After simulating machining at the machine tool using the CAD/CAM-CNC process chain and checking for errors and determining machining time, the next step is to plan and simulate the best possible production concept. Another digital twin now comes into play - Plant Simulation. Plant Simulation makes it possible to simulate the production workflow, the material flow and all the production runtimes.

The simulation tool models either the complete machine fleet of a production facility or at least the section under review. Each machine is then assigned all the relevant times, from the machining and set-up time to the average fault and failure times. The best routes and plant combinations can then be determined for the various products and for different scenarios, for example minimizing throughput time.

Arnold Hauler, responsible for production and assembly planning in the Tübingen plant described a specific example in the factory: Different manufacturing options were considered for making a gearbox housing. Thanks to Plant Simulation, it was possible to decide on the best solution in terms of utilizing human and machine resources as well as optimizing costs. Comparing the different manufacturing options in the real world would have entailed high capital investment costs for additional equipment. So, without simulation, the comparison could not have been done in the first place.

Using digital twins helps to simulate the schedule process modifications, the new concepts and their impact in a very short time over a complete business year, without having to intervene in an active production landscape.