Die Casting Mold: Die Design And Fabrication Guidelines

mold building, mold design

Known for efficiency, precision, and the ability to produce parts with excellent surface finish and dimensional accuracy, die casting has become one of the most popular processes in industrial manufacturing.
Die casting mold or die, is always used in this process. When we use this process to produce our desired custom casting parts, we need to pay more attention to die casting mold design.
Successful die casting mold design can gain the best result of quality parts. Here are a guideline from Sungplastic. Please learn more if you have next similar projects.

injection molding mold types

What is Die Casting Mold?

A die casting mold, also known simply as a die, is a specialized tool used in the die casting process, which is a manufacturing method for producing precise and complex metal parts or components with high efficiency. The die casting mold is a crucial component of this process and plays a key role in shaping and forming the final product.

Die casting molds are typically made of durable materials like steel or, in some cases, less expensive materials like aluminum for lower production volumes. The choice of mold material depends on factors such as the expected production volume, part complexity, and tool longevity. Die casting molds must be meticulously designed and manufactured to meet the specific requirements of each part and ensure consistent, high-quality production.

Components of a Die Casting Mold

  • Cavity
    The cavity is the main part of the mold that defines the shape and features of the final casting. It is a hollow, negative space that corresponds to the desired part’s geometry.
  • Core
    The core is used in conjunction with the cavity to create the desired shape of the casting. It is a solid or hollow component that forms the internal features of the part.
  • Runner System
    The runner system consists of channels or gates that allow molten metal to flow from the melting furnace or crucible into the cavity and core of the mold. It ensures that the metal fills the mold properly.
  • Cooling System
    To control the temperature during the casting process, a cooling system is integrated into the mold. Cooling channels or passages help dissipate the heat generated by the molten metal, allowing the casting to solidify and cool uniformly.
  • Ejector System
    Once the casting has solidified, it needs to be removed from the mold. The ejector system includes pins or other mechanisms that push or pull the casting out of the mold’s cavity and core.
  • Parting Line
    The parting line is the interface or boundary between the two halves of the die casting mold, known as the “cover” and “ejector” halves. It defines how the mold comes apart for the removal of the casting.

Die Casting Mold Design

Die casting mold design plays a crucial role in the mass production of metal products and components. It stands as a pivotal step in the process, as the mold’s shape and characteristics have a direct impact on the final product. In the die casting process, molten metal is forcibly injected into molds under high pressure, necessitating precise mold specifications to accomplish the process.

The success of die casting mold design hinges on several key considerations. During the design phase, these eight critical factors must be carefully taken into account: Die Draft Angle,Fillets on Mold & Part, Casting Die Parting Lines, Casting Part Bosses, Part Ribs, Holes and Windows on Part, Symbols, Wall Thickness of Part.

By attentively addressing these key points during the die casting mold design phase, you can greatly enhance the likelihood of successful die casting die manufacturing and ultimately achieve high-quality metal products.

Read detailed information below.

Key Considerations in Die Casting Mold Design

Designing a high-quality die casting mold requires a combination of design skills, die casting manufacturing expertise, and experience. Achieving the best results hinges on the designer’s ability to navigate these complexities effectively.

Draft Angle

Draft refers to the degree of taper applied to the mold core. Precise draft angles are essential to ensure the smooth ejection of the casting from the die. However, the required draft may vary depending on factors such as the type of molten alloy, wall angle, mold depth, and mold geometry. In general, untapped holes and inner walls may require more tapering to prevent shrinkage issues.


Fillets are concave junctions used to round off angled surfaces in the mold. Sharp corners can impede the casting process, so molds often incorporate fillets to create smooth, rounded edges and reduce the risk of production errors. Fillets can be strategically added to various areas of the mold.

Parting Line

The parting line or parting surface connects different sections of the mold. Precise positioning of the parting line is crucial to prevent material seepage between mold pieces, which can lead to non-uniform molding and excessive seaming. Work strain or deformation of the parting line should be avoided.


Bosses are raised knobs within the die cast that serve as mounting points or stand-offs. To ensure uniform wall thickness in the molded product, manufacturers often incorporate holes in the interior structure of the boss. Deep bosses may require filleting and ribbing to facilitate proper material filling.


Die-cast ribs enhance the material strength of products with insufficient wall thickness for specific applications. Careful placement of ribs can minimize stress cracking, ensure uniform thickness, reduce product weight, and improve material flow during casting.

Holes and Windows

Incorporating holes or windows in the die casting mold impacts ejection ease and enables the creation of necessary drafts. Additional features like overflows, flashovers, and cross feeders may be required to prevent unwanted casting within or around these openings.

Cooling System

The die casting mold cooling system is distinct from plastic injection molds due to the elevated mold temperatures, often exceeding 200 degrees Celsius. Effective cooling, such as a conformal cooling system, is essential for maintaining casting part quality and optimizing cycle times.


Manufacturers may include brand names or product logos in the mold design. While symbols themselves do not typically complicate the die casting process, their use can impact production costs. Raised symbols require additional molten metal volume, whereas recessed symbols reduce material consumption.

Wall Thickness of Part

The wall thickness of the part being cast is a critical design consideration. Maintaining uniform wall thickness throughout the part is essential for producing high-quality die-castings. Inconsistent wall thickness can lead to issues such as porosity, uneven cooling, and warping. It’s important to carefully evaluate the design to ensure that the wall thickness meets the structural and functional requirements of the product. Additionally, thicker sections may require longer cooling times to prevent premature ejection and ensure proper solidification. On the other hand, overly thick sections can result in cooling challenges and may lead to defects in the casting. Therefore, achieving the right balance in wall thickness is crucial for successful die casting mold design.

Sungplastic: Reliable Die Casting Mold Fabricator

Our capabilities include die casting mold fabrication, blow molding, die casting, CNC machining, injection molding, overmolding, rapid tooling manufacturing, assembly, welding, 3D printing, surface finishes, rapid prototyping from prototype to production, design and customization services and so on.

Materials used include:
Metals (Aluminum, steel, stainless steel, cooper, brass, zinc…),
Rubber and other composite material.

We have a skilled team and advanced equipment, mastering ample production experience and industrial knowledge.

Work with Sungplastic, your project will be a success!

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