Laser metal deposition (LMD) is getting more attention as a 3D printing technique recently. Compared to the cladding application, the process of building 3D structures is more challenging to control when it comes to complex structures. Changing heat transfer mechanisms over the building height and at critical part geometries can lead to instabilities during the process. This paper studies the effect of the surface temperature on single track geometry formation during the LMD process. 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 preheated substrate from 25 to 500 °C is used, and the track height, width, and degree of dilution are evaluated. This experiment mimics the varying temperature of the prebuilt 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 the accumulated heat input along the build direction. This helps in defining process strategies and process parameters for the laser metal deposition of components with 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 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 data preprocessing toolbox based on MATLAB has been developed for the implementation of process strategies through user-definable rules and algorithms. This eliminates manual robot code preparation and correction. Implementation and the level of automation of this process preparation toolbox have also been discussed in this paper.

中文翻译：

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激光金属沉积过程中热量积累对单道形成的影响以及用于分析新工艺策略的框架的开发

激光金属沉积 (LMD) 作为一种 3D 打印技术最近越来越受到关注。与覆层应用相比，构建 3D 结构的过程在复杂结构方面更具挑战性。在建筑高度和关键部件几何形状上改变传热机制可能会导致过程中的不稳定性。本文研究了表面温度对 LMD 过程中单轨道几何形状形成的影响。轨道形成的几何特征是一个关键因素，需要在任何沉积过程中进行控制和监测，以实现稳定的构建作业。为了量化表面温度对轨道几何形状的影响，使用了从 25 到 500 °C 的逐步预热基板，并评估了轨道高度、宽度和稀释程度。该实验模拟了在具有多层的自由形式结构的增材制造过程中发生的预构建层的变化温度。了解表面温度对层几何形状的影响可以了解由于沿构建方向累积的热量输入而导致的构建几何形状变化。这有助于为部件的激光金属沉积定义工艺策略和工艺参数，同时提高精度和可重复性。需要将对于成功构建作业必不可少的高级流程策略整合到用于机器人代码生成的数据准备工具中。商业软件包可用于使用工业机器人进行常规附加路径规划。然而，当几个过程策略和过程参数需要沿着构建方向进行调整和变化时，一个被推到了软件功能的极限。因此，开发了基于 MATLAB 的自动化数据预处理工具箱，用于通过用户可定义的规则和算法实现过程策略。这消除了手动机器人代码准备和更正。本文还讨论了该流程准备工具箱的实施和自动化水平。