Characteristics and removal mechanism in laser cutting of cBN–WC–10Co composites

Abstract

Laser cutting of a cBN-WC-10Co composite material was carried out using a pulsed Nd: YAG laser. The cutting characteristics, as well as the changes in microstructure and mechanical property, were investigated. It was found that cracks were induced by laser machining on the sub-surface and the evidence of phase transformation from cBN to hBN was observed on the cut surface. Cutting parameters had significant effect on the cut surface. A higher laser power produced a smoother cut surface, but a larger heat-affected zone, in comparison to the lower laser power used. No radical cracks were found on the cross-section at the laser power of 100 W. The surface roughness and the heat-affected zone depth decreased with the increased cutting speed and the gas pressure. The material removal involved in the laser cutting of cBN-WC-Co composite was attributed to the melting or evaporation of cBN and WC-Co. The dropping of cBN particles from the cut surface was also found during the cutting at the laser power of 30 W for the loss of the supporting from the WC-Co matrix.

Mechanical and tribological performance of Ni–Co-based binders for cubic boron nitride cutting tools

“…For each group, an average of four specimens was tested. The shear strength (MPa) was calculated dividing the maximum load (N) recorded during the test by the cross-section area (mm 2 ).…”

“…Cobalt-based materials are commonly employed as binder in CBN tools, usually combining Co with hard reinforcements like tungsten carbide (WC) to increase mechanical properties, like hardness and consequently raising their wear resistance in order to give rise to cutting tools with enhanced performance. 2,6 While there are studies focused on combining the properties of WC–Co with those of CBN, 2,6 chromium carbide (Cr 3 C 2 ) is not commonly found in these tools, being however a common option in WC−Co cermets for acting as grain growth inhibitors and to improve fracture toughness. 11,12…”

“…Cubic boron nitride (CBN) cutting tools are currently used for severe machining, being one of the main choices for machining most steels (highlighting hardened alloy steels), cast iron, and nickel-based superalloys, due to allowing much higher cutting speeds, and therefore higher material removal rate than cemented carbide tools. [1][2][3] CBN exhibits a cubic structure similar to diamond, being one of the hardest materials, just below diamond. 4,5 One of the advantages of CBN over diamond is that the former is more thermally and chemically stable especially when used in tools for machining ferrous alloys, due to its lack of affinity to carbon, unlike diamond.…”

Recent advances in micro- and nano-machining technologies

“…The machining principle of laser micro-cutting is similar to that of trepan laser micro-drilling. This approach also removes the workpiece material by scanning the contour of the desired cut through the use of pulse lasers to achieve highly accurate cuts with good surface quality and low damage [78]. By using fast galvanometer scanners, laser micro-cutting can facilitate accurate, flexible, and fast cutting processes.…”

Microstructural Characteristics of Cement-Based Materials Fabricated Using Multi-Mode Fiber Laser

“…Laser-Aided Manufacturing (LAM), on the other hand, has many advantages, and is therefore used in a variety of applications such as automotive, aerospace, electronics and semiconductors [6][7][8][9][10][11][12][13][14][15]. LAM has an exceptionally high energy density and can be focused to highly localized areas.…”