An Introduction to Blow Molding

At VI Plastics, we’re proud of our reputation as a leader in the fabrication and design of high quality large part plastic manufacturing and custom molding. Our goal is to design and manufacture the perfect plastic products for your needs using a technique known as blow molding. What is blow molding exactly and how is it used in so many different industries and sectors?

Generally speaking, blow molding uses air pressure to inflate soft plastic into a mold—it’s similar in principle to a glass blower expanding heated glass. Before the actual manufacturing can begin we’ll walk you through the process of creating the mold that will best fit your needs. Our experienced staff will be with you every step of the way, ensuring that you end up with the perfect mold. Once the mold has been created we can begin the manufacturing process.

There are different kinds of processes that are used in blow molding depending on the type of product being manufactured, but the one we use is extrusion blow molding.

In this process, the plastic is first heated until it becomes viscous. The heated plastic is then forced, or extruded, downward into the shape of a tube. Once the tube has reached the proper length for the product the mold is then closed around it, pinching the bottom of the tube shut while keeping the top open. A metal blow pin is inserted in the small opening in the top and air is forced inside—expanding the soft plastic until it fills the shape of the mold. Once the plastic has cooled the mold is removed and we’re left with a plastic product.

You almost certainly use blow molded products more than you think. If you want an example of blow molding that you probably see nearly every day, then look no further than the plastic water bottles that people buy by the dozen at the grocery store. Blow molding allows them to be uniformly mass-produced for our consumption.

At VI Plastics, our business isn’t in water bottles; we manufacture large part plastics for the medical, automotive, and aerospace industries, among others. Our equipment is built for larger products of three gallons or more and our products aren’t just larger than your average water bottle, they’re stronger too. Our products are made of high quality plastics under ISO 9001:2015 standards, ensuring quality and durability.

If you’d like to learn more about the process of blow molding, then give us a call today. We can walk you through the steps of creating a custom mold, or we can give you a quote if you already have an existing mold.