Process Signatures - The Missing Link to Predict Surface Integrity in Machining

The concept of Process Signatures is based on the correlation between the internal material loads in manufacturing processes and the resulting material modifications, thus allowing a deeper and more comprehensive understanding of the underlying mechanisms. Traditionally, the studies on machining regarding surface properties and surface integrity aim at finding correlations between machining parameters or process quantities (forces, power etc.) and part’s properties and performance. Different to this traditional approach, Process Signatures focus on the material’s response to machining generated internal material loads. Knowing these physics- and metallurgy-based correlations allows solving the so called inverse problem in manufacturing processes. This means that surface- and sub-surface properties become predictable and can be generated by machine tools in a knowledge-based approach. This keynote paper addresses the state-of-the-art in developing Process Signatures and gives examples on specific Process Signature Components. For two processes - surface grinding with a predominant thermal effect on the workpiece material and deep rolling with a predominant mechanical effect - the Process Signature approach is utilized to solve the "inverse problem".