COOLING FOR HARD TURNING PROCESS UNDER DRY, MQL, GRAPHEME OXIDE AND ZIRCONIUM OXIDE NANO-CUTTING FLUIDS

Abstract

ABSTRACT “COOLING FOR HARD TURNING PROCESS UNDER DRY, MQL, GRAPHEME OXIDE AND ZIRCONIUM OXIDE NANO-CUTTING FLUIDS” The present invention provides a method for selecting sustainable cooling and lubrication environments during hard turning of AISI D2 steel using coated carbide inserts. It compares dry cutting, MQL with mineral oil, 0.3% ZrO₂-NFMQL, and 0.5% Graphene Oxide (GO)-NFMQL environments. Nanofluids are applied using a dual-nozzle system, improving machinability by reducing cutting temperature, tool wear, surface roughness, and power consumption. The preparation of ZrO₂ and GO nanofluids involves preheating, mechanical stirring, and ultrasonic treatment. The 0.5% GO-NFMQL environment demonstrates the best performance, significantly lowering carbon emissions, noise emissions, and machining costs. This method enhances sustainability, offering improved tool life, environmental benefits, and economic feasibility for industrial hard machining applications. Figure 1

Specification

Description:TECHNICAL FIELD
[0001] The present invention relates to the field of hard tuning processes, and more particularly, the present invention relates to the Selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids.
BACKGROUND ART
[0002] The following discussion of the background of the invention is intended to facilitate an understanding of the present invention. However, it should be appreciated that the discussion is not an acknowledgment or admission that any of the material referred to was published, known, or part of the common general knowledge in any jurisdiction as of the application's priority date. The details provided herein the background if belongs to any publication is taken only as a reference for describing the problems, in general terminologies or principles or both of science and technology in the associated prior art.
[0003] Traditional fluid fails to remove heat during high-speed cutting. In typical flood cooling, too much synthetic oil is utilized, making it hard to dispose of and dangerous to operators. Due to sustainability and superior cooling and lubrication during machining. Achievable tool life and surface finish deteriorate greatly in hard turning. Furthermore, if machining is done without the use of lubricant or cooling agent, chip clings to the tool and the work surface's poor surface quality accelerates tool wear with the production of built-up edges (BUEs).
[0004] Alternatively put, the application of flood cooling is typically avoided since it increases the cutting force and thermal stress, which can cause catastrophic failure and tool-tip fracture. High friction at the tool-workpiece interface raises cutting temperature when machining hardened steel, affecting product quality. Lubricate the machining area with metal cutting fluids. Only high-quality cutting tools and limited machining settings are allowed due to the tremendous heat of the machining zone. CBN, PCBN, and ceramic tools are popular for hard turning due to their edge stability and hardness. However, these tools are expensive, affecting industry or manufacturer production costs.
[0005] Since CBN, PCBN, and ceramic tools are employed largely in dry conditions, the cutting tool is first damaged by the abrupt rise in temperature in the cutting zone and the high friction between the workpiece and cutting tool. Additionally, high cutting temperatures during hard machining are bad for overall machining performance, which has an impact on the economy and quality of the final product. In order to improve machining performance by reducing the localized heating zone, thermal expansion, and workpiece distortion, this must be managed or limited with the application of appropriate lubrication/cutting fluids. Additionally, it shields against corrosion, lessens the need for rewelding, lowers the machine's energy consumption, and extends the life of the tool.
[0006] Dry turning reduce the tool life of the cutting tool and also damages the surface of the workpiece along with possess carbon emission due to the high power consumption. In the absence of coolant friction between workpiece and tool increases which enables rapid tool with unnecessary noise production and vibration. For cost-effective and high precision turning of hardened materials, the right cooling and lubrication approach is needed.
[0007] Although CBN, PCBN, and ceramic tools are frequently used for cutting hard materials, their high cost of acquisition raises the product's entire production cost. Hard turning operations are typically performed in a dry atmosphere in order to minimize the usage of excessive metal cutting fluid. Many industries employ these artificial metal cutting fluids as flood cooling conditions throughout the machining process. Nevertheless, these metal cutting fluids are not only bad for the environment, but also dangerous for the health of the operator and difficult to dispose of. The majority of inventions describe the use of MQL systems with a single nozzle in hard machining. It is more efficient to use multiple MQL mist flows during hard machining in the cutting zone (the tool-workpiece contact zone) and on the cutting insert's primary side face. For sustainability, a thorough analysis is necessary as the impact of using MQL double nozzles on the machining performance of hardened steel (AISI D2 steel) has not been documented in the pertinent invention.
[0008] The following existing solutions are patented for machining applications:
1. Lubricating and cooling method for cutting process and device thereof
Publication number: CN102029551A
Publication type: Grant
Publication date: 24th July 2011

2. A lubrication and cooling device and a method for lubricating and cooling a work piece
Publication number: EP3313610B1
Publication type: Grant
Publication date: 29th July 2020

3. Nanoparticle graphite-based minimum quantity lubrication method and composition
Publication number: US9080122B2
Publication type: Grant
Publication date: 15th July 2015

4. Method and device for measuring particle size of nano particle jet minimum quantity lubrication grinding droplets
Publication number: CN103454190B
Publication type : Grant
Publication date : 20th May 2015

5. System and method for dispensing a minimum quantity of cutting fluid
Publication number: US9931724B2
Publication type : Grant
Publication date : 3rd April 2018
[0009] In light of the foregoing, there is a need for Selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids that overcomes problems prevalent in the prior art associated with the traditionally available method or system, of the above-mentioned inventions that can be used with the presented disclosed technique with or without modification.
[0010] All publications herein are incorporated by reference to the same extent as if each individual publication or patent application were specifically and individually indicated to be incorporated by reference. Where a definition or use of a term in an incorporated reference is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies, and the definition of that term in the reference does not apply.
OBJECTS OF THE INVENTION
[0011] The principal object of the present invention is to overcome the disadvantages of the prior art by providing selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids.
[0012] Another object of the present invention is to provide selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids that include LRT 30 mineral oil and commercially available GO nanoparticles. Nanofluid samples may be created easily and cheaply.
[0013] Another object of the present invention is to provide selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids that is straightforward, affordable, and compact, requiring less space to install. The MQL lubricating system is less costly than a cryogenic system.
[0014] Another object of the present invention is to provide selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids that is employing a 0.5% GO-NFMQL environment resulted in savings of 2.07%, 5.19%, and 5.48% in total machining cost per part compared to 0.3% ZrO2-NFMQL, MQL, and dry conditions, respectively.
[0015] Another object of the present invention is to provide selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids that demonstrate the economic viability and sustainability of using NFMQL conditions for machining hardened steel. Because of this, the most recent breakthrough has a substantial economic impact and has potential for commercial use in machining applications.
[0016] Another object of the present invention is to provide selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids that provide a significant prospect for commercialization in other machining companies due to the technology's environmental friendliness.
[0017] The foregoing and other objects of the present invention will become readily apparent upon further review of the following detailed description of the embodiments as illustrated in the accompanying drawings.
SUMMARY OF THE INVENTION
[0018] The present invention relates to Selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids.
[0019] In this current invention a approach has been made for a selection of suitable cooling and lubrication environment during hard turning of AISI D2 steel, which is the best environment in terms of machinability performance enhancement along with lowest economic environment along with limited carbon emission and noise emission. The current research examines the extensive machinability investigation in relation to measurements of power consumption, cutting temperature, dimensional deviation, wear, and life of tools along with carbon and noise emission during hard turning on AISI D2 steel (55±1 HRC) using coated carbide inserts (MT CVD TiN-TiCN-Al2O3) through the application of novel lubrication techniques under dry, MQL, 0.3%ZrO2-NFMQL, and 0.5% Graphene oxide (GO)-NFMQL(Nanofluid- Minimum quantity lubrication) environments. In only MQL environment pure LRT 30(Mineral oil) has been used. Additionally, the paper examines sustainability studies, including carbon emission, noise emission, and machining economics. The produced nanofluids were sprayed into the cutting zone from two directions using a multi-nozzle application (double nozzle) at high pressure. First nozzle was held vertically facing the cutting zone (tool-workpiece contact zone), and second nozzle, as indicated in Figure 1, was angled 45° from the cutting tool holder axis toward the cutting tool's primary flank face. An MQL system was used to maintain a continuous coolant flow (LRT 30, 0.3% ZrO2 and 0.5% Graphene oxide- Nano-Fluid) of 50 ml/hr at 6 bar of pressure for each nozzle. In Figure 1. the MQL system's components and setup are shown. The hard turning experiments were conducted in the cutting parameter (depth of cut- 0.1 mm, feed- 0.05mm/rev, speed-80 m/min) under dry, MQL,0.3% ZrO2 and 0.5% GO nanofluid environment.
[0020] In the current investigation, a nanofluid with a 0.3% weighted ZrO2 and 0.5% weighted GO concentration was prepared, as seen in Figure 3. The ZrO2 and Graphene oxide (GO) nanoparticles are preheated for three hours at 250°C before being used in the nanofluid production. The preheating process aids in the nanoparticles' moisture removal. Next, ZrO2 and GO nanoparticles are added to base oil LRT 30 (an iron-aluminium-based mineral oil) for pre-dispersing. A mechanical stirrer was employed for 30 minutes at a speed of 1400 rpm to achieve immediate mixing. Nanofluids are made using a two-step verification process. First, nanoparticles are dispersed into base oil containing 0.3% weight of ZrO2 and 0.5% weight of GO. Next, the fluids are mixed continuously for six hours using a magnetic stirrer. Both nanofluids are continuously mixed before being ultrasonically treated for four hours to lessen the amount of nanoparticle clustering in the base oil. A homogenous mixture of Graphene oxide (GO) and ZrO2 nanofluids is created after sonication and utilized for machining. To prevent nanofluid aggregation and sedimentation, both samples undergo a 30-minute magnetic stirring and ultrasonication treatment prior to machining. Preparation of nanofluid has been displayed in Figure 2.
[0021] Abrasion, adhesion, diffusion, chipping, BUE, coating delamination, and catastrophic failure are noted to be the main wear mechanisms. Tool life during machining has been found to be 20.58 min, 65.52 min, 94.41 min, and 136.16 min, respectively, under dry, MQL, 0.3%ZrO2-NFMQL, and 0.5%GO-NFMQL environments maintaining wear criteria of 0.2 mm. By creating a tribological coating to improve lubrication and thermal conductivity, ZrO2 and GO nanofluids both minimize the growth of tool wear and extend tool life. They both enter the cutting zones through pressurized oil-air mist created by MQL action. It was found that adding GO nano cutting fluids reduced the cutting temperature generation, which in turn reduced tool wear. When comparing the 0.5%GO-NFMQL environment to the 0.3%ZrO2-NFMQL environment, as well as the MQL and dry environments, the reduction in cutting temperature was observed to be 14.92% at 5.18 min, 15.06 % at 20.58 min, 17.02 % at 35.77 min, 9.18% at 50.75 min, 7.51% at 65.52 min, 8.18% at 80.07 min, and 11.66% at 94.41 min. When comparing the 0.5%GO-NFMQL environment to the ZrO2-NFMQL environment, as well as to the MQL and dry environments, the surface roughness reduction was observed to be 7.95% at 5.18 min, 9.4% at 20.58 min, 14.16% at 35.77 min, 22.44% at 50.75 min, 29.41% at 65.52 min, 32.91% at 80.07 min, and 33.33% at 94.41 min. The surface roughness that was achieved during machining is considerably below the 1.6-micron threshold. When comparing the 0.5% wt. GO-NFMQL environment to the 0.3% wt. ZrO2-NFMQL and MQL (pure LRT 30) and dry environment, it was found that the power consumption reduction was 13.45% at 5.18 min, 5.98% at 20.58 min, 6.2% at 35.77 min, 8.35% at 50.75 min, 23.16% at 65.52 min, 30.88% at 80.07 min, and 36.37% at 94.41 min. Surface roughness and dimensional deviation are significantly lower in the GO-NFMQL environment compared to all other cutting environments, and the environment performs well because of the decreased tool wear and cutting temperature during machining. By creating a tribological coating to improve lubrication and thermal conductivity, ZrO2 and GO nanofluids both minimize the growth of tool wear and extend tool life. They both enter the cutting zones through pressurized oil-air mist created by MQL action. Comparing the 0.5%GO-NFMQL environment to the 0.3%ZrO2-NFMQL and MQL and dry environment, there was a significant reduction in carbon emissions: 7.88% at 5.18 min, 9.8% at 20.58 min, 8.45% at 35.77 min, 8.4% at 50.75 min, 10.96% at 65.52 min, 15.44 % at 80.07 min, and 24.12% at 94.41 min. Comparing the 0.5%GO-NFMQL environment to the 0.3%ZrO2-NFMQL and MQL environments, as well as the dry cutting environment, it was observed that the noise emission reduction was 1.7% at 5.18 min, 0.97 % at 20.58 min, 1.34 % at 35.77 min, 4.39 % at 50.75 min, 5.05 % at 65.52 min, 3.86 % at 80.07 min, and 2.71 % at 94.41 min. In comparison to 0.3%ZrO2-NFMQL, MQL, and dry environments, respectively, the savings of the total machining cost per part employing the 0.5%GO-NFMQL environment have been shown to be 2.07%, 5.19%, and 5.48%. This shows that machining hardened steel in NFMQL settings is both sustainable and economically feasible. Better sustainability in terms of socio-technological, financial, and environmental benefits is achieved through the application of 0.5%GO-NFMQL settings, which are followed by 0.3%ZrO2-NFMQL, multi-nozzle MQL, and dry environments.
[0022] After a thorough investigation, it was found that the 0.5% wt. of GO-NFMQL environment performed better in terms of machinability improvements than the 0.3%ZrO2-NFMQL, multi-nozzle MQL, and dry environments. It also demonstrated technological, societal, environmental, and economical sustainability when machining hardened AISI D2 steel, meaning it could be used in the shop floor for more productive and clean machining without compromising quality.
[0023] While the invention has been described and shown with reference to the preferred embodiment, it will be apparent that variations might be possible that would fall within the scope of the present invention.
BRIEF DESCRIPTION OF DRAWINGS
[0024] So that the manner in which the above-recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may have been referred by embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0025] These and other features, benefits, and advantages of the present invention will become apparent by reference to the following text figure, with like reference numbers referring to like structures across the views, wherein:
[0026] Figure. 1 Nano MQL system set up for CNC turning process (1- Air compressor, 2-Relief valve and Pressure gauge, 3- Mixing chamber, 4- Moisture control valve, 5- Oil reservoir 6-Cutting tool, 7- 1st nozzle at 90°, 8- 2nd nozzle at 45° from tool axis, 9- AISI D2 workpiece 10- Turret,11- Tool holder, 12- Head stock, 13- Spindle, 14-Tail stock, 15- Coolant(LRT 30/0.3% wt. ZrO2, 0.5%wt. GO); and
[0027] Figure 2. Methodology followed for preparation of Nanofluid.
DETAILED DESCRIPTION OF THE INVENTION
[0028] While the present invention is described herein by way of example using embodiments and illustrative drawings, those skilled in the art will recognize that the invention is not limited to the embodiments of drawing or drawings described and are not intended to represent the scale of the various components. Further, some components that may form a part of the invention may not be illustrated in certain figures, for ease of illustration, and such omissions do not limit the embodiments outlined in any way. It should be understood that the drawings and the detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents, and alternatives falling within the scope of the present invention as defined by the appended claim.
[0029] As used throughout this description, the word "may" is used in a permissive sense (i.e. meaning having the potential to), rather than the mandatory sense, (i.e. meaning must). Further, the words "a" or "an" mean "at least one" and the word "plurality" means "one or more" unless otherwise mentioned. Furthermore, the terminology and phraseology used herein are solely used for descriptive purposes and should not be construed as limiting in scope. Language such as "including," "comprising," "having," "containing," or "involving," and variations thereof, is intended to be broad and encompass the subject matter listed thereafter, equivalents, and additional subject matter not recited, and is not intended to exclude other additives, components, integers, or steps. Likewise, the term "comprising" is considered synonymous with the terms "including" or "containing" for applicable legal purposes. Any discussion of documents, acts, materials, devices, articles, and the like are included in the specification solely for the purpose of providing a context for the present invention. It is not suggested or represented that any or all these matters form part of the prior art base or were common general knowledge in the field relevant to the present invention.
[0030] In this disclosure, whenever a composition or an element or a group of elements is preceded with the transitional phrase "comprising", it is understood that we also contemplate the same composition, element, or group of elements with transitional phrases "consisting of", "consisting", "selected from the group of consisting of, "including", or "is" preceding the recitation of the composition, element or group of elements and vice versa.
[0031] The present invention is described hereinafter by various embodiments with reference to the accompanying drawing, wherein reference numerals used in the accompanying drawing correspond to the like elements throughout the description. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiment set forth herein. Rather, the embodiment is provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those skilled in the art. In the following detailed description, numeric values and ranges are provided for various aspects of the implementations described. These values and ranges are to be treated as examples only and are not intended to limit the scope of the claims. In addition, several materials are identified as suitable for various facets of the implementations. These materials are to be treated as exemplary and are not intended to limit the scope of the invention.
[0032] The present invention relates to Selection of effective sustainable cooling environments for hard turning process improvement under dry, MQL, grapheme Oxide and zirconium oxide Nano-cutting fluids.
[0033] In this current invention an approach has been made for a selection of suitable cooling and lubrication environment during hard turning of AISI D2 steel, which is the best environment in terms of machinability performance enhancement along with lowest economic environment along with limited carbon emission and noise emission. The current research examines the extensive machinability investigation in relation to measurements of power consumption, cutting temperature, dimensional deviation, wear, and life of tools along with carbon and noise emission during hard turning on AISI D2 steel (55±1 HRC) using coated carbide inserts (MT CVD TiN-TiCN-Al2O3) through the application of novel lubrication techniques under dry, MQL, 0.3%ZrO2-NFMQL, and 0.5% Graphene oxide (GO)-NFMQL(Nanofluid- Minimum quantity lubrication) environments. In only MQL environment pure LRT 30(Mineral oil) has been used. Additionally, the paper examines sustainability studies, including carbon emission, noise emission, and machining economics. The produced nanofluids were sprayed into the cutting zone from two directions using a multi-nozzle application (double nozzle) at high pressure. First nozzle was held vertically facing the cutting zone (tool-workpiece contact zone), and second nozzle, as indicated in Figure 1, was angled 45° from the cutting tool holder axis toward the cutting tool's primary flank face. An MQL system was used to maintain a continuous coolant flow (LRT 30, 0.3% ZrO2 and 0.5% Graphene oxide- Nano-Fluid) of 50 ml/hr at 6 bar of pressure for each nozzle. In Figure 1. the MQL system's components and setup are shown. The hard turning experiments were conducted in the cutting parameter (depth of cut- 0.1 mm, feed- 0.05mm/rev, speed-80 m/min) under dry, MQL,0.3% ZrO2 and 0.5% GO nanofluid environment.
[0034] In the current investigation, a nanofluid with a 0.3% weighted ZrO2 and 0.5% weighted GO concentration was prepared, as seen in Figure 3. The ZrO2 and Graphene oxide (GO) nanoparticles are preheated for three hours at 250°C before being used in the nanofluid production. The preheating process aids in the nanoparticles' moisture removal. Next, ZrO2 and GO nanoparticles are added to base oil LRT 30 (an iron-aluminium-based mineral oil) for pre-dispersing. A mechanical stirrer was employed for 30 minutes at a speed of 1400 rpm to achieve immediate mixing. Nanofluids are made using a two-step verification process. First, nanoparticles are dispersed into base oil containing 0.3% weight of ZrO2 and 0.5% weight of GO. Next, the fluids are mixed continuously for six hours using a magnetic stirrer. Both nanofluids are continuously mixed before being ultrasonically treated for four hours to lessen the amount of nanoparticle clustering in the base oil. A homogenous mixture of Graphene oxide (GO) and ZrO2 nanofluids is created after sonication and utilized for machining. To prevent nanofluid aggregation and sedimentation, both samples undergo a 30-minute magnetic stirring and ultrasonication treatment prior to machining. Preparation of nanofluid has been displayed in Figure 2.
[0035] Abrasion, adhesion, diffusion, chipping, BUE, coating delamination, and catastrophic failure are noted to be the main wear mechanisms. Tool life during machining has been found to be 20.58 min, 65.52 min, 94.41 min, and 136.16 min, respectively, under dry, MQL, 0.3%ZrO2-NFMQL, and 0.5%GO-NFMQL environments maintaining wear criteria of 0.2 mm. By creating a tribological coating to improve lubrication and thermal conductivity, ZrO2 and GO nanofluids both minimize the growth of tool wear and extend tool life. They both enter the cutting zones through pressurized oil-air mist created by MQL action. It was found that adding GO nano cutting fluids reduced the cutting temperature generation, which in turn reduced tool wear. When comparing the 0.5%GO-NFMQL environment to the 0.3%ZrO2-NFMQL environment, as well as the MQL and dry environments, the reduction in cutting temperature was observed to be 14.92% at 5.18 min, 15.06 % at 20.58 min, 17.02 % at 35.77 min, 9.18% at 50.75 min, 7.51% at 65.52 min, 8.18% at 80.07 min, and 11.66% at 94.41 min. When comparing the 0.5%GO-NFMQL environment to the ZrO2-NFMQL environment, as well as to the MQL and dry environments, the surface roughness reduction was observed to be 7.95% at 5.18 min, 9.4% at 20.58 min, 14.16% at 35.77 min, 22.44% at 50.75 min, 29.41% at 65.52 min, 32.91% at 80.07 min, and 33.33% at 94.41 min. The surface roughness that was achieved during machining is considerably below the 1.6-micron threshold. When comparing the 0.5% wt. GO-NFMQL environment to the 0.3% wt. ZrO2-NFMQL and MQL (pure LRT 30) and dry environment, it was found that the power consumption reduction was 13.45% at 5.18 min, 5.98% at 20.58 min, 6.2% at 35.77 min, 8.35% at 50.75 min, 23.16% at 65.52 min, 30.88% at 80.07 min, and 36.37% at 94.41 min. Surface roughness and dimensional deviation are significantly lower in the GO-NFMQL environment compared to all other cutting environments, and the environment performs well because of the decreased tool wear and cutting temperature during machining. By creating a tribological coating to improve lubrication and thermal conductivity, ZrO2 and GO nanofluids both minimize the growth of tool wear and extend tool life. They both enter the cutting zones through pressurized oil-air mist created by MQL action. Comparing the 0.5%GO-NFMQL environment to the 0.3%ZrO2-NFMQL and MQL and dry environment, there was a significant reduction in carbon emissions: 7.88% at 5.18 min, 9.8% at 20.58 min, 8.45% at 35.77 min, 8.4% at 50.75 min, 10.96% at 65.52 min, 15.44 % at 80.07 min, and 24.12% at 94.41 min. Comparing the 0.5%GO-NFMQL environment to the 0.3%ZrO2-NFMQL and MQL environments, as well as the dry cutting environment, it was observed that the noise emission reduction was 1.7% at 5.18 min, 0.97 % at 20.58 min, 1.34 % at 35.77 min, 4.39 % at 50.75 min, 5.05 % at 65.52 min, 3.86 % at 80.07 min, and 2.71 % at 94.41 min. In comparison to 0.3%ZrO2-NFMQL, MQL, and dry environments, respectively, the savings of the total machining cost per part employing the 0.5%GO-NFMQL environment have been shown to be 2.07%, 5.19%, and 5.48%. This shows that machining hardened steel in NFMQL settings is both sustainable and economically feasible. Better sustainability in terms of socio-technological, financial, and environmental benefits is achieved through the application of 0.5%GO-NFMQL settings, which are followed by 0.3%ZrO2-NFMQL, multi-nozzle MQL, and dry environments.
[0036] After a thorough investigation, it was found that the 0.5% wt. of GO-NFMQL environment performed better in terms of machinability improvements than the 0.3%ZrO2-NFMQL, multi-nozzle MQL, and dry environments. It also demonstrated technological, societal, environmental, and economical sustainability when machining hardened AISI D2 steel, meaning it could be used in the shop floor for more productive and clean machining without compromising quality.
[0037] Due to superior environmental, financial, and socio-technological advantages, MQL hard machining and nanofluid aided MQL (NFMQL) hard machining for sustainability would greatly benefit from replacing traditional grinding in the machining industries. This might be used on shop floors for more sustainable, ecologically friendly machining. It has been noted that the use of nanofluids in hard machining through MQL is important and is currently developing as a new cooling method. Over the past several years, it has been proven to be appropriate in a variety of cooling applications because of its improved thermal conductivity and viscosity qualities. Their use in hard machining, however, is relatively unknown and merits more study. According to literature reviews, very little research has been done on the use of nano cutting fluids based on graphene oxide (GO) and zirconium oxide (ZrO2) in hard machining of AISI D2 steel. This represents a novelty in research when it comes to the applicability of sustainability in machining. Similar to this, comprehensive comparative machinability studies that compare the characteristics of dry, MQL, GO, and ZrO2 NFMQL environments-including tool wear, tool life, surface roughness, dimensional deviation, cutting temperature, power consumption, and chip morphology-as well as sustainability studies that evaluate carbon emissions, noise emissions, and the economics of machining are seldom conducted. Additionally, very little research has been done on how noise level impacts hardened steel machinability, namely power consumption and surface roughness, which have a significant negative impact on operator health and safety and cause chatter and vibration. Additionally, sound levels exceeding 85 dB are regarded as critical circumstances requiring special attention, therefore they must be taken into consideration while machining hardened steel. Additionally, an investigation into the machinability of hardened steel has been conducted using low-cost coated carbide inserts in order to assess its viability and enhance its performance through the use of a variety of cutting-edge cooling-lubrication techniques, which brings new insights to the field of industrial research.
[0038] The technical differences between the conventional and current process are technically compared in Table 1.
Table 1: Technical differences in between conventional and current process
Conventional/existing process Current process
Lower cutting performance Relatively higher cutting performance
Tool life is minimum The tool life is more
Higher production cost Respectively lower production cost
Hazardous to worker's and operator's health No bad health impact on workers and operators
Environmental and sustainability concerns Sustainable and environment-friendly
[0039] The following innovative characteristics of this invention are as follows:
- The concept of Nano- Fluid MQL (Graphene oxide+ LRT 30) cooling technology is a novel concept and not used so far for machining applications.
- Moreover, in this invention appropriate sustainable cooling method has been suggested for machining application which is a novel concentration and not adopted so far for machining applications.
- Additionally, the trails are carried out employing 0.5% graphene oxide nano-fluid which economically and environmentally best among other environments adopted such as dry, only MQL and 0.3% ZrO2 nano-fluid environment.
[0040] Various modifications to these embodiments are apparent to those skilled in the art from the description and the accompanying drawings. The principles associated with the various embodiments described herein may be applied to other embodiments. Therefore, the description is not intended to be limited to the 5 embodiments shown along with the accompanying drawings but is to be providing the broadest scope consistent with the principles and the novel and inventive features disclosed or suggested herein. Accordingly, the invention is anticipated to hold on to all other such alternatives, modifications, and variations that fall within the scope of the present invention and appended claims. , Claims:CLAIMS
We Claim:
1) A method for selecting a sustainable cooling and lubrication environment in hard turning of AISI D2 steel, the method comprising:
- conducting hard turning operations on AISI D2 steel (55±1 HRC) using coated carbide inserts (MT CVD TiN-TiCN-Al2O3);
- utilizing different cooling environments, including dry cutting, Minimum Quantity Lubrication (MQL) using pure LRT 30 (mineral oil), 0.3% ZrO₂-NFMQL, and 0.5% Graphene Oxide (GO)-NFMQL;
- spraying nanofluid from two nozzles at high pressure into the cutting zone, with one nozzle vertically directed and the second angled at 45°;
- maintaining continuous coolant flow of 50 ml/hr at 6 bar pressure for each nozzle; and
- evaluating machinability performance based on power consumption, cutting temperature, tool wear, surface roughness, dimensional deviation, and tool life.
2) The method as claimed in claim 1, wherein the 0.5% Graphene Oxide (GO)-NFMQL environment shows reduced cutting temperatures and surface roughness compared to the 0.3% ZrO₂-NFMQL, MQL, and dry cutting environments.
3) The method as claimed in claim 1, wherein the 0.5% Graphene Oxide (GO)-NFMQL environment exhibits a significant reduction in power consumption compared to 0.3% ZrO₂-NFMQL, MQL, and dry cutting environments.
4) The method as claimed in claim 1, wherein the nanofluid preparation includes:
preheating ZrO₂ and GO nanoparticles at 250°C for three hours;
- dispersing the nanoparticles into LRT 30 base oil with 0.3% ZrO₂ and 0.5% GO concentrations;
- mechanically stirring the mixture at 1400 rpm for 30 minutes, followed by six hours of magnetic stirring and four hours of ultrasonic treatment to form a homogenous mixture.
5) The method as claimed in claim 1, wherein the GO nanofluids reduce tool wear and extend tool life by forming a tribological coating that improves lubrication and thermal conductivity.
6) The method as claimed in claim 1, wherein the method further comprising:
- reducing carbon emissions and noise emissions during machining operations by using 0.5% GO-NFMQL compared to other cooling environments.

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