Best Practices for Designing Die Cast Parts

Whatever your industry, having access to affordable, custom made cast metal components to create or repair products is essential. From office equipment and sporting goods to lighting fixtures and appliances, die casting can offer an affordable, consistent, and quick way of producing just about any component or end product you can imagine. The design process is what happens when we turn what you’re imagining into what you need us to produce. Some clients who work with us are great at giving the necessary details to create exactly what they need, but others struggle. There’s a lot to consider when designing your dies, and we can help. On this page, you’ll find tips about how to create a die cast design that will result in minimal material waste and fast and affordable output. Don’t hesitate to reach out to learn more. Our team is always happy to help you at every step of the die casting process.

So, What is Die Casting?

Metal casting molds, called dies (think of this as a Jell-O mold for metal), can be produced for simple and complex parts. The versatility of metal casting allows us to form molten metals into just about any shape you need. The process involves designing and crafting the dies to your specifications as well as to ensure end products meet or exceed industry standards. You may have heard about product specification standards like AS9100 for aerospace components, ISO13485 for medical devices, ITAR for defense and military technology, or ISO9001 a general set of quality control standards. Once the dies are designed, the molten metal is injected (cast) into the dies. As the metal cools, it takes on the shape of the die.

Die Cast Design Recommendations

Below are some design suggestions, rules, and general desirable principles for the die cast process. Keep in mind that every order is different, and there are exceptions to these recommendations that may impact the budget or the quality of the final project.

Be Specific

In general, the more specificity you can offer in the design process the better. One big exception is specifying tolerances closer than is absolutely essential to the design as this will unnecessarily increase production costs. Some things we do recommend specifying in your design include:

Specify thin sections that can easily be die cast and still provide adequate strength and stiffness.
Specify the use of ribs wherever possible to attain maximum strength and minimum weight for the final product.
Specify coring for holes or recesses where savings in metal and overall costs outweigh tooling costs.
Specify die cast threads over cut threads when a net savings will result. Cast threads will add increased strength since the thread grain is able to follow the contours of the fastener unlike cut threads. Additionally, cut threads often have flaws, like high spots, that can impact the function and integrity of the overall product design.

Strive for Uniformity & Simplicity

Whenever possible, it’s best to create a die casting design that is simple and uniform. This reduces the risk for imperfections in the final result and minimizes the production costs. Some specific recommendations include:

Keep sections of the die as uniform as possible.
Where sections must be varied, make transitions gradual to avoid stress concentration, which will change the way the metal flows through the die and result in porosity or irregularity in the product.
Keep shapes simple and avoid nonessential projections.

Minimize Design Additions

Allowing the metal to flow smoothly through the die without unnecessary cores, undercuts, or projections ensures a more uniform result and can often reduce the overall production costs. Specifically, keep in mind the following tips for reducing costs related to cores and undercuts.

Design cores for easy withdrawal to avoid complicated die construction and operation.
Avoid small cores. They can be easily bent or broken necessitating frequent replacement. Machining (drilling or piercing small holes) in die castings is often cheaper than the cost of maintaining small cores.
Avoid use of undercuts, which increase die or operating costs, unless savings in metal or other advantages fully warrant these extra costs.
When inserts are necessary, they should be designed to be held firmly in place with proper anchorage provided to retain them in the die casting.
Design die castings to minimize machining. I know we recommended small cores be machined, but in general, machining is an unnecessary added cost.
Design parts to minimize flash removal costs. The more complex the design, the more complex the flash removal process. If we’re able to quickly and efficiently remove flash using a trim die, you’ll receive a more consistent final product with a lower cost than is possible when complex design necessitates individually sanding components to remove flash.

Design for Your Flawless End Product

Finally, your design needs to be geared toward creating a product that meets your specifications and industry safety standards as well as performing necessary function within the larger product. Some ways your design can help to ensure the final product looks and works as expected include:

Die castings that affect the appearance of a finished product should be designed for aesthetics, and to harmonize with mating parts.
A slight crown is more desirable than a large flat surface, especially on plated or highly finished parts.
Provide sufficient draft on side walls and cores to permit easy removal of the die casting from the die without distortion.
Provide fillets at all inside corners and avoid sharp outside corners. Deviation from this practice may be warranted in special circumstances.
Die casting design must provide for location of ejector pins. Take into consideration the effect of resultant ejector marks on the appearance and function of your product. The location of ejector pins is largely determined by the location and magnitude of metal shrinkage on die parts as metal cools in the die.
Where machining is specified, allow sufficient metal for required cuts to avoid impacting the overall design.
Consider contact areas for surfaces that are to be polished or buffed and avoid deep recesses and sharp edges.

Ready to Get Started?

Hopefully, this information helped you feel a little more prepared to design your metal casting molds to get the best results from the aluminum die casting process while minimizing overhead and turnaround time. Our team completes these processes every day, and if you’re new to the die cast process, we can help! While we do offer a range of metal casting services, our team specializes in cast aluminum products to produce high quality results. Contact us to learn more about designing for metal casting and how it can streamline your production.