Plastic Molding

6. Rotational Molding

Hollow molds packed with powdered plastic are secured to pipe-like spokes that extend from a central hub and the molds rotate on separate axes at once. The hub swings the whole mold to a closed furnace room causing the powder to melt and stick to the insides of the tools. As the molds turn slowly, the tools move into a cooling room. Here, sprayed water causes the plastic to harden into a hollow part.

7. Structural Foam Molding

This process of molding is usually used for parts that require thicker walls than standard injection molding. Insertion of a small amount of nitrogen or chemical blow agent into the plastic material makes the walls thicker. Foaming happens as the melted plastic material enters the mold cavity. A thin plastic skin forms and solidifies in the mold wall.

8. Thermoforming

In this plastic molding process, sheets of pre-extruded rigid plastics are horizontally heated and sucked down into hollow one-piece tools. When the hot plastic solidifies, its shape conforms to that of the mold.