Exploration deals with big, early decisions. Are you going to use traditional injection molding, gas-assist, or microcellular techniques? Are you going to use traditional cooling, conformal cooling, or high conductivity inserts? Are you going to try a new material?
That last example is the essence of exploration: the choice between sticking with a trusted approach or trying a new one. Obviously, using a proven method carries fewer risks. But new ideas can deliver huge payoffs, especially if you can explore them within an acceptable timeframe and with enough precision to proceed with confidence.
The kind of exploration that mold engineers can use on relatively short timelines is driven by simulation software. Simulation tools can be used to test different “big decisions” quickly. The idea is to build confidence into your idea, so that you can predict what will happen and be reasonably certain it is a viable alternative to the default process.
The design of the part and the selection of a molding process go hand in hand. If you use gas-assisted injection molding, then the part must be designed so the gas can help hollow it out. If you prefer microcellular foam injection, the walls must be thick enough to withstand the process but not so thick that they create shrinkage issues. These kinds of adjustments must be made concurrently, so it is useful to consider both when it comes to upfront exploration.
One of the most robust approaches to design exploration is generative design. Generative design, found in Autodesk Fusion 360, leverages artificial intelligence to provide the user dozens of design options.
Even small changes in cooling time can have a major impact on cycle time, so exploring various cooling systems can produce useful results. And it can be done relatively quickly. When exploring cooling systems, the point is not to design cooling channels around ejector pins or other components of the mold, but to perform a high-level comparison.
Here is a great case study of generative design in action:
Panasonic Corporation turn to generative design for complex plastic shapes
Injection molding is essential to mass-producing plastic parts with complex shapes. To create higher-quality products at lower costs, the priority has been to develop advanced cooling systems for melted materials. But that is difficult, time-consuming work, even for skilled engineers.
Could automating the design of mold-cooling water channels help the engineers working on this challenge? This is just what Panasonic Corporation’s Life Solutions Company in Japan set about exploring.
As Seiichi Uemoto, an analyst at the company’s Manufacturing Engineering Center where the molds are designed and fabricated puts it, “Topology optimization can produce only one solution from the conditions provided to the system. It is difficult to produce something with smooth contours from the generated result. But it became apparent to me that generative design would inherently result in smoother shapes. I felt with generative design, we would be able to effectively generate multiple concepts that took manufacturing principles into account.” Uemoto hoped that applying generative design to molds would result in new mold shapes and automate the design process itself.
The company’s highly skilled designers developed a variety of products supported by Autodesk Moldflow, which continues to help perform molding simulations to further refine their designs. “I felt that if we use automatic design to provide insights designers may not come up with by themselves, it would give them more freedom in their work,” Uemoto says. The team developed a new manufacturing method for mold-cooling water channels by using the LUMEX Avance-25, the world’s first hybrid metal 3D printer.
Combining additive manufacturing and milling, the result is a conformal-cooling system – which lays out the cooling channels conforming to the shape of the products – that has reduced cooling times by 20 percent compared to conventional methods, where channels are drilled straight through the mold.
During the generative design process, the shape of the product changed over numerous iterations until only the essential components remained for creating the required water channels. Each iteration
So, how could generative design be used by the military and government? One way is with lightweighting.
Using generative design for lightweighting
The convergence of generative design, additive manufacturing, and injection molding has the possibility to rewrite the rules of lightweighting in dozens of applications in aerospace, automotive, medical devices and other industries. Generative design eliminates excess material and improve performance in unexpected ways, as was the case with Panasonic.
While the use of injection molding in die casting is not new, using generative design and simulation software helps everyone involved get more value from these proven processes. These techniques are expanding the boundaries of injection molding and die casting, making mass manufacturing a realistic goal for even the most complex geometries.
To learn more about this – and other technologies in Autodesk Moldflow – that you can leverage for your mold, product and molding process design, check out Part 1 and Part 2 of the four-part Plastics 101 webinar series where we discuss generative design applications.