Particle Swarm Optimisation of Hole Quality Characteristics in Laser Trepan Drilling of Inconel 718 (original) (raw)
Related papers
2019
Inconel-718 is a nickel based super alloy and is extensively in use for working at very high temperature (upto 2000 °C) such as aero engine gas path equipment, nuclear equipment etc. Drilling micro size hole in such material with laser beam has been a proven choice and laser drilling process produces geometrically and dimensionally improved hole. Hole geometrical features can be improved further if laser drilling system operated at optimal input parameter setting. This paper experimentally investigates the behavior of hole geometrical features hole circularity and hole taper in laser trepan drilling of Inconel -718 sheet. Optimal value of laser input parameters for improved hole circularity and reduced hole taper have been suggested with the help of computational intelligence technique particle swarm optimisation. The effect of each laser input parameter on hole quality characteristics are also discussed and demonstrated graphically. Finally the experimental validation of the predic...
Experimental Investigation of Hole Diameter in Laser Trepan Drilling of Inconel718 Sheet
Materials Today: Proceedings, 2017
The applications of super alloys have been found in different technologically advanced industries such as aeronautical, marine, automobile and chemical. But the machining of these alloys is very difficult by using conventional machining methods. Laser beam may be used for machining of these materials with high production rate or less machining times. But due to thermal nature of laser machining, dimensional inaccuracy, geometrical defects, surface roughness, recast layer problems may be found. So the analysis of different process parameters on laser machining becomes necessary. The objective of this research article is to investigate the effect of laser process parameter like, Gas pressure, Current, Stand of distance, and trepanning speed (Cutting speed) on the drilled hole diameter in the laser trepan drilling of Inconel718 sheet. Making the small hole of desired size in the aerospace components is challenging task for the manufactures. This paper investigate the effects of the different process parameters on the drilled hole diameter in trepan drilling. The experiments have been conducted by varying one parameter at a time. The experimental data has been used to developed the multi regression model for hole diameter. The statistical analysis of developed model shows that the model is adequate and may be used for the prediction of hole diameter in laser trepan drilling. The hole diameter has been optimized by using genetic algorithm. The optimum result obtained by genetic algorithm shows certain improvement in hole diameter.
Modeling and optimization of geometrical characteristics in laser trepan drilling of titanium alloy
Journal of Mechanical Science and Technology, 2016
Laser drilling has become an alternative to drilling precise holes in advanced difficult-to-cut superalloys. Due to better hole quality and capability to generate macro-size holes, laser trepan drilling is becoming more popular as compared with laser percussion drilling. This paper presents a study of laser trepan drilling process performance in terms of geometrical quality characteristics, such as hole taper and circularity for drilling small diameter hole in difficult-to-cut Titanium alloy sheet. Due to involvement of different process parameters such as laser power, pulse width, pulse frequency, workpiece thickness, material composition, cutting speed, stand of distance and assist gas pressure, the laser cutting is a highly nonlinear and complex process. To handle this nonlinearity and complexity, genetic algorithm has been applied for the optimization. We used assist gas pressure, pulse width, pulse frequency and trepanning speed as input process parameters. The effect of significant process parameters on hole characteristics are discussed on the basis of data obtained through a well designed orthogonal array experimental matrix. Reliable empirical models have been developed for different quality characteristics. Improvements of 49% and 8% have been registered in hole taper and circularity, respectively, at optimum level of process parameters.
Computer-aided genetic algorithm based multi-objective optimization of laser trepan drilling
The laser trepan drilling (LTD) has proven to produce better quality holes in advanced materials as compared with laser percussion drilling (LPD). But due to thermal nature of LTD process, it is rarely possible to completely remove the undesirable effects such as recast layer, heat affected zone and micro cracks. In order to improve the hole quality, these effects are required to be minimized. This research paper presents a computer-aided genetic algorithm-based multi-objective optimization (CGAMO) methodology for simultaneous optimization of multiple quality characteristics. The optimization results of the software CGAMO has been tested and validated by the published literature. Further, CGAMO has been used to simultaneously optimize the recast layer thickness (RLT) at entrance and exit in LTD of nickel based superalloy sheet. The predicted results show minimization of 99.82% and 85.06% in RLT at entrance and exit, respectively. The effect of significant process parameters on RLT has also been discussed.
Materials Today: Proceedings, 2018
This experimental work describes the utilization of a hybrid approach of regression modeling and particle swarm optimization (PSO) for optimizing the process parameters during the laser cutting of the Inconel-718 sheet. The experiments have been performed by using four machining parameters such as assist gas pressure, standoff distance, cutting speed and laser power. The kerf width and kerf taper are used as an output quality characteristic. The experiments have been performed by using well planned orthogonal array L 27 .The second order regression models have been developed for kerf width and kerf taper by using the experimental data. The developed second order regression models have been utilized in optimization by particle swarm optimization. The comparison of the experimental result with optimum results confirms that the individual improvement in output quality characteristics kerf width and kerf taper is approximate 10% and 57%, respectively. The overall improvement of 46% has been observed during the optimization. Finally, the effects of different process parameters on different performances have also been discussed. The parametric effect analysis shows that minimum kerf taper may be obtained at lowest values of laser power and middle values of standoff distance.
Infrared Physics & Technology, 2018
The Inconel-718 is one of the most demanding advanced engineering materials because of its superior quality. The conventional machining techniques are facing many problems to cut intricate profiles on these materials due to its minimum thermal conductivity, minimum elastic property and maximum chemical affinity at magnified temperature. The laser beam cutting is one of the advanced cutting method that may be used to achieve the geometrical accuracy with more precision by the suitable management of input process parameters. In this research work, the experimental investigation during the pulsed Nd:YAG laser cutting of Inconel-718 has been carried out. The experiments have been conducted by using the well planned orthogonal array L 27. The experimentally measured values of different quality characteristics have been used for developing the second order regression models of bottom kerf deviation (KD), bottom kerf width (KW) and kerf taper (KT). The developed models of different quality characteristics have been utilized as a quality function for single-objective optimization by using particle swarm optimization (PSO) method. The optimum results obtained by the proposed hybrid methodology have been compared with experimental results. The comparison of optimized results with the experimental results shows that an individual improvement of 75%, 12.67% and 33.70% in bottom kerf deviation, bottom kerf width, and kerf taper has been observed. The parametric effects of different most significant input process parameters on quality characteristics have also been discussed.
Experimental study of Hole Taper in Laser Trepan Drilling of Nickel Based Super alloy Sheet
Materials Today: Proceedings, 2018
This research article reports the optimum laser drilling input parameter for getting minimum hole taper and experimentally investigates the behaviour of hole taper in selected laser drilling input parameters on Inconel-718 sheet. Inconel-718 is nickel based super alloy, has diverse application in the field of manufacturing industries, including aerospace, aircraft, automotive, medical equipments, food service equipments and many others. The material is well suited for applications requiring high strength in temperature ranges from cryogenic up to 1400°F. Inconel-718 also exhibits excellent tensile and impact strength. The conventional drilling process faces difficulties to drill quality and precise holes in advanced materials due to its better mechanical properties. Making geometrical better hole is major concerned with conventional drilling process. With the help of Laser drilling process, a geometrically and dimensionally improved hole may be produced. The geometry of hole can be made further better if operating the Laser system at optimum parameters level. In this paper the effects of laser input parameters on hole taper have been investigated and optimal value of input parameters for reduced hole taper has been suggested. The experiments have been conducted by varying one parameter at a time. The experimental data are used to develop the multi regression model for hole taper. A reliable multi regression model is developed for hole taper and modern optimization tool, Genetic algorithm (GA) is used for optimization of the kerf taper. The optimal value of studied laser input parameters such as assist gas pressure, laser Current, stand-off distance, and cutting speed (Trepanning speed) have been suggested for getting lower value of hole taper. Finally, the effects of each laser input parameter of the kerf taper has been discussed.
International Journal of Materials, Mechanics and Manufacturing, 2017
Micro-machining of stainless steel is difficult in conventional machining process due to excessive heat generation and micro-structural changes. Hence, lasers have been widely used to localize the heat affected zone in order to control the micro-structural changes. However, the major difficulty arises while performing laser drilling is the formation of spatter which affects the quality of holes. The present study focuses on reduction of spatter area in CO 2 laser drilling of stainless steel using Taguchi method embedded with Harmony search algorithm. The influence of machining parameters such as flushing pressure, laser power and pulse frequency on spatter area has been studied through Analysis of variance (ANOVA). It has been observed that flushing pressure and pulse frequency are the most influencing factors on formation of spatter. Harmony search algorithm has been used to evaluate the optimal parametric setting that attempts to minimize spatter area.
Lubricants
The conventional (mechanical) micro-drilling of Inconel 625 alloys suffers from premature breakage of the drill bit due to its brittle nature and limited cutting tool life. Even greater problems are encountered when micro-drilling holes at an acute angle to the machining plane. In such a process, there are great difficulties associated with the low stiffness of the tool, which leads to the frequent breakage of the drill during machining. Therefore, in this type of mechanical drilling operation, the hole surface is usually milled with an end mill to provide a flat surface on the entry side of the drill bit. The aim of this article is to recognise the process of sequential micro-drilling and to assess the possibility of its use as an effective and efficient method of micro-drilling in hard-to-cut metals. The paper describes the process of initial laser drilling followed by final mechanical micro-drilling. Inconel 625 Ni-based alloy sheets were used as the test material. The shape and ...
Proceedings of the 6th International Workshop of Advanced Manufacturing and Automation, 2016
In today's industrial scenario, the high cost involved in manufacturing is the major concern apart from the environmental factors. With the manufacturing cost reaching sky high levels, the use of a suitable optimization technique has become one major requirement while designing any manufacturing process. The current study involves a series of milling experiments on Inconel 718 alloy. Minimum quantity lubrication has been used as the cooling technique alongside the flood and the dry conditions. The combined objective functions were generated using ANOVA. Particle swarm optimization (PSO) technique was used to optimize the input parameters i.e. the cutting speed (Vc), cutting feed (F) and the depth of cut (ae) in order to minimize the tool wear (Vbmax). A series of validation experiments were performed and the PSO technique proved to be a highly effective method in predicting the tool wear (Vbmax), also allowing a simultaneous comparison amongst the cooling methods, thus, suggesting MQL to be a better cooling technique when compared to the dry and the flood cooling.