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Kalipada Maity - One of the best experts on this subject based on the ideXlab platform.
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PREDICTIVE MODELING OF SURFACE ROUGHNESS, MATERIAL REMOVAL RATE AND KERF USING MULTIPLE REGRESSION ANALYIS IN Plasma Arc Cutting PROCESS OF HARDOX AND ABREX STEEL
Surface Review and Letters, 2020Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:Plasma Arc Cutting (PAC) process is widely used in metal Cutting industries and modern fabrication units. Precise Cutting of high strength material is still a challenging task to the industries. PA...
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Experimental analysis of the effect of gas flow rate and nature on Plasma Arc Cutting of hardox-400
Welding in The World, 2019Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:This reseArch paper exhibits an experimental investigation of Plasma Arc Cutting of hardox-400 using different types of Plasma gases. Nature and behavior of the Plasma Arc were studied and described the effect of Plasma gas on the workpiece. The experiments were performed on 10 mm hardox-400 using CNC Plasma Cutting machine. The selected workpiece material has very good mechanical properties like high toughness, good bendability, and good weldability. This special abrasion resistance steel is used in part manufacturing of front loaders, buckets, barges, and various mining equipment. Four different Plasma gases were chosen for this experiment, i.e., air, argon, oxygen, and nitrogen. Thermophysical properties of Plasma gases, properties of generated Arc, Cutting performance, and energy balance are explained for different Plasma gases used. The kerf shape and material removal rate (MRR) due to the generated Arc were measured and analyzed the effect. This paper clarifies the potential of Cutting process by varying the flow rate and chemical composition of the Plasma gas.
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Temperature analysis by moving heat source during Plasma Arc Cutting process: an analytical approach
World Journal of Engineering, 2019Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:Purpose This paper aims to work exhibits the temperature distribution over the surface of the workpiece during Plasma Arc Cutting process. Design/methodology/approach The moving heat source is taken into consideration for calculating the heat created by Plasma Arc. The heat is generated at the Plasma – liquid metal boundary. The heat of fusion is also considered for estimation because of molten layer separates the Plasma and solid layer. This causes to hamper the heat transfer towards the melting front. Eliminating the heat resistance may calculation error at high Cutting speed. Power required to melt the material depends on the speed of the cut. Findings Higher Cutting speed increases the power required. The temperature drop over the layer of molten front increases as the speed of cut increases at higher Peclet number. Different thickness of the molten layer was taken for calculation i.e. zero thickness, 10 and 20 per cent. Originality/value The estimated results are shown in non-dimensional form. So, the method can be applied for any other types of material.
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Application of desirability function based response surface methodology (DRSM) for investigating the Plasma Arc Cutting process of sailhard steel
World Journal of Engineering, 2018Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:Purpose Plasma Arc Cutting (PAC) is extensively applicable for Cutting the materials in faster speed with better accuracy in different manufacturing industries. The Cutting of sailhard steel plate plays a great challenge in Plasma Arc Cutting process. Design/methodology/approach In this investigation, a special abrasion-resistant steel known as sailhard of 20 mm thickness plate has been cut by PAC machine. Cutting current, stand-off distance, Cutting speed and gas pressure were selected as Cutting parameters. The corresponding responses focused for this study are material removal rate, kerf and chamfer. L30 orthogonal array based on a central composite design (CCD) of response surface methodology (RSM) was used to design the run of the experiment. For predicting and modeling of optimal Cutting conditions, a hybrid approach of desirability function-based response surface methodology (DRSM) was acquainted. Findings The result of this study determines that desirability index (DI) was affected significantly with the machining parameter as well as their interaction. A confirmation test was carried out to analyze the degree of effectiveness of DRSM technique. Originality/value In PAC, the selection of process parameters and effect of that parameter on the output responses is of greater value because of the selection of best Cutting condition.
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Optimization of Dimensional accuracy in Plasma Arc Cutting process employing parametric modelling approach
IOP Conference Series: Materials Science and Engineering, 2018Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:Plasma Arc Cutting (PAC) is a high temperature thermal Cutting process employed for the Cutting of extensively high strength material which are difficult to cut through any other manufacturing process. This process involves high energized Plasma Arc to cut any conducting material with better dimensional accuracy in lesser time. This reseArch work presents the effect of process parameter on to the dimensional accuracy of PAC process. The input process parameters were selected as Arc voltage, standoff distance and Cutting speed. A rectangular plate of 304L stainless steel of 10 mm thickness was taken for the experiment as a workpiece. Stainless steel is very extensively used material in manufacturing industries. Linear dimension were measured following Taguchi's L16 orthogonal array design approach. Three levels were selected to conduct the experiment for each of the process parameter. In all experiments, clockwise cut direction was followed. The result obtained thorough measurement is further analyzed. Analysis of variance (ANOVA) and Analysis of means (ANOM) were performed to evaluate the effect of each process parameter. ANOVA analysis reveals the effect of input process parameter upon leaner dimension in X axis. The results of the work shows that the optimal setting of process parameter values for the leaner dimension on the X axis. The result of the investigations clearly show that the specific range of input process parameter achieved the improved machinability.
Deepak Kumar Naik - One of the best experts on this subject based on the ideXlab platform.
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PREDICTIVE MODELING OF SURFACE ROUGHNESS, MATERIAL REMOVAL RATE AND KERF USING MULTIPLE REGRESSION ANALYIS IN Plasma Arc Cutting PROCESS OF HARDOX AND ABREX STEEL
Surface Review and Letters, 2020Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:Plasma Arc Cutting (PAC) process is widely used in metal Cutting industries and modern fabrication units. Precise Cutting of high strength material is still a challenging task to the industries. PA...
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Experimental analysis of the effect of gas flow rate and nature on Plasma Arc Cutting of hardox-400
Welding in The World, 2019Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:This reseArch paper exhibits an experimental investigation of Plasma Arc Cutting of hardox-400 using different types of Plasma gases. Nature and behavior of the Plasma Arc were studied and described the effect of Plasma gas on the workpiece. The experiments were performed on 10 mm hardox-400 using CNC Plasma Cutting machine. The selected workpiece material has very good mechanical properties like high toughness, good bendability, and good weldability. This special abrasion resistance steel is used in part manufacturing of front loaders, buckets, barges, and various mining equipment. Four different Plasma gases were chosen for this experiment, i.e., air, argon, oxygen, and nitrogen. Thermophysical properties of Plasma gases, properties of generated Arc, Cutting performance, and energy balance are explained for different Plasma gases used. The kerf shape and material removal rate (MRR) due to the generated Arc were measured and analyzed the effect. This paper clarifies the potential of Cutting process by varying the flow rate and chemical composition of the Plasma gas.
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Temperature analysis by moving heat source during Plasma Arc Cutting process: an analytical approach
World Journal of Engineering, 2019Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:Purpose This paper aims to work exhibits the temperature distribution over the surface of the workpiece during Plasma Arc Cutting process. Design/methodology/approach The moving heat source is taken into consideration for calculating the heat created by Plasma Arc. The heat is generated at the Plasma – liquid metal boundary. The heat of fusion is also considered for estimation because of molten layer separates the Plasma and solid layer. This causes to hamper the heat transfer towards the melting front. Eliminating the heat resistance may calculation error at high Cutting speed. Power required to melt the material depends on the speed of the cut. Findings Higher Cutting speed increases the power required. The temperature drop over the layer of molten front increases as the speed of cut increases at higher Peclet number. Different thickness of the molten layer was taken for calculation i.e. zero thickness, 10 and 20 per cent. Originality/value The estimated results are shown in non-dimensional form. So, the method can be applied for any other types of material.
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Investigation and Optimization of Plasma Arc Cutting Process
2019Co-Authors: Deepak Kumar NaikAbstract:High strength materials are most widely used in producing the parts of military, automobile, marine and mining industries. Special abrasion resistance material is used for above industries because of their superior mechanical properties like good weld capacity, good bendability, higher toughness and better workability. These alloy materials are classified as “Hard-to-cut” type materials and very difficult to cut the work piece. Cutting of high abrasion resistance alloy material with better dimensional accuracy in faster Cutting speed within economic cost is still a challenging task for manufacturing industries. Generally fabrication units employed Plasma Arc Cutting machine to cut the high strength material due to its advantages over the other Cutting processes. The correct selection of machining parameter and Plasma gas is very important for smooth Cutting with high precision. The optimization of input parameters reveals the proper machining condition for Cutting process. In addition to that, it was also noticed that the selection of appropriate Plasma gas could enhanced the Cutting process. Therefore, in the first stage of the reseArch work, Investigation and optimization of Plasma Arc Cutting process using different optimization techniques of some high strength and high abrasion resistance alloy material which was not sufficiently addressed so far were carried out. A CNC Plasma Arc Cutting machine of MESSER industry named (BURNY 1250) was used to conduct the experiment of sailhard steel, abrex 400 steel and hardox 400 steel. These alloy materials have superior mechanical properties for manufacturing the parts of mining, automobile, petrochemical, oil and natural gas industries. On the other hand, a portable laboratorial Plasma Arc Cutting machine was employed to investigate and optimize the Cutting operation of 304L stainless steel. This alloy material has mostly employed for household and commercial application because of its superior corrosion resistance in nature. The Cutting parameters were selected as Cutting current, gas supply pressure, Cutting speed, stand-off-distance and feed rate were selected as Cutting parameter. Surface roughness, material removal rate, kerf, chamfer and dross were considered as output responses. Taguchi’s orthogonal array was taken to design the run of experiment during Cutting process. Additionally, three different multi criteria decision making techniques viz. Desirability approach, Technique for order of preference by similar to ideal solution (TOPSIS) and Vlsekriterijumska optimizacija KOm-promisno Resenje (VIKOR) were suggested to attain optimal Cutting condition in order to minimize the production cost and maximize the productivity without compromising the quality. Also, a prediction model was developed to estimate the responses using multiple regression analysis (MRA). A comparison between experimental and predicted result shows the accuracy of the model. An ANOVA test was established to evaluate the significance of process parameter. Finally, a confirmation test was obtained to show the degree of effectiveness of proposed method. The optimum setting of process parameters will offer a very good Cutting condition in order to achieve the preciseness. In the second stage, an experimental analysis was carried out to observe the effect of different Plasma gas on the work piece material during Plasma Arc Cutting process. The influence of flow rate of Plasma gas on the Plasma Arc Cutting process was investigated. Four different Plasma gases were selected for this experiment viz. air, argon, oxygen and nitrogen. The thermo physical properties of Plasma gases, properties of generated Arc, Cutting performance and energy balance was explained for different Plasma gases. This reseArch work was also clarified the potential of Cutting process by varying the flow rate and chemical composition of the Plasma gas. Finally, a temperature analysis was developed over the surface of work piece during Plasma Arc Cutting process. The moving heat source was taken into consideration for calculation the heat created by Plasma Arc. The heat of fusion was also considered for estimation due to molten layer separates the Plasma and solid layer. Different thickness of molten layer were taken for calculation viz. zero thickness, 10% and 20%. The estimated results are shown in non-dimensional form. So, the method can be applied for any other types of material.
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Application of desirability function based response surface methodology (DRSM) for investigating the Plasma Arc Cutting process of sailhard steel
World Journal of Engineering, 2018Co-Authors: Deepak Kumar Naik, Kalipada MaityAbstract:Purpose Plasma Arc Cutting (PAC) is extensively applicable for Cutting the materials in faster speed with better accuracy in different manufacturing industries. The Cutting of sailhard steel plate plays a great challenge in Plasma Arc Cutting process. Design/methodology/approach In this investigation, a special abrasion-resistant steel known as sailhard of 20 mm thickness plate has been cut by PAC machine. Cutting current, stand-off distance, Cutting speed and gas pressure were selected as Cutting parameters. The corresponding responses focused for this study are material removal rate, kerf and chamfer. L30 orthogonal array based on a central composite design (CCD) of response surface methodology (RSM) was used to design the run of the experiment. For predicting and modeling of optimal Cutting conditions, a hybrid approach of desirability function-based response surface methodology (DRSM) was acquainted. Findings The result of this study determines that desirability index (DI) was affected significantly with the machining parameter as well as their interaction. A confirmation test was carried out to analyze the degree of effectiveness of DRSM technique. Originality/value In PAC, the selection of process parameters and effect of that parameter on the output responses is of greater value because of the selection of best Cutting condition.
Valerian Nemchinsky - One of the best experts on this subject based on the ideXlab platform.
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Erosion of Thermionic Cathodes in Welding and Plasma Arc Cutting Systems
IEEE Transactions on Plasma Science, 2014Co-Authors: Valerian NemchinskyAbstract:Thermionic Arc cathodes are the cathodes where thermionic emission is the main electron emission mechanism. They are used in welding (Tungsten pure or doped with rare earth oxides) and Plasma Arc Cutting (Tungsten for Cutting with inert gas or Hafnium for Cutting with Oxygen Plasma). There are two different sources of erosion: constant current (CC) erosion and erosion during Arc initiation and termination (cycling erosion). Available experimental data for both types of cathode and both types of erosion (CC and cycling) are presented and discussed. For quite some time, it has been clear that CC erosion is due to cathode evaporation. It has been shown that as almost all the evaporated atoms return back to the cathode, the net erosion rate is much lower than the evaporation rate. The existing model allows one to calculate the ratio of these two (escape factor). It is in the range 10-2-10-3. The important role of cathode geometry and Plasma flow pattern in the cathode proximity is discussed. The nature of cathode erosion during Arc start and Arc termination is much less understood in spite the fact that the corresponding erosion could be very important and even dominate for multiple cycles. Different processes that lead to this type of erosion are considered.
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Cathode Erosion due to Evaporation in Plasma Arc Cutting Systems
Plasma Chemistry and Plasma Processing, 2013Co-Authors: Valerian NemchinskyAbstract:Erosion of a hafnium cathode in Plasma Arc Cutting torch using oxygen as Plasma gas is considered. It is shown that approximately 0.001 fraction of the evaporated particles participate in a net erosion, the rest of the evaporated particles return back to the cathode after spending some time in a near-cathode Plasma. Along with erosion rate, the suggested equations allow one to the calculate current density at the cathode, the cathode temperature inside the Arc attachment and the electron temperature at the cathode-Plasma boundary. Comparison of the obtained values with the available information on these parameters shows a reasonable agreement.
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Advances in Plasma Arc Cutting Technology: The Experimental Part of an Integrated Approach
Plasma Chemistry and Plasma Processing, 2012Co-Authors: V. Colombo, Valerian Nemchinsky, A. Concetti, E. Ghedini, F. Rotundo, P. Sanibondi, M. Boselli, S. Dallavalle, M. Gherardi, M. VanciniAbstract:The experimental part of an integrated approach to design and optimization of Plasma Arc Cutting devices will be presented; in particular results obtained through diagnostics based on high speed imaging and Schlieren photography and some evidences obtained through experimental procedures. High speed imaging enabled to investigate start-up transition phenomena in both pilot Arc and transferred Arc mode, anode attachment behaviour during piercing and Cutting phases, cathode attachment behaviour during start-up transient in PAC torches with both retract and high frequency pulse pilot Arc ignition. Schlieren photography has been used to better understand the interaction between the Plasma discharge and the kerf front. The behaviour of hafnium cathodes at high current levels at the beginning of their service life was experimentally investigated, with the final aim of characterizing phenomena that take place during those initial piercing and Cutting phases and optimizing the initial shape of the surface of the emissive insert.
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Plasma Arc Cutting: speed and cut quality
Journal of Physics D: Applied Physics, 2009Co-Authors: Valerian Nemchinsky, W S SeveranceAbstract:When Cutting metal with Plasma Arc Cutting, the walls of the cut are narrower at the bottom than at the top. This lack of squareness increases as the Cutting speed increases. A model of this phenomenon, affecting cut quality, is suggested. A thin liquid layer, which separates the Plasma from the solid metal to be melted, plays a key role in the suggested model. This layer decreases heat transfer from the Plasma to the solid metal; the decrease is more pronounced the higher the speed and the thicker the liquid metal layer. Since the layer is thicker at the bottom of the cut, the heat transfer effectiveness is lower at the bottom. The decrease in heat transfer effectiveness is compensated by the narrowness of the cut. The suggested model allows one to calculate the profile of the cut. The result of the calculations of the Cutting speeds for plates of various thicknesses, at which the squareness of the cut is acceptable, agrees well with the speeds recommended by manufacturers. The second effect considered in the paper is the deflection of the Plasma jet from the vertical at a high Cutting speed. A qualitative explanation of this phenomenon is given. We believe the considerations of this paper are pertinent to other types of Cutting with moving heat sources.
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What we know and what we do not know about Plasma Arc Cutting
Journal of Physics D: Applied Physics, 2006Co-Authors: Valerian Nemchinsky, W S SeveranceAbstract:After a brief history of Plasma Arc Cutting (PAC) is given, its types and abilities are discussed. Experimental data (unfortunately, little is available) on Plasma parameters are reviewed. The status of contemporary understanding of the process involved in PAC is presented. The main emphasis is on those processes that determine the technological abilities of the method. Along with the existing theories reviewed, we propose qualitative hypotheses on some of these processes. Among them are: dependence of the cyclic cathode erosion on the rate of current increase, double Arcing and the role of insulating inclusions at the nozzle orifice on double Arcing, dross formation and the shape of the kerf.
Michele Monno - One of the best experts on this subject based on the ideXlab platform.
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experimental study of the features of the kerf generated by a 200 a high tolerance Plasma Arc Cutting system
Journal of Materials Processing Technology, 2008Co-Authors: Riccardo Bini, Bianca Maria Colosimo, Ali Erkin Kutlu, Michele MonnoAbstract:Abstract In this study a 200 A high tolerance Plasma Arc Cutting (HTPAC) system is utilised to cut plates from 15 mm thick mild steel sheets metals. The Design of Experiments (DoE) technique is used in order to outline the main parameters which define the geometry of the cut profile, as well as its constancy (i.e. stability). Beyond Arc voltage and Cutting speed, Plasma gas flow rate, shield gas flow rate and shield gas composition are included in the analysis and their effects on kerf position and shape are evaluated. The performed analysis indicates that Cutting speed and Arc voltage affect the kerf formation mechanism and their interaction is also important in defining the inclination of the cut. Despite the value selected for these parameters, the analysis shows that plates can have different profiles, depending on the specific side considered. Therefore, this effect has to be taken into account when designing workpieces to be cut with this technology. Eventually, the present paper points out that high quality parts (unevenness class 2, according to ISO9013) can be obtained as a result of an experimental investigation aimed at selecting the proper values of process parameters. Therefore, the type of experimental study proposed in this paper can be applied in different operating condition (i.e. material and thickness of interest) in order to obtain the best performance from the HTPAC system.
Barbara Previtali - One of the best experts on this subject based on the ideXlab platform.
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high tolerance Plasma Arc Cutting of commercially pure titanium
Journal of Materials Processing Technology, 2005Co-Authors: Elisabetta Gariboldi, Barbara PrevitaliAbstract:Abstract The quality of cuts performed on titanium sheets using high tolerance Plasma Arc Cutting (HTPAC) process was investigated under different process conditions. A 5 mm thick sheet of grade 2 commercially pure titanium was cut using several feed rates in the dross-free feed rate range and with the adoption of oxygen or nitrogen as Cutting and shielding gases. When oxygen was used as Cutting gas higher feed rate and geometry attributes (unevenness and kerf width) of better quality were achieved due to the oxidation reaction. The quality features of the Cutting edge of HTPAC of commercially pure titanium were integrated with considerations on microstructural features related to the formation of a wide layer severely affected by Plasma-induced thermal cycle and by interaction with the Cutting gas. In fact, all Cutting edges displayed an external layer of oxide, under which a thin layer of oxygen-enriched α-case was noticed for cuts performed with oxygen. The thickness of the total heat affected zone (HAZ) overcame 1 mm for all the cuts in nitrogen and for the slowest cut in oxygen. Temperature measurements during the passage of the torch defined the thermal cycles of the Cutting process in several locations of the sheet. These are characterised by high heating rates (above 2000 K/s within the HAZ) and low cooling rates (150–580 K/s within the HAZ). An analytical model was applied to simulate the thermal effects of the material interaction with the torch in the case of slow cuts with oxygen. A comparison between predicted thermal cycles, experimental measurements and microstructural observations confirmed the reliability of the estimation in terms of extension of microstructural modifications.