When you have a project then you may need plastic injection molded parts, the first thing you need to do is finding a plastic mold company to make mold & molded parts, but before start this I think you need to check injection molding cost and mold cost in advance for investment budget, multi cavity injection molding will be one of the best way to save unit production cost, but not suitable for all of project, below are some suggestions on how to save injection molding cost, there have both advantages and disadvantages, by reading this you could choose the one base on your project requirement.

What is multi cavity injection molding

Multi-cavity injection molding is typically used when high volume production of identical parts is needed. It allows for the efficient production of multiple parts in a single cycle, which can significantly increase production rates and reduce the cost per part. Additionally, using a multi-cavity mold can also help to reduce the overall cost of the mold itself.

Multiple cavity mold means the number of cavities greater than one, which means that has more than one part in an injection mold, It is usually professional to say cavity, One cavity or two cavities, for examples 8 cavities mold means one molding cycle to mold 8 parts with the 99% same part feature, dimension, shape, size, etc.

Some examples of products that may be produced using multi-cavity injection molding include automotive parts, electronic components, toys, and household items. It is also commonly used in the production of medical devices, personal care products and packaging.

When do we need multi cavity mold?

There are some factors to make decisions before starting to make your plastic mould.
1, the size of the product,
2, the number of the product requirement
3, the size of the machine, if you only buy plastic molded parts then you do not need to care about this point, you plastic molding supplier we check this.

If the size of the product is small, such as the computer keyboard button, usually make 24 or 48 cavities, you must say why not make 30 or 40, this is because for the balance mold layout and material filling balance, especially when you use cold runner mold. so normally multi-cavity mold is 4, 8, 16, 24, 48, 96 cavities are better options.
When we make multiple cavity mold and the cavities are more than 24, we normally suggest making hot runner mold, one part per hot-drop, at least to use 6 hot runners to the cold runner, which means four cavities per hot drop. this could save the cycle time and keeping the best quality of injection molding parts.

The advantages of multi-cavity mold

The reason we make multi-cavity mold, the question is simple, we need to save production unit cost for each plastic molded parts, multi-cavity molds have several advantages over single-cavity molds in injection molding:

1. Increased production efficiency: By producing multiple identical parts in a single cycle, multi-cavity molds can significantly increase production rates and reduce the overall production time.
2. Reduced cost per part: Multi-cavity molds can produce multiple identical parts at a lower cost per part than single-cavity molds.
3. Reduced tooling costs: Since multi-cavity molds require only one tool, the overall cost of the mold is typically lower than that of multiple single-cavity molds.
4. Better consistency: By producing multiple identical parts in a single cycle, multi-cavity molds can improve the consistency of the final product, reducing the need for rework or scrap.
5. Reduced labor costs: Multi-cavity molds require less labor to operate than multiple single-cavity molds, as the operator only needs to monitor one machine.
6. Reduced material consumption: By producing multiple parts in a single cycle, multi-cavity molds can also reduce the amount of raw material required to produce the final product.
7. Improve part quality: Due to the consistency in the process and the precision of the machinery, multi-cavity molds can produce parts with tighter tolerances and better surface finish.

The disadvantages of multi-cavity mold

We all know that all of the customers prefer the multiple cavity mould since this can save lots of production cost, but there are other factors you need to think about before making decision, because make plastic mold is not cheaper, make multi-cavity mould is more expensive than single cavity mold, some times double or even 3 times expensive than single cavity or two-cavity mold, for example if you make 24 cavity mold, then you at least us 6 hot runner drops for the mold, the pure hot runner cost is around USD 5400 ( YUDO brand), if use China local brand of hot runner still need USD 3000, and this cost some times is enough to make 2 cavities cold runner mold, since there are many cavities in one mold, the mold manufacturing cost is high than the less cavity mold as well, this is another cost, so total cost is two or three times more is not surprised, below listed some disadvantages while use multi cavity mold:

1. Higher initial cost: The initial cost of a multi-cavity mold can be higher than that of a single-cavity mold, especially for complex designs.
2. Greater complexity: Multi-cavity molds are more complex than single-cavity molds and require more precise machining and design. This can lead to longer lead times for tooling and increased risk of defects.
3. Higher maintenance costs: Due to the complexity of the mold and the increased number of moving parts, multi-cavity molds may require more maintenance and repairs than single-cavity molds.
4. Greater risk of defects: With multiple cavities, the risk of defects is greater, as a problem in one cavity can affect multiple parts.
5. Increased cycle time: Multi-cavity molds have longer cycle times than single-cavity molds as the machine has to fill multiple cavities at once.
6. Greater potential for warpage: Multi-cavity molds have to be designed to account for the potential warpage that can occur during the cooling phase of the injection molding process.
7. Increased risk of sink marks: As the material cools it will shrink, if the mold design is not optimized for multi-cavity, sink marks may appear on the surface of the parts.
8. Increased risk of flash: Flash is the excess material that is extruded from the mold. Multi-cavity molds can be more prone to flash than single-cavity molds as the pressure and flow rate of the material is increased to fill multiple cavities.

When do you need multiple cavity mold

There is some simple suggestion when do you need to single cavity mold (may 2cavities at fist), when you should make the multi-cavity mold, like 8 cavity mold, 16 cavity mold or more. When you are sure that you will need the plastic parts more than one million or at least 0.5 million, then go to 8 or more mold cavities will surely save cost for you, you may need to pay more cost on plastic mold manufacturing, but compare the production cost you are going to save, this injection mold cost is insignificant, because you will save 10 times more than this injection mold cost.
If you are not sure how many plastic moulding parts needed at the first, or this is depending on your business market sell, then we suggest use the 2 cavity mold at first, because this can save the plastic mold cost for you in advance, after you open your market, and the requirement of injection molded parts increased, you still can save injection molding cost by making new multiple cavity mold, you use the existing mold to produce the parts at the same time and  make new multi-cavity mold, this will not have a delay as well, after the multiple cavity mold finished then you only need to run this multi-cavity mould, but if the quantity requirements are not so high, then you use the currently molds to produce, so you still have good profits with less investment (compare to make multi-cavity mold at first beginning).

What do you think? by reading above I assume you have the idea on how to save injection molding cost for your project.

If you have any project in hands that need to make injection mold for your business, you are welcome to contact us, we will give you some good suggestions and ideas, to help you spend min investment on plastic mold cost and open your market rapidly.

Sincere tech is plastic mold manufacturer in China, we make custom single cavity molds, multiple cavity molds, hot runner mold, cold runner mold, overmolding, 2k injection molding and more, you can call us or send us an email for a quote