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We present and analyze a central cutting surface algorithm for general semi-infinite convex optimization problems and use it to develop a novel algorithm for distributionally robust optimization problems in which the uncertainty set consists of probability distributions with given bounds on their moments. Moments of arbitrary order, as well as nonpolynomial moments, can be included in the formulation. We show that this gives rise to a hierarchy of optimization problems with decreasing levels of risk-aversion, with classic robust optimization at one end of the spectrum and stochastic programming at the other. Although our primary motivation is to solve distributionally robust optimization problems with moment uncertainty, the cutting surface method for general semi-infinite convex programs is also of independent interest. The proposed method is applicable to problems with nondifferentiable semi-infinite constraints indexed by an infinite dimensional index set. Examples comparing the cutting surface algorithm to the central cutting plane algorithm of Kortanek and No demonstrate the potential of our algorithm even in the solution of traditional semi-infinite convex programming problems, whose constraints are differentiable, and are indexed by an index set of low dimension. After the rate of convergence analysis of the cutting surface algorithm, we extend the authors' moment matching scenario generation algorithm to a probabilistic algorithm that finds optimal probability distributions subject to moment constraints. The combination of this distribution optimization method and the central cutting surface algorithm yields a solution to a family of distributionally robust optimization problems that are considerably more general than the ones proposed to date.

In recent years, the application of the difficult-to-machine materials has increased gradually, and the challenging requirements have been placed on cutting. The difficult-to-machine materials suffer from limitations such as large cutting force, high cutting temperature and serious cutting tool wear during processing. In order to improve the cutting performance of cutting tools and attain sustainable development, the green cutting technology has been gradually developed. The cutting tool surface micro-texture and coating represent the key technologies for attaining the green cutting performance. These technologies can improve the cutting performance, thereby prolonging the cutting tool life and improving the workpiece surface quality. This study systematically expounds the latest progress in the field of micro-textured cutting tools, coated cutting tools and micro-textured coated cutting tools. It introduces the existing micro-texture and coating preparation processes and analyzes the mechanism of micro-texture and coating. The compiles the recent developments in the materials and structures, along with summarizing the effect of micro-texture, coating and micro-texture coating synergy on cutting tool performance, cutting performance and workpiece surface quality. Finally, it presents the future development trend for the micro-textured cutting tools, coated cutting tools and micro-textured coating cutting tools. Overall, this study acts as a benchmark for the follow-up development in the field of green cutting technology.

Using cutting fluids is considered in industrial applications and academia due to their increased influence over many aspects such as machinability, sustainability and manufacturing costs. This paper addresses the machinability perspective by examining indicators such as roughness, cutting temperature, tool wear and chip morphology during the milling of mold steel. A special type of steel is Nimaxm which is a difficult-to-cut material because of its high strength, toughness, hardness and wear resistance. Since mold steels have the reverse geometry of the components produced by this technology, their surface quality and dimensional accuracy are highly important. Therefore, two different strategies, i.e., dry and minimum quantity lubrication (MQL), were chosen to conduct an in-depth analysis of the milling performance during cutting at different cutting speeds, feed rates and cutting depths. Without exception, MQL technology showed a better performance than the dry condition in obtaining better surface roughnesses under different cutting parameters. Despite that only a small improvement was achieved in terms of cutting temperature, MQL was found to be successful in protecting the cutting tool from excessive amounts of wear and chips. This paper is anticipated to be a guide for manufacturers and researchers in the area of mold steels by presenting an analysis of the capabilities of sustainable machining methods.

In this study, the effect of both cryogenic and dry machining of AZ31 magnesium alloy on temperature and surface roughness was examined. Cryogenic machining experiments were conducted by applying liquid nitrogen at the cutting zone. The cutting parameters (cutting speed, depth of cut, and feed rate) were varied, and their effect on the results was identified. It was found that the cryogenic machining was able to reduce the maximum temperature at the machined surface to about 60% as compared with dry machining. A finite element model was developed to predict the temperature distribution at the machined surface. The simulated results showed good agreement with the experimental data. After analyzing the temperature distribution, the model also suggested that the cryogenic-assisted machining removes heat at a faster rate as to that of the dry machining. An arithmetic model using the response surface method was also developed to predict the maximum temperature at the surface during cryogenic and dry machining. The analysis pointed out that the maximum temperature was greatly affected by the cutting speed followed by feed rate and depth of cut. Cryogenic machining leads to better surface finish with up to 56% reduction in surface roughness compared with dry machining.

In this study, the surface integrity of nickel-titanium (NiTi) shape memory alloys (SMAs) was investigated after face milling processes with cryogenically treated/untreated cemented carbide cutting tools at the conditions of dry cutting and minimum quantity lubrication (MQL) of cutting fluids depending on the changing cutting parameters. The integrity of surface layer of the workpiece material was evaluated according to the mean surface roughness, microstructure and hardness, as well as according to the resultant cutting force and flank wear of inserts. Cutting tests were carried out at three different cutting speeds (20, 35 and 50 m/min), feed rates (0.03, 0.07 and 0.14 mm/tooth) and a constant axial cutting depth (0.7 mm). The influence of these parameters on the surface integrity was extensively investigated. The face milling tests of NiTi SMA at optimal cutting parameters show that the surface integrity enhanced at a cutting speed of 50 m/min and feed rate of 0.03 mm/tooth using boron-added cutting fluid (EG + %5BX) with deep cryogenic heat treated (− 196 °C) CVD coated S40T grade cutting tool. Under MQL conditions, the minimum mean surface roughness (0.278 µm), resultant cutting force (268.2 N) and flank wear (0.18 mm) were obtained due to the high thermal conductivity and lubrication property of EG + %5BX cutting fluid. The highest hardness values (343 HV) were measured at the zone subjected to the highest deformation, while the lowest one (316 HV) was measured at the zone at the least deformation.

Ultra-precision machining (UPM) is crucial for producing parts with functional surfaces featuring nano textures, yet it faces challenges in generating such textures. This paper explores the potential of magnetic field-assisted UPM to overcome these challenges by leveraging magnetophoresis to generate nanotextures and thoroughly investigating the importance of cutting velocity on magnetophoresis in diamond cutting. Experimental results from cutting force, surface profile, surface topography, and atomic force microscopy images demonstrate that magnetic fields enable nanotexture generation on aluminum alloys surfaces in diamond cutting. Also, increasing cutting speed in diamond cutting under a magnetic field enhances magnetophoresis. This study highlights the advantages of integrating magnetophoresis for advanced nanotexture fabrication in UPM and emphasizes strategies for control cutting speed to achieve nanotextures.

Tungsten alloy has excellent performance and has been widely used in military, aerospace and nuclear energy, and other cutting-edge industries. However, tungsten alloy has large hardness, high strength, and poor plastic deformation ability, which resulted in high cutting force and serious tool wear during the cutting process, leading to low surface quality of the workpiece after molding. Therefore, it is of great significance to strengthen the research on tungsten alloy cutting technology to promote the development of tungsten alloy application. Firstly, the research progress of tungsten alloy cutting process technology has been systematically reviewed, and the current status of cutting parameters optimization, new cutting methods and devices, and cutting fluid technology have been emphatically reviewed. Secondly, the types of tungsten alloy cutting tools, the relevant tool micro-texture, and tool coatings technology have been briefly described, and the composite cutting technology such as cryogenic cutting, electroplastically assisted cutting, and ultrasonic vibration assisted cutting and the effect of cutting performance prediction technology on tungsten alloy machining performance have been summarized. Finally, the development prospect of tungsten alloy cutting technology has been prospected.

The Ti-6Al-4V titanium alloy is a kind of light alloy material with high specific strength, corrosion resistance and heat resistance. Because of its excellent performance, it has become an important material in aerospace industry. However, this kind of alloy has very poor machinability, and rapid tool wear is a very serious problem in titanium alloy processing. At present, it is difficult to guarantee the ultra-precision machining quality of titanium alloy materials, which limits its application in high-tech fields. In order to solve this problem, the influence of cutting speed on ultra-precision cutting process of titanium alloy was analyzed comprehensively. and it was found that better surface quality could be obtained at lower cutting speed. In order to study the influence of cutting speed in ultra-precision cutting of titanium alloys, cutting experiments have been carried out. Additionally, a finite element model was established to analyze the ultra-precision cutting process. Also, the constitutive model, damage model, friction model, and heat transfer in the modeling process were discussed. The chip morphology, cutting temperature, cutting force, and surface morphology under different cutting velocities are analyzed by simulation. Then, the simulation results were compared with the experimental results. The findings show that cutting speed has great influence on the ultra-precision turning of the Ti-6Al-4V alloy and the surface roughness obtained by ultra-precision cutting of titanium alloy can be lower than 20 nm at a lower cutting speed.

The main objective of this article is to perform the turning operation on an EN36B steel work-billet with a tungsten carbide tool, to study the optimal cutting parameters and carry out an analysis of flank-wear. Experimental and simulation-based research methodology was opted in this study. Experimental results were obtained from the lab setup, and optimisation of parameters was performed using RSM (response surface methodology). Using RSM, cutting-tool flank-wear was optimised, and the cutting parameters which affect the flank wear were determined. In results main effect plot, contour plot, the surface plot for flank-wear and forces (Fx, Fy and Fz) were successfully obtained. It was concluded that tool flank-wear is affected by depth of cut, and that flank-wear generally increases linearly with increasing cutting-speed, depth of cut and feed-rate. To validate the obtained results, predicated and measured values were plotted and were in very close agreement, having an accuracy level of 96.33% to 98.92%.

This article focuses on turning superalloy Udimet 720, which is difficult to work with, using different coolant/lubricant methods. The study includes delivering Graphene and Multi-Walled Carbon Nanotubes nanopowders homogeneously dispersed in vegetable oil to the cutting area with the minimum quantity lubrication (MQL) method. Experiments at different cutting speeds and feed rates were repeated in four different cutting environments. Compared to dry turning, the cutting zone temperature of the cutting fluid delivered to the cutting zone by MQL methods decreased. In addition, thanks to the nanopowders, it formed an oil film by better penetrating the cutting tool-chip interface and reducing the cutting tool’s wear. With the reduced cutting tool wear, the cutting tool could maintain its form for a longer period of time, so better quality surfaces were obtained on the workpiece surface. As a result of the study, it was found that cutting zone temperature improved by 30%, tool wear by 51.8% and surface roughness by 43.9%.