How Revolutionary Is Stretch Blow Molding for Plastic Manufacturers?

Stretch Blow Molding

When it was first introduced, the stretch blow molding process made it possible for various industries to offer customers more innovative plastic products. For the plastic manufacturer, this revolutionized its capabilities. A perfect example of this is the soda bottle. Initially, manufacturers made single serve bottles. However, that soon changed to 64 ounces thanks to the stretching process.

This type of machine even improved on overall design. For instance, when Pepsi started making large plastic bottles for its soda, it had a separate molded base cup. With improved materials and the advanced stretch blow molding machine, the bottles are now all one piece. Not only did this prevent problems with accidental leaks, but it also made the product more visually appealing.

Key Advantages

For superior finished plastic products, manufacturers prefer the PET stretch blow molding machine. That means this specific machine produces PET bottles made of polyethylene terephthalate. These bottles are ideal for products like soda, water, juice, and so on. Although it was introduced in the 1970s, the stretching process has come a long way. Today, manufacturing companies use it to make bottles and containers for laundry soap, motor oil, hair shampoo and conditioner, milk, and so on.

Although there are many benefits of this molding process, the fact that the machine stretches the plastic material in both the hoop and axel direction ranks at the top of the list. This biaxial stretching process improves the tolerable drop impact, increases the barrier properties, enhances clarity, and increases both top load and tensile strength. As a result, manufacturers can decrease the weight of a container by as much as 15 percent, which in turn, saves significant money.

Are There Different Types of Stretch Blow Molding Machines?

Yes, there are two types. First is the single-stage machine, and second, the two-stage. The single stage relies on an extruder that injects the parison into a fast cooling preform mold. By reheating the preform and placing it in the container mold, the parison softens to the point that it can stretch to twice its original length. From there, air fills the container, stretching it to fit the mold. Once the plastic cools and hardens, it ejects from the machine in the form of the finished product.

As for the two-stage machine, the manufacturer goes through the same process as mentioned for the single-stage, with the exception that instead of making the preform, the manufacturer uses one that was previously made. For a medium-sized production run or making wide-mouth containers or jars, the single stage is the preferred option. For extremely high production runs and products with narrow mouths, you would choose the two-stage machine.

Buying from the Best

For the best stretch blow molding machine on the market, you cannot beat what we offer at PET All Manufacturing. Call or visit our website today.

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