Which process involves a mould containing heated thermoplastic powder that is rotated while heat is applied to form a hollow product?

Which process involves a mould containing heated thermoplastic powder that is rotated while heat is applied to form a hollow product?

• A. Rotational moulding
• B. Compression moulding
• C. Injection moulding
• D. Line bending

Answer: (A)

Rotational molding is the process where a mould containing heated thermoplastic powder is rotated while heat is applied to form a hollow product. A measured amount of powder is put into a hollow mold, which is then heated and rotated about two perpendicular axes so the powder coats the inner walls. The heat causes the powder to melt and fuse, creating a continuous hollow shell with relatively uniform wall thickness. Once cooled, the part is ejected. This method is distinct from compression molding (which uses solid pellets pressed in a mold) and injection molding (which injects molten plastic under pressure), and from line bending (which heats and bends plastic sheet), none of which produce hollow parts in the same rotating-powder way.

Rotational molding is the process where a mould containing heated thermoplastic powder is rotated while heat is applied to form a hollow product. A measured amount of powder is put into a hollow mold, which is then heated and rotated about two perpendicular axes so the powder coats the inner walls. The heat causes the powder to melt and fuse, creating a continuous hollow shell with relatively uniform wall thickness. Once cooled, the part is ejected. This method is distinct from compression molding (which uses solid pellets pressed in a mold) and injection molding (which injects molten plastic under pressure), and from line bending (which heats and bends plastic sheet), none of which produce hollow parts in the same rotating-powder way.