What Is a Mold Insert? – Mold Inserts Material and Design Guide


The die casting mold or cavity is typically made of a fixed half and a moving half, there are different components of the mold. Today we’ll go over some basics of the mold inserts, and focus on the material and design.

What Is a Mold Insert?

A mold insert is a component of die casting molding system to create a specific feature or shape in a cast part. The mold insert is typically a separate piece of steel or other material that is inserted into the mold cavity before the molding process begins. The mold insert can be used to create various features in the final plastic part, such as threads, logos, or other intricate designs that cannot be formed directly by the mold itself. By using mold inserts, manufacturers can create more complex and detailed parts with greater precision and accuracy. Mold inserts can be used in a variety of industries, including automotive, aerospace, medical, and consumer products. They are often used in the production of high-volume plastic parts, as they can be easily replaced if they become damaged or worn out over time.


The cavity, core, inserts, sliders, and insert pins are all components of the die casting mold or die, which determines the final shape and dimensions of the casting. The cavity is the space within the die where the molten metal is injected and solidifies to form the casting. The core is a movable part of the die that creates internal features, such as holes or cavities, in the casting. Inserts, sliders, and insert pins are additional components that can be used to create complex shapes or features in the casting.

What Material Is Used for Mold Inserts?

The material used for mold inserts depends on the requirements of the injection and die casting molding application, such as the type of plastic material being used, the expected production volume, and the complexity of the part design. Some common materials used for mold inserts include the following options. 

1) Steel is a popular material for mold inserts due to its durability, resistance to wear and tear, and high-temperature resistance. Tool steels such as H13, P20, and S7 are commonly used for mold inserts.

2) Aluminum is a lightweight and cost-effective material for mold inserts. It is often used for low-volume production runs or for parts that require a high level of thermal conductivity.

3) Copper alloys such as beryllium copper and copper tungsten are used for mold inserts that require good thermal conductivity, high strength, and wear resistance.

4) Ceramic materials such as alumina and zirconia are used for high-temperature applications and parts that require a high level of wear resistance.

How to Design Mold Inserts?

Designing mold inserts requires careful consideration of various factors, including part geometry, plastic material, mold tooling, and production requirements. Here are some general steps that can be followed when designing mold inserts:

– Identify the part geometry: Understand the part geometry and identify any features that require a mold insert, such as undercuts or threads.

– Choose the mold insert material: Select the appropriate mold insert material based on the plastic material being used, production volume, and part complexity.

– Design the mold insert: Use CAD software to design the mold insert. Ensure that the mold insert is properly sized to fit into the mold cavity and that any required features are included.

– Consider draft angles: When designing mold inserts, it’s important to include draft angles to ensure that the part can be easily ejected from the mold without damage.

– Incorporate cooling channels: Consider incorporating cooling channels into the mold insert design to help regulate temperature and improve cycle time.

– Verify the design: Verify the mold insert design using simulation software or prototype testing to ensure that it will work as intended.

– Fabricate the mold insert: Once the design has been verified, the mold insert can be fabricated using CNC machining or other methods.

– Assembly and testing: After the mold insert is fabricated, it can be assembled into the mold and tested to ensure that it works as intended and produces high-quality parts.