Additive–subtractive manufacturing combines the geometric freedom of additive production with the precision of subtractive finishing. In particular, compliant aerospace structures with low stiffness place stringent demands on machining. To analyse the interactions between structural stiffness and process execution in a targeted way, characteristic feature elements of a helicopter wing component were extracted and represented in simplified analogue components. These parts were additively manufactured from Scalmalloy and subsequently end-milled.
Because additively manufactured components are typically produced in small quantities and feature complex, individually designed structures, conventional data-driven or analytical models for predicting shape error reach their limits. A simulation-assisted method was therefore developed for this highly variable component landscape, based on a coupled simulation chain. The foundation is the dexel-based machining simulation IFW CutS, which calculates engagement conditions such as chip cross-section, engagement angle and time-resolved chip volume on a time-step basis. Integrated mechanistic force models then determine the magnitude, direction and point of application of the process forces acting on the workpiece.
At defined toolpath intervals, solid models of the partially machined workpiece are generated. These are loaded with the calculated forces in an FEM simulation. By accumulating the path-step-based deformation states, the entire formation process of the shape deviation can be traced. The method makes it possible to adapt machining strategies specifically to the local compliance of the workpiece. The approach enables reliable, quality-compliant finishing of additively manufactured lightweight components. Further information on the project can be found on the OptiWas project page.
Contact:
For further information, please contact Fabian Schlenker by phone at +49 511 762 18162 or via email at schlenker@ifw.uni-hannover.de.
