Improve Tool Life Research Articles

Sustainable machinability of cast iron material by optimizing Mn and S configurations

In manufacturing industry, sustainability plays an important role for increasing the operational functionality of various machined components. Endeavours are made across the world, throughout this century, to bring down tool consumption by optimizing chemical composition on cast iron components. Within the cast iron material, sulphur is considered as an impurity; however it possesses potential to solve this issue when increased with respect to Manganese, in a specific proportion. In casting industry, generally, sulphur is kept at a level of 0.05–0.08% throughout. Series of experiments being conducted to observe the behaviour of sulphur in casting as well as to understand the cumulative effect of P & Mn on mechanical properties followed by its microstructure, globally. The objective of this research was to establish tool life improvement by addition of sulphur in a cost effective unique method by using experimentation in two phases. The phase-1 dealt with the addition of sulphur in molten metal pool inside furnace, at selected foundry plant. The pure sulphur (yellowish coloured, normally known as Gandhak), infused into molten metal using sandwich process followed by casting of chosen product. The phase-2 dealt with the machining of bare & modified samples followed by establishing the results between inserts used for machining. Machining carried out on vertical machining centre using ceramic inserts. The combined results are analysed by wear pattern analysis which finally concluded that 45% less life consumed in machining of modified casting as compare to the bare casting.

Abrasive water jet tool passivation: from mechanism to application

The passivation process of a tool is a necessary step in the manufacturing process, which could improve tool life and machining efficiency by removing microscopic defects of in tool surface (such as burrs and micro cracks) after grinding or polishing. The abrasive water jet passivation (AWJP) is one of the most commonly used processes for carbide, ceramic and steel materials tools. Nevertheless, the complex action law from passivation to machining performance is indistinct, which makes passivation parameters rely on empirical summaries. To fill this gap, this paper concentrates on the detailed review of AWJP and comprehensive assessment between machining performance and AWJP parameters. Firstly, the mechanism of AWJP is analyzed, and the influence law of jet parameters on the tool nose radius is investigated. Secondly, the effect of tool nose radius on the force in turning and milling are summarized and analyzed. The jet pressure, abrasive concentration and jet time are positively correlated with the tool nose radius. Additionally, then the tool nose radius is positively and negatively correlated with cutting force and tool wear, respectively. Finally, future directions regarding the different parameters in AWJP and the machine tool for tool passivation are proposed: to reveal the complex nonlinear relationships between the parameters in AWJP. Develop economical, practical and efficient tool passivation machine tools to improve passivation efficiency and passivation accuracy and apply them to domestic tool passivation technology.

The Use of TOPSIS Method for Multi-Objective Optimization in Milling Ti-MMC

This paper presents the use of TOPSIS, a multi-criteria decision-making model combined with the Taguchi method to find the optimum milling parameters. TOPSIS is the Technique for Order Preference by Similarity to the Ideal Solution and shows the value of closeness to the positive ideal solution. This study shows the optimum combination of process parameters using the shortest distance from the ideal solution. The surface roughness and flank tool wear were considered the objectives for simultaneous optimization. After converting multiple responses into a single response, the Taguchi method was used to analyze and determine the optimum machining parameters. According to reported studies, the initial wear behavior and initial cutting conditions have significant effects on the tool wear progress. Several initial cutting parameters can contribute to tool life and therefore can be used to improve both tool life and surface roughness. However, the cutting speed may significantly affect tool wear and ultimate tool life. In this study, an innovative solution was proposed for interrupted machining with two different cutting speeds. The first level cutting speed was used for 1 s and the second level was used for the rest of the process. The experimental results indicate that the initial speed followed by the feed rate significantly affects tool life. In addition, using the proposed strategy with different levels of cutting speed during machining operations led to improved tool life and surface roughness compared to conventional machining with uniform cutting speed throughout the entire process.

The Influence of Surface Texturing of Ceramic and Superhard Cutting Tools on the Machining Process-A Review.

Machining is an indispensable manufacturing process for a wide range of engineering materials, such as metals, ceramics, and composite materials, in which the tool wear is a serious problem, which affects not only the costs and productivity but also the quality of the machined components. Thus, the modification of the cutting tool surface by application of textures on their surfaces is proposed as a very promising method for improving tool life. Surface texturing is a relatively new surface engineering technology, where microscale or nanoscale surface textures are generated on the cutting tool through a variety of techniques in order to improve tribological properties of cutting tool surfaces by reducing the coefficient of friction and increasing wear resistance. In this paper, the studies carried out to date on the texturing of ceramic and superhard cutting tools have been reviewed. Furthermore, the most common methods for creating textures on the surfaces of different materials have been summarized. Moreover, the parameters that are generally used in surface texturing, which should be indicated in all future studies of textured cutting tools in order to have a better understanding of its effects in the cutting process, are described. In addition, this paper proposes a way in which to classify the texture surfaces used in the cutting tools according to their geometric parameters. This paper highlights the effect of ceramic and superhard textured cutting tools in improving the machining performance of difficult-to-cut materials, such as coefficient of friction, tool wear, cutting forces, cutting temperature, and machined workpiece roughness. Finally, a conclusion of the analyzed papers is given.

Study on Cutting Performance of Micro Groove Tool in Turning AISI 304 and Surface Quality of the Workpiece

AISI 304 has high-tensile strength and excellent corrosion resistance, which is widely needed in the energy industry and equipment manufacturing industry. However, the tools for cutting AISI 304 are easy to wear and have short service life. In order to improve tool life, micro grooves are designed on the rake face of the tool for the machining of AISI 304. Through the single factor cutting experiment, it is found that under the same cutting parameters, the micro groove tool has less cutting depth resistance than the initial tool; the main cutting force and feed resistance are reduced by more than 15%. The shear energy is reduced by more than 13%; the surface roughness and the hardening degree of the workpieces are reduced. Through the durability test, it is found that the service life of the micro groove tool is 57% longer than that of the initial tool, and the abrasive wear, bonding wear, and oxidation wear of the tool are significantly less. Through cutting experiments and theoretical analysis, the cutting performance of the micro groove tool has been improved.

Dry cutting performance and heat transfer simulation of pulsating heat pipe self-cooling tool holder

To reduce the use of cutting fluid, the concept of transforming the tool or holder into an automatic heat dissipation device was proposed. A novel structure of pulsating heat pipe self-cooling tool holder was designed to improve the cutting performance. The temperature of the cutting insert, the flank wear, and tool life improvement of pulsating heat pipe self-cooling tool were studied by experiment for cutting Ti6Al4V alloys. Results show that the cutting temperature of pulsating heat pipe self-cooling tool holder is generally lower than that of the prototype tool holder. The wear reduction ratio is 10 %–20 %, while the ratio of tool life increase is about 10 %. The temperature distribution in the actual cutting process was simulated by FEM with the loading of heat flux on the tool-chip contact area. The FEM simulations show that compared with the prototype tool, the temperature gradient distribution of the pulsating heat pipe self-cooling tool holder is denser. The temperature drops faster along the gradient direction, and the temperature of the tool tip is lower. The FEM simulations show a good agreement with the cutting experiment, as a result, prove the successful application of this novel structure in cooling for dry cutting.

Deep Reinforcement Learning for autonomous pre-failure tool life improvement

Deep Reinforcement Learning for autonomous pre-failure tool life improvement

Machining performance evaluation and tool wear analysis of dry cutting austenitic stainless steel with variable-length restricted contact tools

Austenitic stainless steel during machining still faces several challenges in terms of poor machinability and severe tool wear. In this work, different rake surface restricted contact tools with an inconstant tool-chip contact length are designed and fabricated. An in-depth investigation is then performed to comprehend the influence of the variable-length restricted contact tools on the machining performance and tool wear during dry cutting of AISI 316L austenitic stainless steel. The results indicate that considerable improvements in tribological properties and tool life are achieved with the developed tools. The cutting force, cutting temperature, chip curl radius, and chip thickness decrease compared to traditional restricted contact tools. A dramatic reduction in flank wear of up to 44.18% is obtained in variable-length restricted contact tools compared with traditional restricted contact tools. Variable-length restricted contact structures also reduce the adhesion rate and abrasion damage of tool wear processes. The insights in this study exhibit an efficient method of dry machining stainless steel and may provide a basis for designing cutting tools for green machining of difficult-to-cut materials.

Metallurgical and machining performance aspects of cryotreated tungsten carbide micro-end mill cutters

Demand for miniaturized parts with tight geometrical tolerances and superior surface finish has been increasing. Development of micromachining processes has enabled adaptation of miniaturized parts and products in mechanical systems. Machining at the microscale level has supplementary challenges like high cutting forces, reduced tool life, and damaged machined surfaces. Catastrophic failure of microtools is notable problem, if tool deflection increases significantly. Therefore, incorporating tool life improvement measures are essential to minimize tool replacement cost and also to achieve efficient cutting at micro-level. Cryotreatment imparts better physical properties to cutting tools. In the present work, effects of different cryogenic treatment parameters on micro tungsten carbide-cobalt (WC-Co) end mill cutters and its performance while machining Ti-6Al-4V have been investigated. The metallurgical changes imparted to cutting tool by cryotreatment are studied via micro-hardness test along with EDS, SEM and XRD methods. It is found that all cryotreated tools have higher hardness compared to untreated tools. Additional η (eta) carbide formation has been clearly observed for the tools soaked for 24 h, moreover a variation in other phase of WC is also observed for different set of cryotreatment. Machining process is significantly affected by the low thermal conductivity of Ti-6Al-4V. In case of untreated micro-milling tool, abrasive wear is dominant, whereas built-up-edge affected the performance of cryotreated tools at shallow cryotreatment temperatures for 8–16 h soaking time. Deep cryotreated tool (at 24 h soaking time) performed better in terms of cutting force and surface roughness due to retainment of sharp cutting edge.

Specific force map for smart machining applications with rotating tools

Industry 4.0 is the need of the hour in current global market scenario and all the processes are moving toward automation and smart manufacturing. In machining, smart techniques implementation depends on developing a database for decision-making, which is the case for stack drilling in aerospace industry. In this application, choosing one optimal condition for several materials is a challenge due to their different machinability. Hence, material identification techniques are suitable approaches for adapting the cutting parameters in real time, which improves tool life, hole quality, and productivity. In that regard, the goal of the present paper is to create a specific force data map for axial drilling and circular milling processes based on its experimental force and power measurements. To do that, experiments were separately carried out on Titanium and Aluminum workpieces in a range of cutting speed and feed conditions. The results show that specific cutting and feed forces for each material can be identified on distinct regions of the map, without thresholds overlapping. Given that, these maps can be used as a signature to distinguish two metallic materials in real time machining. In this case, the specific data points at the interface layers may offer advantage to accurately identify tool position unlike monitoring gradient of feed forces while drilling stacked materials. Therefore, smart machining techniques seeking cutting parameters optimization can be implemented for a particular material.

Achieving Desired Machinability in Turning Using The Analytical Hierarchy Process

Machinability plays an important role in material working industries. A material with good machinability requires less force with improved tool life during machining to make a desired surface finish. However, improving productivity as well as finish often faces a big challenge to find appropriate machining conditions to achieve the same. Environment-friendliness is also to be considered. Multi-criteria decision-making (MCDM) method can play an important role to suggest suitable machining conditions in this respect. An experimental work is done on machinability study of hard AISI 4340 steel using different environment. Turning experiments are done using coated carbide inserts through small quantity lubrication (SQL) under different cutting velocity and feed. Dry, rice bran oil-based solution and alkaline solution are chosen to be the environmental conditions. Linder different machining conditions, types of chips, cutting force, surface roughness, etc. are noted. Based on the experimental data, the Analytic Hierarchy Process (AHP), an MCDM method, is used to find optimal machinability condition for rough and finish turning. The AHP results show that for rough turning, the optimal alternative would be with cutting velocity of 237mm/min, feed of 0.16mm/rev, depth of cut of 2mm under wet environment-friendly environment (2:13 rice bran oil and water+ 85g Matic surf in 4 litre). For finish turning, the optimal alternative corresponds to a cutting velocity of 140 mm/min, feed of 0.08 mm/rev, depth of cut of 2 mm under the same wet environment. These conditions may be recommended for use in industry.

Effect of Porosity on Tool Wear During Micromilling of Additively Manufactured Titanium Alloy

Abstract Porosity is a major quality issue in additively manufactured (AM) materials due to improper selection of raw material or process parameters. While porosity is kept to a minimum for structural applications, parts with intentional (engineered) porosity find applications in prosthetics, sound dampeners, mufflers, catalytic converters, electrodes, heat exchangers, filters, etc. During postprocessing of additive manufactured components using secondary machining to obtain required dimensional tolerance and/or surface quality, part porosity could lead to fluctuating cutting forces and reduced tool life. The machinability of the porous AM material is poor compared to the homogenous wrought material due to the intermittent cutting and anisotropy of AM materials. This paper investigates the tool wear progression and underlying mechanisms in relation to the porosity of AM material during their machining. Micromilling experiments are carried out on AM Ti6Al4V alloy with different porosity levels. Insights into tool-workpiece interaction during micromachining are obtained in cases where pore sizes could be comparable to the cutting tool diameter. Findings of this research could be helpful in developing efficient hybrid additive-subtractive manufacturing technologies with improved tool life and reduced costs.

Improving the Efficiency of Cutting Tools through Application of Filtered Cathodic Vacuum Arc Deposition Coating Techniques: A Review

The challenge of enhancing cutting tool life has been dealt with by many research studies. However, this challenge seems endless with growing technological advancement which brings about incremental improvement in tool life. The objective of this review paper is focused at assessing filtered cathodic vacuum arc deposition techniques applied on cutting tools and their effect on tool efficiency. The paper particularly picks filtered cathodic vacuum arc deposition (FCVAD) among other well-identified methods of coating like the Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD). Filtered Cathodic Vacuum Arc Deposition is the state of art in the coating technology finding wide application in the electronics industry and medical industry in addition to the machining industry, which is the concern of this review paper. This review is made in order to summarize and present the various techniques of FCVAD coatings and their applications, as investigated by various researches in the area.

An experimental investigations on effects of cooling/lubrication conditions in micro milling of additively manufactured Inconel 718

The demand for additive manufacturing (AM) technology is recently increased in the aerospace, biomedical, and automobile sectors due to the capability of producing complex components with zero tolerance. However, the small or precise part manufactured by AM process needs post-processing such as machining, polishing, etc. because of the poor surface quality characteristics. Therefore, in this paper, the micro-milling was performed on additively manufactured Inconel-718 alloy under different sustainable cooling conditions. The tool wear, surface roughness, and burr generated during micro-milling experiments were investigated under the effect of air, minimum quantity lubrication (MQL), and flood cooling conditions. The results demonstrated that the MQL conditions provide the proper cooling and lubrication effect, and this results in improved tool life (which is almost 45% higher compared to dry conditions. MQL also improved the product quality in terms of surface roughness (almost 65% less surface roughness). Other machining characteristics, such as burr width and cutting forces, were also improved in MQL and flood environments. However, it was noticed that milling with a chilled air environment has not given any significant improvement in terms of machining characteristics.

Machinability investigation and sustainability analysis of high-pressure coolant assisted turning of the nickel-based superalloy Inconel 718

In recent years, issues related to eco-friendly machining have received more and more attention, leading to the development of new cooling/lubrication techniques. Herein, the paper investigates the effect of high-pressure coolant (HPC) supply on machining performance of Inconel 718 and compare with conventional flood cooling. Significant improvement in tool life, tool wear, tool-chip contact length, material removal volume, and cutting forces have been observed from the outcomes of HPC cooling condition. Moreover, in order to study the environmental impact of machining Inconel 718, a carbon emissions model was established and analyzed for high-pressure and flood cooling conditions, taking into account the carbon emissions from energy, material, cutting tool, and cooling/lubrication fluid. HPC assisted machining was revealed to be better as it makes possible a reduction in overall carbon emissions at higher cutting speeds. In addition, economic analysis for both cutting environments was also carried out. Significant improvement in reduction of the overall machining cost was observed under HPC conditions, especially at higher cutting speeds. In a nutshell, the findings revealed better performance of HPC assisted machining, with regard to machinability, environmental, and economic issues.

Tribological aspects of tool wear during turning Ti-15Mo alloy with cemented tungsten carbide cutting inserts prepared with different surface finishes

Due to the low machinability of titanium alloys, which have been increasingly applied in medical and aerospace industries, several studies have been carried out focusing on the improvement of tool life in machining processes that involve such class of material. Aiming at contributing to the technological investigations and at expanding the knowledge on the phenomena involved in the tool-workpiece contact, this work presents tool wear results and a tribological analysis of the application of cemented tungsten carbide cutting inserts with different roughness characteristics in the edge and flank face as well as grinding marks (grooves) in the rake face in distinct directions. The inserts were prepared by plunge-face grinding and used in turning of a beta-titanium alloy (Ti-15Mo). Results showed that the insert with lower surface and edge roughness and with grooves in the rake face perpendicular to chip flow direction led to the lowest final flank wear value when the tool life criterion was achieved. Higher flank wear values were obtained for the rougher inserts, due to the greater edge chipping produced in grinding.

공구 이송속도를 활용한 NC 절삭 가공 부하 적응 제어

NC machining data, which cause excessive cutting force, accelerate tool wear, reduce the roughness of machined surfaces, and in severe cases, result in tool breakage and material waste. Thus, the cutting conditions should be optimized according to the material-spindle speed-feed rate combination. However, it is very difficult to perfectly predict and optimize the dynamic characteristics of machining, such as tool vibration and wear, and spindle thermal deformation. Further, predicted tool paths are accompanied by machining errors. This study proposes an advanced adaptive control method that can balance the machining load, improve tool life, and reduce machining time. The proposed method 1) synchronizes the spindle load and NC-data and stores it, 2) analyzes the stored data to create a reference curve that can balance the machining load, 3) adjusts the tool feed rate using a reference curve, 4) engages rapid traverse when the load is small, and 5) applies an approach feed rate when the tool approaches a workpiece, reducing the impact on the tool when the tool meets the workpiece. Case examples proved that the use of the proposed balanced load reduced machining time and increased tool life.

Application of statistical and soft computational techniques in machining of Nickel based supper-alloy using cryogenically treated tools for estimation of surface roughness

ABSTRACT In this paper, surface roughness prediction models are developed for turning of Inconel 718 using untreated and cryogenically treated inserts by using Dimensional Analysis, Response Surface Methodology (RSM) and Artificial Neural Network (ANN). Performance of untreated and treated tools is analysed using SEM, Energy-dispersive X-ray analysis, Vicker hardness test and electrical conductivity. For the established surface roughness models by dimensional analysis, RSM and ANN, the mean absolute errors for confirmation tests are 5.32%, 8.28% and 4.15% for untreated inserts and 4.95%, 6.01% and 4.20% for treated inserts, respectively. The effect of cutting parameters on surface roughness is analysed using the main effect plot and 3D surface plots. Based on correlation coefficient (R2 ) values, ANN modelling technique (R2 = 99.68%) is more accurate for predicting surface roughness. Thus, it can be an effective tool for analysing machining responses. The study also noted that while cutting at v= 60 m/min, f= 0.1 mm/rev and d= 0.5 mm, surface roughness and flank wear values are 0.5 µm and 0.45 µm and 0.777 mm and 0.627 mm for untreated and treated inserts, respectively. The use of treated tools resulted in 10% and 19% improvement in surface quality and tool life than the untreated tools.

Predicting Cutting Force and Primary Shear Behavior in Micro-Textured Tools Assisted Machining of AISI 630: Numerical Modeling and Taguchi Analysis.

The cutting tool heats up during the cutting of high-performance super alloys and it negatively affects the life of the cutting tool. Improved tool life can enhance both the machinability and sustainability of the cutting process. To improve the tool life preferably cutting fluids are utilized. However, the majority of cutting fluids are non-biodegradable in nature and pose harmful threats to the environment. It has been established in the metal cutting literature that introducing microgrooves at the cutting tool rake face can significantly reduce the coefficient of friction (COF). Reduction in the COF promotes anti-adhesive behavior that improves the tool life. The current study numerically investigates the orthogonal cutting process of AISI 630 Stainless Steel using different micro grooved cutting tools. Results of the numerical simulations point to the positive influence of micro grooves on tool life. The results of the main effects found that the cutting temperature was decreased by approximately 10% and 7% with rectangular and triangular micro grooved tools, respectively. Over machining performance indicated that rectangular micro groove tools provided comparatively better performance.

Recent developments on sustainable lubricants by using vegetable oil based nanofluids in machining

The conventional lubricants used for machining are mineral based petroleum oils which effects on environment as well as human health and are difficult to dispose. Therefore, there is a need to practice environment friendly vegetable oil based lubricants for machining. Researchers have worked on various organic nanoparticles in combination with vegetable oils as base fluid. In many studies it is found that, such nanofluids exhibited better surface integrity, improved tool life, low temperature & cutting forces. But the major drawback associated with organic nanofluids is that, its solid particles tend to settle down for longer times even though surfactants are added in the mixture. Therefore, in order to overcome this problem the research is being carried out on hybrid nanofluids which is a combination of organic and inorganic nanoparticles in the base fluid along with surfactant. The problem of instability with organic solid nanoparticles can be overcome by adding inorganic nanoparticles in required proportion. This paper gives a detailed review on various vegetable oils and their properties to understand their suitability in machining. Further, more emphasize has given on machining practices with nanofluids and hybrid nanofluids alongwith with their preparation procedure and limitations.