Metal 3D printing is a modern manufacturing process that allows the production of geometrically complex structures from metallic powders of varying chemical composition. This paper shows the results of testing the powder feeding and distribution system of the developed 3D printer. The device using the SLM method (Selected Laser Melting) was developed by research team of WroclawTech and used in this investigation. The powder feeding and distribution system was tested using a vision system integrated into the printer control system. Thousands of tests performed made it possible to identify the reasons corresponding to incorrect powder distribution on the working field. In addition, a quality control algorithm was developed and implemented in the MatLab environment. Algorithms based on image analysis automatically identifies powder distributed in an unacceptable way. An 88% accuracy rate was achieved for identifying defects in all images within a dataset of 600 pictures, classified into following categories OK and NOK consisting of: recoater streaking, recoater hopping, super-elevation. The strength of the algorithm developed lies in its utilization of variations in shades of gray, rather than solely relying on the actual gray values. This approach grants the algorithm a certain degree of adaptability to changing lighting conditions.