Akshay C Gawali
Plastic materials have good mechanical properties. Price and weight of plastic products are less as compared to metallic products. Therefore plastic is replacing to metals in various applications. Most of the plastic products are primarily produced by molding process. For large scale production molding process is preferred, whereas small scale production and requirement of surface quality, machining is preferred. Turning, drilling and milling these are the machining operations mostly carried out in plastic machining. Plastic injection molding is the process primarily used for manufacturing of large quantities of plastic products and suffers through the problems of warp age, poor weld lines, sink marks and poor surface finish. So, post processing or recycling is required in these cases. In majority of the cases, post processing is limited to removing burr, runners, flash etc. However, wherever dimensional accuracy and surface finish requirements cannot be fulfilled by molded components, they are required to be finished by machining. Also quantity requirement of products does not justify investment in tooling, particularly molds; plastic components become economical, if produced by machining. Polymers are organic materials having excellent formability and mouldability. The term plastic is synonymously used for polymers. Depending upon the nature of the intermolecular bonding, plastics can be classified as thermoplastics and thermosets. Generally plastic products are manufactured by molding processes like injection molding, blow molding, compression molding, transfer molding.
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