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The operation of laser marking occurs due to oxidation on the metallic surface at a high temperature, which finds applications in many organisations due to its cleanness and high handling speed with the negligible human association. The generated marked objects are permanent in nature, generally utilised for product identity. From the perspective of laser marking, the general requirement of laser marking is mark clarity or marking quality with minimal effect on the workpiece surface. The paper deals with producing good-quality laser-marked surface by the utilisation of process parameters such as transverse feed, average laser power and scanning speed, which seem to have a significant effect on the surface of designed materials for the development of laser marking qualities. The diode-pumped pulsed fibre laser was utilised for the purpose of marking on the surface in a single pass within the minimum possible time. Experimental studies revealed that decrease in transverse feed from 8 μm to 2 μm/laser stroke had a projection towards the increase in mark intensity which could be reached up to 0.95 on the application of the lower value of transverse feed, i.e., 2 μm/laser stroke upon using a proper set of process parameters.. [ABSTRACT FROM AUTHOR]

Laser spiral microgrooving is a new technology for the micromachining of advanced engineering materials like Al2O3, ZrO2, Al2TiO5, AlN, etc. Due to better accuracy, nowadays the micromachining of aluminium is widely used in various industries. This paper details the study of laser spiral microgrooving process on cylindrical shaped pure aluminium. In this study average power, pulse frequency and workpiece rotational speed are considered as the process variables. The mathematical formulations of laser spiral microgrooving process which correlate the different process parameters and spacing between two consecutive microgrooves have been developed. The geometrical dimensions of the microgroove like groove width and groove depth are measured by using an optical microscope. Microscopic images of microgrooves using high resolution optical microscope are also studied to examine the effect of several process variables on the spiral microgroove dimensions. [ABSTRACT FROM AUTHOR]

Byline: B. Doloi, D. Dhupal, B. Bhattacharyya Pulsed Nd:YAG laser beam is widely applied in micro-machining with different micro-scale geometries on engineering materials such as ceramics, composites, and diamond. The present research papers deals with the Response Surface Methodology (RSM) based mathematical modelling and analysis on machining characteristics of pulsed Nd:YAG laser during micro-grooving operation on flat surface of aluminium titanate. An attempt has been made to optimise laser parametric setting for achieving accurate taper angles of micro-grooves. Based on the modelling and parametric optimisation analysis, the optimal laser process parametric setting has been obtained as air pressure of 0.9 kg/cm[sup.2], lamp current of 20.4 amp, pulse frequency of 2.8 kHz, pulse width of 2.7% of duty cycle and cutting speed 10 mm/s for achieving the optimum taper angle of 11.1[degrees].

Byline: B.R. Sarkar, B. Doloi, B. Bhattacharyya Electrochemical Discharge Machining (ECDM) process has great potential to machine electrically non-conducting engineering ceramics and can be applied for micro-machining operation. This research paper includes the experimental investigation to study the range of the parametric setting for micro-machining operation as well as the effect of various process parameters such as applied voltage, electrolyte concentration and inter-electrode gap on Material Removal Rate (MRR), Radial Over-Cut (ROC) and Heat Affected Zone (HAZ) thickness during micro-drilling of non-conducting engineering ceramic materials such as Aluminium Oxide and Zirconium Oxide. The experiments have been performed using electrolyte of KOH and NaOH salt solution. In this paper, an experimental investigation has been made to find out the optimum value of ECDM process parametric conditions for higher MRR, lower overcut and also lower HAZ thickness during micro-drilling on ceramics. The quality of the hole during micro-drilling greatly depends on the applied voltage and electrolyte concentration.

Byline: A.S. Kuar, B. Doloi, B. Bhattacharyya A laser beam has great ability to machine very hard conductive as well as non-conductive materials such as high speed steel, ceramics, and diamonds, etc. The present paper includes the parametric analysis on performance of CNC pulsed Nd:YAG laser cutting operation on silicon nitride ceramics. The present experimental investigations reveal that the saw cutting operation on silicon nitride can be successfully performed with a better surface finish after proper setting of the machining parameters. The cut quality of the job surface has been presented and analysed through microscopic views. Better quality of the cutting edge can be achieved during the Nd:YAG laser cutting operation when the lamp current, cutting speed and pulse frequency are set at moderate values.