Plastic bottles for beverages make up more than 80 percent of the packaging that the PET industry makes. This does not include other plastic bottles for products such as salad dressing or oils. The process used to create these plastic bottles is known as stretch blow molding.
How Stretch Blow Molding Works
In this type of blow molding, a special stretch blow molding machine is used to expand polyethylene terephthalate with a hollow center. The machine will use a specific amount of air pressure in order to make each bottle a specific size. Depending on the intended use of the bottle or container, the company will consider the different sizes, shapes, and colors that the container or bottle may come in.
The manufacturer must also consider factors such as the properties of each plastic that they will be using. This means the manufacturer will need to use the right tools and the right amount of air pressure, depending on the exact type of plastic the manufacturer is using.
Depending on the desired color of the finished bottle, the manufacturer must use a variety of careful techniques. For example, to create a clear bottle, they must use a very specific heat. If the temperature is too high or too low, the bottle may end up looking pearlescent or an uneven color.
Steps of Stretch Molding
In the first step, the stretch blow molding machine creates a preform, which is a shape used to create the final bottle. Each bottle starts as a preform. Next, the machine will heat the preform to a high temperature to prepare it for stretch blowing. The final step has a few stages in it.
- Low blow delay: A rod will begin to stretch the preform.
- Pre-blow: Next, part of the PET stretch blow molding machine will begin to inflate the preform.
- Blowing period: Finally, the rod will stop stretching the preform, and the air pressure will begin to increase so the preform will be able to fit in the mold. This allows the bottle to be in its final shape.
Choose a Trusted Stretch Blow Molding Machine Manufacturer
Because the molding process is so important when manufacturing bottles, it is vital to choose a trusted manufacturer for your PET stretch blow molding machine. Here at Pet All Manufacturing, we strive for excellence in each and every one of our products. When you choose a machine from us, you can rest assured that you will be receiving a quality machine. Call us today to learn how one of our machines can help your business.