scholarly journals Towards Dry Machining of Titanium-Based Alloys: A New Approach Using an Oxygen-Free Environment

Metals ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1161
Author(s):  
Hans Jürgen Maier ◽  
Sebastian Herbst ◽  
Berend Denkena ◽  
Marc-André Dittrich ◽  
Florian Schaper ◽  
...  
Keyword(s):  
Titanium Alloy ◽  
Wear Mechanism ◽  
Chip Formation ◽  
Cutting Forces ◽  
High Vacuum ◽  
Argon Atmosphere ◽  
Dry Machining ◽  
New Approach ◽  
Underlying Mechanisms ◽  
Free Environment

In the current study, the potential of dry machining of the titanium alloy Ti-6Al-4V with uncoated tungsten carbide solid endmills was explored. It is demonstrated that tribo-oxidation is the dominant wear mechanism, which can be suppressed by milling in an extreme high vacuum adequate (XHV) environment. The latter was realized by using a silane-doped argon atmosphere. In the XHV environment, titanium adhesion on the tool was substantially less pronounced as compared to reference machining experiments conducted in air. This goes hand in hand with lower cutting forces in the XHV environment and corresponding changes in chip formation. The underlying mechanisms and the ramifications with respect to application of this approach to dry machining of other metals are discussed.

FE Simulation of Cryogenic Assisted Machining of Ti Alloy (Ti6AI4V)

2015 ◽  
Author(s):  
Vivek Bajpai ◽  
Ineon Lee ◽  
Hyung Wook Park
Keyword(s):  
Tool Wear ◽  
Chip Formation ◽  
Cutting Forces ◽  
Turbine Blades ◽  
Chip Morphology ◽  
Machining Process ◽  
Burr Formation ◽  
Dry Machining ◽  
Cryogenic Machining ◽  
Ti Alloys

Titanium alloys are well-known material because of the excellent mechanical/chemical properties, corrosion resistance and light weight. These alloys are widely used in the high performance applications such as; aerospace, aviation, bio-implants, turbine blades etc. Machining is commonly used to create products out of Ti alloys. Despite of good material properties, Ti alloys have low thermal conductivity, poor machinability, burr formation, high machining temperature, tool wear and poor machinability. The tool wear and high machining temperature can be controlled through coolant. Cryogenic fluid (liquid nitrogen) is a common material used as coolant in various machining process. The current work is focused on the modeling of cryogenic machining on titanium alloy (Ti6Al4V). Dry machining and cryogenic machining processes are modeled for the chip formation and cutting forces in 2D. Experimental works have been performed to validate the model based on the cutting forces and chip morphology. It is showed that the model is capturing the process, evident by the cutting forces and the chip morphology. The error in prediction is limited to 18%. Model showed that the cutting forces are increasing in cryogenic machining due to the increased strength of the workpiece at low temperature. Chip formation is well captured by the current model. Shear band width have been captured in dry machining. Chip curling has been captured at dry and cryogenic machining. It is expected that the model can further useful in the selection of cryogenic process parameter, such as, flow rate, application techniques etc.

Tool stiffness influence on the chosen physical parameters of the milling process

2012 ◽  
Vol 60 (3) ◽  
pp. 597-604 ◽  
Author(s):  
W. Zębala
Keyword(s):  
Titanium Alloy ◽  
Aluminium Alloy ◽  
Chip Formation ◽  
Cutting Forces ◽  
Contact Point ◽  
Milling Process ◽  
Cutting Process ◽  
Physical Parameters ◽  
Titanium Alloy Ti6al4v ◽  
The Impact

Abstract This article presents our own model researches, relating to the down milling process of Aluminium alloy (Al6061) and Titanium alloy (Ti6Al4V), with a tool made of sintered carbides. These investigations pay the special attention to the impact of the tool rigidity on the process of chip formation. The simulation calculations have been carried out for two cases of the cutting process: case 1 - assuming an ideally rigid construction of a milling cutter (length of tool does not impact its deflection under the cutting forces); case 2 - it is possible that the tool can be subjected to deflection under the cutting forces (length of a tool part is counted from the holder end to the contact point of a cutting edge with the machining material).

On Methodologies inside Two Different Commercial Codes to Simulate the Cutting Operation

2011 ◽  
Vol 223 ◽  
pp. 162-171
Author(s):  
Yan Cheng Zhang ◽  
Domenico Umbrello ◽  
Tarek Mabrouki ◽  
Stefania Rizzuti ◽  
Daniel Nelias ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Titanium Alloy ◽  
Surface Integrity ◽  
Chip Formation ◽  
Cutting Forces ◽  
Orthogonal Cutting ◽  
Cutting Parameters ◽  
Cutting Operation ◽  
Cutting Processes ◽  
Cutting Model

Nowadays, numerical simulation of cutting processes receives considerable interest among the scientific and industrial communities. For that, various numerical codes are used. Nevertheless, there is no uniform standard for the comparison of simulation model with these different software. So, it is often not easy to state if a given code is more pertinent than another. In this framework, the present work deals with various methodologies to simulate orthogonal cutting operation inside two commercial codes Abaqus and Deform. The aim of the present paper is to build a common benchmark model between the two pre-cited codes which can initiate other numerical cutting model comparisons. The study is focused on the typical aeronautical material - Ti-6Al-4V - Titanium alloy. In order to carry out a comparative study between the two codes, some similar conditions concerning geometrical models and cutting parameters were respected. A multi-physic comprehension related to chip formation, cutting forces and temperature evolutions, and surface integrity is presented. Moreover, the numerical results are compared with experimental ones.

scholarly journals Experimental Study of tool Wear Mechanisms in Conventional and High Pressure Coolant Assisted Machining of Titanium Alloy Ti17

2013 ◽  
Vol 554-557 ◽  
pp. 1961-1966 ◽  
Author(s):  
Yessine Ayed ◽  
Guenael Germain ◽  
Amine Ammar ◽  
Benoit Furet
Keyword(s):  
High Pressure ◽  
Titanium Alloy ◽  
Tool Wear ◽  
Titanium Alloys ◽  
Tool Life ◽  
Wear Mechanisms ◽  
Cutting Forces ◽  
Cutting Edge ◽  
Rake Face ◽  
High Pressure Coolant

Titanium alloys are known for their excellent mechanical properties, especially at high temperature. But this specificity of titanium alloys can cause high cutting forces as well as a significant release of heat that may entail a rapid wear of the cutting tool. To cope with these problems, research has been taken in several directions. One of these is the development of assistances for machining. In this study, we investigate the high pressure coolant assisted machining of titanium alloy Ti17. High pressure coolant consists of projecting a jet of water between the rake face of the tool and the chip. The efficiency of the process depends on the choice of the operating parameters of machining and the parameters of the water jet such as its pressure and its diameter. The use of this type of assistance improves chip breaking and increases tool life. Indeed, the machining of titanium alloys is generally accompanied by rapid wear of cutting tools, especially in rough machining. The work done focuses on the wear of uncoated tungsten carbide tools during machining of Ti17. Rough and finish machining in conventional and in high pressure coolant assistance conditions were tested. Different techniques were used in order to explain the mechanisms of wear. These tests are accompanied by measurement of cutting forces, surface roughness and tool wear. The Energy-dispersive X-ray spectroscopy (EDS) analysis technique made it possible to draw the distribution maps of alloying elements on the tool rake face. An area of material deposition on the rake face, characterized by a high concentration of titanium, was noticed. The width of this area and the concentration of titanium decreases in proportion with the increasing pressure of the coolant. The study showed that the wear mechanisms with and without high pressure coolant assistance are different. In fact, in the condition of conventional machining, temperature in the cutting zone becomes very high and, with lack of lubrication, the cutting edge deforms plastically and eventually collapses quickly. By contrast, in high pressure coolant assisted machining, this problem disappears and flank wear (VB) is stabilized at high pressure. The sudden rupture of the cutting edge observed under these conditions is due to the propagation of a notch and to the crater wear that appears at high pressure. Moreover, in rough condition, high pressure assistance made it possible to increase tool life by up to 400%.

scholarly journals Analytical modelling of cutting forces in near-orthogonal cutting of titanium alloy Ti6Al4V

2014 ◽  
Vol 229 (6) ◽  
pp. 1122-1133 ◽  
Author(s):  
Yun Chen ◽  
Huaizhong Li ◽  
Jun Wang
Keyword(s):  
Titanium Alloy ◽  
Cutting Forces ◽  
Chemical Reactivity ◽  
Orthogonal Cutting ◽  
Chip Thickness ◽  
Analytical Modelling ◽  
Shear Instability ◽  
Published Data ◽  
Machining Processes ◽  
Titanium Alloy Ti6al4v

Titanium and its alloys are difficult to machine due to their high chemical reactivity with tool materials and low thermal conductivity. Chip segmentation caused by the thermoplastic instability is always observed in titanium machining processes, which leads to varied cutting forces and chip thickness, etc. This paper presents an analytical modelling approach for cutting forces in near-orthogonal cutting of titanium alloy Ti6Al4V. The catastrophic shear instability in the primary shear plane is assumed as a semi-static process. An analytical approach is used to evaluate chip thicknesses and forces in the near-orthogonal cutting process. The shear flow stress of the material is modelled by using the Johnson–Cook constitutive material law where the strain hardening, strain rate sensitivity and thermal softening behaviours are coupled. The thermal equations with non-uniform heat partitions along the tool–chip interface are solved by a finite difference method. The model prediction is verified with experimental data, where a good agreement in terms of the average cutting forces and chip thickness is shown. A comparison of the predicted temperatures with published data obtained by using the finite element method is also presented.

Cryogenic Machining of Titanium Ti-5553 Alloy

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Yusuf Kaynak ◽  
Armin Gharibi
Keyword(s):  
Titanium Alloy ◽  
Tool Wear ◽  
Cutting Temperature ◽  
Cryogenic Cooling ◽  
Machining Process ◽  
Dry Machining ◽  
Cryogenic Machining ◽  
Machining Performance ◽  
Wide Range ◽  
New Generation

Titanium alloy Ti-5Al-5V-3Cr-0.5Fe (Ti-5553) is a new generation of near-beta titanium alloy that is commonly used in the aerospace industry. Machining is one of the manufacturing methods to produce parts that are made of this near-beta alloy. This study presents the machining performance of new generation near-beta alloys, namely, Ti-5553, by focusing on a high-speed cutting process under cryogenic cooling conditions and dry machining. The machining experiments were conducted under a wide range of cutting speeds, including high speeds that used liquid nitrogen (LN2) and carbon dioxide (CO2) as cryogenic coolants. The experimental data on the cutting temperature, tool wear, force components, chip breakability, dimensional accuracy, and surface integrity characteristics are presented and were analyzed to evaluate the machining process of this alloy and resulting surface characteristics. This study shows that cryogenic machining improved the machining performance of the Ti-5553 alloy by substantially reducing the tool wear, cutting temperature, and dimensional deviation of the machined parts. The cryogenic machining also produced shorter chips as compared to dry machining.

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