Analysis of Distortion Based on 2D MEMS Micromirror Scanning Projection System

To analyze the distortion problem of two-dimensional micro-electromechanical system (MEMS) micromirror in-plane scanning, this paper makes a full theoretical analysis of the distortion causes from many aspects. Firstly, the mathematical relations among the deflection angle, laser incidence angle, and plane scanning distance of the micromirror are constructed, and the types of projection distortion of the micromirror scanning are discussed. Then the simulation results of reflection angle distribution and point cloud distribution are verified by MATLAB software under different working conditions. Finally, a two-dimensional MEMS micromirror scanning projection system is built. The predetermined waveform can be scanned and projected successfully. The distortion theory is proved to be correct by analyzing the distortion of the projection images, which lays a foundation for practical engineering application.

Effect of Optimized Heat Treatments on the Tensile Behavior and Residual Stresses of Selective Laser Melted AlSi10Mg Samples

The use of additive manufacturing (AM) technique is recently increased due to its ability in producing complex-shaped components. AlSi10Mg alloy is largely employed for AM and, in particular, for selective laser melting (SLM). Hence, the interest on this alloy is growing, together with the studies to control its mechanical performances, which can be increased by microstructure modification. With this focus, low temperature heat treatments to enhance AlSi10Mg mechanical behavior have been proposed in the recent literature. The present work focuses on two post-additive thermal treatments, with temperatures specifically selected for SLMed AlSi10Mg alloy. The study investigates their effect on mechanical performances, with a particular attention to residual stresses. Experimental measurements of residual stresses obtained by an X-ray diffractometer (XRD) are presented, considering samples produced with their main dimension along the in-plane scanning directions (XY configuration) and the Z direction. Different conditions are accounted: 1) as-built; 2) after heat treatment at 244°C for 180 minutes; 3) after heat treatment at 290°C for 45 minutes. Tensile properties are correlated with the measurements of the residual stresses, allowing for a critical discussion and for a deeper insight on the correlation of the mechanical performance with the process parameters and the following thermal treatments.