A mould with one hole is usually designed into two-plate type. It is also the simplest mould type.
When settled on the injection machines, the female mould is fixed on the plate of machines and can not move any more. Then, the male mould will move together with injection during work process. The process can be generally divided into two stages, that is, opening process and clamping process.
A. Opening process:
1.Under the tensile force of injection moulding machines, male moulds are pulled away from female moulds to a settled position.
2.Pushed by the backing stems of machines, ejector mechanisms moved forward with ejector plates and push out the finished products.
B. Clamping process:
Being pushed by injection machines, male moulds move toward female moulds. If the RP is not pulled back in advance, it will contact with the female mould firstly. Then under reactive force, the RP will finally go back. Injection machines start to inject once the female moulds and male moulds are completely clamped.
Two-plate moulds with hot sprue technology are suitable for making small products, even when they require a mould with several cavities. However, if the products are ordered at a large quantity, then many materials used in runners might be wasted if they can not be recycled.
If hot sprue technology was adopted in this kind of mould, then the mould could also be transformed to three-plate moulds. It is not necessary to push the runner. Thus, large space between a runner and a mould surface won’t give rise to any problem.
We will continue to focus on this series. The next classical mould type is hot nozzle molding.