Selection of injection mold type depends on component design, budget and production volumes. During new product development, manufacturer always ask. What type of mold is required? 1) single cavity, multi cavity or family mold, 2) Hot runner or cold runner mold 3) Two–plate or three–plate mold. Accordingly manufacturer provide tool estimate. Manufacturer can also suggest ways to reduce mould price. In this article we will discuss two–plate and three–plate mold their construction, advantages and disadvantages.
Two-plate mold are most commonly used type of injection molds. They consist of one parting plane and the mold splits at parting plane. In a multi cavity two plate mold, runner and gate must be in parting plane. So that they can be ejected when mold splits.
Advantages of Two-Plate Mold
- Simple and low cost design.
- Less lead time
- Lower cycle time compared to three plate mold.
Disadvantages of Two Plate Mold
- For multi cavity two plate injection mold, parting line must be aligned with gate.
- In multi cavity injection mold, Molten plastic flow balancing is a challenging task.
Three plate injection mold consist of two parting planes and mold splits in three sections. Therefore runner and component can be located on different parting planes. In three plate molds, runner is ejected separately to molded part.
It’s application includes the positioning of runner system is in different plane to injection location and automatic de-gating.
Advantages of three plate injection mold
- Flexibility in gating location.
- Low cost alternative to hot runner mold.
Gate removal operation is eliminated.
Disadvantages of three-plate mold
- Higher injection time due to ejection of runner system.
- More complex tool design.
- High injection pressure is required.
- High material wastage.
To sum up, two plate molds are most commonly used injection moulds. It consist of one parting plane and mold splits in two halves. Whereas three plate injection mold consist of two parting planes and mold splits in three sections. Two plate mold is a low cost solution. Whereas three plate mold can be an alternative to hot runner mold.
Got Questions? We will be happy to help.
If you think we missed Something? You can add to this article by sending message in the comment box. We will do our best to add it in this post.