An Investigation of the High Speed Machining Process Using a Variable Flow Stress Machining Theory

2004 ◽  
Vol 8 (2) ◽  
pp. 211-233 ◽  
Author(s):  
J. A. Arsecularatne ◽  
B. Kristyanto ◽  
P. Mathew
Keyword(s):  
Flow Stress ◽  
High Speed ◽  
Machining Process ◽  
High Speed Machining ◽  
Variable Flow

Microhardness Prediction Based on a Microstructure-Sensitive Flow Stress Model During High Speed Machining Ti-6Al-4V

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Qingqing Wang ◽  
Zhanqiang Liu
Keyword(s):  
Flow Stress ◽  
Grain Refinement ◽  
High Speed ◽  
Direct Consequence ◽  
Deformation Twinning ◽  
Machining Process ◽  
High Speed Machining ◽  
Stress Model ◽  
Machined Surface ◽  
Flow Stress Model

Exploring the hardening mechanisms during high speed machining (HSM) is an effective approach to improve the fatigue strength and the wear resistance of machined surface and to control the fragmentation of chips in a certain range of hardness. In this paper, the microhardness variation is explored from the perspective of microstructural evolutions, as a direct consequence of the severe deformation during HSM Ti-6Al-4V alloy. A microstructure-sensitive flow stress model coupled the phenomena of grain refinement, deformation twinning, and phase transformations is first proposed. Then the microstructure-sensitive flow stress model is implemented into the cutting simulation model via a user-defined subroutine to analyze the flow stress variation induced by the microstructure evolutions during HSM Ti-6Al-4V. Finally, the relationship between the microhardness and flow stress is developed and modified based on the classical theory that the hardness is directly proportional to the flow stress. The study shows that the deformation twinning (generated at higher cutting speeds) plays a more important role in the hardening of Ti-6Al-4V compared with the grain refinement and phase transformation. The predicted microhardness distributions align well with the measured values. It provides a novel thinking that it is plausible to obtain a high microhardness material via controlling the microstructure alterations during machining process.

A New Microstructure-Sensitive Flow Stress Model for the High-Speed Machining of Titanium Alloy Ti–6Al–4V

2016 ◽  
Vol 139 (5) ◽  
Author(s):  
X. P. Zhang ◽  
R. Shivpuri ◽  
A. K. Srivastava
Keyword(s):  
Flow Stress ◽  
Titanium Alloys ◽  
High Speed ◽  
Flow Behavior ◽  
Stress Sensitivity ◽  
Machining Process ◽  
High Speed Machining ◽  
Stress Model ◽  
Mechanical State ◽  
Flow Stress Model

The flow stress in the high-speed machining of titanium alloys depends strongly on the microstructural state of the material which is defined by the composition of the material, its starting microstructure, and the thermomechanical loads imposed during the machining process. In the past, researchers have determined the flow stress empirically as a function of mechanical state parameters, such as strain, strain rate, and temperature while ignoring the changes in the microstructural state such as phase transformations. This paper presents a microstructure-sensitive flow stress model based on the self-consistent method (SCM) that includes the effects of chemical composition, α phase and β phase, as well mechanical state imposed. This flow stress is developed to model the flow behavior of titanium alloys in machining at speed of higher than 5 m/s, characterized by extremely high strains (2–10 or higher), high strain rates (104–106 s−1 or higher), and high temperatures (600–1300 °C). The flow stress sensitivity to mechanical and material parameters is analyzed. A new SCM-based Johnson–Cook (JC) flow stress model is proposed whose constants and ranges are determined using experimental data from literature and the physical basis for SCM approach. This new flow stress is successfully implemented in the finite-element (FE) framework to simulate machining. The predicted results confirm that the new model is much more effective and reliable than the original JC model in predicting chip segmentation in the high-speed machining of titanium Ti–6Al–4V alloy.

Prediction of High Speed Machining Cutting Forces Using a Variable Flow Stress Machining Theory

2011 ◽  
Vol 188 ◽  
pp. 128-133 ◽  
Author(s):  
Philip Mathew
Keyword(s):  
Flow Stress ◽  
Cutting Forces ◽  
High Speed ◽  
Experimental Results ◽  
The Other ◽  
Cutting Conditions ◽  
High Speed Machining ◽  
Variable Flow ◽  
Machining Conditions

A variable flow stress machining theory is described where it is used to predict the cutting forces associated with High Speed Machining (HSM) process. The predicted and experimental results for different materials and different cutting conditions are presented and compared and it is shown that the theory developed is capable of predicting the cutting forces and the other parameters associated with the HSM process. The extension of the theory to HSM has been successful within the machining conditions presented here in this paper. Further work is necessary to improve this theory further.

Microstructure Sensitive Flow Stress Based on Self Consistent Method

2016 ◽  
Author(s):  
Xueping Zhang ◽  
Rajiv Shivpuri ◽  
Anil K. Srivastava
Keyword(s):  
Flow Stress ◽  
Titanium Alloys ◽  
High Speed ◽  
Machining Process ◽  
High Speed Machining ◽  
Stress Model ◽  
Mechanical State ◽  
Self Consistent ◽  
Consistent Method ◽  
Flow Stress Model

Flow stress in the high speed machining of titanium alloys depends strongly on the microstructural state of the material which is defined by the composition of the material, its starting microstructure and the thermo-mechanical loads imposed during the machining process. Previous researchers have determined the flow stress empirically as a function of mechanical state parameters such as strain, strain rate and temperature while ignoring the changes in the microstructural state such as alpha-beta phase transformations. This paper presents a new microstructure sensitive flow stress model based on the self-consistent method (SCM) that includes the effects of chemical composition, α phase and β phase, as well mechanical state imposed. This flow stress is developed to model the flow behavior of titanium alloys in machining, at speed of higher than 5m/s, characterized by extremely high strains (2∼10 or higher), high strain rates (104∼106s−1 or higher) and high temperatures (600∼1300°C). The flow stress sensitivity to mechanical and material parameters is analyzed. A new SCM-based Johnson-Cook (JC) flow stress model is proposed whose constants and ranges are determined using experimental data and the physical basis for SCM approach from literature. This new flow stress is successfully implemented in the finite element framework to simulate high speed machining process and compared with other types of flow stress models in terms of chip morphology. The predicted results confirm that the new model is much more effective and reliable than the original JC model in predicting chip segmentation in the high speed machining of titanium Ti-6Al-4V alloy.

Numerical Simulation of Cutting Force in High Speed Machining of Inconel 718

2020 ◽  
Vol 856 ◽  
pp. 43-49
Author(s):  
Santosh Kumar Tamang ◽  
Nabam Teyi ◽  
Rinchin Tashi Tsumkhapa
Keyword(s):  
Cutting Force ◽  
Inconel 718 ◽  
High Speed ◽  
Experimental Results ◽  
Machining Process ◽  
Experimental Result ◽  
Work Piece ◽  
High Speed Machining ◽  
Numerical Result ◽  
3D Software

Machining is one of the major manufacturing processes that converts a raw work piece of arbitrary size into a finished product of definite shape of predetermined size by suitably controlling the relative motion between the tool and the work. Lately, machining process is shifting towards high speed machining (HSM) from conventional machining to improve and efficiently increase production, and towards dry machining from excessive coolant used wet machining to improve economy of production. And the tools used are mostly hardened alloys to facilitate HSM. The work piece materials are continually improving their properties by emergence and development of newer and high resistive super alloys (HRSA). In this paper an attempt has been made to validate an experimental result of cutting force obtained by performing HSM on an HRSA Inconel 718, by comparing it with the numerical result obtained by simulating the same setting using DEFORM 3D software. Based on the comparison it is found that the simulated results exhibit close proximity with the experimental results validating the experimental results and the effectiveness of the software.

scholarly journals Impact of Cutting Environments on Sustainable Machining of H13 Tool Steel Alloy

2020 ◽  
Vol 5 (2) ◽  
Author(s):  
Vincent A Balogun ◽  
Isuamfon F Edem ◽  
Etimbuk B Bassey
Keyword(s):  
Tool Life ◽  
Tool Steel ◽  
High Speed ◽  
Machining Process ◽  
Steel Alloy ◽  
High Speed Machining ◽  
Sustainable Machining ◽  
H13 Tool Steel ◽  
Green Machining ◽  
The Impact

The use of electrical energy and coolants/lubricants has been widely reported in mechanical machining. However, increased research and process innovation in high speed machining has brought about optimised manufacturing cycle times. This has promoted dry machining and the use of minimum quantity lubrication (MQL). This work understudies the impact of different cutting environments in machining H13 tool steel alloys at transition speed regime with emphasis on sustainable machining of the alloy. To achieve this, end milling tests were performed on AISI H13 steel alloy (192 BHN) on a MIKRON HSM 400 high speed machining centre using milling inserts. After each cutting pass, the milling insert was removed for tool wear measurement on the digital microscope. The electrical power consumed was measured with the Fluke 435 power clamp meter mounted on the three phase cable at the back of the machine. It was discovered that MQL has a promising advantage in terms of tool life with 25 minutes of machining, net power requirement of 10% when compared to dry cutting, and environmental benefits when machining H13 tool steel alloy. This work is fundamentally important in assessing the environmental credentials and resource efficiency regime for green machining of H13 tool steel alloysKeywords— H13 tool steel, green machining, process optimization, tool life, cutting environments, energy consumption 

Stress Triaxiality in Chip Segmentation During High Speed Machining of Titanium Alloy

2014 ◽  
Author(s):  
Xueping Zhang ◽  
Rajiv Shivpuri ◽  
Anil K. Srivastava
Keyword(s):  
Titanium Alloy ◽  
High Speed ◽  
Split Hopkinson Pressure Bar ◽  
Shear Bands ◽  
Stress Triaxiality ◽  
Machining Process ◽  
High Speed Machining ◽  
Hopkinson Pressure Bar ◽  
Static Tests ◽  
Pressure Stress

Beside strain intensity, stress triaxiality (pressure-stress states) is the most important factor to control initiation of ductile fracture in chip segmentation through affecting the loading capacity and strain to failure. The effect of stress triaxiality on failure strain is usually assessed by dynamic Split Hopkinson Pressure Bar (SHPB) or quasi-static tests of tension, compression, torsion, and shear. However, the stress triaxialities produced by these tests are considerably different from those in high speed machining of titanium alloys where adiabatic shear bands (ASB) are associated with much higher strains, stresses and temperatures. This aspect of shear localization and fracture are poorly understood in previous research. This paper aims to demonstrate the role of stress triaxiality in chip segmentation during machining titanium alloy using finite element method. This research promotes a fundamental understanding of thermo-mechanics of the high-speed machining process, and provides a logical insight into the fracture mechanism in discontinuous chips.

Study on the Green Processing of Impeller

2010 ◽  
Vol 136 ◽  
pp. 148-152
Author(s):  
Ming Jun Feng ◽  
C.T. Sun ◽  
Xue Feng Wang ◽  
H.J. Sun
Keyword(s):  
High Speed ◽  
Production Cost ◽  
Development Trend ◽  
Virtual Manufacturing ◽  
Machining Process ◽  
High Speed Machining ◽  
Good Surface ◽  
Green Processing ◽  
Compressor Impeller ◽  
Good Surface Roughness

According to the characteristics and cutting requirements of the compressor impeller, such as low rigidity, easy to produce deformation and vibration in machining process, the high speed machining technology was adopted to reduce time, the virtual manufacturing technology was used to solve processing problems in computer before the trial machining and improved programming speed and other key supporting technologies were adopted. The study shows that this green processing of impeller had high machining efficiency, good surface roughness and product quality, low production cost and light environmental pollution. It accords with modern green machining development trend.

Reduction of Vibrations due to Unbalance with Anti-Vibration Clearance Angle in High Speed Milling

2016 ◽  
Vol 836-837 ◽  
pp. 161-167
Author(s):  
Anna Thouvenin ◽  
Xin Li ◽  
Ning He ◽  
Liang Li
Keyword(s):  
Material Removal ◽  
High Speed ◽  
Removal Rate ◽  
Machining Process ◽  
High Speed Machining ◽  
Machining Processes ◽  
High Speed Milling ◽  
Clearance Angle ◽  
Fast Solution ◽  
Considerable Problem

High speed milling is one of the most commonly used machining processes in many fields of the industry. It is regarded as a simple and fast solution to achieve a high material removal rate, which allows an important production of parts. Unbalance is a problem in any machining process but becomes a considerable problem when reaching high speed machining. The vibrations due to an unbalanced tool or tool holder can result in a poor surface quality and a damaged tool. The damping of the vibrations can be achieved with a specially designed tool showing an anti-vibration clearance angle. This paper shows the influence of the anti-vibration clearance angle by a computational model and a set of experiments to see if it can reduce or suppress the vibrations due to unbalance in high speed milling.

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