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Interview with Michael Wohlmuth


Michael Wohlmuth is co-founder of Simufact Engineering GmbH in Hamburg, whose Strategic Business Development he is responsible for today. In an interview he explains the role of simulation in additive manufacturing, its added value for users and the contribution that simulation data can make to fully automated AM Smart Factories.


Can you briefly introduce Simufact Engineering GmbH to us?

Michael Wohlmuth: We are a software house specialized in simulation software with almost 100 employees, which Dr. Hendrik Schafstall and I founded 25 years ago. We are both mechanical engineers and see ourselves as production engineers. Originally it was about the optimization of conventional manufacturing processes. Through simulation, we were able to make more and more actual tests unnecessary. We have established this virtualization for more than a dozen processes in the field of massive forming and later in welding technology - in cooperation with automobile manufacturers and other industrial customers. Non-linear simulation is a very complex field in which tool and machine kinematics, material properties and many other parameters are incorporated. Our business model is to break down this complexity to a level where process engineers and shop-floor technicians can work with it without the need for simulation specialists. We have also been using our know-how in the simulation of laser welding processes in additive manufacturing for three years. This area is growing rapidly and already accounts for one third of our turnover. It is also important to mention that we have been part of the US software house MSC Software for five years, which has always been our partner. And the year before last, MSC was acquired by Hexagon, a major player in manufacturing intelligence and measurement technology. This is positive for us because the competences in our network complement each other perfectly. We are now very well positioned for the transformation to Industry 4.0 and Smart Factory.

Which part of the process chain in Additive Manufacturing (AM) does Simufact cover?

Wohlmuth: Our germ cell is the actual building process. Or more precisely: the simulation of the processes that physically take place in the installation space of an AM plant. Powder bed processes in the metal sector were the entry point. Now we are systematically expanding our range into the extended process chain. Our simulation solutions address topics such as material behavior during heat treatment or the behavior of components when separating base plates and support structures. In cooperation with a leading university institute, we are also tackling machining post-processing. For downstream structural analyses, the exact properties of the component that has already been machined must be taken into account from a perspective perspective.

Which concrete added values lie in the simulation of AM processes?

Wohlmuth: For users, there are nasty surprises lurking at all stages of the process. One example is component distortion. This distortion is sometimes so severe that when the powder bed is spread out, the blade sticks to the protruding component and the construction process stops. Our simulation tools make the distortion and residual stress of the components precisely predictable. This enables users to adapt their production strategy in a targeted manner. By modifying the energy input or planning the distortion in the design: Since it is a tool-less process, users can deliberately design a component "incorrectly" so that it distorts to the exact target dimension during the construction process or cooling phase. This only works if the simulation delivers precise distortion values. With the help of our software, users can reduce deviations, some of which are in the millimeter range, to a few tenths. Construction processes are becoming more robust. And the closer the component comes to the planned final contour, the less time and tool costs are required for post-processing. Users still tell us that their cost calculations often get out of hand in AM projects. Because the processes are not sufficiently robust and plannable. Simulation helps here. But its potential goes even further. With MSC we make the simulation data usable for standard structure analyses, i.e. for virtual load analyses of the future component. This saves several iteration loops. And users already know in the design phase what the component will achieve or how far they can push, for example, bionic lightweight construction. For this part, we recently acquired the start-up company AMendate, which specializes in topology optimization. Ultimately, simulation makes process chains transparent - and leads us to digital twins, in this case the Digital Production Twin. The prerequisite is teamwork: simulation, measurement technology, production technology and design must cooperate in order to leverage the added value and potential addressed.

For which AM methods are your simulation tools available?

Wohlmuth: In addition to the classic powder bed processes with laser and electron beam in the metal sector, we also use other AM processes. At formnext we will present a new simulation solution for laser deposition welding processes and thus enter the Direct Energy Deposition (DED) market. The industrial use of DED processes is currently gaining momentum. The high build-up rates and the possibility of additive production of large components independent of the installation space are attractive. However, some effort is still needed to raise the processes to an industrial level. Our simulation solution contributes to this. We are also developing simulation software for binder jetting. This still happens on a laboratory scale, but we will be ready when the market picks up. This will be driven by customers from the automotive industry who are interested in binder jetting because of the high assembly rates and the lower costs that can be achieved as a result. As with all additive processes, the task now is to transfer the good approach into robust industrial processes.

This includes automation. What contribution can simulation make?

Wohlmuth: Among other things, in cooperation with Materialise and various AM plant manufacturers, we have succeeded in converting simulation results directly into build files and printing them. This is a contribution to the automation of a continuous data chain. For the automation of manufacturing processes, we see ourselves more as supporters. Mechanical engineers are working intensively on corresponding solutions in post-processing, where there has been a bottleneck so far. With our tools, we can in principle determine exact component values for each process stage; this can be interesting for automation engineers and is heading in the direction of a Digital Production Twin. Simulation also helps to reduce the overall post-processing effort. For example, by allowing designers to plan fewer material buffers with a view to distortion or by minimizing support structures. On top of that, simulation helps to fulfill a mandatory prerequisite for any automation: Robust, uninterrupted processes.

How do you envisage the typical AM process chain in 2030?

Wohlmuth: Given the dynamics of development, it's a bit of a glass ball reading, but I'll try: When I look at the development of conventional manufacturing processes, I see automation at the highest level, the widespread use of virtual methods and rapid development towards the Smart Factory. I expect the same for additive manufacturing. I am confident that the process chains will be at a similar level in 2030. Highly automated, consistent and truly robust AM process chains are the be-all and end-all. Industrial users are waiting!

Final question: What were your goals in joining the Additive Manufacturing Working Group within the VDMA?

Wohlmuth: We would like to make our contribution to the automation and industrialization of this technology. Simufact has never seen itself as a virtual isolated solution, but has always sought optimal, user-friendly solutions in exchange with industrial users, machine builders and other players. When we heard about the VDMA working group and its automation working group, it was clear to us that we had to get involved! We want to contribute our knowledge about virtual manufacturing. And, of course, the networking opportunity is also very interesting for us. In the working group, we meet the relevant players.

sbr / 12.11.2019