Plastic Production through Injection Moulding

 

Injection Moulding is a type of manufacturing method for shaping a range of raw materials to a desired form or shape.  Materials such as glass, metals, elastomers for synthetic rubber products, confections and especially thermoplastics and thermosetting polymers for plastics are heated and injected into a mold, the raw materials solidifies as it cools inside.  Injection moulding is a widely used manufacturing process for the production of small components to an entire body panel of cars.

Injection moulding Process

            The process starts with the design of the product and the mold design.  Mold designing is done by an industrial designer or engineer. Individual parts of the final product are carefully designed with consideration to how each part is to be molded and assembled to create a finished product.  Properties and capabilities of the molding machine are very well considered in the design process.  Molds are then precision-made out of steel or aluminum.

            The mold is then fitted to the injection moulding machine.  For the manufacture of plastic products, thermoplastic and thermosetting polymers are used.  Thermoplastics are more commonly used because it is more versatile and it softens and flows evenly when heated. Thermoplastics are also easily recyclable and are safer to use than thermosets.  Thermosets needs to be properly heated and injected in a timely manner, otherwise, chemical cross-linking may occur which can damage to the screw and check valves of the machine.

            Thermoplastics or thermosets are place on a funnel which opens to the injection screw inside a barrel with heating elements.  The screw turns and pushes the heated raw material towards the mold which turns to liquid as it approaches the end of the barrel or the nozzle that leads to the mold. Once inside the mold, the raw material cools down and solidifies.  The mold then opens, releasing the newly shaped component.  The mold closes once more and the cycle begins.

Types of Injection Moulding Machines

·         Hydraulic – the only option for molders until 1983 when the first all-electric injection moulding machine was introduced. It is still more predominantly used today.

·         Mechanical – uses the toggle system where tonnage is required to keep the pressure in the mold consistent.

·         Electric – also called the EMT or Electric Machine Technology is quieter, cost efficient and environmentally safer than hydraulics introduced by Nissei Plastic Industrial Co. LTD.

·         Hybrid – claims to have the best features of the hydraulic and electric machine.  Usually features the robotic arm to remove molded components

For suppliers and distributors of Injection Moulded Components in Australia, visit the OZ Suppliers Website.