- Email: [email protected]
Review on multi-stage incremental forming process to form vertical walled cup
Materials Today: Proceedings xxx (xxxx) xxx
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Review on multi-stage incremental forming process to form vertical walled cup G. Vignesh a, C. Pandivelan b, C. Sathiya Narayanan a,⇑ a b
Department of Production Engineering, National Institute of Technology, Tiruchirappalli 620015, India Department of Manufacturing Engineering, Vellore Institute of Technology, Vellore 632014, India
a r t i c l e
i n f o
Article history: Received 6 August 2019 Accepted 18 September 2019 Available online xxxx Keywords: Multi-stage Single Point Incremental Forming process (MSPIF) Tool path Forming strategy Rigid Body Translation Forming Limit Stress Diagram
a b s t r a c t Using incremental forming, forming of a vertical walled cup was impossible in a single-stage due to the reason that failure is followed by thinning at transition region (in between the wall & base of the cup). However in the recent years, forming of a cup with vertical wall or maximum wall angle compared to Single-stage Single Point Incremental Forming (SPIF) are being done successfully by many researchers using Multi-stage Single Point Incremental Forming (MSPIF) process. The reason behind the implementation of MSPIF process is that the thinning will be postponed even when the maximum wall angle is achieved, with number of intermediate stages during Incremental Forming. In the case of Single-stage Incremental Forming, wall angle beyond a certain limit can’t be obtained due to the reason that thinning will occur suddenly at transition region. In this paper, a review is presented on MSPIF process to form cup with vertical wall or maximum wall angle compared to Single-stage Incremental Forming. In addition, tool path design, different forming strategies, effect of forming direction & strategy, Rigid Body Translation (RBT) during intermediate stages, geometrical accuracy of formed part such as dimensional deviation & step formation at base, Formability using Forming Limit Stress Diagram (FLSD) and Thickness distribution and comparisons of MSPIF process are discussed. Further, works proposed for future to improve the process is also presented in this paper. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International conference on Materials and Manufacturing Methods.
1. Introduction Incremental forming is one of the process of sheet metal forming wherein sheet deformed to the shape through small increments. These small increments plastic deformation are given to the sheet metal by movements of ball ended tool along programmed forming path which is controlled by vertical CNC milling machine [1]. The sheet metal is held in a fixture with backing plate which was used to supports the blank from the bottom and the open area in it gives the forming area for the single point forming tool [2]. The incremental forming is majorly classified as SPIF and Two Point Incremental Forming (TPIF). In SPIF, bottom side of the sheet is supported by backing plate alone while forming. In TPIF, backing plate along with full or partial die is used to support the bottom side of sheet [3]. The Incremental forming is mainly used in rapid manufacturing and small batch productions. Doors, front ⇑ Corresponding author. E-mail address: [email protected] (C. Sathiya Narayanan).
& rear bonnet and flaps therein, rear mudguard, front & rear wheel arches and etc., parts of car in automobile industries are formed by IF [4]. Advantages of incremental forming over conventional forming are elimination of die, flexibility in design changes & high formability. Demerits of incremental forming over conventional deep drawing are that they are more time consuming and they have lack of accuracy in formed parts [5]. There were some controversies about mode of deformation (shearing mode and stretching mode) during incremental forming. Some researches have said that shear mode of deformation takes place in incremental forming and some other researches have said differently [6]. Emmens et al. [7] discussed these two modes and developed equation for strain in both modes. The strain in shearing mode was found to be much larger than the strain in stretching mode. In case of stretching mode, it associated with tension so over the limit, onset necking was present but in case of shear mode, it associated with both tension & compression so over the limit necking was not present in the compression action [7]. The Incremental forming also classified in to two types based on number of stages. These two types are
https://doi.org/10.1016/j.matpr.2019.09.116 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International conference on Materials and Manufacturing Methods.
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
2
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
Single-stage incremental forming (SPIF) & Multi-stage incremental forming (MSPIF). SPIF process: The cup with vertical wall is impossible to form due to the sudden thinning will occur at the transition region (in between wall & base of the cup). Hence the fracture will occur at certain wall angle. The maximum wall angle achieved for some of the materials by SPIF process has been reviewed and these are listed in Table 1. MSPIF process: The thinning will be postponed while the maximum wall angle is formed through the number of intermediate stages. Hence the cup with vertical wall can be formed in MSPIF process. The highest possible wall angle based on the Table 1 is 80° [15]. Hence the studies to getting wall angle of >80° or cup with vertical wall forming is limited so far. In this present work, the review on MSPIF process to form the cup with vertical wall or the wall angle of >80° is present. Due to the number of subsequent stages in MSPIF process, the following parameters possess the vital role while forming: tool path, forming strategies and its effect, RBT, geometrical accuracy, formability and thickness distribution. In this review, these parameters are briefly discussed one by one. 2. Discussion 2.1. Tool path in MSPIF According to forming method, tool paths can be majorly categorized into three types in MSPIF. These three forming tool paths are namely parallel line type, curved type, and straight line type with a variable angle as shown in Fig. 1. In parallel line type, at each stage rigid body is displaced by parallel with constant layer thickness through all the stages, which means wall angle is constantly maintained through all stages. In curved type, at each stage rigid body is displaced by curved path with constant layer thickness through all stages. In straight line with a variable wall angle type, wall angle continuously decreases in subsequent stages [19]. According to the forming direction, the tool paths can be further classified into two types in MSPIF. These two tool paths are out to in (OI) & in to out (IO) as shown in Fig. 2. In OI tool path, direction of movement of tool is from the edge of the sheet to the midpoint of sheet while cup forming. In IO tool path, direction of movement of tool is from the midpoint of the sheet to the edge of sheet while
cup forming [20]. Based on OI & IO tool path, two stage Incremental Forming are carried out by two methods. These two methods are namely down-down (DD) & down-up (DU) methods. In DD method, the OI tool path was used in both first stage & second stage of forming. In DU method, the OI tool path was used in the first stage of forming while the IO tool path was used in second stage of forming [21]. Different forming strategies in MSPIF are presented in the next section to define the types of tool movements & tool paths used in intermediate stages. 2.2. Forming strategies in MSPIF Different MSPIF strategies are discussed below: 1. Small corner radius strategy: It is associated with pyramid shape forming. The radius at corner of the pyramid in first stage is smaller than the final stage as shown in Fig. 3. That means that the radius at corner is increased in each intermediate stages from first stage to final stage. 2. Large corner radius strategy: It is associated with pyramid shape forming. The radius at corner of the pyramid in first stage is larger than the final stage as shown in Fig. 3. That means that the radius at corner is decreased in each intermediate stages from first stage to final stage. 3. In plane radius strategy: It is associated with pyramid shape forming. In this strategy, cone shape was formed while the first stage then, that is formed pyramid shape in final stage through number of intermediate stage as shown in Fig. 3 [22]. 4. Down, Down, Down and Down (DDDD) strategy: It is associated with MSPIF by five stages. In this strategy, a cup is formed through three intermediate stages and a final stage by the downward movement of tool path (OI tool path) in all the stages. 5. Down, Down, Down and Up (DDDU) strategy: It is associated with MSPIF by five stages. In this strategy, a cup is formed through three intermediate stages by the downward movement of tool path (OI tool path) and a final stage by upward movement of tool path (IO tool path) [23]. 6. Down, Up, Down and Down (DUDD) strategy: It is associated with MSPIF by five stages. In this strategy, a cup is formed through a one intermediate stage by up-ward movement of tool path (IO tool path) and two intermediate stages & final stage by the downward movement of tool path (OI tool path) [21]. 7. Incremental part diameter strategy: In this strategy, cup diameter is in-creased gradually through all subsequent stages as shown in Fig. 3. 8. Incremental part draw angle strategy: In this strategy, cup wall angle is in-creased gradually through all subsequent stages as shown in Fig. 3. 9. Incremental part height & draw angle strategy: In this strategy, simultaneously cup wall angle & height
Table 1 Maximum wall angle for some of the materials by SPIF process. S. No.
Author
Year
Material
Grade
Max. wall angle
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Joost et al. [8] Hussain et al. [9] Verbert et al. [10] Verbert et al. [10] Varthini et al. [11] Newell et al. [12] Capece et al. [13] Liuru et al. [14] Liuru et al. [14] Verbert et al. [10] Radu et al. [15] Neagoe et al. [16] Raju et al. [17] Verbert et al. [10] Joost et al. [8] Suresh et al. [18] Verbert et al. [10] Joost et al. [8]
2013 2008 2008 2008 2014 2015 2007 2010 2010 2008 2011 2013 2016 2008 2013 2014 2008 2013
Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Carbon steel Carbon steel Carbon steel Copper Stainless steel Stainless steel Steel Titanium Titanium
1050 2024 3003 3103 5052 5754 7075 08Al 2A12 DC01 DC01 DC04Am Commercially pure 304 304 EDDQ 2 2
76° [8] 47° [9] 76° 75° [10] 71.6° [11] 61° [12] 66° [13] 78° 79° [14] 67° [10] 80° [15] 68° [16] 55° [17] 63° [10] 63° [8] 75° [18] 47° [10] 47° [8]
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
3
Fig. 1. Forming tool path types [19].
Fig. 2. (a) OI tool path & (b) IO tool path [20].
Fig. 3. Forming strategies [22,24].
are increased gradually through all subsequent stages as shown in Fig. 3 [24].
2.3. Effect of forming direction & strategy on MSPIF Skjoedt et al. [21] conducted the FEA simulation for two stage MSPIF by down-down (DD) & down-up (DU) direction and verified by experimental result. MSPIF with DD forming direction were conducted experimentally & simulated using FEA simulation. At the second stage, the tool moves downwards which is not full depth forming as in first stage and it leaves a residual cone at the midpoint due to enlarging in height of the cup. The result of FEA simulation matches well with experimental result. MSPIF with DU forming direction was conducted experimentally & simulated using FEA simulation. At the second stage, the tool moves upwards which is for full depth as in first stage. The predicted depth
through FEA simulation is 10 mm deeper than that through experimental result [21]. Cups by DDDU strategy was formed without fracture. In case of DUDD strategy, it results in fracture in fourth stage where the thickness strain was high. A Minimum thickness of the formed portion was found at transition region of the cup in both strategies as shown in Fig. 4. From this, it is concluded that thickness strain was found as maximum at transition region of the cup. Equal bi-axial stretching was present at this transition zone. These conclusions also agreed well with theoretical strain from FEA simulation [21]. Newell et al. [12] conducted experiments to study two strategies named as Corner Pushing Strategy & Flat Bottom Strategy. In Corner Pushing Strategy, material near corner fillet is squeezed to the neighboring region. By using Corner Pushing Strategy, a 72° wall angle can be achieved. In Flat Bottom Strategy, the height of the cup in consecutive stages was increased with specific quan-
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
4
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
Fig. 4. Thickness distribution in DDDU & DUDD strategies [21].
tity of interchanging OI and IO tool movements. By using Flat Bottom Strategy, an 86° wall angle can be achieved [12]. The term namely RBT are presented in the next section which is necessary to considering during subsequent stages. 2.4. Rigid Body Translation prediction in MSPIF RBT or Rigid Body Displacement (RBD) is the distance of wall angle rigidly displaced to next step wall angle as shown in Fig. 5. RBD at any spot of forming is dependent on blank material & thickness used. The tool path generation of MSPIF without considering RBT will results stepped undesired features at the base [25]. The factors affecting geometrical accuracy in MSPIF is presented in the next section. The expression for RBT in OI & IO tool path was given below. The parameters used in the expression are specified in the Fig. 5 [26]. P ÞEðu0 ;RÞ Z RBTOI ¼ Dy cL 1 2K½EððRRÞF &Z RBTIO ¼ Ni¼1 ðdIO Þ ðu ;RÞ 0
2.5. Geometrical accuracy in MSPIF Geometrical accuracy is affected by RBT in MSPIF. If this RBT is not taken into account while tool path design, it will results lack of geometrical accuracy [25].
According to Zhengfang et al. [27], largest deviation in height direction & sinking defect were found to check the geometrical accuracy of formed part. Stepping rate is the sheet formed in height direction per minute. Sinking defect is the dimensional variation in height direction caused by the axial force which was created by the stepping rate. Effect of strength coefficient (K) which gives positive effect on the dimensional accuracy was found as a major factor in material properties, Based on this effect of strength coefficient (K), Largest deviation in height direction is present when strength coefficient (K) is around 100–400 MPa & small deviation in height direction is present when strength coefficient (K) is around 400–530 MPa [27]. Zhengfang et al. [28] also concluded that strength coefficient (K) gives positive impact on the dimensional accuracy by the result obtained as same as above i.e. larger deviation when K 100– 400 MPa, smaller deviation when K 400–530 MPa [28]. Sinking defect depends on stepping rate. Sinking defect is present at the stepping rate was around 50–250 mm/min and beyond this stepping rate, the sinking defect tends to be stabilized. When stepping rate smaller than 50 mm/min, dimensional deviation is not present [27]. Zhengfang et al. [28] also concluded that the sinking defect is the dimensional inaccuracy and it comes to effect when the stepping rate is greater than 50 mm/min [28]. Tingting et al. [29] presented an article about predicting thickness based on geometrical calculation of intermediate shape in MSPIF. This geometry of Intermediate shape is found by marking the nodes in material before forming and tracing the nodes after forming by developed algorithm for prediction [29].
2.6. Formability in MSPIF To evaluate forming limit of materials in MSPIF, Forming Limit Diagram (consists major & minor true strain relationship) is unreliable in fracture indicator due to the impact of loading path. Therefore, Mengling et al. [30] demonstrated that FLSD was trustworthy measurement in fracture indicator which was not affected by loading path in MSPIF. In this work, FLSD were formed by FEA simulation. From FEA simulation, Forming Limit Stress Curve (FLSC) can be found by two methods and these methods are namely FLSC drawn to stress directly obtained from FEA and FLSC drawn to stress calculated from the strain given by FEA. In this study, experimental works were done for (Aluminium Alloy)
Fig. 5. Rigid Body Translation [25].
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
5
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
AA2024, AA3003, DC04 steel having 0.9 mm thickness at forming speed of 20 m/s using 45°-90°, 45°-65°-90°, 55°-65°-75°-90° forming strategies to form a conical cup having 24.8 mm depth. From this experiment, highest major strain and minor strain were found be 1.531 & 0.291 respectively. In addition to these, FEA simulation was also done for the material condition as same as experimental work. From this simulation, highest major strain and minor strain were found be 1.492 & 0.312 respectively and it was found that these strains values approximately match with the experimental results. Calculated major and minor stresses from the strains obtained from FEA were 305 MPa & 196 MPa respectively. This simulation also can be used to find the highest major & minor stresses which was shown as 269 & 210 respectively [30]. 2.7. Thickness distribution Verbert et al. [10] found the thickness distribution in incremental forming by single and multi-steps and compared with each other. In both cases, cone upper diameter of 178 mm, backing plate of diameter 182 mm, depth of 30 mm, wall angle of 70° were selected to form AA 3003 sheet having a thickness, 1.2 mm by single and multi-step forming. In multi-step forming, cones were formed with 50° wall angle at first stage & 10° wall angle incrementally added through two intermediate stages. Thickness distribution of both cases were plotted with respect to radius of the cup as shown in Fig. 6a. This experiment results that thickness cone in multi-step forming process in the wall region was much higher than that of single-step forming process and Thickness of cone in multi-step forming process in the base region was much lower than that in single-step forming process [10]. Liuru et al. [19] conducted some MSPIF experiments for three different forming tool paths as shown in Fig. 6b to determine thickness distribution. These forming tool paths are parallel line type, curved type and straight line with a variable wall angle type. The thickness with respect to distance is indicated in Fig. 6b. The curve 1 in Fig. 6b represents parallel line type, curve 2 represents curved type, and curve 3 represents straight line type with a variable angle. From curve 1, it is known that thinning was uniformly present and much lower than others. From curve 2, it is concluded that thinning was not uniformly present. From curve 3, it is clear that thinning is not uniformly present and much higher than others. From this study, it is
Fig. 6b. Thickness distribution comparison of forming tool path 1, 2 & 3 [19]
concluded that the best tool path is the parallel line type, which gives uniform thinning so good formability will present [19]. Newell et al. [12] developed a formulation by simple modification of the sine law which is suitable for MSPIF process.
tf to
¼
Aa3 þ Ba2 þ C a þ D. Where, tf- final thickness, to- initial thickness, a- Wall angle and A, B, C, D- Constants respectively. This formulation was well matched with sine law only up to 50° and beyond that the angle shows some difference [12]. 3. Scope for future works In MSPIF, time consumption was more compared to single stage incremental forming. A new methodology has to be found for vertical walled cup forming for quick operation. In MSPIF Geometrical inaccuracy was more due to number of intermediate stages compared to single stage incremental forming. More studies required on sinking defect, step formation on base of cup, dimensional deviation on height direction to form with good geometrical accuracy. More analyze on forming strategy, RBT & Thickness distribution was required to decide intermediate & final stages. A new methodology has to be developed for MSPIF to accurately decide intermediate shapes of forming. A comparison between FLSD and FLD have to be studied for MSPIF process. Surface texture, Surface finish and corrosion behavior of formed part have to be study in MSPIF for post preparation of formed part. Optimization technique have to be developed in MSPIF to find the most influence parameters. Fracture analysis & void analysis have to be carried out for MSPIF. 4. Conclusion In this review paper,
Fig. 6a. Thickness distribution comparison of Single & Multi-step incremental forming [10].
Different tool paths and forming strategies in MSPIF were studied. The term RBT in intermediate stage of MSPIF designing were studied. The term geometrical accuracy and its affecting parameters such as strength coefficient ‘‘K” and stepping rate in MSPIF were studied. It is concluded that ‘‘K” gives positive impact on the dimensional accuracy, Sinking defect comes to impact on dimensional accuracy when the stepping rate was greater than 50 mm/min. By using Digital Image Correlation (DIC) Metal flow by tracing to predict intermediate stages also was studied. Effect of DD, DU forming direction on MSPIF were studied. Effect of DDDU, DUDD, Corner Pushing Strategy and Flat Bottom Strategy on MSPIF also was studied.
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
6
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
Formability of MSPIF by using FLSD were studied. FLSD was formed by two methods, these are FLSC by direct FEA obtained stress and FLSC by calculated stress from FEA obtained strain. Thickness distribution comparison of single-stage and multistage incremental forming was studied. Thickness distribution comparison in between three forming tool path types also was studied. Development of modified sine law for final formed thickness which is suitable for MSPIF also was studied. Scope for future works are presented.
References [1] A.M. Habraken, Single Point Incremental Forming to increase material knowledge and production flexibility, J. Phys. Conf. Ser. 734 (2016). [2] I. Bagudanch, G. Centeno, C. Vallellano, M.L. Garcia-Romeu, Forming force in Single Point Incremental Forming under different bending conditions, Procedia Eng. 63 (2013) 354–360. [3] M.B. Silva, P.A.F. Martins, Two-point incremental forming with partial die: theory and experimentation, J. Mater. Eng. Perform. 22 (2013) 1018–1027. [4] Soren Scheffler, Alexander Pierer, Peter Scholz, Sebastian Melzer, Dieter Weise, Zdenek Rambousek, Incremental sheet metal forming on the example of car exterior skin parts, Procedia Manuf. 29 (2019) 105–111. [5] Jigar Pathak, A brief review of Incremental sheet metal forming, Int. J. Latest Eng. Manage. Res. 2 (2017) 35–43. [6] M. Skjoedt, M.B. Silva, P.A.F. Martins, N. Bay, Strategies and limits in multistage single-point incremental forming, J. Strain Anal. Eng. Des. 45 (2009) 33– 44. [7] W.C. Emmens, A.H. van den Boogaard, Strain in shear, and material behaviour in incremental forming, Key Eng. Mater. 344 (2007) 519–526. [8] R. Joost Duflou, Amar Kumar Behera, Hans Vanhove, Liciane S. Bertol, Manufacture of accurate titanium cranio-facial implants with high forming angle using single point incremental forming, Key Eng. Mater. 549 (2013) 223– 230. [9] G. Hussain, N. Hayat, L. Gao, An experimental study on the effect of thinning band on the sheet formability in negative incremental forming, Int. J. Mach. Tools Manuf. 48 (2008) 1170–1178. [10] J. Verbert, B. Belkassem, C. Henrard, A.M. Habraken, J. Gu, H. Sol, B. Lauwers, J. R. Duflou, Multi-Step toolpath approach to overcome forming limitations in single point incremental forming, Int. J. Mater. Form. 1 (2008) 1203–1206. [11] R. Varthini, R. Gandhinathan, C. pandivelan, A.K. jeevanantham, Modelling and optimization of process parameters of the single point incremental forming of aluminium 5052 alloy sheet using genetic algorithm-back propagation neural network, Int. J. Mech. Prod. Eng. Res. Dev. 2 (2014) 55–62. [12] Newell Moser, Ebot Ndip-Agbor, Huaqing Ren, Zixuan Zhang, Kornel Ehmann, Jian Cao, Challenges and process strategies concerning multi-pass double sided incremental forming, Key Eng. Mater. 651–653 (2015) 1122–1127.
[13] F. Capece Minutolo, M. Durante, A. Formisano, A. Langella, Evaluation of the maximum slope angle of simple geometries carried out by incremental forming process, J. Mater. Process. Technol. 194 (2007) 145–150. [14] Liuru Zhou, The effect of forming half-apex angle on incremental sheet metal forming, Adv. Mater. Res. 139–141 (2010) 1514–1517. [15] Radu crina, Determination of the maximum forming angle of some carbon steel metal sheets, J. Eng. Stud. Res. 17 (2011) 71–74. [16] Neagoe Ion, Filip Alexandru Catalin, Vasiloni Mircea Anton, Experimental researches on the limit angle of conical parts manufactured by single stage incremental forming on CNC lathes, Appl. Mech. Mater. 371 (2013) 168–172. [17] C. Raju, C. Sathiya Narayanan, Application of a hybrid optimization technique in a multiple sheet single point incremental forming process, Measurement 78 (2016) 296–308. [18] Suresh Kurra, Srinivasa Prakash Regalla, Experimental and numerical studies on formability of extra-deep drawing steel in incremental sheet metal forming, J. Mater. Res. Technol. 3 (2) (2014) 158–171. [19] Z. Liuru, Z. Yinmei, L. Zhongmin, Study on forming method of vertical wall cylinder parts formed by multi-stage incremental forming, Mater. Res. Innov. 19 (2015) 102–104. [20] R. Malhotra, A. Bhattacharya, A. Kumar, N.V. Reddy, J. Cao, A new methodology for multi-pass single point incremental forming with mixed toolpaths, CIRP Ann. – Manuf. Technol. 60 (2011) 323–326. [21] M. Skjoedt, N. Bay, B. Endelt, G. Ingarao, Multi stage strategies for single point incremental forming of a cup, Int. J. Mater. Form. 1 (2008) 1199–1202. [22] M. Bambach, B. Taleb Araghi, G. Hirt, Strategies to improve the geometric accuracy in asymmetric single point incremental forming, Prod. Eng. Res. 3 (2009) 145–156. [23] Kurra Suresh, H.R. Nasih, N.V.K. Jasti, Maheshwar Dwivedy, Experimental studies in multi stage incremental forming of steel sheets, Mater. Today: Proc. 4 (2017) 4116–4122. [24] Zhaobing Liu, Yanle Li, Paul Anthony Meehan, Vertical wall formation and material flow control for incremental sheet forming by revisiting multistage deformation path strategies, Mater. Manuf. Processes 28 (2013) 562–571. [25] R. Lingam, A. Bansal, N.V. Reddy, Analytical prediction of formed geometry in multi-stage single point incremental forming, Int. J. Mater. Form. 9 (2015) 395–404. [26] Dongkai Xua, N. Rajiv Malhotra, Venkata Reddy, Jun Chen, Jian Cao, Analytical prediction of stepped feature generation in multi-pass single point incremental forming, J. Manuf. Processes 14 (2012) 487–494. [27] Zhengfang Li, Lu. Shihong, Tao Zhang, Zhixiang Mao, Chun Zhang, Analysis of geometrical accuracy based on multistage single point incremental forming of a straight wall box part, Int. J. Adv. Manuf. Technol. 93 (2017) 2783–2789. [28] Zhengfang Li, Lu. Shihong, Peng Chen, Improvement of dimensional accuracy based on multistage single point incremental forming of a straight wall cylinder part, Int. J. Precis. Eng. Manuf. 18 (2017) 1281–1286. [29] Tingting Cao, Lu. Bin, Xu. Dongkai, Huan Zhang, Jun Chen, Hui Long, Jian Cao, An efficient method for thickness prediction in multi-pass incremental sheet forming, Int. J. Adv. Manuf. Technol. 77 (2014) 469–483. [30] Wu. Mengling, Guangcheng Zha, Gan Zirui, FEA of vertical parts formed with multistage incremental sheet metal forming based on the forming limit stress diagram, Int. J. Adv. Manuf. Technol. 93 (2017) 2155–2160.
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
Contents lists available at ScienceDirect
Materials Today: Proceedings journal homepage: www.elsevier.com/locate/matpr
Review on multi-stage incremental forming process to form vertical walled cup G. Vignesh a, C. Pandivelan b, C. Sathiya Narayanan a,⇑ a b
Department of Production Engineering, National Institute of Technology, Tiruchirappalli 620015, India Department of Manufacturing Engineering, Vellore Institute of Technology, Vellore 632014, India
a r t i c l e
i n f o
Article history: Received 6 August 2019 Accepted 18 September 2019 Available online xxxx Keywords: Multi-stage Single Point Incremental Forming process (MSPIF) Tool path Forming strategy Rigid Body Translation Forming Limit Stress Diagram
a b s t r a c t Using incremental forming, forming of a vertical walled cup was impossible in a single-stage due to the reason that failure is followed by thinning at transition region (in between the wall & base of the cup). However in the recent years, forming of a cup with vertical wall or maximum wall angle compared to Single-stage Single Point Incremental Forming (SPIF) are being done successfully by many researchers using Multi-stage Single Point Incremental Forming (MSPIF) process. The reason behind the implementation of MSPIF process is that the thinning will be postponed even when the maximum wall angle is achieved, with number of intermediate stages during Incremental Forming. In the case of Single-stage Incremental Forming, wall angle beyond a certain limit can’t be obtained due to the reason that thinning will occur suddenly at transition region. In this paper, a review is presented on MSPIF process to form cup with vertical wall or maximum wall angle compared to Single-stage Incremental Forming. In addition, tool path design, different forming strategies, effect of forming direction & strategy, Rigid Body Translation (RBT) during intermediate stages, geometrical accuracy of formed part such as dimensional deviation & step formation at base, Formability using Forming Limit Stress Diagram (FLSD) and Thickness distribution and comparisons of MSPIF process are discussed. Further, works proposed for future to improve the process is also presented in this paper. Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International conference on Materials and Manufacturing Methods.
1. Introduction Incremental forming is one of the process of sheet metal forming wherein sheet deformed to the shape through small increments. These small increments plastic deformation are given to the sheet metal by movements of ball ended tool along programmed forming path which is controlled by vertical CNC milling machine [1]. The sheet metal is held in a fixture with backing plate which was used to supports the blank from the bottom and the open area in it gives the forming area for the single point forming tool [2]. The incremental forming is majorly classified as SPIF and Two Point Incremental Forming (TPIF). In SPIF, bottom side of the sheet is supported by backing plate alone while forming. In TPIF, backing plate along with full or partial die is used to support the bottom side of sheet [3]. The Incremental forming is mainly used in rapid manufacturing and small batch productions. Doors, front ⇑ Corresponding author. E-mail address: [email protected] (C. Sathiya Narayanan).
& rear bonnet and flaps therein, rear mudguard, front & rear wheel arches and etc., parts of car in automobile industries are formed by IF [4]. Advantages of incremental forming over conventional forming are elimination of die, flexibility in design changes & high formability. Demerits of incremental forming over conventional deep drawing are that they are more time consuming and they have lack of accuracy in formed parts [5]. There were some controversies about mode of deformation (shearing mode and stretching mode) during incremental forming. Some researches have said that shear mode of deformation takes place in incremental forming and some other researches have said differently [6]. Emmens et al. [7] discussed these two modes and developed equation for strain in both modes. The strain in shearing mode was found to be much larger than the strain in stretching mode. In case of stretching mode, it associated with tension so over the limit, onset necking was present but in case of shear mode, it associated with both tension & compression so over the limit necking was not present in the compression action [7]. The Incremental forming also classified in to two types based on number of stages. These two types are
https://doi.org/10.1016/j.matpr.2019.09.116 2214-7853/Ó 2019 Elsevier Ltd. All rights reserved. Selection and peer-review under responsibility of the scientific committee of the International conference on Materials and Manufacturing Methods.
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
2
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
Single-stage incremental forming (SPIF) & Multi-stage incremental forming (MSPIF). SPIF process: The cup with vertical wall is impossible to form due to the sudden thinning will occur at the transition region (in between wall & base of the cup). Hence the fracture will occur at certain wall angle. The maximum wall angle achieved for some of the materials by SPIF process has been reviewed and these are listed in Table 1. MSPIF process: The thinning will be postponed while the maximum wall angle is formed through the number of intermediate stages. Hence the cup with vertical wall can be formed in MSPIF process. The highest possible wall angle based on the Table 1 is 80° [15]. Hence the studies to getting wall angle of >80° or cup with vertical wall forming is limited so far. In this present work, the review on MSPIF process to form the cup with vertical wall or the wall angle of >80° is present. Due to the number of subsequent stages in MSPIF process, the following parameters possess the vital role while forming: tool path, forming strategies and its effect, RBT, geometrical accuracy, formability and thickness distribution. In this review, these parameters are briefly discussed one by one. 2. Discussion 2.1. Tool path in MSPIF According to forming method, tool paths can be majorly categorized into three types in MSPIF. These three forming tool paths are namely parallel line type, curved type, and straight line type with a variable angle as shown in Fig. 1. In parallel line type, at each stage rigid body is displaced by parallel with constant layer thickness through all the stages, which means wall angle is constantly maintained through all stages. In curved type, at each stage rigid body is displaced by curved path with constant layer thickness through all stages. In straight line with a variable wall angle type, wall angle continuously decreases in subsequent stages [19]. According to the forming direction, the tool paths can be further classified into two types in MSPIF. These two tool paths are out to in (OI) & in to out (IO) as shown in Fig. 2. In OI tool path, direction of movement of tool is from the edge of the sheet to the midpoint of sheet while cup forming. In IO tool path, direction of movement of tool is from the midpoint of the sheet to the edge of sheet while
cup forming [20]. Based on OI & IO tool path, two stage Incremental Forming are carried out by two methods. These two methods are namely down-down (DD) & down-up (DU) methods. In DD method, the OI tool path was used in both first stage & second stage of forming. In DU method, the OI tool path was used in the first stage of forming while the IO tool path was used in second stage of forming [21]. Different forming strategies in MSPIF are presented in the next section to define the types of tool movements & tool paths used in intermediate stages. 2.2. Forming strategies in MSPIF Different MSPIF strategies are discussed below: 1. Small corner radius strategy: It is associated with pyramid shape forming. The radius at corner of the pyramid in first stage is smaller than the final stage as shown in Fig. 3. That means that the radius at corner is increased in each intermediate stages from first stage to final stage. 2. Large corner radius strategy: It is associated with pyramid shape forming. The radius at corner of the pyramid in first stage is larger than the final stage as shown in Fig. 3. That means that the radius at corner is decreased in each intermediate stages from first stage to final stage. 3. In plane radius strategy: It is associated with pyramid shape forming. In this strategy, cone shape was formed while the first stage then, that is formed pyramid shape in final stage through number of intermediate stage as shown in Fig. 3 [22]. 4. Down, Down, Down and Down (DDDD) strategy: It is associated with MSPIF by five stages. In this strategy, a cup is formed through three intermediate stages and a final stage by the downward movement of tool path (OI tool path) in all the stages. 5. Down, Down, Down and Up (DDDU) strategy: It is associated with MSPIF by five stages. In this strategy, a cup is formed through three intermediate stages by the downward movement of tool path (OI tool path) and a final stage by upward movement of tool path (IO tool path) [23]. 6. Down, Up, Down and Down (DUDD) strategy: It is associated with MSPIF by five stages. In this strategy, a cup is formed through a one intermediate stage by up-ward movement of tool path (IO tool path) and two intermediate stages & final stage by the downward movement of tool path (OI tool path) [21]. 7. Incremental part diameter strategy: In this strategy, cup diameter is in-creased gradually through all subsequent stages as shown in Fig. 3. 8. Incremental part draw angle strategy: In this strategy, cup wall angle is in-creased gradually through all subsequent stages as shown in Fig. 3. 9. Incremental part height & draw angle strategy: In this strategy, simultaneously cup wall angle & height
Table 1 Maximum wall angle for some of the materials by SPIF process. S. No.
Author
Year
Material
Grade
Max. wall angle
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
Joost et al. [8] Hussain et al. [9] Verbert et al. [10] Verbert et al. [10] Varthini et al. [11] Newell et al. [12] Capece et al. [13] Liuru et al. [14] Liuru et al. [14] Verbert et al. [10] Radu et al. [15] Neagoe et al. [16] Raju et al. [17] Verbert et al. [10] Joost et al. [8] Suresh et al. [18] Verbert et al. [10] Joost et al. [8]
2013 2008 2008 2008 2014 2015 2007 2010 2010 2008 2011 2013 2016 2008 2013 2014 2008 2013
Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Aluminium alloy Carbon steel Carbon steel Carbon steel Copper Stainless steel Stainless steel Steel Titanium Titanium
1050 2024 3003 3103 5052 5754 7075 08Al 2A12 DC01 DC01 DC04Am Commercially pure 304 304 EDDQ 2 2
76° [8] 47° [9] 76° 75° [10] 71.6° [11] 61° [12] 66° [13] 78° 79° [14] 67° [10] 80° [15] 68° [16] 55° [17] 63° [10] 63° [8] 75° [18] 47° [10] 47° [8]
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
3
Fig. 1. Forming tool path types [19].
Fig. 2. (a) OI tool path & (b) IO tool path [20].
Fig. 3. Forming strategies [22,24].
are increased gradually through all subsequent stages as shown in Fig. 3 [24].
2.3. Effect of forming direction & strategy on MSPIF Skjoedt et al. [21] conducted the FEA simulation for two stage MSPIF by down-down (DD) & down-up (DU) direction and verified by experimental result. MSPIF with DD forming direction were conducted experimentally & simulated using FEA simulation. At the second stage, the tool moves downwards which is not full depth forming as in first stage and it leaves a residual cone at the midpoint due to enlarging in height of the cup. The result of FEA simulation matches well with experimental result. MSPIF with DU forming direction was conducted experimentally & simulated using FEA simulation. At the second stage, the tool moves upwards which is for full depth as in first stage. The predicted depth
through FEA simulation is 10 mm deeper than that through experimental result [21]. Cups by DDDU strategy was formed without fracture. In case of DUDD strategy, it results in fracture in fourth stage where the thickness strain was high. A Minimum thickness of the formed portion was found at transition region of the cup in both strategies as shown in Fig. 4. From this, it is concluded that thickness strain was found as maximum at transition region of the cup. Equal bi-axial stretching was present at this transition zone. These conclusions also agreed well with theoretical strain from FEA simulation [21]. Newell et al. [12] conducted experiments to study two strategies named as Corner Pushing Strategy & Flat Bottom Strategy. In Corner Pushing Strategy, material near corner fillet is squeezed to the neighboring region. By using Corner Pushing Strategy, a 72° wall angle can be achieved. In Flat Bottom Strategy, the height of the cup in consecutive stages was increased with specific quan-
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
4
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
Fig. 4. Thickness distribution in DDDU & DUDD strategies [21].
tity of interchanging OI and IO tool movements. By using Flat Bottom Strategy, an 86° wall angle can be achieved [12]. The term namely RBT are presented in the next section which is necessary to considering during subsequent stages. 2.4. Rigid Body Translation prediction in MSPIF RBT or Rigid Body Displacement (RBD) is the distance of wall angle rigidly displaced to next step wall angle as shown in Fig. 5. RBD at any spot of forming is dependent on blank material & thickness used. The tool path generation of MSPIF without considering RBT will results stepped undesired features at the base [25]. The factors affecting geometrical accuracy in MSPIF is presented in the next section. The expression for RBT in OI & IO tool path was given below. The parameters used in the expression are specified in the Fig. 5 [26]. P ÞEðu0 ;RÞ Z RBTOI ¼ Dy cL 1 2K½EððRRÞF &Z RBTIO ¼ Ni¼1 ðdIO Þ ðu ;RÞ 0
2.5. Geometrical accuracy in MSPIF Geometrical accuracy is affected by RBT in MSPIF. If this RBT is not taken into account while tool path design, it will results lack of geometrical accuracy [25].
According to Zhengfang et al. [27], largest deviation in height direction & sinking defect were found to check the geometrical accuracy of formed part. Stepping rate is the sheet formed in height direction per minute. Sinking defect is the dimensional variation in height direction caused by the axial force which was created by the stepping rate. Effect of strength coefficient (K) which gives positive effect on the dimensional accuracy was found as a major factor in material properties, Based on this effect of strength coefficient (K), Largest deviation in height direction is present when strength coefficient (K) is around 100–400 MPa & small deviation in height direction is present when strength coefficient (K) is around 400–530 MPa [27]. Zhengfang et al. [28] also concluded that strength coefficient (K) gives positive impact on the dimensional accuracy by the result obtained as same as above i.e. larger deviation when K 100– 400 MPa, smaller deviation when K 400–530 MPa [28]. Sinking defect depends on stepping rate. Sinking defect is present at the stepping rate was around 50–250 mm/min and beyond this stepping rate, the sinking defect tends to be stabilized. When stepping rate smaller than 50 mm/min, dimensional deviation is not present [27]. Zhengfang et al. [28] also concluded that the sinking defect is the dimensional inaccuracy and it comes to effect when the stepping rate is greater than 50 mm/min [28]. Tingting et al. [29] presented an article about predicting thickness based on geometrical calculation of intermediate shape in MSPIF. This geometry of Intermediate shape is found by marking the nodes in material before forming and tracing the nodes after forming by developed algorithm for prediction [29].
2.6. Formability in MSPIF To evaluate forming limit of materials in MSPIF, Forming Limit Diagram (consists major & minor true strain relationship) is unreliable in fracture indicator due to the impact of loading path. Therefore, Mengling et al. [30] demonstrated that FLSD was trustworthy measurement in fracture indicator which was not affected by loading path in MSPIF. In this work, FLSD were formed by FEA simulation. From FEA simulation, Forming Limit Stress Curve (FLSC) can be found by two methods and these methods are namely FLSC drawn to stress directly obtained from FEA and FLSC drawn to stress calculated from the strain given by FEA. In this study, experimental works were done for (Aluminium Alloy)
Fig. 5. Rigid Body Translation [25].
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
5
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
AA2024, AA3003, DC04 steel having 0.9 mm thickness at forming speed of 20 m/s using 45°-90°, 45°-65°-90°, 55°-65°-75°-90° forming strategies to form a conical cup having 24.8 mm depth. From this experiment, highest major strain and minor strain were found be 1.531 & 0.291 respectively. In addition to these, FEA simulation was also done for the material condition as same as experimental work. From this simulation, highest major strain and minor strain were found be 1.492 & 0.312 respectively and it was found that these strains values approximately match with the experimental results. Calculated major and minor stresses from the strains obtained from FEA were 305 MPa & 196 MPa respectively. This simulation also can be used to find the highest major & minor stresses which was shown as 269 & 210 respectively [30]. 2.7. Thickness distribution Verbert et al. [10] found the thickness distribution in incremental forming by single and multi-steps and compared with each other. In both cases, cone upper diameter of 178 mm, backing plate of diameter 182 mm, depth of 30 mm, wall angle of 70° were selected to form AA 3003 sheet having a thickness, 1.2 mm by single and multi-step forming. In multi-step forming, cones were formed with 50° wall angle at first stage & 10° wall angle incrementally added through two intermediate stages. Thickness distribution of both cases were plotted with respect to radius of the cup as shown in Fig. 6a. This experiment results that thickness cone in multi-step forming process in the wall region was much higher than that of single-step forming process and Thickness of cone in multi-step forming process in the base region was much lower than that in single-step forming process [10]. Liuru et al. [19] conducted some MSPIF experiments for three different forming tool paths as shown in Fig. 6b to determine thickness distribution. These forming tool paths are parallel line type, curved type and straight line with a variable wall angle type. The thickness with respect to distance is indicated in Fig. 6b. The curve 1 in Fig. 6b represents parallel line type, curve 2 represents curved type, and curve 3 represents straight line type with a variable angle. From curve 1, it is known that thinning was uniformly present and much lower than others. From curve 2, it is concluded that thinning was not uniformly present. From curve 3, it is clear that thinning is not uniformly present and much higher than others. From this study, it is
Fig. 6b. Thickness distribution comparison of forming tool path 1, 2 & 3 [19]
concluded that the best tool path is the parallel line type, which gives uniform thinning so good formability will present [19]. Newell et al. [12] developed a formulation by simple modification of the sine law which is suitable for MSPIF process.
tf to
¼
Aa3 þ Ba2 þ C a þ D. Where, tf- final thickness, to- initial thickness, a- Wall angle and A, B, C, D- Constants respectively. This formulation was well matched with sine law only up to 50° and beyond that the angle shows some difference [12]. 3. Scope for future works In MSPIF, time consumption was more compared to single stage incremental forming. A new methodology has to be found for vertical walled cup forming for quick operation. In MSPIF Geometrical inaccuracy was more due to number of intermediate stages compared to single stage incremental forming. More studies required on sinking defect, step formation on base of cup, dimensional deviation on height direction to form with good geometrical accuracy. More analyze on forming strategy, RBT & Thickness distribution was required to decide intermediate & final stages. A new methodology has to be developed for MSPIF to accurately decide intermediate shapes of forming. A comparison between FLSD and FLD have to be studied for MSPIF process. Surface texture, Surface finish and corrosion behavior of formed part have to be study in MSPIF for post preparation of formed part. Optimization technique have to be developed in MSPIF to find the most influence parameters. Fracture analysis & void analysis have to be carried out for MSPIF. 4. Conclusion In this review paper,
Fig. 6a. Thickness distribution comparison of Single & Multi-step incremental forming [10].
Different tool paths and forming strategies in MSPIF were studied. The term RBT in intermediate stage of MSPIF designing were studied. The term geometrical accuracy and its affecting parameters such as strength coefficient ‘‘K” and stepping rate in MSPIF were studied. It is concluded that ‘‘K” gives positive impact on the dimensional accuracy, Sinking defect comes to impact on dimensional accuracy when the stepping rate was greater than 50 mm/min. By using Digital Image Correlation (DIC) Metal flow by tracing to predict intermediate stages also was studied. Effect of DD, DU forming direction on MSPIF were studied. Effect of DDDU, DUDD, Corner Pushing Strategy and Flat Bottom Strategy on MSPIF also was studied.
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116
6
G. Vignesh et al. / Materials Today: Proceedings xxx (xxxx) xxx
Formability of MSPIF by using FLSD were studied. FLSD was formed by two methods, these are FLSC by direct FEA obtained stress and FLSC by calculated stress from FEA obtained strain. Thickness distribution comparison of single-stage and multistage incremental forming was studied. Thickness distribution comparison in between three forming tool path types also was studied. Development of modified sine law for final formed thickness which is suitable for MSPIF also was studied. Scope for future works are presented.
References [1] A.M. Habraken, Single Point Incremental Forming to increase material knowledge and production flexibility, J. Phys. Conf. Ser. 734 (2016). [2] I. Bagudanch, G. Centeno, C. Vallellano, M.L. Garcia-Romeu, Forming force in Single Point Incremental Forming under different bending conditions, Procedia Eng. 63 (2013) 354–360. [3] M.B. Silva, P.A.F. Martins, Two-point incremental forming with partial die: theory and experimentation, J. Mater. Eng. Perform. 22 (2013) 1018–1027. [4] Soren Scheffler, Alexander Pierer, Peter Scholz, Sebastian Melzer, Dieter Weise, Zdenek Rambousek, Incremental sheet metal forming on the example of car exterior skin parts, Procedia Manuf. 29 (2019) 105–111. [5] Jigar Pathak, A brief review of Incremental sheet metal forming, Int. J. Latest Eng. Manage. Res. 2 (2017) 35–43. [6] M. Skjoedt, M.B. Silva, P.A.F. Martins, N. Bay, Strategies and limits in multistage single-point incremental forming, J. Strain Anal. Eng. Des. 45 (2009) 33– 44. [7] W.C. Emmens, A.H. van den Boogaard, Strain in shear, and material behaviour in incremental forming, Key Eng. Mater. 344 (2007) 519–526. [8] R. Joost Duflou, Amar Kumar Behera, Hans Vanhove, Liciane S. Bertol, Manufacture of accurate titanium cranio-facial implants with high forming angle using single point incremental forming, Key Eng. Mater. 549 (2013) 223– 230. [9] G. Hussain, N. Hayat, L. Gao, An experimental study on the effect of thinning band on the sheet formability in negative incremental forming, Int. J. Mach. Tools Manuf. 48 (2008) 1170–1178. [10] J. Verbert, B. Belkassem, C. Henrard, A.M. Habraken, J. Gu, H. Sol, B. Lauwers, J. R. Duflou, Multi-Step toolpath approach to overcome forming limitations in single point incremental forming, Int. J. Mater. Form. 1 (2008) 1203–1206. [11] R. Varthini, R. Gandhinathan, C. pandivelan, A.K. jeevanantham, Modelling and optimization of process parameters of the single point incremental forming of aluminium 5052 alloy sheet using genetic algorithm-back propagation neural network, Int. J. Mech. Prod. Eng. Res. Dev. 2 (2014) 55–62. [12] Newell Moser, Ebot Ndip-Agbor, Huaqing Ren, Zixuan Zhang, Kornel Ehmann, Jian Cao, Challenges and process strategies concerning multi-pass double sided incremental forming, Key Eng. Mater. 651–653 (2015) 1122–1127.
[13] F. Capece Minutolo, M. Durante, A. Formisano, A. Langella, Evaluation of the maximum slope angle of simple geometries carried out by incremental forming process, J. Mater. Process. Technol. 194 (2007) 145–150. [14] Liuru Zhou, The effect of forming half-apex angle on incremental sheet metal forming, Adv. Mater. Res. 139–141 (2010) 1514–1517. [15] Radu crina, Determination of the maximum forming angle of some carbon steel metal sheets, J. Eng. Stud. Res. 17 (2011) 71–74. [16] Neagoe Ion, Filip Alexandru Catalin, Vasiloni Mircea Anton, Experimental researches on the limit angle of conical parts manufactured by single stage incremental forming on CNC lathes, Appl. Mech. Mater. 371 (2013) 168–172. [17] C. Raju, C. Sathiya Narayanan, Application of a hybrid optimization technique in a multiple sheet single point incremental forming process, Measurement 78 (2016) 296–308. [18] Suresh Kurra, Srinivasa Prakash Regalla, Experimental and numerical studies on formability of extra-deep drawing steel in incremental sheet metal forming, J. Mater. Res. Technol. 3 (2) (2014) 158–171. [19] Z. Liuru, Z. Yinmei, L. Zhongmin, Study on forming method of vertical wall cylinder parts formed by multi-stage incremental forming, Mater. Res. Innov. 19 (2015) 102–104. [20] R. Malhotra, A. Bhattacharya, A. Kumar, N.V. Reddy, J. Cao, A new methodology for multi-pass single point incremental forming with mixed toolpaths, CIRP Ann. – Manuf. Technol. 60 (2011) 323–326. [21] M. Skjoedt, N. Bay, B. Endelt, G. Ingarao, Multi stage strategies for single point incremental forming of a cup, Int. J. Mater. Form. 1 (2008) 1199–1202. [22] M. Bambach, B. Taleb Araghi, G. Hirt, Strategies to improve the geometric accuracy in asymmetric single point incremental forming, Prod. Eng. Res. 3 (2009) 145–156. [23] Kurra Suresh, H.R. Nasih, N.V.K. Jasti, Maheshwar Dwivedy, Experimental studies in multi stage incremental forming of steel sheets, Mater. Today: Proc. 4 (2017) 4116–4122. [24] Zhaobing Liu, Yanle Li, Paul Anthony Meehan, Vertical wall formation and material flow control for incremental sheet forming by revisiting multistage deformation path strategies, Mater. Manuf. Processes 28 (2013) 562–571. [25] R. Lingam, A. Bansal, N.V. Reddy, Analytical prediction of formed geometry in multi-stage single point incremental forming, Int. J. Mater. Form. 9 (2015) 395–404. [26] Dongkai Xua, N. Rajiv Malhotra, Venkata Reddy, Jun Chen, Jian Cao, Analytical prediction of stepped feature generation in multi-pass single point incremental forming, J. Manuf. Processes 14 (2012) 487–494. [27] Zhengfang Li, Lu. Shihong, Tao Zhang, Zhixiang Mao, Chun Zhang, Analysis of geometrical accuracy based on multistage single point incremental forming of a straight wall box part, Int. J. Adv. Manuf. Technol. 93 (2017) 2783–2789. [28] Zhengfang Li, Lu. Shihong, Peng Chen, Improvement of dimensional accuracy based on multistage single point incremental forming of a straight wall cylinder part, Int. J. Precis. Eng. Manuf. 18 (2017) 1281–1286. [29] Tingting Cao, Lu. Bin, Xu. Dongkai, Huan Zhang, Jun Chen, Hui Long, Jian Cao, An efficient method for thickness prediction in multi-pass incremental sheet forming, Int. J. Adv. Manuf. Technol. 77 (2014) 469–483. [30] Wu. Mengling, Guangcheng Zha, Gan Zirui, FEA of vertical parts formed with multistage incremental sheet metal forming based on the forming limit stress diagram, Int. J. Adv. Manuf. Technol. 93 (2017) 2155–2160.
Please cite this article as: G. Vignesh, C. Pandivelan and C. Sathiya Narayanan, Review on multi-stage incremental forming process to form vertical walled cup, Materials Today: Proceedings, https://doi.org/10.1016/j.matpr.2019.09.116