Novel bisection-method laser scanning strategy for laser powder bed fusion

Laser scanning strategy is one of the most factors affecting on the temperature gradient for the laser powder bed fusion (L-PBF). In this work, we propose a new Bisection-Method Scanning Strategy (BM-SS) based on dichotomous approximation, to reduce the heat accumulation effect between paths. The results show that BM-SS can effectively optimize the temperature gradient of the sample compared with that of the traditional sequential scanning strategy (TS-SS). The temperature gradient significantly optimizes as the n value increase, and the highest temperature is reduced by about 85K. Further experiments and numerical simulation indicate that BM-SS can effectively increase the cooling time between adjacent paths to reduce the temperature gradient and thermal stress of the sample from both time and space dimensions. The warpage of the sample reduces by up to 5 times without losing the mechanical properties. This BM-SS provides a new insight to improve the temperature gradient during L-PBF.