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Laser marking is the process to mark an image by utilizing laser thermal energy used primarily for product identifications and traceability. It is versatile and well known process employed by the manufacturers to mark various materials. The mark produced by a fibre laser beam produces one of the fine marking components and it is well accepted form of marking used nowadays. The research paper revealed that laser beam marking quality is the function of various input controlling factors like laser spot size, transverse feed, scan rate, laser power which had a significant impact on quality attributes. The paper focuses on the creation of better quality equilateral triangular-shaped laser inscribed image on grade 304 stainless steel surface in a shortest possible time. The process variables involved in the present study includes pulse rate, duty cycle, laser power, and scan rate which were varied one at a time for obtaining better marking quality characteristics like high mark quality, closer to target mark angle and less deviation of marked area. The observed results revealed that pulse rate of 50 kHz, laser power of 12.5 W, scan rate of 35 mm/s and duty cycle of 99% provides better marking quality. [ABSTRACT FROM AUTHOR]

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]

Laser micro-turning process is one of the latest and emerging technologies in the field of laser materials processing of engineering materials. The present paper deals with experimental investigation on Nd:YAG laser micro-turning operation of cylindrical shaped Al2O3 ceramic to explore the effect various significant process parameters such as laser beam average power, workpiece rotating speed, axial feed rate, pulse frequency and assist air pressure. Experiments were conducted considering the response surface methodology (RSM) based design of experiments (DoE). Mathematical models were developed for the responses; namely, surface roughness (Ra) and depth deviation. The validity and correctness of the developed mathematical models is carried out through analysis of variance (ANOVA) test. The target surface roughness and machining depth are as 6.0 and 100.0 μm, respectively. To achieve these target criteria, optimum parametric combination is found through RSM. [ABSTRACT FROM AUTHOR]

Experimental studies of fibre laser microchanneling on polymethyl methacrylate (PMMA) sheets at atmospheric conditions intend to find out the effect of various process parameters on the response criteria: depth and width of the microchannels and the widths of the heat affected zone (HAZ). A basic experimental study has been reported for the microfabrication of PMMA microchannels to utilize them for various microfluidic applications. The significance of the current research work is not only confined to facilitate the fibre laser system for microfluidic applications, but also to improve the aspect ratios (microchannel depth/width) of the fabricated microchannels as well as to identify significant reduction of HAZ from the microchanneling zones. The various process parameters: scan speed; average power; pulse frequency and number of passes with different ranges, were considered to achieve the aforementioned response criteria. The range of the process parameters includes scan speed of 10 to 300 mm/s, pulse frequency of 50 to 90 kHz, average power of 5.0 to 15.0 W and number of passes of 1 to 5; while pulse width was held constant at 90% of the cycle time. The experimental research work also includes the physical phenomena behind the fibre laser microchanneling of PMMA as well as the intricate analyses and explanations of each process parameter on the outcome of the microchannel geometries. [ABSTRACT FROM AUTHOR]

Laser micro-turning process is one of the latest promising laser material processing techniques which can be employed for generation of micro-turning surface of particular surface profile and dimensional accuracy on cylindrical workpiece. The present paper addresses the laser micro-turning process of cylindrical shaped 99 % pure aluminium oxide (AlO) ceramics of size 10 mm in diameter and 40 mm in length. The experiments have been conducted using response surface methodology design of experiments. The targeted depth was set at 100 μm. Laser average power, pulse frequency, workpiece rotating speed, air pressure and Y feed rate were considered as process variables. After each experiment, surface roughness (Ra) and micro-turning depth deviation have been measured. Empirical models of the responses have been developed based on the test results achieved during measurements of surface roughness and machined depth deviation. Analysis of variance was conducted. Multi-objective optimal parametric combination of process variables has been obtained for achieving least values of responses, i.e. surface roughness and depth deviation. To achieve further high-quality machined surface, machining was done at various defocusing conditions of laser beam and also by varying the number of laser scan passes. Other process parameters were kept constant at optimal parametric combination obtained in multi-objective optimization. From the experimental results, it was revealed that surface roughness decreases with increase in defocusing positions. With increase in number of passes up to a certain limit, surface roughness decreases. However, depth deviation increases with number of laser scan passes at all levels of defocus planes. [ABSTRACT FROM AUTHOR]

Abstract: The present study investigates the relationship of processes parameters of pulsed Nd:YAG laser-turning operation for production of micro-groove on cylindrical workpiece of ceramic material. A microprocessor-based work holding device has been developed to provide the rotational motion of cylindrical work pieces for micro-turning operation. Laser turning of micro-grooves on ceramics is highly demanded in the present industry because of its wide and potential uses in various fields such as automobile, aerospace and bio-medical engineering applications, etc. Experiments have been conducted on laser micro-grooving of aluminum oxide (Al2O3). The central composite second-order rotatable design (CCD) had been utilized to plan the experiments and response surface methodology was employed for developing empirical models. Analysis on machining characteristics of pulsed Nd:YAG laser micro-grooving operation was made based on the developed models. In this study, lamp current, pulse frequency, pulse width, assist air pressure and cutting speed of work piece are considered as laser machining process parameters. The process performances such as upper deviation ( Y uw), lower deviation ( Y lw) and depth ( Y d) characteristics of laser-turned micro-grooves produced on cylindrical work piece made of Al2O3 were evaluated. Analysis of variance (ANOVA) test had also been carried out to check the adequacy of the developed regression empirical models. The observed optimal process parameter settings are lamp current of 22.517A, pulse frequency of 1.477kHz, pulse width of 2.394% of duty cycle, cutting speed of 10.4283rpm and assist air pressure of 1.3kgf/cm2 for achieving minimum upper deviation, lower deviation and depth of laser-turned micro-grooves, and finally the results were experimentally verified. From the analysis, it was found that proper control of the process parameters lead to achieve minimum upper deviation, lower deviation and depth of laser-turned micro-grooves produced on cylindrical workpiece of Al2O3. [Copyright &y& Elsevier]