How to Choose the Right Mold Material for Your Project – 2024 Guide

The first and the foremost thing to do, when you have a molding project to complete, is the selection of the correct mold. The profile of every material is different and they all possess different characteristics and thus you need to select one that suits the product well, in which it is used. In addition to it, the molds used must provide cost-effectiveness and the best value to a particular product.

Injection molding is the first preference for a company that is into rubber and plastic making. It provides quality results at pocket-friendly budgets. Furthermore, it helps fulfill all requirements and specifications. While picking the best mold material for your project, there are a few things you need to consider to make an apt choice.

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Mold-Material Selection

When selecting the material of your mold, there are a few things based on which your choice will be different. That said, you need to take into account the volume of product, part finish, part material, time for which a cycle would last, and the details of the mold such as molding resin. can decide better regarding what will be the apt choice

Molding a part successfully takes much more than just perfecting the design of that part. That said, to mold your product correctly, you will need a quality mould, and for that you need a mold made of adequate items so that it performs its job as expected. Hence, it is important to work with a team that has knowledge of the different available mold materials to ensure that you get a particular product as desired, at the correct time and on budget.

If you need to consider molding for a project, the engineers and product designers will not only have to make a choice about the thermoplastic resin that is to be used, but will also have to make a choice regarding the metal of the molding tool.

Let us dive deep into a few popular picks to help you make an informed choice.

1. AL-7075


It is an aluminium alloy of high strength and contains high zinc percentage.

It has an amazing property of heat transfer as compared to the other alternatives. Now, you would ask, why is heat transfer property critical? It refers to the property that enables a mold to expand and compress down rapidly and easily. Well, this feature offers two advantages, one is that it needs the least engineering for various channels used for cooling and the second one being that one can cycle it easily and rapidly as compared to the steel counterpart.

The major drawback of using this is that it is not very durable. We recommend not to use this to inject resins that are corrosive in nature that include PVC or POM. Also, don’t use the ones that have glass fibres mixed with them as it can easily erode the surface of the molds.

This option is the best for PP, ABS, PE and Nylon.

2. NAK80


This is another tool steel that is available in semi-hardened form and is used in some of the most demanding applications.

It is tougher than the other available choices such as P20. It has the capability of allowing rapid machining. It can hold tough tolerances and doesn’t require any kind of stress reliefs, even after the 250K cycles. It is highly resistant to corrosion.

The flaw of using this material is that its heat transference quality is not that great and therefore it should be cooled carefully by allowing ample amount of time. Also, the cost of this choice is more than few of its counterparts that include AL-7075.

This option is best used for plastics that are of engineering grade, such as the acetal and delrin. You can use this material for all high volume productions that involve high clamping pressures.

3. P20


It is another semi hardened as well as reliable tool steel and the one that is most commonly used.

This option costs much more than AL-7075 and also with resins that are abrasive in nature. These resins can last for many cycles based on the geometry and the tolerance of the part. This material is beneficial as it machines the product properly and can be easily welded, if any repairs in the mold is required. The material can be easily given a polished look and it is highly resistant to scratches.

The material is tougher, which means it can handle high injections and also more clamping pressures.

There are some other alternatives available in the market, such as PVC that are corrosive by nature, chemically. This option is not very resistant to here factors and so the life of the tool can be impacted. In some instances, aluminium stands as a superior material.

The material is generally recommended for abrasive resins for glass fibers, high clamping pressures and injections, and some larger parts as well. It can handle production volume of upto 50K.

4. H13


This material is a fantastic choice for all larger volumes of productions or during the production processes.

The material is considered as a steel of Hot work, meaning it has excellent capability of resistance to continuous cooling and heating cycles. The material can be easily machined, even before providing treatment with heat, when the metal being molded is soft. You can use H13 million times per mold. You can choose to polish it to obtain a mirror effect for optical and clear parts.

The heat transfer capacity of this material is average and is also costlier than P20 and AL-7075.

The material is best used for all optical parts that are made up of clear plastics, such as polycarbonate or acrylic. They are suitable for high volume productions as well.


The choice of resin and mold also depends on the design and material that you have. Some more details are to be considered when determining the right mold material for your production process. The mold details include, gate style, molding resin, finish requirements, print tolerances and part configurations. By understanding the composition of the part and general uses of the industry, one can decide which material would be appropriate for their mold.