Laser Calibration for Powder Bed Fusion Additive Manufacturing Process

Laser powder bed fusion systems use a high-power laser, steered by two galvanometer mirrors to scan a pattern on metal powder layers. The laser spot size, position, and synchronization between the laser power and position are critical to the build quality. This paper describes in-situ calibration techniques utilizing a digital camera to image the attenuated laser beam directly. The laser spot size is measured using laser beam images taken by the camera at different heights. The laser position measurement involves commanding the galvanometer motor to scan through a grid of points on the camera sensor. The synchronization of laser power and position is verified by observing the intersections of the adjacent scan vectors. These methods provide not only a tool for calibration but also insights into the laser control for the laser powder bed fusion additive manufacturing process.Mechanical Engineerin