The Complete Guide to Die Casting Mold Design and Manufacturing

Table of Contents

Melting Die-cast material
Melting Die-cast material

I. Introduction

Manufacturing components with precision can be daunting, especially for industries like medicine and automotive where part precision is crucial to device functionality, aesthetics, and user safety. Thankfully, innovative manufacturing methods like die casting rank very high on the list of precision-based manufacturing techniques. 

This production method finds applications across various sectors including energy, medical, aerospace, and many others. Nevertheless, the denominator across these industries is their need for accurate dimensions and durable, and high-quality parts. Hence, the importance of critically evaluating the mold design process in die casting to help achieve these objectives. 

Fortunately, we have curated all this information to help you understand and apply everything you need to know to make your die-casting mold designs and manufacturing accurate and easy. Without further ado, let’s dive right in.

die casting partss
Die-casting parts

II. What is a Die Casting Mold?

Similar to mold-reliant manufacturing processes such as injection molding, die casting’s success heavily depends on the accuracy and durability of the production mold. 

For instance, if the mold is defective or misaligned, there is a high probability that the product or part emerging from such a manufacturing process will be defective.

Consequently, a die-casting mold is not just a container for holding molten fluids but a vital tool which ensures the accuracy of the product as designed. These accuracies include dimensional, surface finish, and functional.

Furthermore, die-casting molds ensure that parts with complex geometries including intricate details of the product are achieved easily and quickly making it possible to produce parts in large volumes.

However, it is important to note the features of a die-casting mold to fully understand its workings.

Such features as its cavity and core are responsible for holding the molten fluid in place to form the shape of the product once it cools and then ejects. Also, there is the runner system which mainly contains the sprue, runners, and a gate that acts as the link between the pressure chamber and mold cavity.

Lastly, there is the ejector system that facilitates the easy removal of the finished product and ensures it is not damaged during removal. All of these components combine to ensure a perfectly working die-casting mold.

Still, these components have to be subjected to critical evaluation when designing a die-casting mold to ensure that the mold performs excellently well.

Die-casting Mold Design
Die-casting Mold Design

III. Designing Die-Casting Molds:

Designing die-casting molds is not a walk in the park. The truth is that several factors need to be carefully thought through to design a mold that helps achieve a flawless product. Frankly, these considerations are in two broad categories – initial considerations and mold layout design considerations.

Initial Considerations:

To begin with, die-casting mold is often subjected to high pressure and extreme temperatures in the cause of casting molten parts. This pressure contributes significantly to ensuring that the fluid flows adequately into every corner and crevice of the mold.

But here is the problem.

The mold material is also subjected to this pressure which can wear out the mold if the material is not sturdy enough to withstand the pressure. This is why mold designers need to carefully consider the material choice for constructing die-casting mold.

Robust and durable materials such as steel or other alloys of steel often serve satisfactorily in withstanding the pressure during die casting and it’s no wonder they are specified for mold manufacturing.

Another initial consideration for mold design in die casting is part geometry, especially with complex shapes and intricate details. Designers must consider how the molten material will flow easily into the crevices of the mold to ensure that those intricate details come out flawlessly in the final product.

Thankfully, Computer Aided Design (CAD) software applications are available to help designers clearly communicate these complex part geometries and intricate details. Some of these applications are also capable of mold flow simulations, giving designers real-time analysis of the fluid movement in the mold and a chance to correct any errors before producing the mold.

Mold Layout and Design Principles:

The choice of mold material and the part geometry are not the only considerations required for an optimally functional die-casting mold. The mold layout is another vital consideration in the mold design process. 

Think of the mold as a puzzle having a layout but with features like runner systems and mold gates acting as the missing pieces required to complete it. In die-casting mold design, these features are inserted one after the other using critical design principles to form the complete picture.  

For instance, when designing the mold gate the design logic is to allow a turbulence-free flow of molten material through the runner into the mold cavity. This will guarantee an even flow thereby reducing the risk of producing a defective part.

Also, when designing the die-casting mold vents, the appropriate design principle is to place the vents in strategic locations on the mold, especially where heat is likely to be trapped. These places can include areas with intricate details and thin walls. 

Also, vents should be designed to ensure that the cooling is not too slow or too fast but adequate and even across all mold areas. The truth is that a balanced cooling thermal and cooling system enhances the production process to produce high-quality parts.

Die-cast Mold machining
Die-cast Mold machining

IV. Manufacturing Die Casting Molds:

Once done with the mold design, the stage is then set for the main event – die-casting mold manufacturing. However, like the designing stage, careful consideration of all manufacturing factors should be observed to ensure that a flawless mold is produced.

Material Selection:

Starting with material selection, your choice of material for die-casting mold manufacturing can be the deciding factor between an effective mold manufacturing process or a defective one. 

For example, even though steel is a choice material for die-casting mold manufacturing especially given its tensile strength and stress resistance, it is still instructive to choose the right grade of steel to avoid a disastrous outcome. 

Factors such as the required production volume and the casting alloy should inform your choice of steel grade. Frankly, mild steel should not be used for molds intended for high-volume die casting. Its resistance to pressure and heat is significantly lower than that of high-tensile steel and alloys like stainless steel.

Machining and Tooling:

To produce a die-casting mold that is both exceptionally functional and aesthetically pleasing, the mold has to go through a machining process. As such, the level of experience and expertise of the machinist is critical to the quality of the mold.

Incidentally, several innovative machines are available to deliver the mold design with precision. However, the choice of machine will largely depend on several factors, including the level of precision required, mold size, dimensions, shape, material, and the surface finish specified for the mold.

CNC (Computer Numerically Controlled) machine, for instance, is a computer-based machine with a reduction manufacturing process for molds. The level of precision for this machine is very high and it’s especially suitable for mold design that has several intricate details.

But here’s the kicker: CNC machines have a steep initial cost of purchase. Nevertheless, the return on investment is also high if well maintained.

But while CNC uses sharp tools for machining a mold, others like EDM (Electrical Discharge Machine) use electrical sparks to cut a mold. Still, you need to check the machining requirements for a die-casting mold manufacturer to choose the right machine for your project.

More importantly, ensuring that you use precision tooling is critical to achieving a high-quality die-casting mold with excellent longevity.  

die casting process
Die-casting process

V. Types of Die Casting Molds:

With all that has been said about die-casting mold, this guide will not be complete without highlighting the different types of die-casting molds and options available to you. Even then, your choice of a suitable die-casting mold – conventional or bespoke, will depend on what your manufacturing objectives are.

Firstly, there are standard single-cavity and multi-cavity molds known also as production dies that utilize simple mold core and cavity formation which is less cumbersome to assemble. 

The major difference between the two is that single-cavity mold has no slide while multi-cavity molds have numerous slide options for manufacturing parts in mass. Still, the criteria for choosing between the two boils down to the volume of production required.

While the single-cavity mold is suitable for simple low-volume production, the multi-cavity mold can manufacture many parts at a go making it more suitable for high-volume part production.

However, when it comes to manufacturing parts with complex designs and geometries, specialized molds such as rapid tooling and trim dies find a suitable application.

For instance, trim dies are often the mold of choice when the need to remove excess materials from the product becomes critical. Trim dies can remove traces of flash, overflow, and runner materials from the final product, which explains the trim in its name. 

Consequently, this ability makes it easy to demold parts with trim dies as there is no excess material holding it down.

In the case of rapid tooling die-casting molds, manufacturers looking to significantly cut down on production time often turn to this die-casting mold. It employs inserts made from modern rapid tooling methods like direct metal deposition and selective laser sintering making it faster to produce parts.

machine shop process die cast
Machine shop process die-cast

VI. Die Casting Mold Maintenance

To enhance the efficiency of the mold as an important unit of the die-casting operation and to increase its lifespan, you must ensure that the mold is well maintained while you check for wear, dirt, and lack of lubrication. However, these activities fall into the regular routine maintenance and troubleshooting activities which helps to quickly arrest any anomalies before they escalate into something costly.

Routine Maintenance Practices:

Routine maintenance is essential to make sure that the mold components are working as designed without external elements causing any hindrance.

Firstly, you need to carry out regular cleaning of the mold components including the cavity and core. A good wire brush always comes in handy for this. It’s also not uncommon to find debris and dirt that has built up over many die-casting operations. You need to ensure that all dirt, grease, and residue are thoroughly cleaned out to give the mold a new lease of life.

Similarly, mold joints, pins, and inserts need adequate lubrication before the commencement of any operation. This will reduce the friction responsible for wear and tear between mold parts and ultimately increase the mold’s lifespan as well as the quality of its output.

Additionally, changing worn parts immediately when you identify them can be a crucial step to the optimal function of the mold. You don’t want to be held ransom to a worn-out part in the middle of an important die-casting procedure.

Furthermore, the mold storage environment is an indication of the mold’s lifespan. So, always store the mold in a clean dry environment to guarantee its longevity.

Troubleshooting Common Issues:

Sometimes, carrying out troubleshooting activities can reveal hidden issues that are just waiting to cause chaos for you and your die-casting project.

However, if you carry out troubleshooting exercises regularly, you can arrest this situation and avoid unnecessary malfunctions. To reveal challenges such as thermal fatigue ensure you check the mold temperature every time to ensure that stresses due to overheating of the mold do not build up leading to thermal fatigue.

Again, wear is a common anomaly for molds and you can only arrest by consistently inspecting the mold to reveal any signs of wear and erosion.

Automated die-casting process
Automated die-casting process

VII. Innovations in Die Casting Mold Design

Technology is fast becoming the bedrock of almost every industry providing innovative, cost-effective, and efficient solutions to many agelong challenges in these fields. Fortunately, die casting has not been left out, especially in the area of mold design.

Significant among these innovative solutions include the use of 3D printing for rapid prototyping in mold manufacturing. 3D printing has enabled die-casting mold manufacturers to quickly produce prototypes that can be analyzed in real-time to identify errors that need to be corrected before committing resources to manufacture the actual mold.

Also, the use of biodegradable materials in 3D printing has helped in preserving the environment, removing the pollution and wastage that has been attributed to conventional die-casting mold manufacturing in the past.

Another important innovation in die-casting mold design is the use of simulation software to help study fluid flow within the mold in real-time. This gives designers adequate information to produce excellent molds that address the peculiarities and common mistakes associated with conventional ways of designing molds.

Thankfully, the train of innovation is still in motion with future technological trends already showing promise of beneficial applications that will help make the die-casting mold design process more efficient.

Some of these future trends include Artificial Intelligence (AI) and the Internet of Things (IoT) where data can be generated and collected for instant decision-making that makes mold manufacturing easier, faster, and more cost-effective.

In the end, technology will help take care of the mundane part of die-casting mold design and designers can focus on other things to move the die-casting industry forward.

VIII. Conclusion

So, it all adds up to this, die-casting mold design and manufacturing is critical to the whole part production process. Moreover, getting a flawless part will largely depend on your thoroughness with the mold design process. It will also significantly depend on your production objectives and the considerations you’ve made during the design stage.

Vital consideration that includes the mold material choice, the geometry of the part, and the part’s intended use will form the basis for your die-casting mold design.

Apparently, you still need to consider the type of die-casting mold options that will be the best fit for your production requirements including production volume and the required surface finish.

Ultimately, giving adequate care and maintenance to your mold including regular cleaning, lubricating, and a conducive storage environment will increase its lifespan and keep it functioning excellently for a long time.


Steven Paul

Steven Paul

Steven Paul is the Technical Director in TDL, he has more than 15 years experience in Injection molding design.

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