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Effect of machining process parameters on productivity rate and surface roughness of machined TiNiCo alloy
Available online at www.sciencedirect.com
ScienceDirect Materials Today: Proceedings 5 (2018) 19166–19171
www.materialstoday.com/proceedings
ICMPC_2018
Effect of machining process parameters on productivity rate and surface roughness of machined TiNiCo alloy *Hargovind Soni, Narendranath S. and Ramesh M R Department of Mechanical Engineering, National Institute of Technology Karnataka, India
Abstract TiNiCo based shape memory alloy is an important alloy for biomedical applications such as bone staple due to their excellent biocompatibility, corrosion resistance, shape memory effect (SME) and pseudoelasticity (PE). Traditional machining of such kind of alloys is difficult due to their outstanding properties. Wire electro discharge machining (WEDM) is most suitable nontraditional machining process for machining of these alloys. Present study focuses on effect of WEDM process parameters on productivity rate and surface roughness. Pulse on time, servo voltage and wire speed were considered as WEDM process parameters with their five levels in the current study. Our observation exhibit that productivity rate and surface roughness increases with increasing pulse on time and both outputs decrease with increasing servo voltage while wire speed does not show much effect on productivity rate as well as surface roughness. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization. Keywords: TiNiCo shape memory alloy; Wire electro discharge machinig; productivity rate; surface roughness .
1. Main text TiNiCo Shape memory alloy are unique class of shape memory material because of their outstanding properties such as shape memory effect, pseudoelasticity. Because these properties SMAs are widely used in the biomedical and aerospace applications [1]. Even though TiNi SMAs exhibit good properties but still by adding third element in TiNi, properties of TiNi alloy can be improve. By adding Co in TiNi they found drastically decrease in phase
* Corresponding author. Tel.: +91-9993706033; E-mail address: [email protected] 2214-7853 © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization.
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
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Nomenclature WEDM Wire electro discharge machining SMAs Shape memory alloys PR Productivity rate SR Surface roughness Ton Pulse on time Toff Pulse off time SV Servo voltage WS Wire speed
transformation temperature, improvement in corrosion resistance [2]. Machining of TiNiCo alloy is very difficult through traditional machining due to poor surface quality, burr formation therefore non-traditional machining process such as WEDM, electro discharge machining, water jet machining are very suitable for machining of such kind of alloys. WEDM process is most suitable machining of TiNi based alloys [3], [4], [5], [6]. Productivity rate and surface roughness are most significant output responses of any machining method; these responses exhibit the abilities of machining methods. It has been found form the literature that WEDM can be machine with good surface quality and productivity rate of all conductive or semi conductive material without disturbing their internal properties [7], [8],[9], [10]. WEDM process is controlled by their input process parameters such as Ton, Toff, SV and WS [4]. Present study exhibit the influence of WEDM process parameters (Ton, SV and WS) on productivity rate and surface roughness during the WEDM of selected alloy. 2. Experimental Procedure 2.1 Development of material Conventional vacuum arc melting was employed to prepare the Ti50Ni38Co12 alloy ingot was produced by melting four times (both sides). Titanium (purity 99.7%), Nickel (99.89 %) and Cobalt (99.99%) respectively of 8 g in total weight were filled into the copper mold and repeated the same procedure six times in the presence of argon gas which is filled inside the melting chamber. 10−5 m bar vacuum has been created for melting the material. 2.2 Machining of material The EDM specimens were performed on a Wire EDM (model Electronica ELPULS15 CNC). The response used for this study were SR and PR are correlated with machining parameter such as Ton, SV and WS. 0.25 mm brass wire wad used as a tool electrode due to brass wire proves good surface quality comparatively [11] and de-ionized water used as dielectric fluid during the WEDM. Fig. 1 exhibits the setup of WEDM process. 2.3 Measurement of output responses Productivity rate is calculated by equation 1 and surface roughness was measured by using “surface roughness tester SJ-301 (Mitutoyo). Where cut off length was 0.8mm and length of evolution was 3 mm during roughness measurement. On the basis of selected input process parameters of WEDM has been carried out and the values of machining performance such as PR and SR (Ra) were found and which are presented in Table 1. PR (mm3/min) = cutting speed (mm/min) x Kerf width (mm) x work piece height (mm) ----- (1) Kerf width (mm) = 2 x gap of tool and workpiece + wire diameter
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Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
Figure 1. Full setup of WEDM process Table 1. Process parameters and their levels Levels
Ton (µs)
SV (V)
WS (m/min)
1
105
20
2
2
110
30
3
3
115
40
4
4
120
50
5
5
125
60
6
3. Result and Discussion Table 2 indicated the results of productivity rate and surface roughness with respect to all input process parameters and their levels. Table 2. Obtained values of PR and SR Levels
Ton (µs)
SV (V)
PR
SR
PR
1
2.45
2.63
2
2.64
2.72
3
3.39
3.31
4
4.56
3.69
5
6.96
3.65
WS (m/min)
SR
PR
SR
6.55
5.6
4.95
5.01
6.15
5.18
4.90
4.99
4.35
4.5
4.86
4.82
3.68
3.96
4.81
4.75
2.66
3.69
4.77
4.68
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
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3.1 Effect of Ton on productivity rate and SR Pulse on time exhibits the time interval of spark allowed per cycle with the range of 100 µs to 129 µs according to ‘Electronica Eco-cut WEDM’. Pulse on time is most important parameters for wire electro discharge machining. Higher values of pulse on time give higher productivity rate but more frequent wire breakage seems at the higher values of this parameters hence the rang of this parameter will be different for different – different materials then only possible to machining of those materials without wire breakage with higher material removal rate and good surface finish. Fig. 2a exhibit the productivity rate increases with increasing Ton because at higher Ton spark intensity is high which in turn removes more amount of material (unwanted material) from the machined surface that results in higher PR. At same time SR increases with respect to higher values of Ton which can be seen in Fig. 3a. This is due to, at high Ton, spark intensity is high and some amount of melted material is removed from the surface of workpiece through dielectric fluid and rest of the material is melted on the machined surface in the form of microglobules, micro cracks leading to higher surface roughness. Similar work was presented by Soni et al. [4] during the wire electro discharge machining of TiNiCo shape memory alloy. 3.2 Effect of SV on productivity rate and SR SV is another important process parameter for wire electro discharge machine which is send signals to servo system through gap voltage sensor to control a predetermined gap between tool and workpiece. The range of the servo voltage is 1-100 V in wire EDM. Effect of this parameter is more during the machining, increase in SV materials removal rate and surface roughness are decreases because increase in servo voltage results in larger spark gap thereby reducing the spark intensity and eventually lesser amount of material is removed from the surface of the workpiece which leads to lower productivity rate and can be seen in Fig. 2b. On other hand less amount of material are melted on machined surface; this can be easily flushed away through dielectric fluid from the surface of machined component leading to low SR (Fig. 3b). Same as presented by Sharma et al. [12] during the WEDM of Inconel 706 alloy. 3.3 Effect of WS on productivity rate and SR WS is indicated the speed at which the wire-electrode travels along the wire guide path and is fed nonstop for sparking. The rang of this parameter is 1-15 m/min as per used WEDM for present work. For better machining performance and stability wire feed should be desirable to set the wire feed to maximum. During our observation it has been found that productivity rate (Fig. 2c) and surface roughness (Fig. 3c) both were constant at all levels of WS which means that this parameter is not much affected in present study.
19170
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
Figure 2. Effects of process parameters on productivity rate
Figure 3. Effects of process parameters on Surface roughness
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
19171
Conclusion Based on the above study it has been concluded that Ton and SV are most significant process parameters of WEDM for the current study. Moreover productivity rate increased with increasing pulse on time same trend has been noticed with surface roughness. While both responses (Productivity rate and surface roughness) were decreased with increasing the values of servo voltage. However wire speed was not much affected process parameter for the presents study. All results can be seen in Table 2. Acknowledgements Thanks to Department of Science and Technology (DST) Government of India for your financially support (Project reference no. SB/S3/MMER/0067/2013) in the present work. References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
A. Fasching, D.W. Norwich, T. Geiser, G.W. Paul, An Evaluation of a NiTiCo Alloy and its Suitability for Medical Device Applications, J. Mater. Eng. Perform. 20 (2011) 641–645. doi:10.1007/s11665-011-9845-z. J. Rui-rui, L.I.U. Fu-shun, The Influence of Co Addition on Phase Transformation Behavior and Mechanical Properties of TiNi Alloys, 20 (2007) 153–156. A. Kumar, V. Kumar, J. Kumar, Multi-response optimization of process parameters based on response surface methodology for pure titanium using WEDM process, Int. J. Adv. Manuf. Technol. 68 (2013) 2645–2668. doi:10.1007/s00170-013-4861-9. H. Soni, N. Sannayellappa, R. Motagondanahalli Rangarasaiah, An experimental study of influence of wire electro discharge machining parameters on surface integrity of TiNiCo shape memory alloy, J. Mater. Res. (2017) 1–9. doi:10.1557/jmr.2017.137. S. Daneshmand, V. Monfared, A.A. Lotfi Neyestanak, Effect of Tool Rotational and Al2O3 Powder in Electro Discharge Machining Characteristics of NiTi-60 Shape Memory Alloy, Silicon. (2016) 1–11. doi:10.1007/s12633-016-9412-1. H. Soni, S. Narendranath, M.R. Ramesh, Effect of Machining Parameters on Wire Electro Discharge Machining of Shape Memory Alloys Analyzed using Grey Entropy Method, 2 (2015) 50–54. K. Gupta, N.K. Jain, Analysis and optimization of micro-geometry of miniature spur gears manufactured by wire electric discharge machining, Precis. Eng. 38 (2014) 728–737. doi:10.1016/j.precisioneng.2014.03.009. S. Kumar Majhi Ȧ, Ȧ Tkm., Ḃ Mkp., H. Soni Ȧ Ȧ, Effect of Machining Parameters of AISI D2 Tool Steel on Electro Discharge Machining, Int. J. Curr. Eng. Technol. 1944 (2014) 19–23. http://inpressco.com/category/ijcet. S. Daneshmand, V. Monfared, A.A. Lotfi Neyestanak, Effect of Tool Rotational and Al2O3 Powder in Electro Discharge Machining Characteristics of NiTi-60 Shape Memory Alloy, Silicon. 9 (2017) 273–283. doi:10.1007/s12633-016-9412-1. A. Roy, S. Narendra Nath, D. Nedelcu, Experimental investigation on variation of output responses of as cast TiNiCu shape memory alloys using wire EDM, Int. J. Mod. Manuf. Technol. 9 (2017). M.T. Antar, S.L. Soo, D.K. Aspinwall, D. Jones, R. Perez, Productivity and workpiece surface integrity when WEDM aerospace alloys using coated wires, Procedia Eng. 19 (2011) 3–8. doi:10.1016/j.proeng.2011.11.071. P. Sharma, D. Chakradhar, S. Narendranath, Evaluation of WEDM performance characteristics of Inconel 706 for turbine disk application, Mater. Des. 88 (2015) 558–566. doi:10.1016/j.matdes.2015.09.036.
ScienceDirect Materials Today: Proceedings 5 (2018) 19166–19171
www.materialstoday.com/proceedings
ICMPC_2018
Effect of machining process parameters on productivity rate and surface roughness of machined TiNiCo alloy *Hargovind Soni, Narendranath S. and Ramesh M R Department of Mechanical Engineering, National Institute of Technology Karnataka, India
Abstract TiNiCo based shape memory alloy is an important alloy for biomedical applications such as bone staple due to their excellent biocompatibility, corrosion resistance, shape memory effect (SME) and pseudoelasticity (PE). Traditional machining of such kind of alloys is difficult due to their outstanding properties. Wire electro discharge machining (WEDM) is most suitable nontraditional machining process for machining of these alloys. Present study focuses on effect of WEDM process parameters on productivity rate and surface roughness. Pulse on time, servo voltage and wire speed were considered as WEDM process parameters with their five levels in the current study. Our observation exhibit that productivity rate and surface roughness increases with increasing pulse on time and both outputs decrease with increasing servo voltage while wire speed does not show much effect on productivity rate as well as surface roughness. © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization. Keywords: TiNiCo shape memory alloy; Wire electro discharge machinig; productivity rate; surface roughness .
1. Main text TiNiCo Shape memory alloy are unique class of shape memory material because of their outstanding properties such as shape memory effect, pseudoelasticity. Because these properties SMAs are widely used in the biomedical and aerospace applications [1]. Even though TiNi SMAs exhibit good properties but still by adding third element in TiNi, properties of TiNi alloy can be improve. By adding Co in TiNi they found drastically decrease in phase
* Corresponding author. Tel.: +91-9993706033; E-mail address: [email protected] 2214-7853 © 2018 Elsevier Ltd. All rights reserved. Selection and/or Peer-review under responsibility of Materials Processing and characterization.
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
19167
Nomenclature WEDM Wire electro discharge machining SMAs Shape memory alloys PR Productivity rate SR Surface roughness Ton Pulse on time Toff Pulse off time SV Servo voltage WS Wire speed
transformation temperature, improvement in corrosion resistance [2]. Machining of TiNiCo alloy is very difficult through traditional machining due to poor surface quality, burr formation therefore non-traditional machining process such as WEDM, electro discharge machining, water jet machining are very suitable for machining of such kind of alloys. WEDM process is most suitable machining of TiNi based alloys [3], [4], [5], [6]. Productivity rate and surface roughness are most significant output responses of any machining method; these responses exhibit the abilities of machining methods. It has been found form the literature that WEDM can be machine with good surface quality and productivity rate of all conductive or semi conductive material without disturbing their internal properties [7], [8],[9], [10]. WEDM process is controlled by their input process parameters such as Ton, Toff, SV and WS [4]. Present study exhibit the influence of WEDM process parameters (Ton, SV and WS) on productivity rate and surface roughness during the WEDM of selected alloy. 2. Experimental Procedure 2.1 Development of material Conventional vacuum arc melting was employed to prepare the Ti50Ni38Co12 alloy ingot was produced by melting four times (both sides). Titanium (purity 99.7%), Nickel (99.89 %) and Cobalt (99.99%) respectively of 8 g in total weight were filled into the copper mold and repeated the same procedure six times in the presence of argon gas which is filled inside the melting chamber. 10−5 m bar vacuum has been created for melting the material. 2.2 Machining of material The EDM specimens were performed on a Wire EDM (model Electronica ELPULS15 CNC). The response used for this study were SR and PR are correlated with machining parameter such as Ton, SV and WS. 0.25 mm brass wire wad used as a tool electrode due to brass wire proves good surface quality comparatively [11] and de-ionized water used as dielectric fluid during the WEDM. Fig. 1 exhibits the setup of WEDM process. 2.3 Measurement of output responses Productivity rate is calculated by equation 1 and surface roughness was measured by using “surface roughness tester SJ-301 (Mitutoyo). Where cut off length was 0.8mm and length of evolution was 3 mm during roughness measurement. On the basis of selected input process parameters of WEDM has been carried out and the values of machining performance such as PR and SR (Ra) were found and which are presented in Table 1. PR (mm3/min) = cutting speed (mm/min) x Kerf width (mm) x work piece height (mm) ----- (1) Kerf width (mm) = 2 x gap of tool and workpiece + wire diameter
19168
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
Figure 1. Full setup of WEDM process Table 1. Process parameters and their levels Levels
Ton (µs)
SV (V)
WS (m/min)
1
105
20
2
2
110
30
3
3
115
40
4
4
120
50
5
5
125
60
6
3. Result and Discussion Table 2 indicated the results of productivity rate and surface roughness with respect to all input process parameters and their levels. Table 2. Obtained values of PR and SR Levels
Ton (µs)
SV (V)
PR
SR
PR
1
2.45
2.63
2
2.64
2.72
3
3.39
3.31
4
4.56
3.69
5
6.96
3.65
WS (m/min)
SR
PR
SR
6.55
5.6
4.95
5.01
6.15
5.18
4.90
4.99
4.35
4.5
4.86
4.82
3.68
3.96
4.81
4.75
2.66
3.69
4.77
4.68
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
19169
3.1 Effect of Ton on productivity rate and SR Pulse on time exhibits the time interval of spark allowed per cycle with the range of 100 µs to 129 µs according to ‘Electronica Eco-cut WEDM’. Pulse on time is most important parameters for wire electro discharge machining. Higher values of pulse on time give higher productivity rate but more frequent wire breakage seems at the higher values of this parameters hence the rang of this parameter will be different for different – different materials then only possible to machining of those materials without wire breakage with higher material removal rate and good surface finish. Fig. 2a exhibit the productivity rate increases with increasing Ton because at higher Ton spark intensity is high which in turn removes more amount of material (unwanted material) from the machined surface that results in higher PR. At same time SR increases with respect to higher values of Ton which can be seen in Fig. 3a. This is due to, at high Ton, spark intensity is high and some amount of melted material is removed from the surface of workpiece through dielectric fluid and rest of the material is melted on the machined surface in the form of microglobules, micro cracks leading to higher surface roughness. Similar work was presented by Soni et al. [4] during the wire electro discharge machining of TiNiCo shape memory alloy. 3.2 Effect of SV on productivity rate and SR SV is another important process parameter for wire electro discharge machine which is send signals to servo system through gap voltage sensor to control a predetermined gap between tool and workpiece. The range of the servo voltage is 1-100 V in wire EDM. Effect of this parameter is more during the machining, increase in SV materials removal rate and surface roughness are decreases because increase in servo voltage results in larger spark gap thereby reducing the spark intensity and eventually lesser amount of material is removed from the surface of the workpiece which leads to lower productivity rate and can be seen in Fig. 2b. On other hand less amount of material are melted on machined surface; this can be easily flushed away through dielectric fluid from the surface of machined component leading to low SR (Fig. 3b). Same as presented by Sharma et al. [12] during the WEDM of Inconel 706 alloy. 3.3 Effect of WS on productivity rate and SR WS is indicated the speed at which the wire-electrode travels along the wire guide path and is fed nonstop for sparking. The rang of this parameter is 1-15 m/min as per used WEDM for present work. For better machining performance and stability wire feed should be desirable to set the wire feed to maximum. During our observation it has been found that productivity rate (Fig. 2c) and surface roughness (Fig. 3c) both were constant at all levels of WS which means that this parameter is not much affected in present study.
19170
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
Figure 2. Effects of process parameters on productivity rate
Figure 3. Effects of process parameters on Surface roughness
Hargovind Soni et al./ Materials Today: Proceedings 5 (2018) 19166–19171
19171
Conclusion Based on the above study it has been concluded that Ton and SV are most significant process parameters of WEDM for the current study. Moreover productivity rate increased with increasing pulse on time same trend has been noticed with surface roughness. While both responses (Productivity rate and surface roughness) were decreased with increasing the values of servo voltage. However wire speed was not much affected process parameter for the presents study. All results can be seen in Table 2. Acknowledgements Thanks to Department of Science and Technology (DST) Government of India for your financially support (Project reference no. SB/S3/MMER/0067/2013) in the present work. References [1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12]
A. Fasching, D.W. Norwich, T. Geiser, G.W. Paul, An Evaluation of a NiTiCo Alloy and its Suitability for Medical Device Applications, J. Mater. Eng. Perform. 20 (2011) 641–645. doi:10.1007/s11665-011-9845-z. J. Rui-rui, L.I.U. Fu-shun, The Influence of Co Addition on Phase Transformation Behavior and Mechanical Properties of TiNi Alloys, 20 (2007) 153–156. A. Kumar, V. Kumar, J. Kumar, Multi-response optimization of process parameters based on response surface methodology for pure titanium using WEDM process, Int. J. Adv. Manuf. Technol. 68 (2013) 2645–2668. doi:10.1007/s00170-013-4861-9. H. Soni, N. Sannayellappa, R. Motagondanahalli Rangarasaiah, An experimental study of influence of wire electro discharge machining parameters on surface integrity of TiNiCo shape memory alloy, J. Mater. Res. (2017) 1–9. doi:10.1557/jmr.2017.137. S. Daneshmand, V. Monfared, A.A. Lotfi Neyestanak, Effect of Tool Rotational and Al2O3 Powder in Electro Discharge Machining Characteristics of NiTi-60 Shape Memory Alloy, Silicon. (2016) 1–11. doi:10.1007/s12633-016-9412-1. H. Soni, S. Narendranath, M.R. Ramesh, Effect of Machining Parameters on Wire Electro Discharge Machining of Shape Memory Alloys Analyzed using Grey Entropy Method, 2 (2015) 50–54. K. Gupta, N.K. Jain, Analysis and optimization of micro-geometry of miniature spur gears manufactured by wire electric discharge machining, Precis. Eng. 38 (2014) 728–737. doi:10.1016/j.precisioneng.2014.03.009. S. Kumar Majhi Ȧ, Ȧ Tkm., Ḃ Mkp., H. Soni Ȧ Ȧ, Effect of Machining Parameters of AISI D2 Tool Steel on Electro Discharge Machining, Int. J. Curr. Eng. Technol. 1944 (2014) 19–23. http://inpressco.com/category/ijcet. S. Daneshmand, V. Monfared, A.A. Lotfi Neyestanak, Effect of Tool Rotational and Al2O3 Powder in Electro Discharge Machining Characteristics of NiTi-60 Shape Memory Alloy, Silicon. 9 (2017) 273–283. doi:10.1007/s12633-016-9412-1. A. Roy, S. Narendra Nath, D. Nedelcu, Experimental investigation on variation of output responses of as cast TiNiCu shape memory alloys using wire EDM, Int. J. Mod. Manuf. Technol. 9 (2017). M.T. Antar, S.L. Soo, D.K. Aspinwall, D. Jones, R. Perez, Productivity and workpiece surface integrity when WEDM aerospace alloys using coated wires, Procedia Eng. 19 (2011) 3–8. doi:10.1016/j.proeng.2011.11.071. P. Sharma, D. Chakradhar, S. Narendranath, Evaluation of WEDM performance characteristics of Inconel 706 for turbine disk application, Mater. Des. 88 (2015) 558–566. doi:10.1016/j.matdes.2015.09.036.