EFFECT OF COATING ON MACHINING PERFORMANCE OF HARD SURFACES

Abstract

Machining of the material in the hardened state is one of the challenging tasks. But this is possible due to development or innovation in the area of cutting tools. Machining of the material in the hardened state gives good surface finish as given by the grinding at the minimum cost and time. Many researchers have analysed the effect of machining parameters on the tool wear, machining force and surface roughness as well as compared the coated and the uncoated tool life to suggest which tool is preferable. The aim of this work is to analyse the effect of titanium based coatings on the tool wear, surface roughness, machining forces, temperature of the cutting tool and the type of chip formation. In this work three type of coatings - TiN,TICN and TiAIN are used on the ceramic inserts for machining (turning) of AISI A2 tool steel and further an ANOVA was carried out to investigate statistical significance among all cutting parameters. It shows that speed has been found to be the most dominant factor in the tool wear, tool temperature and machining force but feed has been found to be the most dominant factor in for surface - roughness. Grey relation analysis is used to optimise cutting condition. The result indicated that, the TiAIN coating tool has less tool wear followed by TiCN and TiN but in terms of roughness, TiN showed better result, except dimension accuracy. Due to higher tool wear, TiN coated tool gives relatively lower dimensional accuracy.