Molding, also sometimes spelled molding, is the process of manufacturing by shaping liquid or pliable material using a rigid frame called a mold or matrix. When molding plastics, powder or liquid polymers are placed into a vacant mold so the polymer can take its form. Depending on the type of method used, various ranges of heat and pressure are used to create an end product. Plastic molding started in the late 1800’s to satisfy the need for plastic billiard balls.
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 developed and registered a machine to automate the production. That was the first ever plastic injection molding machine in history, and it used a primary plunger to insert plastic into a mold through a tube.
In 1946, the screw injection molding machine was developed by James Hendry, which replaced the first injection technique. This technique is most commonly used today. Modern rotational molding has a rich history beginning in 1855 when rotational molding was used to produce metal artillery shells in old Britain.
Injection molding is the method of making custom plastic components by injecting molten plastic with high pressure into a metal frame. Similar to other forms of plastic molding, after the molten plastic is inserted into the cavity, the frame is cooled and reopened to show a hard plastic part. The process is similar to a Jello mold which is filled with hot Jello then cooled to create the final product.
Rotational Molding is a production process for manufacturing large hollow components and goods by placing powder or liquid resin into a metal mold. It is then rotated it in an oven until the resin coats the inside of the shell. The continuous rotation of the mold creates centrifugal force forming even-walled products. Once the shell cools, the solid plastic is extracted from the shell. Wastage is often very low, and excess material is often re-used, making it economical and environmentally friendly.
These two processes of molding plastics are very popular these days and are the only two being used on a large scale. If you would like to learn more about plastic molding, here is a simple guide to it – https://fibertechinc.net/custom-rotational-molding/a-simple-guide-to-plastic-molding/. The company also produces plastics in case you may be interested, feel free to contact them.