To develop realistic process planning simulation tools and build strategies, an understanding of realistic transient conditions needs to be explored for multiple overlapping beads and 3D build ups. In the past, most of the research has focused on optimization strategies for a process configuration, typically for a single-track bead in steady state conditions. Changes in the bead geometry are inherent when depositing material; consequently, understanding dynamic, time varying heating and solidification conditions for multiple bead scenarios needs to be investigated. It is important to understand the system characteristics and its influence on the all the bead geometry parameters (not just the width) and the resultant hardness. Initially, a set of physical laser cladding experiments have been performed for single and multiple bead scenarios using 420 stainless steel powder being deposited onto mild steel plate with step variations being applied for the process power. For this research, complementary simulation models are developed, and the effects of the transient conditions on the bead hardness for several scenarios are investigated for four process power input step-functions using an imposed thermal cycling simulation approach. It is observed that the hardness values change from higher to lower values between the first and third beads, and for all scenarios, the hardness converges to a uniform value. When comparing geometry and hardness results, it can be seen that the geometry has more oscillations than the hardness. More research in this area is essential to develop robust real-time control solutions that encompass functional requirements such as hardness as well as the bead geometry.

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