Rapid Analysis of Steel Powder for 3D Printing Using Laser- Induced Breakdown Spectroscopy

In recent years, metal additive manufacturing technology (also known as 3D printing) has achieved dramatic development and has gradually occupied an indispensable position in modern manufacturing. However, the purity and uniformity of the metal powder, which is the raw material for additive manufacturing, generate significant impacts on the performance of the product. Therefore, a rapid analysis method of the steel powders based on laser induced breakdown spectroscopy (LIBS) is investigated for the potential applications in 3D printing process. In the current experiment, two pretreatment methods of the novel adsorbing process and the traditional tableting process are employed for performing comparative study. Through the adsorbing process with conductive tape, the signal intensity of LIBS spectrum has been significantly enhanced. The crater topography demonstrates that the adsorption band samples can effectively overcome the shock wave effect of the laser induced plasma. The calibration curve of LIBS measurement indicates that the pellet samples can be easily affected by the plasma shock wave. Differently, the adsorption band samples are slightly influenced by the plasma shock wave. The determination coefficient and data stability of the calibration curve are better in the condition of adsorption band samples. Through the simulated quantitative analysis with totally 11 artificial steel powder samples, the analytical performance of the two sample pretreatment processes is compared. Manganese (Mn) is selected as the target element with the matrix element of iron (Fe). When compared with the pellet samples, the average value of Relative Error of Prediction (REP) is reduced from 7.73% to 1.36% and the average value of Relative Standard Deviation (RSD) is reduced from 20.34% to 6.22% for the adsorption band samples. Based on the experimental results in the current work, it can be verified that the adsorbing process is a promising sample pretreatment method for steel powders. Moreover, this provides an effective sample pretreatment method for LIBS analysis of steel powder for 3D printing.