The effect of wet blasting as a pre-deposition treatment for thick TiAlN PVD coating on machining performance

Edge preparation techniques are known to be an effective method to adjust the microgeometry and improve the mechanical properties of cutting tools. These techniques can also be used on tools prior to coating deposition to further improve the coating quality on the cutting edge and, consequently, tool life. In this research, wet blasting was used on indexable turning inserts to adjust the cutting-edge radius in order to address quality issues associated with thick PVD coatings while investigating subsequent changes in the substrate and coating properties. For this purpose, a multilayer TiAlN coating with an approximate thickness of 10 μm was deposited on prepared and unprepared inserts. Moreover, machining tests were conducted on compacted graphite iron (CGI) to understand the effect of pre-deposition edge preparation on cutting performance. The results show that wet blasting has minimal effects on substrate properties, such as hardness. However, it is an effective method to eliminate micro breakage along the cutting edge by reducing geometrically induced stresses. Wet blasting as a pre-deposition treatment also provided a better coating quality, lower cutting forces, longer tool life, and greater consistency in coated tool microgeometry.