Laser Metal Deposition (LMD) is getting more attention as a 3D printing technique lately. By overlapping several layers on top of each other, three-dimensional structures can be achieved. Compared to the cladding application, the process is more challenging to control when it comes to complex structures. Changing heat transfer mechanisms over the build height and in critical part geometries, can lead to instabilities during the process

This paper studies the effect of the surface temperature on the single track geometry formation during LMD. Especially the geometrical characteristic of the track formation is a key factor that needs to be controlled and monitored in any deposition process for a stable build job. To quantify the effect of the surface temperature on the track geometry, a stepwise pre-heated substrate from 20°C to 500°C is used and the track height, width and fusion zone are evaluated.

This experiment mimics the varying temperature of the pre-built layers that occur during additive manufacturing of freeform structures with many layers. Understanding the influence of the surface temperature over the layer geometry gives an idea of build geometry variation due to accumulated heat input along the build direction. This helps in defining process strategies and process parameters for Laser Metal Deposition of components with an increased accuracy and reproducibility.

Advanced process strategies that are essential for a successful build job need to be incorporated into a data preparation tool for the robot code generation. Commercial software packages are available for regular additive path planning using industrial robots. However, when several process strategies and process parameters need to be adapted and varied along the build direction, one is pushed to the limits of the software capabilities.  Therefore, an automated process preparation toolbox based on MATLAB has been developed for implementation of process strategies through user-definable rules and algorithms. This eliminates manual robot code preparation and correction. Features of this toolbox includes uni- and multi-directional slicing, toolpath generation, process parameter and process strategy integration and a post-processor for robot code generation. The algorithms are developed for processing STL based CAD file format.  Implementation and the level of automation of this process preparation toolbox has also been discussed in this paper.