scholarly journals Influence of metal working fluid on chip formation and mechanical loads in orthogonal cutting

2021 ◽  
Author(s):  
Berend Denkena ◽  
Alexander Krödel ◽  
Lars Ellersiek
Keyword(s):  
Chip Formation ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Machining Process ◽  
Working Fluid ◽  
Rake Face ◽  
Metal Working ◽  
Mechanical Loads ◽  
Working Fluids ◽  
Process Forces

AbstractMetal working fluids are used in machining processes of many hard-to-cut materials to increase tool life and productivity. Thereby, the metal working fluids act on the thermal and on the mechanical loads of the tool. The changing mechanical loads can mostly be attributed to the changing friction between rake face and chip and changes in the chip formation, e.g., the contact length between rake face and chip. However, analyzing those effects is challenging, since a detailed look at the chip formation process is prevented by the metal working fluid. In this paper, a novel planing test rig is presented, which enables high-speed recordings of the machining process and process force measurements while using metal working fluids. Experiments reveal that process forces are reduced with increasing pressure of the metal working fluid. However, the average friction coefficient only changes slightly, which indicates that the reduced process forces are mainly the result of reduced contact lengths between rake face and chip.

Multivariate Analysis of Orthogonal Tube Cutting Forces With 3-D Tool Wear Analysis of AISI 1020 Alloy Steel Using Cold Compressed Air Versus Liquid Nitrogen as Metal Working Fluids

2015 ◽  
Author(s):  
Vishnu Vardhan Chandrasekaran ◽  
Lewis N. Payton ◽  
Wesley S. Hunko
Keyword(s):  
Multivariate Analysis ◽  
Liquid Nitrogen ◽  
High Speed ◽  
High Speed Steel ◽  
Compressed Air ◽  
Working Fluid ◽  
Metal Working ◽  
Factor Level ◽  
Working Fluids ◽  
Force Data

The growing cost associated with insurance, handling and disposing of conventional metal working fluids (oil and water based) continues to drive a need for alternative metal working fluids. An orthogonal tube turning machining experiment on AISI 1020 alloy steel was conducted to study the performance of High Speed Steel (HSS) tool inserts and carbide tool inserts utilizing cold compressed air and liquid nitrogen environments as the metal working fluid of choice The use of both high speed steel and carbide inserts allowed for direct comparison of geometrically identical inserts in customized tool holders that were used to present the tools with the geometrically identical tool rake angle alpha. Tool holder stiffness was therefore common to all tool rake angles compared. AISI 1020 steel was used because of its commercially dominant availability and usage. Cold cryogenic cooling was selected because of its growing usage in high performance machining applications. The use of cold compressed air has been much less studied in the machining of metals than in the machining of plastics and composites where it is quite commonly used. The comparisons between these two methods represent the first published values comparing the current extremes of gaseous metal working fluid applications in a commercial steel. This statistically designed experiment produced a large amount of comparative data that focused on the wear of the tools in two different cutting environments allowing for multivariate analysis of variance and regressive curve fitting. The orthogonal tube turning was set up on a conventional two axis HAAS TL-2 CNC tool room lathe. Forces were collected utilizing a standard Kistler force dynamometer to record the force data in X, Y and Z axes. Two levels of uncut chip thickness, 0.002 and 0.004” per revolution were maintained with a constant feed and depth of cut of 0.125” at different tool rake angles of 0°, 7° and 15°, with no chip breaker installed in the tool. Tool rake angles and depth of cuts were selected to ensure maximum statistical power/decisiveness of the experiment. The experiment was carried out for duration of 1 minute while the force data was collected for the entire duration of cut. New tool insert was used for each factor level combination. The traditional force analysis results are provided for an orthogonal tube turning experiment. In addition, all tools were analyzed for 3-dimensional rake face wear using an innovative Keyence white light microscope. Surprisingly, the inexpensive, simple cold compressed air produced less wear than the more expensive liquid nitrogen for all cutting factor level combinations.

Tool Wear Mechanisms in High Speed Machining Ductile Cast Iron

2010 ◽  
Vol 29-32 ◽  
pp. 1527-1531
Author(s):  
Fa Zhan Yang ◽  
Jian Qiang Zhou ◽  
Guang Yao Meng ◽  
Jun Zhao ◽  
Chang He Li
Keyword(s):  
Cast Iron ◽  
Tool Wear ◽  
Tool Life ◽  
High Speed ◽  
Wear Behavior ◽  
Orthogonal Cutting ◽  
Ductile Cast Iron ◽  
Cemented Carbide ◽  
Rake Face ◽  
High Speed Cutting

Wear behavior of WC based nanocomposite cutting tool when high speed cutting ductile cast iron was investigated. Orthogonal cutting tests were carried out on a CA6140 lathe using three speeds, namely, 100, 215 and 287m min-1. The WC based nanocomposite tool is found to be superior to cemented carbide tools (YG8). The tool life is prolonged 60% as compared to cemented carbide, as the width of the wear land (VB), which was monitored at selected time intervals. Meanwhile, the topography of worn surfaces was scanned by a profilemeter. Wear characterization of the rake face and the flank surfaces as well as of the collected chips was conducted using a scanning electron microscopy (SEM). Results showed that distinctive traces of single abrasive tool wear event were found on the rake face of the tool, additionally, the adhesion wear is the main wear mechanism in the flank face of the tool. However, the extent of improvement in tool life depends strongly on the cutting conditions, with the greatest benefits being seen at higher cutting speeds and feed rates.

Investigation of adsorption behaviour of lubricants in near-dry machining

2005 ◽  
Vol 219 (9) ◽  
pp. 665-671 ◽  
Author(s):  
S Min ◽  
I Inasaki ◽  
S Fujimura ◽  
T Wakabayashi ◽  
S Suda
Keyword(s):  
Vacuum Chamber ◽  
Orthogonal Cutting ◽  
Economic Benefits ◽  
Performance Comparison ◽  
Working Fluid ◽  
Dry Machining ◽  
Metal Working ◽  
Adsorption Behaviour ◽  
Lubrication Film ◽  
Lubrication Conditions

Near-dry machining (NDM) is a technology with many ecological and economic benefits that uses very small amounts of metal working fluid (MWF). In order to increase the applications of this technology, the tribological mechanism during this process needs to be better understood. To accomplish this, two experimental set-ups were configured. The first involved a vacuum chamber where changes of gas near the cutting area can be traced by a mass spectrometer. The second has an atmospheric chamber where practical cutting can be done for cutting-performance comparison. Three gases - argon, nitrogen, and oxygen - were used with and without an ester in a series of orthogonal cutting tests to understand their roles in lubrication. It was found that oxygen adsorbs best onto a newly generated work surface and plays a significant role in promoting adsorption of the ester and, in turn, creating a lubrication film. Therefore, it is important to supply an abundant amount of oxygen in NDM to provide good lubrication conditions.

Finite Element Simulation of High-Speed Hard Turning

2011 ◽  
Vol 308-310 ◽  
pp. 1465-1470
Author(s):  
Guo Chen Du ◽  
Ying Chen ◽  
Jin Feng Zhang ◽  
Zhi Zhen Wei
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Hard Turning ◽  
Orthogonal Cutting ◽  
Relevant Literature ◽  
Processing Parameters ◽  
Machining Process ◽  
Third Wave ◽  
Machining Time ◽  
Element Simulation

The results reported in this paper pertain to the simulation of high speed hard turning when using the finite element method. In recent years high speed hard turning has emerged as a very advantageous machining process for cutting hardened steels. Among the advantages of this modern turning operation are final product quality, reduced machining time, lower cost and environmentally friendly characteristics. For the finite element modelling a commercial programme, namely the Third Wave Systems AdvantEdge, was used. This programme is specially designed for simulating cutting operations, offering to the user many designing and analysis tools. In the present analysis orthogonal cutting models are proposed, taking several processing parameters into account; the models are validated with experimental results from the relevant literature and discussed. Additionally, oblique cutting models of high speed hard turning are constructed and discussed. From the reported results useful conclusions may be drawn and it can be stated that the proposed models can be used for industrial application.

Siloxanes as Working Fluids for Mini-ORC Systems Based on High-Speed Turbogenerator Technology

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Antti Uusitalo ◽  
Teemu Turunen-Saaresti ◽  
Juha Honkatukia ◽  
Piero Colonna ◽  
Jaakko Larjola
Keyword(s):  
Molecular Weight ◽  
Power Output ◽  
High Speed ◽  
Thermodynamic Cycle ◽  
Turbine Rotor ◽  
Working Fluid ◽  
Specific Enthalpy ◽  
Working Fluids ◽  
Simulated Performance ◽  
Component Design

This paper presents a study aimed at evaluating the use of siloxanes as the working fluid of a small-capacity (≈10kWe) ORC turbogenerator based on the “high-speed technology” concept, combining the turbine, the pump, and the electrical generator on one shaft, whereby the whole assembly is hermetically sealed, and the bearings are lubricated by the working fluid. The effects of adopting different siloxane working fluids on the thermodynamic cycle configuration, power output, and on the turbine and component design are studied by means of simulations. Toluene is included into the analysis as a reference fluid in order to make comparisons between siloxanes and a suitable low molecular weight hydrocarbon. The most influential working fluid parameters are the critical temperature and pressure, molecular complexity and weight, and, related to them, the condensation pressure, density and specific enthalpy over the expansion, which affect the optimal design of the turbine. The fluid thermal stability is also extremely relevant in the considered applications. Exhaust gas heat recovery from a 120 kW diesel engine is considered in this study. The highest power output, 13.1 kW, is achieved with toluene as the working fluid, while, among siloxanes, D4 provides the best simulated performance, namely 10.9 kW. The high molecular weight of siloxanes is beneficial in low power capacity applications, because it leads to larger turbines with larger blade heights at the turbine rotor outlet, and lower rotational speed if compares, for instance, to toluene.

scholarly journals Strain Rate of Metal Deformation in the Machining Process from a Fluid Flow Perspective

2020 ◽  
Vol 10 (9) ◽  
pp. 3057
Author(s):  
Keguo Zhang ◽  
Keyi Wang ◽  
Zhanqiang Liu ◽  
Xiaodong Xu
Keyword(s):  
Fluid Flow ◽  
Strain Rate ◽  
High Speed ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Shear Plane ◽  
Cutting Process ◽  
Machining Process ◽  
Rake Face ◽  
Metal Deformation

Metal cutting speeds are getting faster with the development of high-speed cutting technology, and with the increase in cutting speed, the strain rate will become larger, which makes the study of the metal cutting process more inconvenient. At the same time, with the increase in strain rate, the dislocation movement controlling the plastic deformation mechanism of metal will change from thermal activation to a damping mechanism, which makes the metal deformation behave more like a fluid. Therefore, it is necessary to explore new ways of studying machining from the perspective of fluid flow. Based on this, a fluid model of the metal cutting process is established, and a method for calculating the strain rate is proposed from the point of view of flow. The results of the simulation and measurements are compared and analyzed. The results show that the strain rate on the rake face will be affected by the friction between the chip and tool; the nearer the distance between the chip layer and tool rake face, the bigger the strain rate will be. The strain rate in the central shear plane is much larger than in other areas along the shear plane direction, and in which two ends are the biggest. It can achieve rougher, quantitative research. This shows it is feasible to study machining from the viewpoint of fluid flow, though it still needs a lot of theoretical support and experimental confirmation.

Study on the Orthogonal Cutting Process of Al7050T7451 with Uncoated and Coated Tools

2008 ◽  
Vol 392-394 ◽  
pp. 990-995 ◽  
Author(s):  
Hui Yue Dong ◽  
Pu Jin Huang ◽  
Y.B. Bi
Keyword(s):  
Finite Element ◽  
High Speed ◽  
High Strain ◽  
Bulk Material ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Machining Process ◽  
Workpiece Material ◽  
Coated Tool ◽  
The Impact

Tool wear during high speed machining process plays an important role in machining cost and efficiency. The purpose of this study is to examine the impact of tribological properties of coatings on cutting performance. Finite element methods (FEM) were used to model the effect of coated and uncoated cutting tools (K10) on the machinability of the aluminum alloy 7050T7451. Uncoated, Single coated, such as TiC, TiN and Al2O3 and multi-coated tool were studied. All finite element models were assumed to be plane strain. To achieve constitutive model of Al7050T7451 under conditions of machining that high strain rate, high strain and high temperature occur, high speed impact experiment and material drawing experiment were done. Comparison of FEM results shows that the highest temperatures in tools, the temperature change rates of different tools from surface to its bulk material, and the temperatures in chips are changed greatly. It also shows that the cutting temperature of coated tool is lower than uncoated tools, but cutting forces change very little. All these results show that coatings can be used to reduce adhesion between a tool and a workpiece material. The wear resistance of coated tool can be improved effectively and tool life is increased correspondingly.

Investigations on the Nature of Surface Finish and Its Variation With Cutting Speed

1964 ◽  
Vol 86 (2) ◽  
pp. 134-140 ◽  
Author(s):  
K. L. Chandiramani ◽  
N. H. Cook
Keyword(s):  
Surface Finish ◽  
Chip Formation ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Cutting Temperature ◽  
Cutting Speed ◽  
Relative Importance ◽  
Cutting Mechanism ◽  
Low Speed

An attempt has been made to investigate the nature and cause of the variation of surface finish with cutting speed during orthogonal cutting operations. It is found that the variation of cutting speed alone is sufficient to give rise to the three different mechanisms of chip formation, conventionally known as discontinuous, continuous without “bue” (built-up-edge) and continuous with bue. The transition from low-speed, nonbue cutting to high-speed, bue cutting is found to greatly influence the surface finish and in fact the entire cutting mechanism. Photomicrographs of the cutting zones, the chips, and the profiles of the finished surfaces have been taken to observe these changes closely. Tests have also been carried out to determine the relative importance of cutting speed and cutting temperature in affecting the surface finish of the workpiece being machined.

scholarly journals High-Speed Cutting of Synthetic Trabecular Bone– A Combined Experimental-Computational Investigation

2021 ◽  
Author(s):  
Macdarragh O'Neill ◽  
Ted J Vaughan
Keyword(s):  
Trabecular Bone ◽  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Computational Modelling ◽  
Isotropic Hardening ◽  
Test Machine ◽  
Modelling Framework ◽  
Wide Range

Orthopaedic surgical cutting instruments are required to generate sufficient forces to penetrate bone tissue, while minimizing the risk of thermal and mechanical damage to the surrounding environment. This study presents a combined experimental-computational approach to deter-mine relationships between key cutting parameters and overall cutting performance of a polyu-rethane-based synthetic trabecular bone analogue under orthogonal cutting conditions. An ex-perimental model of orthogonal cutting was developed, whereby an adaptable cutting tool fix-ture driven by a servo-hydraulic uniaxial test machine was used to carry out cutting tests on Sawbone® trabecular bone analogues. A computational model of the orthogonal cutting process was developed using Abaqus/Explicit, whereby an Isotropic Hardening Crushable Foam elas-tic-plastic model was used to capture the complex post-yield behaviour of the synthetic trabecu-lar bone. It was found that lower tool rake-angles resulted in the formation of larger discontin-uous chips and higher cutting forces, while higher rake angles tended to lead to more continu-ous chip formation and lower cutting forces. The computational modelling framework provided excellent predictions of both chip formation and axial cutting forces over the wide range of cut-ting parameters, when compared to experimental observations. This represents the first experi-mentally-validated computational modelling framework for orthogonal cutting of trabecular bone and excellent potential to be applied to more complex three-dimensional cutting processes in the future.

Multi-Scale Fe Modeling Inconel718 Machining Process and Crack Initiation of Brittle Particle

2012 ◽  
Vol 500 ◽  
pp. 574-579 ◽  
Author(s):  
Xiao Jin Xu ◽  
Li Qiang Ding ◽  
Xue Ping Zhang
Keyword(s):  
Crack Initiation ◽  
High Speed ◽  
Orthogonal Cutting ◽  
Great Influence ◽  
Cutting Process ◽  
Machining Process ◽  
Fe Model ◽  
Multi Scale ◽  
Feed Force ◽  
The Impact

nconel718 is particle reinforced metal matrix composites widely applied in important fields. To evaluate the impact of particles on the machined subsurface in Inconel718 during high-speed machining operation, a multi-scale orthogonal cutting finite element (FE) model is established. A cohesive element technique is adopted to predict particle crack initiation process. The multi-scale FE model is validated with experimental data in terms of cutting forces and chip morphology. The simulation reveals that particle has a great influence on surface roughness and the feed force when particles are located in the sub-surface within the depths of 30μm, and the cutting process has less effect on the particle crack initiation when the particles in the depths of more than 40μm or deeper. The interaction effects generated from particle sizes in the same depth are investigated on the cutting process and particle crack initiation.

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