At Dynacast we are often asked what tips we have that can improve a part design. I wanted to share with you some of the more common design tips that we recommend for die casting. Die casting can be done in various metals and the parts that are created differ widely. These tips listed below can help with the design of many parts. Also, remember to take into consideration the alloy that you would like to use, as well as any surface finishing that you’d like done after the part has been cast.
Die Casting Variables
The first tip that I’d like to share is regarding adding draft to a part. Adding draft means applying a slight taper on the internal and external walls of a part, normal to the parting line. This offsets the effects of shrinkage and makes it easier for the casting to be removed from the cavity. Adding draft makes it easier for a part to be cast. In general, recommended draft angles are in the range of ¼ degree to one degree per side depending on the alloy and process choices. Be sure to inform your Dynacast technical representative about critical areas where draft must be kept to a minimum. In many cases, near zero draft can be achieved in specific areas. Try to be mindful of draft when you are designing your component and apply liberal draft in non-critical areas from the beginning.
Fillets and Radii
Also, be sure to incorporate fillets and radii into your component design. Wherever possible, use generous fillets and radii, especially in non-critical areas. If you have an area where a fillet or radius is not possible or desirable, be sure to note it on your component drawing. Fillets and radii strengthen the component, improve metal flow and make the application of subsequent finishes easier.
Ribs and Bosses
Ribs and bosses are used commonly in the design of a part in order to increase its strength. They should be blended with fillets and radii to eliminate sharp corners whenever possible. Since most ribs and bosses have non-critical side surfaces, be sure to apply draft accordingly.
If the part that is being designed needs to be lightweight, one option commonly used is to design pockets in solid sections. This not only reduces the weight of the part but also decreases cycle time and reduces the cost. Again, be sure to apply draft and radii accordingly.
When designing a die cast component, take into account everything the process has to offer. Consider adding features that have little-to-no added cost. For instance: logos, surfaces textures, integrated fasteners (rivets, studs), embossed part numbers, etc. The 4-slide die casting process can offer even more flexibility. Your Dynacast technical representative can help you with these options and more.
Optimizing Material Flow
Finally, there are tips I’d like to share for assisting with the flow of the metal into the cavity, to produce the final part. If a part has smooth corners and uniform sections, the metal can flow easier throughout the entire cavity, which means faster filling without producing metal flow turbulence. However, I know a uniform part is not always an option. In regards to flow, parts with long “windows” or slots can severely restrict metal flow, while round holes assist in the flow.
I hope these tips have been useful to you. If you’d like to see more about these options, as well as additional options that I didn’t discuss, please see our part improvement page on our site. It contains a wealth of knowledge on how to improve part design.
Dynacast has a great design for manufacturing (DFM) service, which you can learn more about here. This service allows Dynacast experts to look at your design and suggest tips on how to make the design easier to die cast and/or more cost effective.