Wet Machining Research Articles

Effects of TiAlN Coating Thickness on Machined Surface Roughness, Surface Residual Stresses, and Fatigue Life in Turning Inconel 718

The surface roughness and surface residual stresses are affected by the coating thickness of physical vapor deposition (PVD) TiAlN tools, which could alter the service performance of machined components. However, the relationships among the tool coating thickness, the machined surface roughness, the surface residual stress, and the fatigue life are still not sufficiently illustrated. In this research, PVD TiAlN coatings with several thicknesses of 1.6 μm, 2 μm, 2.5 μm, and 3 μm were deposited on carbide tools. Turning experiments using Inconel 718 were conducted with uncoated and various TiAlN tools under flood cooling conditions. The surface roughness could be improved with the selection of thin PVD TiAlN coating thicknesses of 1.6 μm and 2 μm compared to that of uncoated tools. The tensile residual stresses at the machined surface in the directions of cutting speed and feed rate linearly decreased by 148.67% and exponentially decreased by 92.24% when the TiAlN coating thickness was increased from 0 μm to 3 μm. The values of the low-cycle fatigue life of machined Inconel 718 linearly increased by 15.60% with the increase in TiAlN coating thickness from 0 μm to 3 μm, which was mainly due to the improvement of surface residual stresses. The results could provide guidance for the selection of suitable TiAlN coating thicknesses for wet machining Inconel 718 based on the part service conditions.

Internally cooled tools: An eco-friendly approach to wear reduction in AISI 304 stainless steel machining

Austenitic stainless steel 304 is widely used in various applications due to its mechanical strength, toughness, and, most importantly, its corrosion resistance. However, machining this material presents significant challenges, primarily due to its high tendency for work hardening and generation of elevated temperatures. In the cutting process, this temperature rise can result in premature tool wear, leading to a reduction in their lifespan. To address these issues, cutting fluids are typically applied. Although this component offers advantages, it also contributes to environmental pollution, health risks, and significant costs, including disposal.Therefore, this study introduces an Internally Cooled Tool (ICT) method aimed at reducing the heat generated during machining. In this study, an analysis of tool life and wear was conducted to evaluate the effectiveness of ICTs compared to conventional machining methods during the turning of austenitic stainless steel 304 using double-coated tools (AlCrN on TiAlN, PVD (Physical Vapor Deposition)). Additionally, the use of ICTs in combination with lubrication (hybrid machining Minimum Quantity Lubrication (MQL) + ICT) was also investigated. The study covered five machining atmospheres (ICT, ICT + MQL, dry, wet, MQL). Cutting conditions were kept constant, including cutting speed (vc = 400 m/min), feed rate (f = 0.1 mm/rev), and depth of cut (ap = 0.5 mm). Scanning electron microscopy (SEM) analyses were conducted to examine the wear mechanisms and types present in each condition, along with statistical tests such as analysis of variance and Tukey tests to validate the experiments. The results indicated that ICTs (ICT and ICT + MQL) showed a longer tool life compared to dry machining and MQL techniques, while the wet machining method did not demonstrate significance compared to this technique. The observed wear mechanisms included abrasion, adhesion, and diffusion, with abrasion being the predominant mechanism. In summary, it was found that the durability of the inserts was directly related to coating adhesion, as coating detachment quickly led to the end of the insert's lifespan.

Preparation of asymmetrical cutting edge geometries on micro end mills using pressurized wet abrasive jet machining for hard micromachining of AISI M3:2

Cutting edge preparation is an established approach in the field of machining technology for optimizing the performance of cutting tools. However, the potential of asymmetric geometries has not yet been sufficiently utilized for filigree micromilling tools. In this regard, the study presents investigations on the adjustment of asymmetric microgeometries through the design of the pressurized air wet abrasive jet machining (PAWAJM). The study features results regarding the design of the preparation process as well as subsequent application tests in a hard micromilling process of the hardened high-speed steel AISI M3:2. The application tests focus on the effect of the conditioned cutting edge on the process forces and the surface quality as well as the tool life. The results show that asymmetrical microgeometries with small average cutting edge rounding and a form-factor of K > 1.2 can be achieved by PAWAJM. Machining tests revealed a potential reduction of the wear development and process forces for modified tools with low cutting edge rounding and asymmetrical microgeometry.

Investigation on femtosecond laser combined with dynamic wet etching machining of SiC/SiC

SiC/SiC (Silicon Carbide fiber reinforced Silicon Carbide) is widely used in aerospace and gas turbine fields due to its excellent resistance to high temperature, corrosion and low density. However, the difficult processing of SiC/SiC is the main factor limiting its further application. To address these issues, this paper proposes a novel method for processing SiC/SiC using femtosecond laser combined with dynamic wet etching. A comparative analysis of the micro-pore morphology and elemental composition obtained through processing in air, water, and NaOH solution is presented. Demonstrates the excellent surface quality achieved with NaOH processing, which effectively reduces defects such as recast layers and microcracks. The results suggest that the operating mechanism involves the combined effects of a wet-oxygen coupling environment, high-temperature decomposition, localized chemical wet etching, and the influence of the liquid layer.

English

English

Experimental investigations on the performance of ductile cast iron with palm oil during turning process using MQL technique

This project focuses on turning of ductile cast iron using the MQL (Minimum Quantity Lubrication) technique. Vegetable oil is used as a substitute cutting fluid, and the results are compared with dry conditions to demonstrate the benefits of turning the material under MQL environment. Three process parameters, namely cuttingspeed (V), feed (F), and depth of cut (D), are varied to obtain the responses like cutting force (Fc) and surface roughness (Ra). In wet turning edible vegetable palm oil is misted onto the tool-workpiece contact. The cutting force and surface roughness are tabulated for both dry and wet machining. Based on these data, Taguchi optimization is performed using L27 design for both wet and dry conditions. The optimization of the process parameters is done for both dry and wet turning. There is a significant difference with respect to cutting force and surface roughness is appreciated to demonstrate the effectiveness of MQL turning over dry turning of ductile cast iron. The cutting force during wet turning is reduced, from 5.89 kgf to 4.91 kgf and surface roughness is reduced from 0.832 µm to 0.629 µm compared with dry turning. The optimized parameters are included in the conclusion of this paper.

INTEGRATION OF TAGUCHI AND PROMETHEE FOR CNC MILLING MACHINING PARAMETER OPTIMIZATION ON AA6061

In the manufacturing industry, machining has developed quite rapidly from the use of conventional machines to unconventional machines. Unconventional machines that are often used today are optimize computer numerically controlled (CNC), the use of CNC in the manufacturing industry provides many benefits in product quality and productivity. One of them is CNC milling, this type is one of the main machines on the production floor. Machining optimization becomes the main goal to achieve the ideal response in order to produce products with good and consistent quality and productivity. Surface quality leads to surface roughness, while productivity leads to material removal rate. This study aims to optimize CNC milling machining parameters on AA6061 with Taguchi experimental design and preference ranking organization method for enrichment evaluation (PROMETHEE) method. Machining was controlled using wet machining conditions to maintain temperature during machining. Experiments were conducted nine times with three factors and levels. These factors included spindle speed, feed rate, and depth of cut. The result of this research is the ideal value of the combination of surface roughness and material burning rate which is 0.565 (experiment 3). This best experiment is influenced by spindle speed 2600 rpm, feed rate 65 mm/min, and depth of cut 2.5 mm. Feed rate has the largest contribution in influencing the response which is 43.23%, followed by depth of cut 25.24%, and spindle speed 15.91%.

In process temperature and tool wear for the machining of aeronautic aluminum under different lubrication conditions

The use of aluminum-lithium alloys in aeronautics is an efficient solution for lightweight structures, but its machinability can cause increased tool wear. The cutting temperature is one of the most important parameters controlling the tool wear and the quality of machined surfaces. Therefore, its measurement is of great interest to analyze the heat generation during the cut and then being able to limit it in the cutting edge. This article presents an original experimental study of the cutting temperature of two aluminum alloys (7000 series and Li-containing 2000 series), for dry, MQL: Minimum Quantity of Lubrication and wet machining conditions. The interactions between tool wear and cutting temperature are also investigated. To be able to observe tool wear, the milling of very large volumes of aluminum alloys has been necessary since the tool lifetime is several hours when machining this kind of material. To measure temperature as close as possible the cutting zone, an original set-up with machinable thermocouples was used, enabling measurements on a large frequency bandwidth. Complementary investigations by Second Ion Mass Spectroscopy revealed a diffusion of lithium in the cutting insert, which can reduce its lifetime (divided by 8, with the Li-containing 2000 series compared to the 7000 series).

Sustainable machining: A review

This paper's goal is to review pertinent material on machining with minimum lubrication for green manufacturing. Due to the fact that it has an impact on so many various industrial businesses, sustainability has grown to be a very important research topic. The implementation of sustainable manufacturing techniques and technologies has given the sector a workable way to enhance its performance in terms of the economy, environment, and society. The machining system is a crucial component of sustainable manufacturing on the factory floor since it is a significant production process. Therefore, leaders should prioritise technology for monitoring, evaluating, estimating, and optimizing machining systems' impact on the environment. The study also discusses the testing procedures, results, and use of a variety of workpiece materials, tool materials, and cutting solutions made of vegetables. The results show that the MQL system is effective in achieving a smoother surface, decreasing friction, removing chips, and cooling the workpiece. The literature review demonstrates that the MQL system outperforms both dry machining and wet machining in terms of performance. This paper provides a quick overview of the machining of various materials utilizing the MQL system as a sustainable machining.

Machining grade 4 titanium alloy by minimum quantity lubrication for enhanced sustainable manufacturing

AbstractMachining is a widely used class of industrial manufacturing operation, wherein cutting fluids play a vital role in terms of machining accurate dimensional quality objects due to their cooling, lubricant, and chip removal abilities. Although certain advanced cutting fluids have changed the manufacturing industry for the better, there are some environmental concerns associated with some of these fluids. The use and disposal of cutting fluids may be costly and subjected to stringent government laws. Hence, the ever-growing research conducted on environmentally friendly cutting fluids may lead to enhanced sustainable manufacturing. The aim of this investigation is therefore to investigate the viability of minimum quantity lubrication (MQL) during machining of titanium alloys with specific focus on the commercially pure grades (grade 4). A comparative study was conducted in order to establish the effects of different modes of lubrication, i.e., dry, wet, and MQL machining on titanium.

In pursuit of sustainability in machining thin walled α‑titanium tubes: An industry supported study

Cryogenic machining has emerged as a major sustainable machining techniques especially for difficult-to-cut alloys, including titanium, Inconel alloys in terms of its impact on cost savings for high-value manufacturing projects reduced energy consumption, enhanced worker safety, and eliminating the infrastructure and disposal needed for flood coolants. However, further study is needed to quantify the sustainable elements of machining processes to have a clearer vision for industries to transition from traditional techniques to such advanced techniques. In the currently known literature, the topic of high-speed machining of titanium tubes with thin walls is yet to be explored under advanced cooling technique. The studies on the machinability indicators including tool wear, power consumption etc. are the backbone to the assessment of sustainability aspect of machining. The quantification of sustainability indicators in terms of machining costs and carbon emissions will provide better insights to the industries to maximise their profits and have least negative impacts on the environment. Thus, this study focuses on analyzing sustainability of the machining processes in terms of economic and environmental factors while turning thin walled α‑titanium tubes under different cutting environments which include dry, wet and cryogenic machining under two different high cutting speeds of 150 m/min and 200 m/min. The economical aspect comprises the assessment of the different machining costs occurring during the machining. The environmental aspect includes the assessment of carbon emissions occurring during the machining operation. The backbone of the sustainability analysis is the machinability analysis which involves the investigation of power consumption and cutting tool-wear. A comprehensive study of tool wear and total power consumption has been presented to get a better perspective in the machinability of thin walled α‑titanium tubes while working in the cryogenic environment in comparison with dry and wet environments. The total machining cost is relatively less (approximately 27%) under cryogenic environment in comparison with a wet environment making it a more economical process. The total emissions of carbon are also found to be lowered (up to 9%) while machining under cryogenic environment in comparison with a wet environment making it a more environmentally friendly process. The cutting tool wear is found to be relatively low (up to 38.68% and 72.24%) under cryogenic environment in comparison with wet and dry environments respectively. Power consumption was compared for the three different environments to have detailed analysis in terms of productivity and sustainability. A significant reduction in total power consumption (up to 19.25%) was observed under cryogenic environment in comparison with wet environment.

티타늄 소재 극저온 가공 시 극미량 윤활 조건에 따른 가공 특성 분석 연구

Titanium alloys are used in various industries due to their superior mechanical strength and corrosion resistance. However, titanium is classified as a difficult-to-machine material due to its low thermal conductivity that consequently causes poor tool life. In this study, cryogenic+MQL milling was performed to improve the machinability of Ti-6Al-4V; a cryogenic coolant and a minimum quantity fluid were sprayed simultaneously. The machinability was analyzed according to the cooling and lubrication conditions, focusing on the cutting force and tool wear. When the minimum quantity fluid was injected using two nozzles during cryogenic machining, the cutting force remained low despite the increase in machining distance due to the effective lubrication. The average cutting force at the long machining distances (82-86 passes) was 14.8% lower than that under the wet condition. The tool wear progressed without chipping, and the flank wear length was 55.5% lower than that of the wet machining because the cryogenic cooling and minimum quantity lubrication reduced the tool temperature, friction, and thermal shock.

Tool wear effects on green and WCO/MoS2 nanofluid clean machining

The philosophy of conventional machining is use of hard tool to machine soft or less hard materials. Though the hard tool is used for machining, the high friction at interface causes the wear or damage of tool. The tool wear or damage effects on the machined surfaces and degrades the quality gradually. Hence tool wear is considered as an important measure of performance in the machinability investigation. This investigation compares the tool wear on conventional green machining and proposed wet machining of SAE1144 steel. Four different Grade Nanofluids prepared with four different concentration of Molybdenum disulfide Nano-particles (0.10 wt%, 0.15 wt%, 0.20 wt%, 0.25 wt%). Other process independent parameters are also varied at four levels like Cutting Velocity (40, 90, 140 and 190 m/min), Tool Feed (0.05, 0.10, 0.15 and 0.20 mm/rev) and Nose Radius (0.30, 0.60, 0.90 and 1.20 mm). Taguchi L16 experimental Design used for conducting experiments. The experimental results are statistically validated and found significant and acceptable. The proposed novel nanofluid based wet machining reduced the average tool wear of 38% than conventional green machining.

Investigating concentration of nano-particles influence in Molybdenum disulfide waste cooking oil nanofluid for machining of SAE 1144 in surface finish enhancement

When a shaft breaks under fatigue, the condition of its surface is crucial. The precise shafts used in this application are machined using used cooking oil or waste cooking oil from a Kerala chips store. This study looks into how a Nano fluid containing Molybdenum disulfide Nano-particles enriched in used cooking oil can reduce the surface roughness of a material. In this study, two groups of samples were used: one group had their samples machined (turned) using a green machining method on a heavy-duty lathe, and the other group had their samples machined using a wet machining method that took a clean technology approach by varying the concentration of Molybdenum disulfide Nano-particles in waste cooking oil. It was determined that 12 people each group would be needed to run reliable studies with a G-Power of 80%, but 16 people per group were seriously evaluated. Material processing of SAE 1144 shaft by graphite enriched waste cooking oil based wet machining method significantly decreased Surface Roughness when compared to green machining and Molybdenum disulfide Nano-particles enriched waste cooking oil based wet machining method under similar input conditions. The condition of p < 0.05 indicates a significant value of 0.012. The experimental results show that the use of proposed Molybdenum disulfide greatly reduced the average surface roughness from 9.216875 µm to 1.3825 µm. Nano-particles enriched waste cooking oil based wet machining method, and the results do not contradict the statistical assumption. This method is therefore recommended for processing the SAE 1144 material for shaft manufacturing.

Effects of Molybdenum disulfide nano-particles’ concentration on waste cooking oil nanofluid in reduction feed force in CNC wet machining of SAE 1144 steel

Effects of Molybdenum disulfide nano-particles’ concentration on waste cooking oil nanofluid in reduction feed force in CNC wet machining of SAE 1144 steel

Identification of the process damping coefficient in dry and wet machining of steel

Flank face chamfers are an effective way to suppress vibrations and increase the productivity of milling processes. The underlying process damping mechanism is the so-called indentation effect. The effect describes the process damping as a result of an additional force due to the indentation of workpiece material under the flank face. In literature, this force is commonly modeled by the volume indented under the flank face and a process damping coefficient. To determine the process damping coefficient, various approaches with partly contradictory results exist. In this paper, a novel method to calculate the process damping coefficient based on process forces measurements in orthogonal cutting is applied for steel machining. The method considers ploughing effects of flank face chamfer and cutting edge rounding as well as plastic deformation effects. In the current investigation, the approach is applied to different cooling strategies, chamfer widths, and cutting speeds. The results show that the cutting speed has the most significant influence on the process damping coefficient. With increasing cutting speed, the process damping coefficient increases, which can be attributed to strain rate hardening effects.

An experimental evaluation of cryogenic machining in the drilling of carbon fiber reinforced plastics for aerospace

The present research aims at studying both dry machining and alternative solutions to wet machining in the drilling of carbon fiber-reinforced polymers (CFRPs). CFRPs are key materials in aerospace and their drilling is critical and challenging. Specifically, cryogenic fluids such as CO2 and N2 were investigated. Drilling tests were performed using three different CFRP laminates. These CFRP laminates are composed of various unidirectional plies of different orientations. Thus, the configurations to analyze were: 0/90/45, 30/60 and 0/90. As output variables, surface roughness, diameter deviation, delamination and thrust forces were analyzed. In general, the internal application of CO2 and dry machining were the best- and worst-performing techniques for surface roughness, respectively. Regarding the dimensional quality, both CO2 and dry machining offered the best results. In the case of LN2 or LN2 + CO2, the results showed that the CFRP configuration is critical for the obtained results. However, it was identified that cryogenics can improve the results of the dry machining process under certain conditions in terms of delamination. Finally, in general, CO2 provided the worst results when attending to the thrust forces.

Influence of advanced coated tools on surface integrity characteristics of Nimonic C263

Advanced coated tool and cooling techniques were used for trial on Ni-based superalloy Nimonic C 263 to improve surface integrity, such as a white layer, grain refinement, and surface defect. Toolmaker microscope, Field emission scanning electron microscopy (FESEM), and X-ray diffraction (XRD) system were employed to characterize the tool after machining, machined surface, and subsurface alteration. A possible cause of tool failure at high cutting speed and feed was severe plastic deformation and chipping of the cutting edge and nose, abrasive nose and flank wear, and the formation of a built-up layer (BUL). The white layer, surface defect, and grain refinement are always found less on machined surfaces with the PVD-coated tool under dry machining than with an uncoated tool under wet machining at a high rate. TiN/TiAlN multilayer coated WC tool can be suggested for good machinability and surface integrity in a sustainable, eco-friendly way to the industry for machining Nimonic C-263. MQL and flood mode cooling are also preferred at a cutting speed near 84 m/minute and a feed rate of 0.14 mm/rev.

Performance of eco-benign lubricating/cooling mediums in machining of superalloys: A comprehensive review from the perspective of Triple Bottom Line theory

Nickel, titanium, and cobalt-based superalloys are utilized in several engineering applications. The unique material properties, for instance, low thermal conductivity and high strength, make it a challenge to machine them easily. The utilization of appropriate lubricating technology is crucial for increasing the machinability of superalloys. Superalloys are frequently machined using mineral oils as lubricants. However, various biological and environmental issues could be caused by these mineral oils. To eliminate the harmful consequences, it's indeed necessary to switch to the use of environmentally friendly lubricants/coolants. Sustainable lubricating/cooling mediums use a minimum quantity of lubricants, liquid nitrogen, dry ice, vegetable oil, nanofluid and compressed air as a cutting fluid, which is thought to be environmentally beneficial and biodegradable. In this review paper, a comprehensive analysis of different eco-benign lubricating/cooling methods used in superalloy machining specifically for turning, milling, drilling, and grinding, etc. is presented. In comparison to traditional wet machining, it has been discovered that these methods produce significantly enhanced surface morphology and tool life, lower cutting temperatures, and cutting forces. The current paper also discusses the benefits and drawbacks of various lubrication/cooling strategies for enhancing superalloy machinability. Following that, for the first time, a review is conducted from the perspective of the Triple Bottom Line, demonstrating that the majority of previous surveys focus on the environmental and economic dimensions of lubrication/cooling techniques used in machining, so more emphasis should be put on the social dimension. In summary, this paper presents a detailed collection of information concerning eco-friendly lubrication/cooling systems that would assist new researchers in recognizing the latest progress as well as potential future research areas on the sustainability elements of superalloy machining.

Surface Topography Description after Turning Inconel 718 with a Conventional, Wiper and Special Insert Made by the SPS Technique.

This paper presents a comparison of surface morphology obtained after machining Inconel 718 by the conventional insert, by Wiper insert and by using the cutting insert made by Spark Plasma Sintering (SPS). The shape of the special insert was obtained by employing Wire Electrical Discharge Machining (WEDM). The paper focuses on the description of surface topography after turning in dry and wet conditions. The performed investigation included longitudinal turning tests of Inconel 718 performed in a range of variable feeds. Surface topography measurements have been performed with the application of Nanoscan 855. The performed analysis includes a parametric evaluation of the obtained surfaces. With the Wiper insert, the Sa surface roughness parameter was obtained below 0.6 µm in the whole range of used feed rates. The surface roughness parameter Sa measured on the surface after machining by special insert depends on the cutting conditions (wet and dry machining). After, the dry machining parameter Sa, similar to the Wiper insert, was below 0.6 µm in the whole range of used feed rates. Unfortunately, cutting Inconel 718 using special insert with feed rate f = 0.25 mm/rev and cooling generated a surface with Sa parameter over 2 times higher than for the same feed rate without cooling, while this parameter, after turning by conventional insert, increases over 4 times using feed rate f = 0.25 mm/rev compared to feed rate f = 0.05 mm/rev during machining with cooling. This ratio is lower for conventional insert in dry machining because of sticking, which arises at the smallest feed rate according to previous research.