Plastic Injection Moulding FAQ What is plastic? Any synthetic organic material that can be moulded under heat and pressured into a shape that is retained after the heat and pressures are removed.There are two basic types of plastic: thermoset, which cannot be resoftened after being subjected to heat and pressures; and thermoplastic, which can be repeatedly softened and reshaped by heat and pressure. Plastics are made up mainly of a binder consisting of long chainlike molecules called polymers. Binders can be natural materials, or (more commonly) synthetic resins. Adding plasticizers and fillers to the binder improves a wide range of properties, e.g., hardness, elasticity, and resistance to heat, cold, or acid. Adding pigment gives colour to the finished product. What is plastic injection moulding? Injection moulding is a manufacturing process where heated plastic is forced into a mould cavity under pressure. A mould cavity is essentially a negative of the part being produced. The cavity is filled with plastic, and the plastic changes phase to a solid, resulting in a positive. Typically injection pressures range from 5000 to 20,000 psi. Because of the high pressures involved, the mould must be clamped shut during injection and cooling. Clamping forces are measured in tons. Injection moulding is well suited to applications requiring 10 or 20 pieces to billions of pieces. Sometimes there is no other way to produce parts from certain materials except through injection moulding. Injection moulding is a process with large numbers of variables. A great deal of experience is involved with certain materials or when high precision is desired.The moulding tools must be manufactured to high levels of precision and must be robust enough to withstand the moulding process. Because of this, moulds are usually constructed in hardened steel but can be made out of aluminium or other soft metals when tooling life is not an issue. Why do we have different kinds of plastics? Gold, copper and aluminium are all different kinds of metals but each of them has different properties. Cars are not made of gold and cans are not made of copper because the properties of these metals are not chemically or physically able to create the most effective final product. The same idea can be applied to plastics. There are literally hundreds of different plastic resins and each has different attributes that make it better suited to a particular application. This is possible because their material family is so versatile. Why are plastics used in durable goods? Manufactured items with a useful life of more than three years -- cars, appliances, computers, etc. -- are called durable goods. Manufacturers of durable goods choose plastics for many reasons: The automotive industry chooses plastic for its durability, corrosion resistance, ease of colouring and finishing, resiliency, energy efficiency and light weight. Lightweight, for instance, translates into lowered handling and transportation costs all down the line. Major appliance manufacturers use plastics because of their ease of fabrication and outstanding thermal insulation -- characteristics that significantly reduce energy consumption. The building and construction industry uses vinyl siding for homes because of its appearance, durability, ease of installation and energy efficiency. Plastics can reduce energy consumption for the auto, appliance, and building and construction industries, providing a substantial saving in production costs. How are plastics helping the environment? Plastics are not only very durable with their increased life-span but also easily recyclable. Most plastics can be reclaimed by regrinding up old products and using the pellets to make new products which obviously means no waste. In fact, plastics generally exhibit superior resistance to breakage and denting and are usable over and over again before recycling.