AN EVALUATION OF THE USE OF LASER-VIBRATION MELTING TO INCREASE THE SURFACE ROUGHNESS OF METAL OBJECTS

摘要

This paper presents preliminary, experimental results of a new, hybrid method of increasing the surface roughness of metal objects. In this new approach, metal objects are melted with a mobile laser beam while they are being rotated. A vibration generator provides circular vibrations with an amplitude of 3 mm, and the vibration plane is perpendicular to the moving laser beam. The melting tests were performed using flat carbon steel samples at a predetermined frequency of circular vibrations. The effects of laser power and laser beam scanning velocity on the melted shapes were studied. All laser melting procedures were performed at a vibration frequency of 105 Hz. The melted samples were subjected to microscopic evaluation and the R-a parameter, which characterises mean roughness, was measured using a profilometer. Melting metal samples with physically smooth surfaces ( R-a = 0.21 mu m) resulted in surface structures of varied roughness values, with R-a ranging from 5 mu m to approximately 58 mu m. The studies were undertaken to employ this technology for the purpose of passive heat exchange intensification of heating surfaces in practical applications.