Wear performance of laser precoating treated cemented carbide milling tools

Abstract

Coated cemented carbide is a key material for cutting tools and its manufacturing includes pretreatment of the substrate surface before coating deposition. To obtain a durable tool edge, this pretreatment must achieve two objectives: high adhesive strength of the substrate-coating interface and low coating surface roughness to reduce friction with the workpiece and the chips removed during the machining process. Several methods have been researched for substrate surface pretreatment, including micro-sandblasting—the standard industrial procedure, which is an economic and effective process. In this work, a laser substrate surface treatment was examined as an alternative to micro-sandblasting, because the laser process does not produce waste material flux, allows for the selective treatment of surface areas, and involves a potentially shorter processing time per piece. A pulsed CuHBr laser (510 nm, 30 ns, 13.8 kHz) was used, and for the tested MT-CVD TiCN/Al 2O 3/TiN coated cemented carbide cutting tools, the optimal laser intensity and number of laser shots were identified by trial-and-error based on the Rockwell C adhesion test. Using the optimal set of laser parameters, a group of tools was then prepared for face end milling tests on P20 mold steel. Lastly, a comparison was made of the tool lifetime, tool wear profile, and tool wear mechanisms of the experimental laser-treated tools and the commercial micro-sandblasted ones.