Gate of injection mould is the entrance that molten plastic to be injected into cavity of mould. It connects runners with cavity of mould. Gate shape, quantity and location have important effects on the part such as gate removal or vestige, cosmetic appearance, etc. So, choosing a right gate type is a key point for mould design. There are many different gate designs available based on the size and shape of your part. Below are some popular gate types used for our customers:

Common Gate Types
Direct Gate (Sprue Gate)
Direct gate is commonly used for single cavity mould and large part or big thickness part. As molten plastic is directly injected into cavity of mould, it requires less injection pressure and feeding time is short. Injection molding also is easier. With this gate, mould structure is simple and easy for manufacturing with lower cost. But it is difficult to be removed and leaves a large mark/scar on the part.

Edge Gate
As the name indicates, this gate is located on the edge of the part and is best suited for flat parts. Edge gates are ideal for medium and thick sections and can be used on multicavity two plate tools. This gate will leave a scar at the parting line.

Point Gate(Pin Gate)
Point gate is specially used for three plate mould. As this gate is very small and leaves small point scar on the part, it doesn’t effect on appearance of part. It is trimmed automatically when mould opens. For large parts, it usually choose multi point gates for feeding to avoid warping.

Sub Gate
This gate is usually located at covert place of inside surface or side surface of part. It doesn’t effect on appearance of part. The gate is automatically trimmed when mould opens. Ejector pins will be necessary for automatic trimming of this gate. Sub gates are quite common and have several variations such as banana gate, tunnel gate and smiley gate to name a few. The sub gate allows you to gate away from the parting line, giving more flexibility to place the gate at an optimum location on the part. This gate leaves a pin sized scar on the part.

There are many other types of gate we didn’t list on. The choice for gate type and location is very important for part quality. If you want more information about gates or need help from us, don’t hesitate to contact us.