A generalized model for predicting the optimal overlap rate and height of successive single-layer involved in laser metal deposition process based on the aspect ratio

Abstract

The surface flatness of single-layer islands deposition is essential for high-quality multi-layer component deposition and the stability of the Laser metal deposition (LMD) manufacturing process. The aspect ratio of single-track deposition and the overlap rate are critical factors influencing the flatness of single-layer island deposition. Existing methods for determining the optimal overlap rate, whether through experimental approaches or simplified recursive overlap models, still suffer from long development cycles and limited accuracy. In this study, a generalized, efficient and reliable model for predicting the optimal overlap rate only using the aspect ratio of the single-track deposition as the input parameter was developed after fully understanding the influence of the aspect ratio and overlap rate on the morphology, stacking effect and flatness of single-layer islands. Besides, a prediction model for the height of the single-layer island, based on the input parameters of the aspect ratio and the overlap rate has also been developed. Further, verification datasets from different experimental batches and materials were used to validate the accuracy and generalizability of the island height prediction model. The validation results indicated that the relative error between the predicted and actual values was less than 10%. The single-track aspect ratio can be directly used to guide the LMD multi-layer component deposition, regardless of the combination of powder and substrate materials, using these reliable and generalized prediction models for the optimal overlap rate and the island height developed in current study. The single-layer island deposition stage was completely eliminated, thereby significantly shorten the development cycle and reduce the cost of LMD process parameter development.