Generative design used to have a reputation that it was only for simulation analysts, mathematics PhDs, or engineers inventing new spacecraft. This is simply not the case anymore. In fact, Autodesk Fusion 360 is making generative design technology accessible to the everyday engineer. With the ability to apply manufacturing constraints, such as 2.5-axis CNC machining, there is no better time to get started with generative design.
If your objective is to have the lightest possible part that still meets your load criteria, you can use an unconstrained generative design outcome that utilises additive manufacturing. However, if you need to minimise the weight of a product and cost is a critical factor, you could explore outcomes only suitable for traditional manufacturing methods like 2.5-axis CNC machining.
This is exactly what the engineers at Ethereal, an immersive VR gaming start-up, did to come up with an affordable solution for a virtual reality (VR) gaming experience. The Ethereal VR gaming station requires on-demand, full-force feedback from multiple vectors of the player’s arms and legs to simulate various fitness experiences. In other words, the player might perform a motion that replicates a chest press or a lateral pulldown.
The real-world challenge is that this requires the central carriage to move up and down in a full range of motion with very little resistance. Zero resistance is not possible, but Ethereal intends to get as close as possible. “Strength to weight ratio is critical, especially for the suspended carriage that holds the user interface,” explains the company’s Founder Scott Summit. “Every gram we can remove helps. We want a machine that can handle a 250lb person hanging on it but be light enough to give the perception of zero mass in free motion.”
Ethereal explored generative designs using the 2.5-axis manufacturing constraint within Autodesk Fusion 360. The main target is the carriage, which is milled from a piece of 6″ x 6″ box tubing and includes critical suspension points where bearings meet the frame and rail. “The 2.5-axis constraint ensures that we’ll be able to manufacture our product using standard plate and billets,” says Summit. “That’s vital. To 3D print one of our components would cost many thousands of dollars, but now we can hog out material from about $100 worth of box tubing.”
Another example of practical, everyday generative design is from MJK Performance, a company that designs, manufactures, and sells speciality aftermarket parts for Harley Davidson motorcycles – all in-house from a small, four-machine shop in Calgary, Canada.
Collaborating with Autodesk, MJK used generative design technology to create a set of triple clamps for a drag bike. The resulting designs were not only lighter and stronger, but appropriately stylish and fully machinable on a 2.5-axis mill. Triple clamps are a part of the fork that connects the handlebars, steering stem, and shock absorbers. Because these clamps tend to be large and bulky, they are a perfect candidate for light weighting. Using generative design for 2.5-axis milling helped the MJK team to reduce the weight by 23% at comparable costs without sacrificing safety.
Finally, another great application for generative design is the design of robot end effectors. Robotic manufacturing continues to grow and evolve at an extremely rapid pace. This trend depends on the ability to design end effectors quickly so that the same robotic arm can be used for multiple tasks in one shop – whether it be to pick up objects, drill, cut, or extrude material.
Effectors also must be designed to hit a ‘sweet spot’ of structural stiffness, durability and weight. This is a relatively simple part, so you might not think of using generative design at first. But by limiting Fusion 360 to 2.5-axis manufacturing, the designs were very close to what a human engineer would have come up with – just much, much faster. Generative design can explore multiple ideas simultaneously, and the designs it produces are fully FEA validated to the desired safety factor, so you can be sure they won’t bend or break.
Identifying opportunities to use generative design
A few questions we often hear are: ‘Why should I use generative design?’ and ‘What are the ideal applications for generative design?’ Here is a quick checklist to help you spot the best opportunities:
Are you looking to improve the performance of your product?
- Light weighting
- Increased structural integrity
- Extended durability
Are you trying to improve your engineering ideation/productivity?
- Explore design alternatives quickly
- Expand beyond past references (tribal knowledge)
- Save engineering time and iterations
Are you trying to reduce the cost of your product?
- Part consolidation to reduce the number of parts in an assembly
- Reduced raw materials
- Evaluate different manufacturing methods
If one or more of these factors are important to your design, then it’s likely a good candidate for generative design. As you can see from these examples, everyday engineers use generative design to come up with practical designs that can be manufactured using traditional methods.
So, there’s no reason to be intimidated by generative design. Start identifying opportunities in your products and begin exploring various outcomes with generative design in Autodesk Fusion 360.
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