Posts Tagged ‘plastic injection mould’

How Does an Injection Moulding Machine Work?

The technique begins with the creation of a mould. The mould is created by the Toolmakers from the specifications given to them from the designer or engineer by a 3D computer-generated model. The mould is carefully constructed to permit the halves of the mould – the mould cavity & the mould core – to separate along the parting line. This will permit simple ejection from the injection moulding machine when the part has cooled. If the mould is designed incorrectly the part may catch on the mould, leading to feasible destroy.

An injection moulding machine is a complex piece of machinery that creates solid piece by injecting molten materials through a reciprocating screw technique in to a mould. This machine is made of lots of components; it is primarily consisted of a hopper, a barrel containing a reciprocating screw, temperature control devices, a clamping unit & the injection mould itself.

The specifications & parts of the machine must be carefully set up before the technique of injection moulding can start. Temperatures & PE blowing mould (Aluminum alloy)pressures will be programmed according to the size & shape of the mould & the material that the part is to be made from. One time the machine is set, the cycle will start & the machine can be left unattended to work its magic.

This is the way it works:

The basic idea of the plastic moulding machine has been around for over seventy years. Since then the original idea – injecting molten plastic in to a mould – has evolved dramatically in to an efficient, elegant & versatile gizmo for generating everyday items.

Raw material & colour is fed in to the barrel of the machine by the hopper. In the barrel the raw materials are subjected to pressure & temperature until they are melted & pliable. The reciprocating screw inside the barrel will turn, injecting a exact amount of the now molten plastic in to the injection mould at a set & controlled temperature, pressure & speed. One time the mould is filled with the molten plastic the injection technique will shut off. The part is then allowed to chilled until it is prepared to be taken from the mould. This can take some time depending on the materials, wall thickness, overall size & shape of the part being manufactured. When chilled, the mould will open automatically. The mould is inbuilt with an ejecting mechanism which ejects the part in preparation for a new cycle. If a portion of the completed part is still caught in the mould at this point the mould will reopen until the part has been ejected. When the part is clear of the machine, the hopper will release more raw material & colour in to the barrel as well as a new cycle will start. The autonomous nature of the injection moulding machine means it can be left unattended one time programmed, & may run continuously throughout day & night.