Influence of cutting parameters on surface integrity and machining forces in top milling of metallic spraying metal coatings

Abstract

This work aims to evaluate the behavior of coatings applied by electric arc thermal spraying on a low carbon steel substrate when subjected to a milling process under different cutting conditions (cutting speed and tool tip radius). It was observed how these cutting conditions influenced the surface integrity of the machined part (roughness) and the machining forces generated during the process. An evaluation of the types and levels of tool wear in the milling operations was carried out. To obtain the results, samples of ASTM-A36 steel sheets thermally sprayed with and without sealant were milled with cutting speeds of 50 m/min and 84 m/min, and inserts with tip radius of 0.4 mm and 0.8 mm. The cutting parameters used were based on previous work and information from the cutting tool manufacturer. The present work indentifies that cutting speed set to 50m/min led to lower machining forces and better tool wear performance. The results obtained indicated that the tool with the smallest tip radius provided better cutting conditions, in the coating without application of sealant. The tool with the largest tip radius presented lower machining forces for the application of sealant. There were no expressive differences in the finish of the machined surfaces, but the experimental values obtained for the average roughness (1µm to 1,79 µm) remained in accordance with the limits indicated in the literature. The predominant tool wear was the plastic deformation in the tip of the inserts and crater wear located on rake face. This work aims to evaluate the behavior of coatings applied by electric arc thermal spraying on a low carbon steel substrate when subjected to a milling process under different cutting conditions (cutting speed and tool tip radius). It was observed how these cutting conditions influenced the surface integrity of the machined part (roughness) and the machining forces generated during the process. An evaluation of the types and levels of tool wear in the milling operations was carried out. To obtain the results, samples of ASTM-A36 steel sheets thermally sprayed with and without sealant were milled with cutting speeds of 50 m/min and 84 m/min, and inserts with tip radius of 0.4 mm and 0.8 mm. The cutting parameters used were based on previous work and information from the cutting tool manufacturer. The present work indentifies that cutting speed set to 50m/min led to lower machining forces and better tool wear performance. The results obtained indicated that the tool with the smallest tip radius provided better cutting conditions, in the coating without application of sealant. The tool with the largest tip radius presented lower machining forces for the application of sealant. There were no expressive differences in the finish of the machined surfaces, but the experimental values obtained for the average roughness (1µm to 1,79 µm) remained in accordance with the limits indicated in the literature. The predominant tool wear was the plastic deformation in the tip of the inserts and crater wear located on rake face.