Laser Beam Machining (LBM) is one of the versatile non-traditional manufacturing processes. Material removal in LBM is based on high heat flux generated by laser beam which melts and vaporizes the workpiece material in the focused point. Laser Beam Machining process can shape almost all range of engineering materials from metallic alloys to non-metallic alloys as well as composite materials. But one of the main limitations of laser beam machining is the machining of reflective materials. When laser beam is focused on the reflective surface, part of the energy is reflected by the surface and the remaining is absorbed. In this study, an attempt has been made to increase the absorptivity of the reflective material by coating anti-reflective coating on the surface of the material. Glass has been used as reflective material in this study because of its extensive applications in the micro-opto-electro-mechanical systems. The optimal machining depends on both laser parameters and properties of the workpiece material. There are number of laser parameters that can be varied in the laser machining process. It is difficult to find optimal laser parameters due to mutual interaction of laser parameters. A statistical study based on design of experiment (DoE) has been made to study the effect of anti-reflective coating and parameters like laser power, laser scanning speed, angle of inclination of the workpiece on depth of the slot, width of the slot, aspect ratio and material removal rate (MRR) in the laser machining process using 2 k factorial design and ANOVA. On an average 4 times increase in depth of the slot, 2 times increase in width of the slot and 7 times increase in the MRR was observed in the glass work samples with anti-reflective coating when compared to glass work samples without anti-reflective coating.

The quality of light reflectance model mainly depends upon the correctness of cloud of points generated by the high-resolution charge coupled-device (CCD) camera. We have performed an experiment to capture the dimension of an object using Optigo 200 robot which provides an innovative way for solving dimensional control related challenges. The integrated system collects highly accurate and dense cloud of points for measuring an object at different design of experiment (DOE) levels. It also performs immediate analysis of collected data and calculates the deviations from the given specifications. Thus we tried to visualize the object using its key parameters. In this paper, we describe the functional relationship of real-world surfaces with the dependence of light exposure and camera direction. Seven step wedge (as a measurement object) is used in our case study to carry out the stereovision based experiment. Finally, a comparative analysis shows model accuracy over conventional measurement techniques.

To improve the copper absorption coefficient to lasers, and to realize a high welding quality with a low power laser machine, a black-treating method was proposed in this study. With this method, the reflection coefficient of the copper to lasers with 1064nm wavelength could be reduced from 95% to 15.5%. The experimental study of copper welding with a 500 W fiber laser machine was carried out. The shape, the strength and the micro-hardness of the welding seam with different welding velocity and defocus amount were compared. And, the best welding parameter was obtained. Moreover, the laser welding quality of copper with black-treating and that with graphite coating was compared, and the result showed that the micro-hardness and the strength of the welding seam of copper with black-treating was better than that with graphite coating.

Previous methods of measuring high velocity deformation in electromagnetic forming and magnetic pulse welding include Photon Doppler Velocimetry (PDV), laser micrometers, and high speed photography. In this paper an alternative method is presented, implementing a fiber optic, reflectance dependent displacement sensor. The sensor is shown to be an attractive low cost solution to measurement of high velocities in high voltage, magnetic environments. Data is shown with respect to sensor characterization including various surface reflectivity values, curvatures, and misalignments; implementation in two forming and welding processes; and verification with high velocity measurement in parallel with PDV. The sensor system is one twentieth the cost of a PDV system, and yet measures velocities accurately to at least 140 m/s. Sensor performance is also enhanced by the use of retroreflective tape, which is shown to increase the displacement range by 9×, decrease sensitivity to misalignment, and increase repeatability and ease of implementation.