Intelligent Process Control for Laser Direct Metal Deposition

Laser Direct Metal Deposition (DMD) is a revolutionary approach to manufacturing or repairing a range of metal components. In its simplest form, the process works in much the same way as stereo-lithography: a layer-by-layer approach to building up a three dimensional solid object. In the case of DMD this occurs by building up layers of metal by completely melting and re-solidifying metal powder using a laser. The result of the process is a fully dense structure close to the required net shape. The static and dynamic properties of the structure can be equivalent or superior to wrought material, as in the case of titanium and stainless steel alloys. This paper discusses closing the process loop (Intelligent Process Control) in DMD in order to move the technology from a black art, operable only by research scientists, into a production-ready state. The approach uses sensors to monitor a range of parameters that characterize the process. This sensor information is fed to a controller that uses fuzzy logic to analyze the data and change the process input variables to ensure the stability and correctness of the process.