Realizing the potential of Production 3D Printing with Simulation

By Eric Miller, Co-Owner & Principal, PADT, Inc.

Eric Miller, Co-Owner & Principal, PADT, Inc.
Eric Miller, Co-Owner & Principal, PADT, Inc.

3D Printing is on the brink of not only changing the way we make products – it is poised to change the shape and performance of those products. Because this way of building parts, also referred to as additive manufacturing or AM, does not use tools to cut or shape material, it does not have the limitations of traditional manufacturing. It frees designers and gives them a much broader envelope of possibilities to work within. Companies across industries are turning to 3D Printing as a way to provide them with a competitive advantage in time to market and performance.

There is only one problem. Because the technology is new, the industry doesn’t have the decades, and in some cases, centuries of experience to guide them on what will and will not work with a new design. Early attempts at using AM for production parts did not fully take advantage of the technology, have reliability issues in the field, or the components being manufacturing are not made accurately enough.

That is why companies implementing additive manufacturing for production are leveraging numerical simulation as a way to optimize and test their ideas quickly, and also improve the build process itself. Numerical simulation is a method where a component’s geometry is entered into a computer and then subdivided into small chunks, and the software creates simple equations that characterize each chunk. All of these equations are then solved together to calculate what will happen to the geometry when forces act upon it. The technique can be used to represent distortion, failure, fluid flow, temperatures, sound, radio waves, chemical reactions, and even how light behaves.

Drive the Design
In the past, product design was often a process of coming up with what you wanted, then pulling back to define what you could actually build. The flexibility of 3D Printing removes a large number of constraints and allows creativity to take over. The question this creates is what new ideas and concepts are feasible. One approach is to build each idea and test it. An expensive and time-consuming solution at best.

By creating computer models, engineers can conduct virtual tests and explore new design spaces quickly and in an automated fashion. One of the more popular approaches is a process called Topological Optimization. It starts with a block of material, applies whatever forces the real part will see, and organically removes material to find the best shape. The results are not only stronger and lighter; they are often aesthetically pleasing. Engineers can also explore more traditional forms of optimization as well as honeycomb-like lattice structures to arrive at better components that will also has lower raw material costs. Simulation can drive the design to levels of performance, enabled by the freedom of 3D Printing, only hoped for in the past.

Verify the Performance
Once the advantages of 3D Printing technology have been explored and implemented, the chosen design requires testing to determine if it meets specifications and performance requirements. Once again, legacy knowledge from traditionally manufactured parts does not apply, and the unique behavior of parts produced with Additive Manufacturing can also result in surprises when components are used in the field.

The flexibility of working in a virtual world enables a far more rigorous, and often accurate, exploration of behavior and response. Modern simulation tools also allow users to look at the interaction of different environments and how products behave over time. Since a company is taking risk through the use of a new manufacturing process, verifying performance with simulation is an effective way to minimize that risk.

Optimize the Process
All 3D Printing technologies use methods that create parts by adding layers of material on top of each other. They may use a laser to melt powder or a projected light to transform a liquid polymer into a solid. Many deposit glue into a powder to form a solid, and still others spray liquid metal onto geometry. Each of these methods has distinct advantages, and each has significant limitations. Companies that want to maximize the advantages and minimize the limitations need to optimize the manufacturing process for whichever 3D Printing technology they are applying.

Initially, building parts and seeing what happens was the only way to figure out who to make a part accurately. Many early adopters had a large and full bin of broken dreams where they tossed failed components as they tweaked the settings on their Additive Manufacturing process. Over time, the vendors who offer simulation software added the capability to model the AM process and give manufacturing engineers the same types of tools that design engineers used to drive their design and verify product performance.

With simulation, process engineers can explore how parts can be made and, just as importantly, how they are processed after creation. Many 3D Printing methods use heat to create geometry. The most popular technique for production melts powdered metal and then solidifies it. This causes significant internal stresses in parts, and they distort or even fail during and after their creation. Trial and error is a much more cost-effective and timely way to optimize the process.

Industries around the world, starting with Aerospace and Medical, are just now beginning to take advantage of the geometric freedom that 3D Printing offers. The consistent lesson they have learned is not to treat this new set of processes any differently than other ways to manufacture components. Standard engineering practices, testing, and process control are the keys to success. They are also finding that the right simulation tools can enable all of these with greater precision and speed.