Unlike injection blow molding that is used to create very small containers, stretch blow molding is commonly used for making soda bottles, personal care containers, household cleaner containers, and so on. Depending on what the customer wants, extrusion blow molding products are made. If the final product will consist of plastic, then plastic blow molding is the correct process. Regardless of the material, container, or part created, it is imperative to rely on a high-quality blow molding machine.
There are several benefits to the injection stretch blow molding process. While learning about those, you will also gain insight into the blow molding process, step by step. With this molding process, PET bottles used for soda, water, juice, package detergent, and various other products are made. Depending on which type of stretch blow molding is used, single-stage or two-stage, the advantages differ slightly.
With the single-state process, an extruder injects parison into a fast-cooling preform mold. This preform is then reheated and placed into the container mold. Because the parison is hot and soft, its original length can actually be doubled. Once stretched, high-pressure air fills the container, which is then stretched to fit the mold. It remains in place until completely cooled and hardened. This single-stage stretch molding process is beneficial for producing jars with wide mouths when a high production rate is not required.
There are not a lot of differences between the single- and two-stage processes. However, the two-stage process uses two machines, one for making the preform in advance and another for stretching and blowing. The downside is that the two-stage process is quite expensive. However, for runs of high-volume containers like liquid bottles, peanut butter jars, and narrow-mouthed water bottles, it is the most beneficial option.
Regardless of the method, one of the greatest advantages of stretch blow molding is that the container is stretched in the hoop and axel direction. Known as biaxial stretching, this helps to increase the barrier properties, clarity, top load, tensile strength, and tolerable drop impact. Because stronger products are made, the weight of the container is decreased between 10 and 15 percent, saving money.
For all three types of blow molding machinery, we can help. At PET All Manufacturing, we offer years of industry experience coupled with unrivaled expertise. When the quality of a finished glass or plastic container matters, you want a top-of-the-line machine, which is exactly what we manufacture. You can visit our website to look at our full range of machines or call us to speak directly to a company representative.