A beginner's guide to die casting design

New to the die casting process? Learn how to apply design strategies effectively for optimal manufacturability here.

Design for manufacturability

Optimising your component design to take advantage of the die casting process is key to achieving a return on your investment. Whether your project is best suited to conventional die casting, multi-slide die casting or injected metal assembly, it is best to design your component with the production process in mind. In other words, engineers should approach each project with the aim of designing for optimal manufacturability.

Design for manufacturing (DFM) is a core methodology that ensures die cast parts perform to specification and reduces the need for secondary operations. As these operations can often represent as much as 80% of the component cost, it is important to minimise them during the design stage.

DFM is more than just a concept—it is a way to remove cost and eliminate inefficiencies before your project moves towards production. In this blog, we will guide you through three ways to design your die cast component for maximum ROI.

Reduce weight and wall thickness

In die casting, two of the highest cost drivers are material and machine time. You can reduce the need for both by adding weight-saving pockets and reducing wall thickness.

Reducing weight and wall thickness in cross-sections may seem like an obvious solution. Less weight means less material, and less material means lower material cost. It also means reduced solidification time, which means you achieve more shots per minute. However, some companies find themselves sacrificing performance for cost.

With part performance in mind, it is important to reduce weight and wall thickness deliberately while maintaining part strength. When designing your component, you will need to use your project's mechanical and physical requirements to select the most appropriate alloy that will perform effectively with thin walls.

For example, if your part needs to be corrosion-resistant and stable, thin-wall aluminium is a good fit. Aluminium is corrosion-resistant and retains high dimensional stability and hardness.

Would you like to learn which alloy is the best fit for your project? Use our dynamic metal selector tool to filter for your required mechanical and physical properties!

Maintain consistent wall thickness

While seeking reduced wall thickness, it is perhaps even more important to maintain uniformity. This will help ensure a consistently stable, repeatable casting optimised for manufacturing.

Varying wall thickness can lead to porosity caused by varying flow pressures and non-uniform solidification. At Dynacast, our engineers have many techniques for achieving a net-shape component through die casting while maintaining consistent wall thickness.

In Figure 2, you can see that the component on the left has several walls that are much thicker than the thinnest part of the component. If cast this way, it would produce a weaker, porous part. Instead, our engineers will core out the thicker walls to achieve greater uniformity and incorporate ribs in the cored sections to guarantee part strength.

Consider draft angle and tolerance zones

When designing your component, it is important to consider the achievable draft angles and tolerances for your project's materials to avoid delays caused by redesigns. For draft angles, in general, 0.5º is achievable for zinc; 1º-2º is achievable for aluminium. For exact tolerances, generally between ±0.001" and ±0.002" is possible for zinc, whereas aluminium can hold between ±0.002" and ±0.004".

With achievable draft angles and tolerances in mind, you are better equipped to avoid engineering unnecessary cost into the design. Too often, companies request exacting tolerances and minimal draft angles when such features are not needed to maximise part performance. As a result, their castings fail.

Instead, take a more holistic approach to your design. Identify the non-critical dimensions of your component to allow for more lenient tolerance zones. In addition to extending the life of your tool because there are fewer exact geometries that wear down, allowing for tolerance zones also makes it easier to plan the tolerance stack-up of your entire component. This will help you avoid machining and secondary operations wherever possible, making your design work for you to get the most from the die casting process.

Work smarter, not harder

Modifying your part design to take advantage of the die casting process not only enables you to fully leverage the efficiencies of die casting, but can also better meet your business needs.

Are you interested in learning more about efficiently designing your die cast component for optimal manufacturability? Register for our webinar, Removing Cost in the Design Stage.