scholarly journals Cutting forces and chip morphology in LCO2 + MQL assisted robotic drilling of Ti6Al4V

Procedia CIRP ◽  
2021 ◽  
Vol 102 ◽  
pp. 299-302
Author(s):  
Damir Grguraš ◽  
Luka Sterle ◽  
Franci Pušavec
Keyword(s):  
Cutting Forces ◽  
Chip Morphology ◽  
Robotic Drilling

Predicting the High Speed Cutting Process of Titanium Alloy by Finite Element Method

2011 ◽  
Author(s):  
Xiangqin Zhang ◽  
Xueping Zhang ◽  
A. K. Srivastava
Keyword(s):  
Finite Element ◽  
Cutting Forces ◽  
High Speed ◽  
Cutting Temperature ◽  
Chip Morphology ◽  
Cutting Process ◽  
Fe Model ◽  
Dry Cutting ◽  
Friction Coefficients ◽  
Machining Conditions

To predict the cutting forces and cutting temperatures accurately in high speed dry cutting Ti-6Al-4V alloy, a Finite Element (FE) model is established based on ABAQUS. The tool-chip-work friction coefficients are calculated analytically using the measured cutting forces and chip morphology parameter obtained by conducting the orthogonal (2-D) machining tests. It reveals that the friction coefficients between tool-work are 3∼7 times larger than that between tool-chip, and the friction coefficients of tool-chip-work vary with feed rates. The analysis provides a better reference for the tool-work-chip friction coefficients than that given by literature empirically regardless of machining conditions. The FE model is capable of effectively simulating the high speed dry cutting process of Ti-6Al-4V alloy based on the modified Johnson-Cook model and tool-work-chip friction coefficients obtained analytically. The FE model is further validated in terms of predicted forces and the chip morphology. The predicted cutting force, thrust force and resultant force by the FE model agree well with the experimentally measured forces. The errors in terms of the predicted average value of chip pitch and the distance between chip valley and chip peak are smaller. The FE model further predicts the cutting temperature and residual stresses during high speed dry cutting of Ti-6Al-4V alloy. The maximum tool temperatures exist along the round tool edge, and the residual stress profiles along the machined surface are hook-shaped regardless of machining conditions.

Experimental Investigation of the Machinability of Polycarbonate Reinforced With Multiwalled Carbon Nanotubes

2005 ◽  
Vol 128 (2) ◽  
pp. 465-473 ◽  
Author(s):  
J. Samuel ◽  
R. E. DeVor ◽  
S. G. Kapoor ◽  
K. J. Hsia
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Fiber ◽  
Multiwalled Carbon Nanotubes ◽  
Cutting Forces ◽  
Fiber Composite ◽  
Chip Morphology ◽  
Surface Characteristics ◽  
Carbon Fiber Composite ◽  
Multiwalled Carbon ◽  
Machined Surface

The machinability of a polycarbonate nanocomposite containing multiwalled carbon nanotubes is investigated and contrasted with its base polymer and with a conventional carbon fiber composite. The material microstructures are characterized using transmission electron and scanning electron microscopy methods. Micro-endmilling experiments are conducted on the three materials. Chip morphology, machined surface characteristics, and the nature of the cutting forces are employed as machinability measures for comparative purposes. Polycarbonate chips are seen to transition from being discontinuous to continuous as the feed-per-tooth (FPT) increases, while, at all FPT values the nanocomposite is seen to form comparatively thicker continuous chips. The nanocomposite and the carbon fiber composite are seen to have the lowest and the highest magnitudes, respectively, for both the surface roughness and cutting forces. Shearing along the nanotube-polymer interface and better thermal conductivity are speculated to be the mechanisms responsible for the observations seen in the nanocomposite.

Research on Adiabatic Shear during Serrated Chip Formation of High Speed Turning of Hardened Steel

2010 ◽  
Vol 139-141 ◽  
pp. 743-747
Author(s):  
Chun Zheng Duan ◽  
Hai Yang Yu ◽  
Min Jie Wang ◽  
Bing Yan ◽  
Yu Jun Cai
Keyword(s):  
Chip Formation ◽  
Cutting Forces ◽  
High Speed ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Rake Angle ◽  
Adiabatic Shear ◽  
Cutting Condition ◽  
Serrated Chip ◽  
Serrated Chip Formation

The development of chip morphology, critical cutting condition of adiabatic shear during serrated chip formation and cutting forces were observed and measured by high speed turning experiment for 30CrNi3MoV hardened steel. Results show that the cutting speed and rake angle are leading factors to influence chip morphology and cutting forces. With the increase of cutting speed, the continuous band chip transforms into serrated chip at a certain critical value. As the rake angle is changed from positive to negative, the critical cutting speed of adiabatic shear significantly decreases, the cutting forces abruptly reduces when the serrated chip forms. The results from predicting critical cutting speed using the critical cutting condition criterion of adiabatic shear in metal cutting process show that the leading reason of serrated chip formation is that the adiabatic shear fracture repeatedly occurs in the primary shear zone.

The Effect of Build Up Edge Formation on the Machining Characteristics in Austempered Ferritic Ductile Iron

2013 ◽  
Author(s):  
Şakir Yazman ◽  
Ahmet Akdemir ◽  
Mesut Uyaner ◽  
Barış Bakırcıoğlu
Keyword(s):  
Surface Roughness ◽  
Ductile Iron ◽  
Cutting Forces ◽  
Cutting Speed ◽  
Chip Morphology ◽  
Salt Bath ◽  
Chip Formation Mechanism ◽  
Machining Properties ◽  
Machining Characteristics ◽  
Cutting Speeds

In this study, chip formation mechanism during the machining of austempered ferritic DI and the effect of the emerging chip morphology on such machining properties as surface roughness and cutting forces has been scrutinized. After austenitizing at 900 °C for 90 min, DI specimens were austempered in a salt bath at 380 °C for 90 min. Chip roots were produced by using a quick stop device during the machining of austempered specimens in different cutting speeds. The metallographies of these specimens were performed and chip morphologies were examined. The fact that the cutting speed increased led to a decrease in built-up edge formation. Depending on this fact, it was detected that the change in built-up edge thickness substantially affected the surface roughness and cutting forces. It was also detected that during the machining, with the effect of cutting forces and stress, spheroidal graphites were broken off in the chip and lost their sphericity and so that the chip became fragile and unstable and grafites here displayed a lubricant feature.

A smooth particle hydrodynamic model for two-dimensional numerical simulation of Ti–6Al–4V serrated chip deformation based on TANH constitutive law

2018 ◽  
Vol 233 (9) ◽  
pp. 3004-3017 ◽  
Author(s):  
Weilong Niu ◽  
Rong Mo ◽  
Huibin Sun ◽  
Balachander Gnanasekaran ◽  
Yihui Zhu ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Chip Formation ◽  
Cutting Forces ◽  
Damage Model ◽  
Smooth Particle Hydrodynamic ◽  
Chip Morphology ◽  
Constitutive Law ◽  
Cutting Process ◽  
Serrated Chip ◽  
Cutting Model

The saw-tooth chip formation is one of the main machining characteristics in cutting of titanium alloys. The numerical simulation of saw-tooth chip formation, however, is still not accurate, since most of these numerical simulation models are based on traditional finite element method, which have difficulties in handling extremely large deformation that always occurs in the cutting process. Furthermore, these models adopt the Johnson–Cook damage constitutive law that is implemented in commercial codes such as ABAQUS® and LS-DYNA® to describe the dynamic mechanical properties of material, but Johnson–Cook damage constitutive law cannot account for the material of behavior due to strain softening and the dynamic recrystallization mechanism that occurs in the cutting process of Ti–6Al–4. Therefore, this work introduces a material constitutive model named hyperbolic tangent (TANH) and an improved smooth particle hydrodynamics method, and then develops an improved cutting model for Ti–6Al–4V titanium alloy through our in-house code to predict saw-tooth chip morphology and cutting forces. When compared to the experiments and Johnson–Cook damage model, the improved cutting model better explains and predicts the shear localized saw-tooth chip deformation as well as cutting forces.

Study on the machining process of micro V-shaped groove by using a revolving tip

2017 ◽  
Vol 232 (9) ◽  
pp. 1523-1537
Author(s):  
Bo Xue ◽  
Yongda Yan ◽  
Gaojie Ma ◽  
Zhenjiang Hu
Keyword(s):  
Cutting Forces ◽  
Chip Thickness ◽  
Chip Morphology ◽  
Machining Process ◽  
Burr Formation ◽  
Uncut Chip Thickness ◽  
Machined Surface ◽  
Advantages And Disadvantages

This paper proposed a machining method for micro V-shaped grooves, which was achieved by introducing the revolving trajectory on the basis of tip scratching process. By coordinating the revolving direction and the tip orientation, four kinds of revolving scratches were developed which had the revolving radii larger than the groove depths. It was found that there were two revolving scratches among these four being able to eliminate the side burrs and produce much smaller cutting forces during machining grooves compared to the traditional scratch, respectively named as the up-milling of face-forward and the down-milling of edge-forward. By considering the tip geometry in the traditional scratching process, the burr formation has been studied which was mainly affected by the effect of chip interference and the amount of uncut chip thickness. By analyzing the machining trajectory, the undeformed chip, the machined surface and the chip morphology, the reason why the up-milling of face-forward and the down-milling of edge-forward had good performances for machining V-grooves was elucidated in detail. Meanwhile, the differences between these two revolving scratches were discussed, and their advantages and disadvantages were also given.

The Influence of Cryogenic Coolants in Machining of Ti–6Al–4V

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
B. Dilip Jerold ◽  
M. Pradeep Kumar
Keyword(s):  
Carbon Dioxide ◽  
Tool Wear ◽  
Cutting Forces ◽  
Cutting Temperature ◽  
Chip Morphology ◽  
Cutting Fluids ◽  
Cryogenic Machining ◽  
The Past ◽  
Carbon Dioxide Co2 ◽  
Made In

Machining of titanium alloy Ti–6Al–4V is a challenging task because of the greatly increased cutting temperature that results in short tool life. Numerous attempts have been made in the past by employing various cutting fluids for machining purpose, including liquid nitrogen (LN2) as the cryogenic coolant. This study deals with the influence of cryogenic coolants, especially LN2 and carbon dioxide (CO2), in machining of Ti–6Al–4V and its effects on cutting temperature, cutting forces, surface roughness, chip morphology, and tool wear. The results obtained in cryogenic machining are compared with that of dry and wet machining. Cutting temperature was reduced to an extent of 36% and 47% in cryogenic CO2 machining and cryogenic LN2 machining in comparison with wet machining. The application of CO2 produced reduced cutting forces up to 24% and improved surface finish up to 48% compared to cryogenic LN2 machining. It also produced better chip control and minimized tool wear than dry, wet, and LN2 machining.

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