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 mold price. In this article we will discuss single cavity multi cavity and family molds.
Single Cavity Mold
Single cavity injection mold consist of one cavity. Therefore one component is produced per injection cycle. If product volumes are not very high, single cavity mold is a good choice.
Advantages of Single Cavity Injection Mould
- Single cavity mold cost is very low compared to multi cavity injection mold. Therefore initial investment will be less.
- Single Cavity Mold is very easy to manufacture because it requires less machining. Therefore lead time for single cavity mould will be less.
- Instead of producing one two cavity mold companies prefer two single cavity mold. Because in case of breakdown in one injection mold, second mould still can be used.
Disadvantages of Single Cavity Injection Mold
- Single Cavity mold produces one component per injection shot. Therefore production rate will be less.
- Only one component is produced in single cavity tool. Therefore component unit price increases.
Multi Cavity Mold
Multi cavity mold consist of more than one cavity. Therefore more than one part is produced per injection cycle.
Multi cavity injection mould produces more than one part per cycle. Initial investment cost is higher but unit part cost is low for multi cavity injection tool.
Multi cavity mold are used to increase production rate.
Advantages of Multi Cavity Injection Mold
- In multi cavity mold, more than one part is produced per injection cycle. Therefore manufacturing cycle time and cost will be reduced.
- Higher volumes of injection molding part can be produced in small time. That results in high production rate
Disadvantages of Multi Cavity Injection Mold
- Multi cavity injection molds are more expensive compared to single cavity injection mold.
- Higher tonnage machine is required to run a multi-cavity mould.
- Longer lead time for mold manufacturing.
Family molds are used to produce two or more different components in the same material per injection cycle. With Family mold overall tool manufacturing cost is reduced because two different parts are manufactured with single mold.
Advantages of Family Molds
- Family mold is a cost effective solution. Molding two single cavity mold is more expensive compared to one family mold for two components.
- Similar to multi cavity molds, In family mold two or more components are produced in one injection cycle.
Disadvantages of Family Mold
- Molten plastic flow balancing in cavities of different geometry parts becomes a challenging task. This can results in various injection molding defects.
- Family mold produces different parts in the same material. Therefore requirement of different materials for different components can not be fulfilled.
To sum up, A single cavity mold produces single component per injection cycle and multi cavity mold produces more than one component per injection cycle. Whereas in family mold multiple components are produced in one injection cycle. To understand type of molds, we suggest you to read this article on hot runner and cold runner molds.
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.