scholarly journals On the mechanism of three-body adhesive wear in turning

2021 ◽  
Vol 113 (11-12) ◽  
pp. 3457-3472
Author(s):  
Inge Svenningsson ◽  
Kourosh Tatar
Keyword(s):  
Metal Cutting ◽  
Cutting Speed ◽  
Feedback System ◽  
Sound Waves ◽  
Transient Vibration ◽  
Cycle Frequency ◽  
Stochastic Duration ◽  
Internal Excitation ◽  
Three Body ◽  
Mechanical Dynamics

AbstractThe paper reveals a hypothesis regarding the adhesive mechanism in metal cutting and its mechanical dynamics. One steel grade, 34CrNiMo 6, 285 HB, and one set of coatings on the cutting tool are reviewed. The adhesive mechanism is a transient vibration, including a feedback system limited by the plastic deformation in the chip. The vibration shows as a cluster of waves with stochastic duration in time. It starts up again after a stochastic lapse of silence. The cycle frequency is around 12.5 kHz and the internal excitation is twice that frequency, as the cutting speed and feed are 200 m/min and 0.2 mm, respectively. The adhesive frequency and amplitude are influenced by the cutting speed and the current wear status. The adhesion is monitored by the sound waves emanating from vibrations in the chip, the part still in the workpiece.

Possible examinations of stone machining focused on the relationship between technological parameters and surface quality

2013 ◽  
Vol 4 (1) ◽  
pp. 63-68 ◽  
Author(s):  
Zs. Kun ◽  
I. G. Gyurika
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Theoretical Background ◽  
Motion Path ◽  
Depth Of Cut ◽  
Manufacturing Cost ◽  
Technological Parameters ◽  
The Relationship ◽  
Manufacturing Time

Abstract The stone products with different sizes, geometries and materials — like machine tool's bench, measuring machine's board or sculptures, floor tiles — can be produced automatically while the manufacturing engineer uses objective function similar to metal cutting. This function can minimise the manufacturing time or the manufacturing cost, in other cases it can maximise of the tool's life. To use several functions, manufacturing engineers need an overall theoretical background knowledge, which can give useful information about the choosing of technological parameters (e.g. feed rate, depth of cut, or cutting speed), the choosing of applicable tools or especially the choosing of the optimum motion path. A similarly important customer's requirement is the appropriate surface roughness of the machined (cut, sawn or milled) stone product. This paper's first part is about a five-month-long literature review, which summarizes in short the studies (researches and results) considered the most important by the authors. These works are about the investigation of the surface roughness of stone products in stone machining. In the second part of this paper the authors try to determine research possibilities and trends, which can help to specify the relation between the surface roughness and technological parameters. Most of the suggestions of this paper are about stone milling, which is the least investigated machining method in the world.

Tool Wear Mechanisms during Machining of Alloy 625

2011 ◽  
Vol 275 ◽  
pp. 204-207 ◽  
Author(s):  
Lenka Fusova ◽  
Pawel Rokicki ◽  
Zdeněk Spotz ◽  
Karel Saksl ◽  
Carsten Siemers
Keyword(s):  
Wear Mechanisms ◽  
Gas Turbines ◽  
Metal Cutting ◽  
Elevated Temperatures ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Production Costs ◽  
Chemical Compositions ◽  
Alloy 625 ◽  
Wide Range

Nickel-base superalloys like Alloy 625 are widely used in power generation applications due to their unique properties especially at elevated temperatures. During the related component manufacturing for gas turbines up to 50% of the material has to be removed by metal cutting operations like milling, turning or drilling. As a result of high strength and toughness the machinability of Alloy 625 is generally poor and only low cutting speeds can be used. High-speed cutting of Alloy 625 on the other hand gets more important in industry to reduce manufacturing times and thus production costs. The cutting speed represents one of the most important factors that have influences on the tool life. The aim of this study is the analyses of wear mechanisms occurring during machining of Alloy 625. Orthogonal cutting experiments have been performed and different process parameters have been varied in a wide range. New and worn tools have been investigated by stereo microscopy, optical microscopy and scanning electron microscopy. Energy-dispersive X-ray analyses were used for the investigation of chemical compositions of the tool's surface as well as the nature of reaction products formed during the cutting process. Wear mechanisms observed in the machining experiments included abrasion, fracture and tribochemical effects. Specific wear features appeared depending on the mechanical and thermal conditions generated in the wear zones.

scholarly journals Influence of Chatter of VMC Arising During End Milling Operation and Cutting Conditions on Quality of Machined Surface

1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Metal Removal ◽  
End Milling ◽  
Cutting Speed ◽  
Cutting Conditions ◽  
End Mill ◽  
Machined Surface ◽  
Operating Cycle ◽  
Wide Range

Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC), which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.

Influence of the Process Variables on the Temperature Distribution in AISI 1045 Turning

2012 ◽  
Vol 557-559 ◽  
pp. 1364-1368
Author(s):  
Yong Feng ◽  
Mu Lan Wang ◽  
Bao Sheng Wang ◽  
Jun Ming Hou
Keyword(s):  
Temperature Distribution ◽  
High Speed ◽  
Metal Cutting ◽  
Constitutive Relations ◽  
Orthogonal Cutting ◽  
Cutting Speed ◽  
Fe Model ◽  
Process Variables ◽  
Machined Surface ◽  
Aisi 1045

High-speed metal cutting processes can cause extremely rapid heating of the work material. Temperature on the machined surface is critical for surface integrity and the performance of a precision component. However, the temperature of a machined surface is challenging for in-situ measurement.So, the finite element(FE) method used to analyze the unique nonlinear problems during cutting process. In terms of heat-force coupled problem, the thermo-plastic FE model was proposed to predict the cutting temperature distribution using separated iterative method. Several key techniques such as material constitutive relations, tool-chip interface friction and separation and damage fracture criterion were modeled. Based on the updated Lagrange and arbitrary Lagrangian-Eulerian (ALE) method, the temperature field in high speed orthogonal cutting of carbon steel AISI-1045 were simulated. The simulated results showed good agreement with the experimental results, which validated the precision of the process simulation method. Meanwhile, the influence of the process variables such as cutting speed, cutting depth, etc. on the temperature distribution was investigated.

Effect of Large Cross-Section Oxygen-Propane Flame Cutting on Microstructure in Heat-Affected Zone

2013 ◽  
Vol 274 ◽  
pp. 249-252
Author(s):  
Zhi Xin Wang ◽  
Yong Kui Han ◽  
Yong Qiu Chen
Keyword(s):  
Cross Section ◽  
Heat Affected Zone ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Pressure Vessels ◽  
Manufacturing Industries ◽  
Cutting Process ◽  
Pure Oxygen ◽  
Cutting Processes ◽  
34Crnimo6 Steel

Many metal-manufacturing industries include oxyfuel gas cutting among their manufacturing processes because cutting was often used in metal-cutting processes, specifically in the large castings and forgings and the fabrication of pressure vessels. The oxyfuel gas cutting process uses controlled chemical reactions to remove preheated metal by rapid oxidation in a stream of pure oxygen. Previous research has demonstrated microstructure in heat-affected zone varied depending on the gas used for the combustion as well as the cutting speed (Vc) used during the process. In this research, 34CrNiMo6 steel of 900 mm in thickness and 45 carbon steel of 450 mm in thickness were cut using an oxygen-propane flame cutting process. Then, macroscopic morphology and microstructure test were done to analyze the influence of the thickness of cutting cross-section. The results showed, in general, the width of heat-affected zone increased with the thickness of cutting cross-section. Also, it was demonstrated that heat-affected zone in the bottom and top section was wider than others.

Determination of optimal coordinates for switching processing cycles on metal-cutting machines

2021 ◽  
Vol 23 (1) ◽  
pp. 56-67
Author(s):  
Vilor Zakovorotny ◽  
◽  
Valery Gvindjiliya ◽  
Keyword(s):  
Metal Cutting ◽  
Cutting Speed ◽  
Subject Area ◽  
Cnc System ◽  
Machining Processes ◽  
Processing Efficiency ◽  
Tool Replacement ◽  
Cutting Path ◽  
The Given ◽  
Cutting System

Introduction. One of the ways to improve the efficiency of processing on machines is to coordinate the CNC program with the changing properties of the dynamic cutting system. If this takes into account the tool wear and the associated with it changes in the parameters of the dynamic cutting system, then the cutting speed to ensure the minimum wear rate is reduced along the cutting path. The corresponding feed rate is reduced even faster, since it is necessary to ensure a constant deformation displacement of the tool relative to the workpiece. The evolution of the properties of the cutting process (for matching with which the trajectories of the operating elements of the machine are corrected) depends on the power of irreversible transformations of the energy supplied to cutting. This reduces the processing efficiency. Therefore, a new for the considered subject area problem of determining the coordinates of the tool movement relative to the workpiece is formulated, starting from which further processing is economically inexpedient. In this case, it is necessary, after processing the next part, to ensure the replacement of the tool and carry out its changeover. Subject. A metal-cutting machine of a turning group, the trajectories of the executive elements of which are controlled, for example, by a CNC system. The purpose of the work. Mathematical simulation and methods for determining the coordinates at which it is necessary to replace the tool. Method and methodology. The necessary conditions for the optimality of determining these coordinates are proved. Mathematical tools are provided that allow calculating the coordinates at which the given manufacturing costs take the minimum value according to the given trajectories. The probabilistic characteristics of evolutionary trajectories are taken into account. Results and discussions. The analysis of the efficiency of using the technique in industry depending on the cost of the machine and tool together with its replacement and readjustment is given. The proven optimality conditions and the given mathematical tools complement the knowledge about the optimization of controlled machining processes on machines. Conclusions. The results of the study show new options for the organization of tool replacement, aimed at improving the efficiency of processing by software methods using a CNC system.

Development of Cutting Tools With Micro-Textured Surface for High Speed Machining of Ti-6Al-4V

2021 ◽  
Author(s):  
Mitsuru Hasegawa ◽  
Tatsuya Sugihara
Keyword(s):  
Tool Life ◽  
High Speed ◽  
Metal Cutting ◽  
Failure Process ◽  
Cutting Tools ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Cutting Fluid ◽  
Textured Surface ◽  
Textured Surfaces

Abstract In cutting of Ti-6Al-4V alloy, the cutting speed is limited since a high cutting temperature leads to severe tool wear and short tool life, resulting in poor production efficiency. On the other hand, some recent literature has reported that various beneficial effects can be provided by forming micro-textures on the tool surface in the metal cutting process. In this study, in order to achieve high-performance machining of Ti-6Al-4V, we first investigated the mechanism of the tool failure process for a cemented carbide cutting tool in high-speed turning of Ti-6Al-4V. Based on the results, cutting tools with micro textured surfaces were developed under the consideration of a cutting fluid action. A series of experiments showed that the textured rake face successfully decreases the cutting temperature, resulting in a significant suppression of both crater wear and flank wear. In addition, the temperature zone where the texture tool is effective in terms of the tool life in the Ti-6Al-4V cutting was discussed.

Grey-Based Taguchi Analysis Approach for Optimization of Multi-Objective Problem

2014 ◽  
pp. 219-239
Author(s):  
Nirmal S Kalsi ◽  
Rakesh Sehgal ◽  
Vishal S. Sharma
Keyword(s):  
Feed Rate ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Removal Rate ◽  
Cutting Speed ◽  
Optimization Techniques ◽  
Depth Of Cut ◽  
Multi Objective ◽  
Analysis Technique ◽  
Grey Relation

Due to the increase in complexity and expectations of more reliable solutions for a problem, the importance of multi-objective problem solutions is increasing day by day. It can play a significant role in making a decision. In the present approach, many combinations of the optimization techniques are proposed by the researchers. These hybrid evolutionary methods integrate positive characteristics of different methods and show the advantage to reach global optimization. In this chapter, Taguchi method and the GRA (Grey Relation Analysis) technique are pronounced and used to optimize a multi-objective metal cutting process to yield maximum performance of tungsten carbide-cobalt cutting tool inserts in turning. L18 orthogonal array is selected to analyze the effect of cutting speed, feed rate, and depth of cut using cryogenically treated and untreated inserts. The performance is evaluated in terms of main cutting force, power consumption, tool wear, and material removal rate using main effect plots of S/N (Signal to Noise) ratios. This chapter indicates that the grey-based Taguchi technique is not only a novel, efficient, and reliable method of optimization, but also contributes to satisfactory solution for multi-machining objectives in the turning process. It is concluded that cryogenically treated cutting tool inserts perform better. However, the feed rate affects the process performance most significantly.

scholarly journals Investigation of AlCrN-Coated Inserts on Cryogenic Turning of Ti-6Al-4V Alloy

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1338
Author(s):  
Lakshmanan Selvam ◽  
Pradeep Kumar Murugesan ◽  
Dhananchezian Mani ◽  
Yuvaraj Natarajan
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Physical Vapor Deposition ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Machined Surface ◽  
Coated Carbide ◽  
Cryogenic Conditions

Over the past decade, the focus of the metal cutting industry has been on the improvement of tool life for achieving higher productivity and better finish. Researchers are attempting to reduce tool failure in several ways such as modified coating characteristics of a cutting tool, conventional coolant, cryogenic coolant, and cryogenic treated insert. In this study, a single layer coating was made on cutting carbide inserts with newly determined thickness. Coating thickness, presence of coating materials, and coated insert hardness were observed. This investigation also dealt with the effect of machining parameters on the cutting force, surface finish, and tool wear when turning Ti-6Al-4V alloy without coating and Physical Vapor Deposition (PVD)-AlCrN coated carbide cutting inserts under cryogenic conditions. The experimental results showed that AlCrN-based coated tools with cryogenic conditions developed reduced tool wear and surface roughness on the machined surface, and cutting force reductions were observed when a comparison was made with the uncoated carbide insert. The best optimal parameters of a cutting speed (Vc) of 215 m/min, feed rate (f) of 0.102 mm/rev, and depth of cut (doc) of 0.5 mm are recommended for turning titanium alloy using the multi-response TOPSIS technique.

scholarly journals Investigation into Performance of Multilayer Composite Nano-Structured Cr-CrN-(Cr0.35Ti0.40Al0.25)N Coating for Metal Cutting Tools

Coatings ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 447 ◽  
Author(s):  
Sergey Grigoriev ◽  
Alexey Vereschaka ◽  
Alexander Metel ◽  
Nikolay Sitnikov ◽  
Filipp Milovich ◽  
...  
Keyword(s):  
Tool Life ◽  
Metal Cutting ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Constructional Steel ◽  
Wear Process ◽  
Layered Architecture ◽  
Process Pattern ◽  
Resistant Layer ◽  
Cutting Speeds

This paper deals with the Cr-CrN-(Cr0.35Ti0.40Al0.25)N coating. It has a three-layered architecture with a nano-structured wear-resistant layer. The studies involved the investigation into the microstructure (with the use of SEM and TEM), elemental and phase composition (XRD and SAED patterns), wear process pattern in scratch testing, crystal structure, as well as the microhardness of the coating. Cutting tests of tools with the above coating were carried out in dry turning of steel 1045 at cutting speeds of vc = 200, 250, and 300 m·min−1. The comparison included uncoated tools and tools with the commercial TiN and (Ti,Al)N coatings with the same thickness. The tool with the Cr-CrN-(Cr0.35Ti0.40Al0.25)N coating showed the longest tool life at all the cutting speeds under consideration. Meanwhile, a tool with the coating under study can be recommended for use in turning constructional steel at the cutting speed of vc = 250 m·min−1. At this cutting speed, a tool shows the combination of a rather long tool life and balanced wear process, without any threat of catastrophic wear.

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