Plastic Molding
Plastic polymers, in the form of thermoplastics, thermosets and elastomers, are a popular manufacturing material because of plastic's durability and malleability. The process of plastic molding is used for mass production and prototyping because of its ability to yield high runs at close tolerances. Plastic molding typically involves a pre-made mold and liquid plastics; however other manufacturing methods include vacuum forming, injection molding, blow molding and compression molding. The type of molding process chosen usually depends on the final intended use of the product being made, and the process is commonly used in the consumer, food service, medical, plumbing, computer and automotive industries.
Materials used in plastic molding differ in important ways: thermoplastics can be melted and molded into a wide variety of shapes as they become more pliable with the application of heat. Shapes can be remolded and adjusted if need be, however, thermoplastics tend to be more brittle in cold or freezing temperatures. Thermosets, such as melamine resin or polyimides, dry hard and brittle and can only be melted and molded once. They are however more suited to applications that require exposure to cold. Elastomers, for example, those known as rubber, maintain a property of elasticity once cooled which is a required characteristic for some molded plastic products. Elastomers are used in the molding of children's toys, or other objects such as tool handles which benefit from the comfort of elasticity. There are numerous advantages to plastic molding, including: fast turnaround times, lower labor costs and the ability to make complex plastic products and minimal waste. Other materials such as metal or wood are hard to mold, especially into small and complex shapes, and without having the ability to melt and harden, can result in heavy wastage costs. Plastic however, can be bent, twisted, squeezed or turned into an almost limitless range of shapes. The negligible amounts of waste produced can be recycled through the melt and mold process, making plastic molding a responsible manufacturing choice.
