Everything to Know About Extrusion Blow Molded Bottles

Everything to Know About Extrusion Blow Molded Bottles
Published in Peter Parker | 7 months ago

Extrusion blow molding results in flash, which is plastic that ends up outside of a container’s body after blow molding ends. This is important for the container during the process, but in the end, the company will discard it. The way that an extrusion blow molding company handles the flash will determine if the finished container has quality or not.

About Extrusion Blow Molding Machines

The idea of extrusion blow molding comes from the world of glass blowing. A company will use a hollow, heated tube of warm plastic. This is a parison and it is between the sides of the mold. Then the machine will close the mold around the parison.

The machine will then trim off the bottom and the top of the parison and the machine will fill the mold’s cavity with a gas such as air. This pressure will move the parison’s walls out to fill the whole mold.

There is always extra plastic at the top and bottom of the mold, and the design and the pressure of the mold will determine how much extra plastic gets squeezed away from the container’s bottom. The extra plastic will move into the flash pockets, where it can cool, and then the extrusion blow molding machine can remove it.

Pinch-Off Problems

It might seem like the flash is just an unnecessary extra amount of waste. But the way that the machine engineers it is vital to ensure the integrity of the part. For instance, the flash pocket may not fill enough, which means there is not enough pressure moving the plastic toward the container. You might notice a v notch near the pinch-off, which shows there may be a weak bond where the seam splits.

Fixing Potential Extrusion Blow Molding Issues

You can make several adjustments to solve any issues with the pinch-off and the flash. For example, pay attention to the land area near the pinch-off area. That will ensure that you have a good gap. If the gap is too small, the flash might fall toward the molding assembly. On the other hand, if you have too big of a gap, it is hard to trim the flash, so it will not look good. Look at your mold regularly to make sure that the pinch-off area is in good condition.

Choose the Best Extrusion Blow Molding Machine Manufacturer

You can make many adjustments with the design process when you are working with extrusion molded plastic parts to improve their quality. Using the right extrusion blow molding machine is also important, so you should look for the right supplier. To learn more about our products, contact Pet All Manufacturing Inc. today.