Blow Molding Comapny

In 2011, STM Plastics acquired Heartland Plastics, a blow molding company specializing in small to medium sized production runs of polyethylene and polypropylene plastic bottles for health & beauty, food & drug, sports drinks, and more. STM continues to produce the high quality products that were associated with Heartland Plastics and has expanded the product line.

Bottles range in size from 8oz. to 32oz. and other custom items with part weights of under one pound, and while we maintain a stock FDA natural color, we have the ability to match any custom color.

What is Blow Molding?

Blow molding is a manufacturing process used to produce hollow plastic parts, such as bottles, containers, and other hollow objects. There are different types of blow molding, but the most common, and the process we use here at STM, is called “extrusion blow molding.”

Basic steps involved in the extrusion blow molding process:

1. Plastic pellets, usually made from polyethylene (PE) or polypropylene (PP), are melted and formed into a long tube called a parison.
2. The parison is then clamped into a mold in the shape of the final product.
3. Compressed air is blown into the parison, causing it to expand and take the shape of the mold.
4. The plastic cools and hardens, and the mold is opened to release the finished product.

Blow molding is an efficient and cost-effective way to produce high volumes of hollow plastic products with consistent quality.