The Injection plastic mold 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.
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.
If you want to purchase Straight ejector pin, send us messages if you have interests!