Good designers continue to explore new ideas, iterate, and refine their design until they are able to devise a solution that satisfies all of the constraints the best. However, in the real world, as we are all well aware, time is in very short supply. In order for designers to meet the production deadlines, they are often forced to settle for something much less than ideal.
This problem is tackled head-on by generative design ideas. It allows designers to explore many more potential solutions that are possible by a human, especially with a boss breathing down their neck. In this article, we will be explaining what exactly generative design is, and what it can do for product engineers and manufacturers. We will be sharing some thoughts on what it can mean and do for the metal fabrication industry as well.
Using Generative Design to Find the Optimal Solution
An engineer uses generative design to define the goal of the design and any constraints such as expected loads, maximum weight, material, and mounting faces. The software will then work out solutions to the problem and then present them for the engineer to review. So far so good. However, you might be wondering how this results in the organic shapes that you have seen. Let’s take a deeper look.
Basics of Generative Design
CAD companies a couple of years ago started to discuss “topology optimization.” It a tool used for determining where the material in a component is needed and where it is not. The engineer produces a design in CAD and then informs the system about the various forces that are going to be applied. Then the load paths are worked out by the software. The engineer can use that information to delete material to the areas where it is not contributing to the strength and add it into places where it is.
This process is automated by generative design. It takes the design through a massive number of iterations and continues to do so until a set of solutions are achieved. (You may see this called “psychic-driven design” also since it applies physics to design optimization). However, that is not the only thing that it does.
In order to create these strange shapes, “form synthesis” is used by generative design. That frees them from the constraints associated with conventional manufacturing software. This software is able to grow structures around “obstacle” and “preserve” regions that are defined by the design engineer in CAD in order to create the most efficient shape possible.
As you may imagine, lots of computing power is needed by generative design. That is why generative products such as Autodesk’s Fusion 360 do their processing within the cloud and only send the engineer results.
Additive and Generative
Coming up with the design is all well and good, however, someone needs to make them. This is where additive comes into play. These structures are built by additive manufacturing (3D printing), in polymers or metal, piece by piece. It is, in fact, the only way that most products that are designed generatively can be made.
Of course, there are some limitations to additive manufacturing. Minimum wall thicknesses must be maintained, it is hard to produce overhangs, and support structures are frequently needed. However, those constraints all can go into the initial model, to ensure the final design can be printed.
The Driving Forces Backing Generative Design
It is always a good thing to help designers be able to explore more options, especially when you are a designer. However, that is not what is really pushing the technology forward. Lightweighting is the big thing, and then part consolidation follows that.
The automotive and aerospace industries are really big into lightweighting. When there is less mass that can translate into a higher payload, better fuel efficiency, and improved performance. For example, GM’s seat bracket is 20% stronger and 40% lighter compared to its conventional equivalent.
The other important and notable point about the bracket is it combines eight different parts into one. There are many benefits to part count reduction for companies like GM. It allows tolerance stack-ups to be avoided and there is much less waste since you are never out of a component or overstocked on any either. In addition, it simplifies inventory management, purchasing and so forth. Admittedly the part is not in production, however, those are the factors that drive generative design interest.
Generative Design for Metal Fabrication
Generative design so far has been developed in order to use additive methods for making parts. However, it is recognized that generative can fit in with processes that are more conventional and that is something that is being worked on by CAD companies.
An obvious candidate is casting. What makes generative so valuable is being able to place material only where it is actually needed. Therefore, why not use it for molds and design casting dies. We can even imagine 3D printing patterns that have all kinds of complex features.
Within the subtractive realm (just a fancy way to say machining), one thing that looks like it fits well with generative design is 5-axis milling. A mill follows complex cutting paths and could hollow-out cavities and ribs, and only leave material where it is needed.
In our view, the same is true for fabrication. Lots of bracing is used by fabricated structures for creating stiffness. It is possible that generative design might be able to help to optimize the location and size of the bracing.
There are also sheet metal parts with bends that are added to provide stiffness. Generative design can help to identify where it is possible to take out material. If that information were fed to a laser cutter or turret punch, we then could remove what was not necessary before the blank went into the folder or press brake.
Higher Performance, New Appearance
Design should always be an iterative process. However, it is a lucky designer who has enough time to explore numerous options. Generative design provides the process with that freedom once again. When additive manufacturing is combined, it can result in strange organic shapes that would never be conceived of by human designers. Light and stronger than results from human design efforts, these products that generative design creates are going to look like nothing that we have seen in the past, and some may even be fabricated!