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Family Mold Injection Molding

“Family” plastic injection molds or multi-cavity injection molding creates a series of products in similar size at the same time, in the same quantities, in the same material and color. Family molds can produce plastic injection molded parts in sets at the same time. The parts which are created from a family mold are usually used together, for example, the two halves of a product.


A single-cavity injection mold is a mold that produce only one product at a time. A family mold is a mold that produce two or more different plastic part at a time.The single cavity molding process is high precise, easy control. The single cavity molds have simple mold structure. The single cavity mold cost is low the cycle time is short.


However, the productivity of plastic single cavity injection molding is low, and the cost of plastic parts is high. So, it is suitable for producing order of large plastic parts, high precision requirements, small batches and trial production.


The plastic parts produced by the multi-cavity mold or family mold have lower precision, it is hard to control the process parameters. The mold structure of multi-cavity mold or family mold is relatively complicated. The mold cost of multi-cavity mold or family mold is high. And the cycle time of multi-cavity mold or family mold is longer. Productivity of multi-cavity mold or family mold is higher, the product is lower, it is suitable for high volume and long-term production of small-sized parts.

Family Mold


Two Methods to Design a Mulit-cavity Mold

The number of cavities depends on budget, clamping force, plastic part structure, and injection volume. There are two methods to design a multi-cavity mold:

Injection Molding Machine’s Capabilities

Determine the model of the injection molding machine, and calculate the number of cavities according to the technical parameters of the injection molding machine and the technical requirements and specifications of the plastic injection molding parts.


Cavity Number

Determine the number of cavities according to the requirements for production efficiency and the structure of the part. Choose the right injection molding machine or check the existing injection molding machine.


At TEAM Rapid, we make the multi-cavity mold with 2 cavities, 4 cavities, 8 cavities, 16 cavities, 32 cavities, 48 cavities and more. For family mold, we make at 1+1 cavities, 2+2 cavities, 4+4 cavities, 8+8 cavities. The numbers we can see are always double. Family mold allows to mold different plastic parts in the same mold which will saves tooling and molding cost. For most family mold, the plastic part should be in the same material & similar size. At TEAM Rapid, we will help customers to analyze the projects to make the best economic plastic injection molds.

What are the advantages of family molds?


1, Lower tooling and production cost

A single family mold can be built with multi-cavities to produce more than one product. So, there is no need to create multiple single cavity injection mold which will need to pay the tooling cost for each one. By creating only one mold, tooling costs are dramatically cheaper. Production cost are also lowered because of the number of molds need to be switched out in a production run are needed.


2, Family molds make it easier to order

It is easier to place order with family injection mold. For example, if the parts need a left and right side. And those parts are in one multi-cavity mold, when you place an order, you only have to order them from that mold instead of multiple molds. This can ensure you will always get the correct quantity of parts to complete a product.


TEAM Rapid’s lifetime warranty on family molds


At TEAM Rapid, we provide a lifetime warranty on production family molds. When you have us to make create your family mold and run your parts production in our manufacturing factory, we provide your mold with a lifetime warranty. That means we maintain and refurbish your family mold as needed at no charge, for the life of the mold.


Requirements for using family molds

Parts must be made in the same color and material

It is impossible to change the parts material or color during the plastic injection molding process since a single multi-cavity mold is used. If one of the parts needs to be a different color, material, or quantity then these parts can be made together with other parts in a family mold.

Parts must be in the same quantity

This requirement is not so much a requirement because something to be careful when building family molds. For example, if your family mold which produces 1 piece of part A and 2 pieces of part B and the end product only needs 1 piece of each, part B will be eventually excess. Each time a multi-cavity mold is filled in the plastic injection molding process, all of the parts in the mold are created parts in a family mold don’t need to follow the standard of 1 to 1 ratio. For example, a multi-cavity mold can include 2 pieces of part A and 1 pieces of part B, and as long as the end product uses these parts in standard of a 2 to 1 ratio, there is no excess parts which can not be used will be created.

Parts must be roughly equal in size to one another within reason

For family molds, it is important rule that the parts must be roughly equal in size to one another within reason. As all parts in a multi-cavity mold are filled at the same time, at the same rate, if the parts in different size or volume, it will be some problems:


1, The large part cavity can be short shot or underfilled. This will lead to the part completely unusable and must be discarded.


2, The smaller part cavity will have flash which means excess material that seeps out of the mold during plastic injection. It will need someone to cut off the excess or to discard the part all together manually. And flash which is continually created will shorten the family mold’s production life because flash can deform the mold until it is no longer useable.


Process of creating family injection mold at TEAM Rapid

At TEAM Rapid, our quoting system allow us to simplify and shorten the quoting and tooling creating process for plastic injection molding.

1, Simply load your 3D CAD file, we will get you a fast mold and part quote.

2, When order is confirmed, we will start the mold and part order process.

3, Our engineering team will review tooling design.

4, When the design is approved, we will begin creating injection molds.

5, Customers approve samples

6, Mass production for parts start


Benefits of TEAM Rapid’s family mold

1. Quick mold quote

2. Low cost, fast build and great quality

3. Mold frame sharing technology

4. Lifetime warranty on family production molds

5. Online project management

6. Meet customers’ specifications

7. No size limitations with the exception that all family injection molded parts should be roughly the same size within reason.

8. Any commercially material and surface finish is available


Contact TEAM Rapid today for your family mold injection molding now!

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