Machining of aluminium nitride with ultra-violet and near-infrared Nd:YAG lasers

A parametric study was performed by producing laser-machined lines and single-layer pockets on the surface of aluminium nitride (AlN) ceramic with an ultra-violet (UV) and near-infrared (NIR) laser. The effect of pulse overlap and pulse frequency were studied. The maximum material removal rate (MRR) was 0.011 mm3/s with the UV laser and 0.094 mm3/s with the NIR laser. The steepest wall angle produced with the UV laser was 86° while the NIR laser produced walls with a maximum angle of 88°. The wall angle was virtually independent of pulse frequency for both lasers. A minimum surface roughness of Sa = 0.88 μm was produced using the NIR laser.