Numerical simulation and experimental investigation of surface roughness during internal finishing of thin-walled slender tubes with a cylindrical diamond tool

This paper used a cylindrical diamond tool to finish the inner surface of thin-walled slender tubes. Considering the actual geometry and protrusion height of diamond abrasives, the abrasive-workpiece interactions involving rubbing, plowing and cutting during finishing were analyzed using contact mechanics theory. A mechanical model was established to correlate macroscopic contact force with the microscopic force acting on a single abrasive, whereby the cutting depth of the abrasive was calculated. The abrasive trajectory was subsequently analyzed based on kinematic theory, the material removal distribution was further determined, thereby establishing a predictive model for workpiece surface roughness. The single-factor polishing verification experiments were conducted and the simulated results of the model agreed well with the experimental results, with an average error below 15%. Meanwhile, the influence of various process parameters on the surface roughness was analyzed. After polishing for 45 min at an elongation of 20 mm, a workpiece feed speed of 600 mm/s, the surface roughness Sa was reduced from the initial value of 1.046 μm to 0.362 μm. A smooth surface without micro-peaks was obtained.