Processing of Plastics

Some methods of production of plastic include:

• Injection molding
• Compression molding
• Extrusion molding
• Calendering

Injection Molding:

The most commonly used manufacturing process for the fabrication of plastic parts is injection molding. A wide variety of products are manufactured using injection molding. The injection molding process requires the use of raw plastic material, a mold, and an injection molding machine. The plastic is melted in the injection molding machine and then injected into the mold, where it cools and solidifies into the final part.

Compression Molding:

Compression molding is a forming process in which a plastic material is placed directly into a heated metal mold then is softened by the heat and therefore forced to conform to the shape of the mold, as the mold closes.

Extrusion Molding:

Extrusion is a plastic manufacturing process that is used to make hoses, pipes, drinking straws, and rods.  The process usually begins with a thermoplastic in the form of pellets or granules. The granules melt into a liquid which is forced through a die forming a long ‘tube-like’ shape. The shape of the die is determined by the shape of the tube. The extrusion is then cooled and forms a solid shape. 

Calendering:

Calendering is a finishing process used on cloth and fabrics. It is used to smooth, coat, or thin a material. The fabric is passed between calender rollers at high temperatures and pressures.