Experimental and numerical analysis of

single point incremental forming of tailor

welded blanks

Sitanshu Sekhar Mohanty

Roll No: 17ME31011

Supervisor: Dr. Sushanta Kumar Panda

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 Introduction: Incremental Sheet Forming

● ISF is a forming technique which

involves the movement of tool in a
predefined path forming the sheet in a
progressive fashion.
● Localized deformation is caused by the fig. 1: Schematic of SPIF
tool as the tool moves over the part
with an incremental depth.

fig. 2: Experimental setup of SPIF 2

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 Application of Incremental Sheet Forming

❖ Producing light weight components for various

automobiles and aviation industry.

❖ To form hard-to-form materials at ambient

temperature, especially magnesium and titanium
alloys, hot incremental forming has been developed

❖ Biomedical implants made through ISF are now much

lighter, with better surface finish

fig. 3: Application in Bullet trains and biological implants

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 Tailor Welded Blanks

Tailor welded blank (TWB) is the result of

joining sheet metal plates with the same
or different thicknesses or strengths,
welded together, to produce a single
blank prior to the forming process which
has significant advantages like cost and
weight reduction, enhancement of
corrosion resistance

fig. 4: tailor-welded blanks produced by different welding direction

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Applications of Tailor Welded Blanks

fig. 5: Applications of TWBs

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 Motivation of Study

❏ Tailor Welded Blanks and Incremental Sheet Forming can help design solutions to
reduce material cost and weight, improve quality and performance while optimizing
the production processes of large industries

❏ Since TWBs have low formability whereas SPIF process increases formability hence SPIF
on TWBs can produce extremely light weight material and higher formability the
combination of these two process can prove very vital and may bring a significant
change in the manufacturing industry

❏ Our literature review will focus on studying about different parameters affecting these
process and how can they be optimized for better use.The literature review for single
point incremental sheet forming and tailor welded blanks will help us to learn about
these two forming techniques holistically and through simulations.

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 Literature Review
Research Authors Results

The influence of process Gatea, S., Ou, H. & ● The formability of material was increased by
parameters in incremental McCartney. increasing the temperature of forming
sheet forming ● In the case of a small tool radius, there is a highly
concentrated zone of deformation that causes high
strain and leads to better formability
● The formability decreased with increased step size

Effect of Weld Line Hong-Seok Choi and ● The TWB with a weld line orientation of 90° had
Orientation on Formability of Dae-Cheol Ko better formability than the other TWBs
Tailor Welded Blank of ● In TWBs with weld line orientations of 0° and 45°
22MnB5 , the dome height was decreased compared to that of
the base metal because of deformation concentration
at a thinner material.

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 Research Authors Results

Investigation of forming Shalin Marathe and ● The forming behaviour TWBs(HSLA-DP) is investigated
behaviour of Tailor welded Harit Raval using weld line shift various regions of TWBs using
blanks (TWBs) during Single LDH and SPIF processes.
point incremental forming (SPIF)
process ● The weld line shift observed for the SPIF process is quite
low compared to the LDH test. The nature of weld line
shift for LDH test is only towards strong material while
for the SPIF the trend is sinusoidal in nature

FE Analysis of Single Point Hong-Seok Choi and ● The main motive of the paper is to predict the effect of
Incremental Forming (SPIF) for Dae-Cheol Ko various tool initial positions on the Plastic strain using
Tailor Welded Blanks (TWBs) TWBs from AA 5754 H22 and AA 5052 H32.
● If the tool is initially at the strong side then more amount
of plastic strain is observed in the weak side. Due to
in-homogeneity near the weld zone, strain is higher, else
the plastic strain was found to be equal.
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 Gaps in Literature and Objectives

Earlier researches have performed

incremental sheet forming on tailor welded
There has been research on both blanks using various materials but none of
incremental sheet forming and Tailor them were done on TWBs made up of EDD
welded blanks, but a very limited and DP590 which have significantly better
amount of research has been done on mechanical properties that can be used in
application of both these processes in automobile industries, so the objective is to
SPIF. perform experiments SPIF on TWBs and
collect experimental data like strain and
thickness distribution.

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 Experimental Methodology :Selection of materials

● The materials that were used for the

experiments of single point incremental Weldline
forming in tailor welded blanks are DP Weldline
590 and EDD of thickness 1.2 mm that EDD
steels offer a good combination of EDD DP590
DP590
strength and stampability

● The sheets were welded in a vertical

and diagonal direction as shown in the
figure
fig. 15: DP590 and EDD steels welded in different orientations.

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 Experimental Methodology : Single point incremental forming

● The experimental setup consisted of the

backing plate, blank holder and hemispherical
tip forming tool of 10 mm diameter. The
fabricated setup was attached to a three-axis
CNC milling machine through a tool holder
● Two types of wall angle were formed, both
variable and non variable wall angle.

fig. 16: Experimental setup of SPIF. 12

Experimental Methodology : Deformed blanks

fig. 17 : TWBs after

performing SPIF, the red
rectangles are to show
where the fractures
occurred during the
forming process

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 Experimental Methodology : Test for weld integrity

Two tests were performed for evaluating if the weld quality

is good and if the Tailor welded blank is suitable for
performing SPIF process. The tests are:
● Uniaxial tensile test
● Biaxial stretch forming test
The failure occurred in weaker EDD side in the stretch
forming test which suggested that weld integrity was good
enough for performing further SPIF experiments

fig. 18 : Stretch formed TWB

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 Experimental Methodology : Finite element modelling process

● Weld zone approach is used during

the simulation in order to define the
weld zone properties. For simulation
purposes we do separate meshing for
base metal 1, base metal 2 and the
weld zone.
● Doing such a kind of meshing and
providing the properties increases
the accuracy of simulation by many
folds.

fig. 19 : Mesh of blanks with different weld

orientation and meshing of the tool using LS
DYNA software

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 Experimental Methodology : Post Forming characterization

● Prior to forming all the blanks were etched

with circles of diameter 2500 micron to
perform circle grid analysis (CGA)
● These major and minor diameters were
measured using the stereozoom microscope.

true strain = ln (Lf / Li )

fig. 20 : Ellipses formed after deformation

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 Results : Failure Location

● Failure occurred in the deformed samples due to weld split

● The constant wall angle deformed blank had the maximum deformable depth in
comparison with variable wall angle blanks.

Pyramidal vertical weld Pyramidal diagonal weld Conical vertical weld

fig. 21 : Failure location in the deformed blanks

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 Results : Strain measurements

fig. 22 : Vertical weld with variable wall angle fig. 23 : Diagonal weld with constant wall angle

Distance from the

weld line is in mm fig. 24 : Diagonal weld
with variable wall angle

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Results : Thickness distribution and FE simulations

fig. 25 : Thickness distribution from FE simulations and experimental data

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 Conclusion
● In the present work, DP590 and EDD steels were welded together to fabricate TWBs of different weld
orientations. Subsequently, variable angle cone and square pyramidal components were fabricated in order
to find out the formability of fabricated TWBs in terms of wall angle.

● It was observed that these TWBs can be deformed upto 67° wall angle. In all these TWBs, failure occurred
in the weld zone, while the failure occurred in weaker EDD steel sheets in uniaxial tensile tests and biaxial
stretch forming tests. This could be avoided by optimizing welding parameters and SPIF process parameters
so that weld can withstand excessive deformation. However, a 60° wall angle square pyramidal component
is successfully formed without any weld failure.

● It was observed that the straight wall deformed in plane strain mode while the corner of the square
pyramid deformed in biaxial mode.

● Moreover, a model was successfully developed to predict the deformation behaviour during SPIF
accurately. It was observed that the developed FE model was able to predict the thickness distribution
profile accurately.

● It can be concluded that large depth components of TWBs can be formed using the SPIF process.

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 Future work

1) As the severe deformation takes place in SPIF, the optimization of laser welding process
parameters can be done to achieve higher weld strength.
2) Optimization of various SPIF process parameters such as feed rate, step depth, tool path
definition, rotation speed, frictional conditions etc. can be optimized to improve the
formability of the TWBs.

3) The various tool designs e.g. roller tool can be developed to ensure more localized tool
deformation in order to increase the formability of TWBs in SPIF.
4) A FE model should be developed incorporating anistopy property and weld zone
properties for accurate prediction of non uniform deformation of TWBs during SPIF. This
will save the excessive time, labour and material in experimental trials.

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 References
[1] S. Gatea, H. Ou, and G. McCartney, “Review on the influence of process parameters in incremental sheet forming,”
Int. J. Adv. Manuf. Technol., vol. 87, no. 1, pp. 479–499, 2016, doi: 10.1007/s00170-016-8426-6.
[2] B. Lu et al., “Mechanism investigation of friction-related effects in single point incremental forming using a
developed oblique roller-ball tool,” Int. J. Mach. Tools Manuf., vol. 85, pp. 14–29, 2014, doi:
https://doi.org/10.1016/j.ijmachtools.2014.04.007.
[3] P. A. F. Martins, N. Bay, M. Skjoedt, and M. B. Silva, “Theory of single point incremental forming,” CIRP Ann., vol.
57, no. 1, pp. 247–252, 2008, doi: https://doi.org/10.1016/j.cirp.2008.03.047.
[4] J. Raut, S. Marathe, and H. Raval, “Numerical Investigation on Single Point Incremental Forming (SPIF) of Tailor
Welded Blanks (TWBs),” in Advances in Simulation, Product Design and Development, 2020, pp. 43–54.
[5] P. A. F. Martins, N. Bay, M. Skjoedt, and M. B. Silva, “Theory of single point incremental forming,” CIRP Ann. -
Manuf. Technol., vol. 57, no. 1, pp. 247–252, 2008, doi: 10.1016/j.cirp.2008.03.047.
[6] M. Parente, R. Safdarian, A. D. Santos, A. Loureiro, P. Vilaca, and R. M. N. Jorge, “A study on the formability of
aluminum tailor welded blanks produced by friction stir welding,” Int. J. Adv. Manuf. Technol., vol. 83, no. 9, pp.
2129–2141, 2016, doi: 10.1007/s00170-015-7950-0.
[7] G. Sripathireddy, S. Marathe, and H. Raval, “Investigation on Formability of Tailor Welded Blanks (TWBs) During
Single Point Incremental Forming (SPIF) Process,” in Recent Advances in Manufacturing Processes and Systems,
2022, pp. 731–746.
[8] S. Marathe and H. Raval, “FE Analysis of Single Point Incremental Forming (SPIF) for Tailor Welded Blanks
(TWBs),” in Advances in Computational Methods in Manufacturing, 2019, pp. 49–63.
[9] Y. H. Kim and J. J. Park, “Effect of process parameters on formability in incremental forming of sheet metal,” J.
Mater. Process. Technol., vol. 130–131, pp. 42–46, 2002, doi: https://doi.org/10.1016/S0924-0136(02)00788-4.

22
[10] A. D. Anggono and T. W. B. Riyadi, “Finite Element Simulation of the Drawability of Tailor-Welded Blank,” in
Advances in Mechanical, Materials and Manufacturing Engineering, 2014, vol. 660, pp. 3–7. doi:
10.4028/www.scientific.net/AMM.660.3.
[11] J. R. Duflou, B. Lauwers, and J. Verbert, “Study on the achievable accuracy in single point incremental
forming,” Adv. Methods Mater. Form. With 264 Fig. 37 Tables, pp. 251–262, 2007, doi:
10.1007/3-540-69845-0_15.
[12] H. S. Choi, D. C. Ko, and B. M. Kim, “Effect of weld line orientation on formability of tailor welded blank of
22MnB5 at elevated temperature,” Adv. Mech. Eng., vol. 2014, 2014, doi: 10.1155/2014/698910.
[13] “Properties of Dual Phase (DP) Steel.” https://www.azom.com/article.aspx?ArticleID=11245
[14] “Low Carbon Extra Deep Drawing ( Edd ) Cold Rolled Steel Sheets And A Process For Its.”
https://www.quickcompany.in/patents/low-carbon-extra-deep-drawing-edd-cold-rolled-steel-sheets-and-a-proces
s-for-its-production
[15] G. Kumar and K. Maji, “Forming limit analysis of friction stir tailor welded AA5083 and AA7075 sheets in
single point incremental forming,” Int. J. Mater. Form., vol. 15, no. 3, p. 20, 2022, doi:
10.1007/s12289-022-01675-7.
[16] S. Basak, K. Bandyopadhyay, S. K. Panda, and P. Saha, “Prediction of Formability of Bi-axial Pre-strained Dual
Phase Steel Sheets Using Stress-Based Forming Limit Diagram,” no. August, 2015, pp. 167–192. doi:
10.1007/978-81-322-2355-9_8.
[17] L. Kilani, T. Mabrouki, M. Ayadi, H. Chermiti, and S. Belhadi, “Effects of rolling ball tool parameters on
roughness, sheet thinning, and forming force generated during SPIF process,” Int. J. Adv. Manuf. Technol., vol.
106, no. 9–10, pp. 4123–4142, 2020, doi: 10.1007/s00170-019-04918-1.

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Thank You

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