molding process? Well, injection blow molding, or IBM, is a transformation process for thermoplastic resins that, as its name suggests, is made up of injection molding and blow molding. Injection blow molding is generally used for the manufacture of small-sized containers without the option of a handle. It is used for containers that have short tolerance ranges with threaded necks, wide mouth openings, solid handles, and styled shapes.
The resins used in the Blow Injection process are: High Density Polyethylene (HDPE) and Polypropylene (PP).
The Blow Injection process is relatively, very simple. It consists of injecting resin into a pin-shaped core, which forms what we call the preform; the core then goes to the blowing station to inject air and shape the resin according to the mold, and then it is cooled.
In short, there are three steps:
What is the preform? It is the stage in which the resin takes the shape to become the final product and is made up of a fully formed neck attached to a resin tube that will form the body of the container.
We already know the process and the resins used for this molding, now let's talk a little about the machinery and its components.
The blow molding machine consists of an injection unit to melt the resin. The melt is fed into a hot runner manifold where it is injected through nozzles into a hot mold. Inside the mold cavities the preform is formed around a core. The preform mold opens and the center bar is rotated and clamped in the hollow, cooled blow mold. The tip of the bar opens allowing compressed air to enter the preform, which is inflated to the shape of the final product. The blown product has a programmed weight that cannot be easily changed.
Generally, the molded container material is evenly distributed and no trimming or milling is necessary. After a cooling period, the blow mold is opened to eject the finished product, which is then leak tested before being shipped to the customer.
Grupo Arcoíris Plásticos manufactures products using this process, with state-of-the-art technology and under strict quality standards for the pharmaceutical (syringe bottles, pill dispensers and squeezable "dropper" bottles), food (PET bottles) and cosmetic industries.
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