Experimental Evaluation of the Laser Assisted Machining of Silicon Nitride Ceramics

Abstract

To assess the feasibility of the laser assisted machining (LAM) process for the machining of difficult-to-machine materials such as structural ceramics, experiments were performed on silicon nitride workpieces for a wide range of operating conditions. Data for cutting forces and surface temperatures indicate that the lower bound of the material removal temperature for avoidance of cutting tool and/or workpiece fracture corresponds to the YSiAlON glass transition temperature (920–970°C). As temperatures near the cutting tool increase to values above the glass transition temperature, the glassy phase softens, facilitating visco-plastic flow and, correspondingly, the production of semi-continuous or continuous chips. The silicon nitride workpiece machined had a surface roughness of Ra=0.39 μm at the nominal LAM operating condition. Examination of the machined surfaces and chips reveals no detectable sub-surface cracking or significant changes in microstructure, respectively. Relative to grinding, the most significant advantage of LAM is its ability to achieve much larger material removal rates with high workpiece surface quality and reasonable levels of tool wear. [S1087-1357(00)00704-8]

3D Transient Thermal Modelling and Experimental Validation of the Temperature Distribution during Laser Heating of Ti6Al4V Alloy

“…The titanium alloy (Ti6Al4V) tests were carried out at four laser scanning speed (33.33, 66.66, 100, 133.30, 166.70 mm/s) and eight laser power levels ((500, 750, 1000, 1250, 1500, 1750, 2000 and 2378 W). In this case the beam diameter is equal to 6.2 mm, the thermal conductivity k is 7 3 …”

“…There is good correlation between FEM and experiment results. [3] The thermal model can be used to predict the temperature distribution on Ti6Al4V alloy plate workpiece and this provides important information to optimize and improve the LAM technique.…”

“…Laser assisted machining (LAM) has been considered as an alternative to conventional machining of hard and/or difficult-to-process materials, such as metallic alloys and silicon nitride ceramics [2][3][4][5]. The main advantage that laser assisted machining has over conventional machining is the higher material removal rate, increased productivity, and longer tool life.…”

A review of hybrid manufacturing processes – state of the art and future perspectives

“…Laser assisted mechanical machining (LAMM) has been developed and investigated for over twenty years (Rozzi et al, 2000;Lei et al, 2001). Recently, LAMM has been considered as an alternative process for machining of high-strength materials, such as ceramics, metal matrix composites, high-temperature alloys (Rebro et al, 2002;Tian et al, 2008;Bejjani et al, 2011).…”

A study on the development of milling process for silicon nitride using ball end-mill tools by laser-assisted machining

“…Rozzi et al [13][14][15] analyzed the influence of conditions on machining silicon nitride in a LAM experiment and also investigated chips and the characteristics of machining surfaces. They also predicted the temperatures of machining areas using a heat transfer simulation.…”