Selection of injection mold type depends on component design, budget and production volumes. During new product development, manufacturers 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 manufacturers provide tool estimates. Manufacturers 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.
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, the parting line must be aligned with the gate.
- In multi cavity injection mold, Molten plastic flow balancing is a challenging task.
Three plate injection mold consists of two parting planes and mold splits in three sections. Therefore runners and components can be located on different parting planes. In three plate molds, the runner is ejected separately to the molded part. Therefore automatic degating is possible.
It’s application includes the positioning of the runner system in different planes to injection location and automatic degating.
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 the ejection of the 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 consists of one parting plane and mold splits in two halves. Whereas three plate injection mold consists 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.
We will keep adding more information on two plate and three plate mold. Please add your suggestions, comments or questions on the difference between two plate and three plate injection molds in the comment box.