Blow Molding

Blow molding is a widely used plastic molding process that uses pressurized air to form plastic shapes that have internal cavities, like in plastic bottles or containers. A blow molded part almost always starts as a small preformed tube or cup shape with a wall thickness several times larger than the final product. The plastic ‘preform’ is heated to soften the plastic and then pressured air is blown into the opening of the part, expanding the plastic. The air is only added when the part is inside a mold, the mold that forms the outer profile of the part. When the warm plastic expands and hits the wall of the mold, the plastic cools and creates the final part, which is ejected. This process can be done very quickly and produces internal cavities that would be impossible to form via any other plastic manufacturing method. Rotaloc has considerable experience in blow molding and can help design parts to take advantage of the blow molding process.