Is Rotational Molding Right For You?

So you need a custom plastic part or product, but you don’t know how to get it made.

Is it large or small? Should it be flexible or stiff? Is it round, square, or some weird shape? Do you already have a mold, or do you need to have one made?

It will explain the different kinds of molding processes available today to help you discover the ideal process for your product.

What Is Plastic Molding?
Molding, also sometimes spelled moulding, is the process of manufacturing by shaping liquid or pliable material using a rigid frame called a mold or matrix.

When molding plastics, a powder or liquid polymer such as polyethylene or polypropylene is placed into a hollow mold so the polymer can take its shape. Depending on the type of process used, various ranges of heat and pressure are used to create an end product.

The History of Plastic Molding
Plastic molding began in the late 1800’s to fill the need for plastic billiard balls as opposed to the commonly used ivory billiard balls of the time. In 1868, John Wesley Hyatt invented a way to make billiard balls by injecting celluloid into a mold. Four years later, Hyatt and his brother invented and patented a machine to automate the process. This was the first plastic injection molding machine in existence and it used a basic plunger to inject plastic into a mold through a heated cylinder.

In 1946, the screw injection molding machine was invented by James Hendry, which replaced the plunger injection technique. This is the technique most commonly used today.[2]

Modern rotational molding also has a rich history beginning in 1855 when rotation and heat were used to produce metal artillery shells in Britain.

Plastics were introduced into the process in the early 1950’s, when rotational molding was first used to manufacture doll heads. And then in the 1960’s the modern process of rotational molding that allows us to create large hallow containers with low-density polyethylene was developed. In recent history, process improvements, better equipment, and plastic powder developments have sped up the process of creating finished products which has caused rotational molding to grow rapidly in popularity.