Characterization & modeling of chip flow angle & morphology in 2D & 3D Turning process

83 Pages·2016·6.62 MB·English

Licentiate Thesis
Production Technology
2015 No.5
Characterization & modeling of
chip flow angle & morphology in
2D & 3D Turning process
Ashwin Moris Devotta
Acknowledgements
Foremost, I would like to thank Sandvik Coromant for providing me the
opportunity to carry out this research work, KK-Foundation, University West
and industrial research school, SiCoMaP for providing a stimulating work
environment and doctoral candidates to work with.
Needless to say, My Supervisor, Prof. Tomas Beno and Co Supervisor, Assoc.
Prof. Mahdi Eynian have been instrumental in pushing me to search for the
fundamental questions and working in a methodical way taking enormous effort
in grooming me into a researcher in the field of metal cutting.
My industrial supervisors, Ronnie Löf and Erik Tyldhed have played a very
significant part in helping me with all the aspects of research and providing me
their valuable knowledge in metal cutting. They have also been supportive in
times of need providing me mental support. I extend my thanks to Niklas
Wahlman for his expertise with high-speed videography, Emil Espes and Elias
Nyrot for their support in computed tomography measurement. Special thanks
are due to my managers, Daniel Edler and Maths Scherman for being supportive
during this work.
I would like to take the opportunity to acknowledge my fellow doctoral
candidates and colleagues at Sandvik Coromant and University West for the
technical discussions, which help me to be still puzzled, intrigued and be in awe
of metal cutting and manufacturing in general.
Finally, I would like to acknowledge the foundation of my life, my loving family
and my dear friends who have been my punching bag at times of despair and have
still stayed to sculpt me into a refined soul.
Thank you all.
University West
SE-46186 Trollhättan Ashwin Moris Devotta
Sweden
[phone] March 2016
www.hv.se
© Ashwin Moris Devotta 2015
ISBN 978-91-87531-20-0 (Printed version)
978-91-87531-21-7 (Electronic version)
iii
Acknowledgements
Foremost, I would like to thank Sandvik Coromant for providing me the
opportunity to carry out this research work, KK-Foundation, University West
and industrial research school, SiCoMaP for providing a stimulating work
environment and doctoral candidates to work with.
Needless to say, My Supervisor, Prof. Tomas Beno and Co Supervisor, Assoc.
Prof. Mahdi Eynian have been instrumental in pushing me to search for the
fundamental questions and working in a methodical way taking enormous effort
in grooming me into a researcher in the field of metal cutting.
My industrial supervisors, Ronnie Löf and Erik Tyldhed have played a very
significant part in helping me with all the aspects of research and providing me
their valuable knowledge in metal cutting. They have also been supportive in
times of need providing me mental support. I extend my thanks to Niklas
Wahlman for his expertise with high-speed videography, Emil Espes and Elias
Nyrot for their support in computed tomography measurement. Special thanks
are due to my managers, Daniel Edler and Maths Scherman for being supportive
during this work.
I would like to take the opportunity to acknowledge my fellow doctoral
candidates and colleagues at Sandvik Coromant and University West for the
technical discussions, which help me to be still puzzled, intrigued and be in awe
of metal cutting and manufacturing in general.
Finally, I would like to acknowledge the foundation of my life, my loving family
and my dear friends who have been my punching bag at times of despair and have
still stayed to sculpt me into a refined soul.
Thank you all.
University West
SE-46186 Trollhättan Ashwin Moris Devotta
Sweden
[phone] March 2016
www.hv.se
© Ashwin Moris Devotta 2015
ISBN 978-91-87531-20-0 (Printed version)
978-91-87531-21-7 (Electronic version)
iii
Populärvetenskaplig Sammanfattning
Nyckelord: Spånform; Spånflöde; Datortomografi; Spånbildning; Bearbetning
Inom tillverkning av metallkomponenter spelar bearbetning en viktig roll och är
av avgörande betydelse för att säkerställa en produkts kvalitet.
Från ett skärverktygs konstruktionsperspektiv är utformningen av ett verktygs
makrogeometri baserad på en fysikbaserad numerisk modell en nödvändigt för
att kunna förutsäga spånans morfologi. Spånans morfologi beskriver spånans
form, utseende och geometri. Att kunna förutse spånflöde och spånform är
avgörande för att i sin tur kunna förutsäga spånbrytning och säkerställa att en god
spånevakuering erhålls tillsammans med en bättre ytjämnhet. För detta ändamål
behövdes en numerisk modell som plattform där spånformen kan förutsägas för
att sedan kunna jämföras med experimentella undersökningar, denna är i fokus
för detta arbete. De undersökta bearbetningsprocesserna utgörs av den rena
ortogonala bearbetningsprocessen och en där skärverktygets nosradie är i
ingrepp. Numeriska modeller som simulerar spånbildningsprocessen användes
för att förutsäga spånans morfologi och åtföljdes av bearbetningsexperiment.
Datortomografi användes för att mäta de erhållna spånorna från
bearbetningsexperimenten så att variationen hos spånornas morfologi kunde
utvärderas. För en bearbetningsprocess där skärverktygets nosradie är i ingrepp
under skärprocessen måste parametrar som beskriver spånformen beräknas.
Kharkevich modellen används i detta sammanhang för att beräkna parametrarna
hos spånformen under ingrepp. Höghastighetsvideo används för att mäta spånans
sidoflödesvinkel under ingreppet i experiment och kunde därmed direkt jämföras
med förutsägelsen i från den numeriska modellen.
Resultaten visar att den metod som utvecklats ger en möjlighet till utvärdering av
framsteg inom numeriska modeller kan utvärderas på ett tillförlitligt sätt utifrån
spånans morfologi hos svarvprocesser där nosradien är i ingrepp.
Vidare visar resultaten ifrån den numeriska modelleringen att spånans morfologi
varierar för varierande skärförhållanden och kan förutsägas kvalitativt.
Beträffande felet hos den kvantitativa utvärderingen av spånans morfologi är
dessa ännu för stora för att kunna användas för modellering.
v
Populärvetenskaplig Sammanfattning
Nyckelord: Spånform; Spånflöde; Datortomografi; Spånbildning; Bearbetning
Inom tillverkning av metallkomponenter spelar bearbetning en viktig roll och är
av avgörande betydelse för att säkerställa en produkts kvalitet.
Från ett skärverktygs konstruktionsperspektiv är utformningen av ett verktygs
makrogeometri baserad på en fysikbaserad numerisk modell en nödvändigt för
att kunna förutsäga spånans morfologi. Spånans morfologi beskriver spånans
form, utseende och geometri. Att kunna förutse spånflöde och spånform är
avgörande för att i sin tur kunna förutsäga spånbrytning och säkerställa att en god
spånevakuering erhålls tillsammans med en bättre ytjämnhet. För detta ändamål
behövdes en numerisk modell som plattform där spånformen kan förutsägas för
att sedan kunna jämföras med experimentella undersökningar, denna är i fokus
för detta arbete. De undersökta bearbetningsprocesserna utgörs av den rena
ortogonala bearbetningsprocessen och en där skärverktygets nosradie är i
ingrepp. Numeriska modeller som simulerar spånbildningsprocessen användes
för att förutsäga spånans morfologi och åtföljdes av bearbetningsexperiment.
Datortomografi användes för att mäta de erhållna spånorna från
bearbetningsexperimenten så att variationen hos spånornas morfologi kunde
utvärderas. För en bearbetningsprocess där skärverktygets nosradie är i ingrepp
under skärprocessen måste parametrar som beskriver spånformen beräknas.
Kharkevich modellen används i detta sammanhang för att beräkna parametrarna
hos spånformen under ingrepp. Höghastighetsvideo används för att mäta spånans
sidoflödesvinkel under ingreppet i experiment och kunde därmed direkt jämföras
med förutsägelsen i från den numeriska modellen.
Resultaten visar att den metod som utvecklats ger en möjlighet till utvärdering av
framsteg inom numeriska modeller kan utvärderas på ett tillförlitligt sätt utifrån
spånans morfologi hos svarvprocesser där nosradien är i ingrepp.
Vidare visar resultaten ifrån den numeriska modelleringen att spånans morfologi
varierar för varierande skärförhållanden och kan förutsägas kvalitativt.
Beträffande felet hos den kvantitativa utvärderingen av spånans morfologi är
dessa ännu för stora för att kunna användas för modellering.
v
Abstract Appended Publications
Title: Characterization and modeling of chip flow angle and
morphology in 2D and 3D turning process Paper A. Quantitative characterization of chip morphology using computed
tomography in orthogonal turning process
Keywords: Chip curl, Chip flow, Computed tomography, Chip formation, Presented at “9th CIRP Conference on Intelligent Computation in Manufacturing Engineering –
Machining CIRP ICME 2014” in Capri (Naples), Italy, July 2014
Authors: Ashwin Devotta, Tomas Beno, Ronnie Löf and Emil Espes.
ISBN: 978-91-87531-20-0 (Printed version)
Authors’ contribution: The planning, evaluation and writing of the paper was done by me and Tomas
Beno. Ronnie Löf provided the experimental results and the CT measurements were carried out by Emil
978-91-87531-21-7 (Electronic version)
Espes.
Within manufacturing of metallic components, machining plays an important role
and is of vital significance to ensure process reliability. From a cutting tool design
Paper B. Modeling of chip curl in orthogonal turning using spiral galaxy
perspective, tool macro geometry design based on physics based numerical
describing function
modelling is highly needed that can predict chip morphology. The chip
Presented at “6th International conference on competitive manufacturing – COMA 2016” in
morphology describes the chip shape geometry and the chip curl geometry. The
Stellenbosch, South Africa, January, 2016.
prediction of chip flow and chip shape is vital in predicting chip breakage,
Authors: Ashwin Devotta, Tomas Beno and Ronnie Löf.
ensuring good chip evacuation and lower surface roughness. To this end, a
platform is developed, to compare numerical model’s chip morphology Authors’ contribution: Tomas Beno and I carried out the planning, evaluation and writing of the paper
prediction with experimental results in this work. The investigated cutting with experimental results provided by Ronnie Löf.
processes are orthogonal cutting process and nose turning process. Numerical
models that simulate the chip formation process are used to predict the chip
Paper C. Characterization of chip morphology in oblique nose turning
morphology and are accompanied by machining experiments. Computed
employing high-speed videography and computed tomography
tomography is used to scan the chips obtained from machining experiments and
technique.
its ability to capture the variation in chip morphology is evaluated. For nose
turning process, chip curl parameters during the cutting process are to be Presented at “6th International conference on competitive manufacturing – COMA 2016” in
calculated. Kharkevich model is utilized in this regard to calculate the ‘chip in Stellenbosch, South Africa 2016.
process’ chip curl parameters. High-speed videography is used to measure the Authors: Ashwin Devotta and Tomas Beno.
chip side-flow angle during the cutting process experiments and is directly
Authors’ contribution: The planning, evaluation and writing of the paper was carried out by me and
compared to physics based model predictions. The results show that the
Tomas Beno. Experimental investigation was carried out with help from the operators at Sandvik
methodology provides the framework where an advance in numerical models is Coromant, Sandviken. The CT measurement was carried out under the guidance of Elias Nyrot.
evaluated reliably from a ‘chip morphology prediction capability’ viewpoint for
nose turning process. The numerical modeling results show that the chip
morphology variation for varying cutting conditions is predicted qualitatively. The Paper D. FE modelling and characterization of chip curl in nose turning
results of quantitative evaluation of chip morphology prediction shows that the process.
error in prediction is too large to be used for predictive modelling purposes Accepted for publication in the Journal, “International journal of machining and machinability of
materials”. Authors: Ashwin Devotta, Tomas Beno and Ronnie Löf.
Authors’ contribution: The planning, evaluation and writing of the paper was carried out by me and
Tomas Beno. Experimental investigation was carried out by me with guidance from Ronnie Löf. CT
measurement was carried out under the guidance of Elias Nyrot.
vi vii
Abstract Appended Publications
Title: Characterization and modeling of chip flow angle and
morphology in 2D and 3D turning process Paper A. Quantitative characterization of chip morphology using computed
tomography in orthogonal turning process
Keywords: Chip curl, Chip flow, Computed tomography, Chip formation, Presented at “9th CIRP Conference on Intelligent Computation in Manufacturing Engineering –
Machining CIRP ICME 2014” in Capri (Naples), Italy, July 2014
Authors: Ashwin Devotta, Tomas Beno, Ronnie Löf and Emil Espes.
ISBN: 978-91-87531-20-0 (Printed version)
Authors’ contribution: The planning, evaluation and writing of the paper was done by me and Tomas
Beno. Ronnie Löf provided the experimental results and the CT measurements were carried out by Emil
978-91-87531-21-7 (Electronic version)
Espes.
Within manufacturing of metallic components, machining plays an important role
and is of vital significance to ensure process reliability. From a cutting tool design
Paper B. Modeling of chip curl in orthogonal turning using spiral galaxy
perspective, tool macro geometry design based on physics based numerical
describing function
modelling is highly needed that can predict chip morphology. The chip
Presented at “6th International conference on competitive manufacturing – COMA 2016” in
morphology describes the chip shape geometry and the chip curl geometry. The
Stellenbosch, South Africa, January, 2016.
prediction of chip flow and chip shape is vital in predicting chip breakage,
Authors: Ashwin Devotta, Tomas Beno and Ronnie Löf.
ensuring good chip evacuation and lower surface roughness. To this end, a
platform is developed, to compare numerical model’s chip morphology Authors’ contribution: Tomas Beno and I carried out the planning, evaluation and writing of the paper
prediction with experimental results in this work. The investigated cutting with experimental results provided by Ronnie Löf.
processes are orthogonal cutting process and nose turning process. Numerical
models that simulate the chip formation process are used to predict the chip
Paper C. Characterization of chip morphology in oblique nose turning
morphology and are accompanied by machining experiments. Computed
employing high-speed videography and computed tomography
tomography is used to scan the chips obtained from machining experiments and
technique.
its ability to capture the variation in chip morphology is evaluated. For nose
turning process, chip curl parameters during the cutting process are to be Presented at “6th International conference on competitive manufacturing – COMA 2016” in
calculated. Kharkevich model is utilized in this regard to calculate the ‘chip in Stellenbosch, South Africa 2016.
process’ chip curl parameters. High-speed videography is used to measure the Authors: Ashwin Devotta and Tomas Beno.
chip side-flow angle during the cutting process experiments and is directly
Authors’ contribution: The planning, evaluation and writing of the paper was carried out by me and
compared to physics based model predictions. The results show that the
Tomas Beno. Experimental investigation was carried out with help from the operators at Sandvik
methodology provides the framework where an advance in numerical models is Coromant, Sandviken. The CT measurement was carried out under the guidance of Elias Nyrot.
evaluated reliably from a ‘chip morphology prediction capability’ viewpoint for
nose turning process. The numerical modeling results show that the chip
morphology variation for varying cutting conditions is predicted qualitatively. The Paper D. FE modelling and characterization of chip curl in nose turning
results of quantitative evaluation of chip morphology prediction shows that the process.
error in prediction is too large to be used for predictive modelling purposes Accepted for publication in the Journal, “International journal of machining and machinability of
materials”. Authors: Ashwin Devotta, Tomas Beno and Ronnie Löf.
Authors’ contribution: The planning, evaluation and writing of the paper was carried out by me and
Tomas Beno. Experimental investigation was carried out by me with guidance from Ronnie Löf. CT
measurement was carried out under the guidance of Elias Nyrot.
vi vii
Table of Contents
Acknowledgements ........................................................................ iii
Populärvetenskaplig Sammanfattning .............................................. v
Abstract .......................................................................................... vi
Appended Publications .................................................................. vii
Table of Contents ........................................................................... ix
Nomenclature ................................................................................. xi
1 Introduction .................................................................... 1
1.1 Scope and aim of the study .................................................. 5
1.2 Delimitations ........................................................................ 5
1.3 Research questions ............................................................. 5
1.4 Research approach .............................................................. 7
1.5 Thesis outline ....................................................................... 7
2 Chip morphology ........................................................... 9
2.1 Chip shape .......................................................................... 9
2.2 Chip curl ............................................................................ 12
3 Modeling of chip formation process ........................... 17
3.1 Methodologies for modelling of chip formation ................... 18
4 Chip morphology characterization ............................. 27
4.1 Computed tomography (CT) as a metrological tool ............ 28
4.2 Chip morphology characterization using CT ....................... 30
4.3 Chip curl characterization in nose turning process ............. 31
4.4 Chip curl characterization using spiral galaxy function ....... 32
5 Experimental investigation .......................................... 35
5.1 Orthogonal turning experiments ......................................... 35
5.2 Nose turning experiments .................................................. 36
6 Finite element modeling .............................................. 39
6.1 2D FE modeling of orthogonal turning process .................. 39
Table of Contents
Acknowledgements ........................................................................ iii
Populärvetenskaplig Sammanfattning .............................................. v
Abstract .......................................................................................... vi
Appended Publications .................................................................. vii
Table of Contents ........................................................................... ix
Nomenclature ................................................................................. xi
1 Introduction .................................................................... 1
1.1 Scope and aim of the study .................................................. 5
1.2 Delimitations ........................................................................ 5
1.3 Research questions ............................................................. 5
1.4 Research approach .............................................................. 7
1.5 Thesis outline ....................................................................... 7
2 Chip morphology ........................................................... 9
2.1 Chip shape .......................................................................... 9
2.2 Chip curl ............................................................................ 12
3 Modeling of chip formation process ........................... 17
3.1 Methodologies for modelling of chip formation ................... 18
4 Chip morphology characterization ............................. 27
4.1 Computed tomography (CT) as a metrological tool ............ 28
4.2 Chip morphology characterization using CT ....................... 30
4.3 Chip curl characterization in nose turning process ............. 31
4.4 Chip curl characterization using spiral galaxy function ....... 32
5 Experimental investigation .......................................... 35
5.1 Orthogonal turning experiments ......................................... 35
5.2 Nose turning experiments .................................................. 36
6 Finite element modeling .............................................. 39
6.1 2D FE modeling of orthogonal turning process .................. 39
6.2 3D FE modeling of nose turning process ........................... 40
Nomenclature
7 Results .......................................................................... 41
Variable Description [unit]
7.1 Influence of work piece material modeling on chip curl ...... 41
Johnson Cook model constant: (Strain hardening component)
7.2 Chip curl characterization in orthogonal turning ................. 43
Johnson Cook model constant: (Strain hardening component)
7.3 Chip curl characterization in nose turning .......................... 46 𝐴𝐴b1 Slant width of helical chip [mm]
𝐵𝐵a Depth of cut [mm]
p
8 Conclusion .................................................................... 53
Johnson Cook model constant (Strain-rate hardening component)
9 Discussion .................................................................... 55 Taylor constants: Intercept on the speed axis
𝐶𝐶e Distance between plane of helix's axis and YZ plane [mm]
9.1 Chip characterization methodology .................................... 55
𝐶𝐶f 𝑡𝑡 Feed rate [mm/rev [turning process]; mm [orthogonal cutting]]
9.2 FE Simulation of chip curl in 2D & 3D ................................ 57 F Friction force [N]
f
10 Future work ................................................................... 61 Fn Normal force [N]
h Projection length of slant width of helical chip parallel to helix axis [mm]
1
11 References .................................................................... 63
Chip thickness [mm]
h Maximum chip thickness [mm]
max
ℎh𝑐𝑐 Minimum chip thickness [mm]
min
Appended Publications Incident intensity of X-ray [R]
Reduced intensity of X-ray after passing through object of interest [R]
Paper A. Quantitative characterization of chip morphology using 𝐼𝐼l0 Tool chip contact length [mm]
c
computed tomography in orthogonal turning process
𝐼𝐼l Length of sticking contact [mm]
p
Paper B. Modeling of chip curl in orthogonal turning using spiral l Chip segmentation width [mm]
s
galaxy describing function Johnson Cook model constant (Thermal softening component)
Johnson Cook model constant (Strain hardening component)
Paper C. Characterization of chip morphology in oblique nose
𝑚𝑚 Taylor constant: Slope of tool life vs cutting speed in log-log plot
turning employing high speed videography and computed
𝑛𝑛p Pitch of screw chip [mm]
tomography technique
𝑛𝑛P𝑡𝑡 Tool rake face plane
r
Paper D. FE modelling and characterization of chip curl in nose Inherent radius of chip curvature (Nakayama equation) [mm]
turning process
Limiting radius of chip curvature to contact obstacle (Nakayama
𝑅𝑅0 equation) [mm]
𝑅𝑅𝐿𝐿 Initial chip curl radius [mm]
Chip curl radius based on galaxy describing function [mm]
𝑟𝑟𝑖𝑖𝑐𝑐 Cutting velocity [m/min or rpm]
𝑟𝑟𝑠𝑠 Tool life [min]
𝑣𝑣𝑐𝑐 Johnson Cook model variable: work piece temperature [°C]
𝑡𝑡 Johnson Cook model constant: work piece melting temperature [°C]
𝑇𝑇 Johnson Cook model constant: room temperature [°C]
𝑇𝑇A𝑚𝑚H Axis of screw chip helix
𝑇𝑇A𝑟𝑟H𝑟𝑟𝑟𝑟r𝑚𝑚' Projection of A on tool rake plane
H
XYZ Cartesian coordinated system with Z axis positively directed outward
from tool rake face, X is parallel to A and Y axis perpendicular to AHr
H
while being parallel to tool rake face.