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Proc. of Int. Conf. on Recent Trends in Mechanical, Instrumentation and Thermal Engineering 2012
Mechanical Properties Analysis of Copper Wire
Drawn by Step Reduction
Mandeep Singh, C. S. Kalra a, Rahul Mehra,
a
ME Department, SUSCET, Tangori, Mohali, E-Mail ID: charana_1984@yahoo.co.in
Abstract: Drawing is a metal forming process of bars, rods
and wires basically used in the electrical, electronics, cable
transport, sports and automotive sectors. The process
consists of reducing the cross-sectional area by pull the
wire through series of dies while the volume remains the
same. The material is elongated during the drawing process
depending on the drawability of the material. In the
experiment wire drawing process was used to reduce the
diameter from 3.2 mm to 2.6 mm. Wires are drawn stepwise
with the reduction of 0.1mm, 0.2mm and 0.3mm mm in
diameter. The reduction is done in different dies of final
diameter of 3.1mm, 3.0mm, 2.9mm, 2.8mm, 2.7mm, and
2.6mm.
the design of the die stated by Nikkei (2000) and S.
Norasethasopon (2003). Drawing is usually performed at room
temperature, known as cold working process, but to reduce
required tensile forces it may be performed at different
elevated temperatures for larger diameter wires by Kalpakjian,
(2007). The wire is prepared by shrinking the beginning of it,
by hammering, filing, rolling or swaging, so that it will easily
pass through the die, the wire is then pulled through the die
stated by Degarmo (2010). The reduction in cross-sectional
area, die angle, friction along the die–workpiece interfaces
and drawing speed are the major variables in the drawing
process stated by D.A. Lucca. (1991)
Keywords: Wire Drawing, Die Design, Copper Wire Drawing,
Drawing Procedure, Forces in Drawing.
II. DESIGN AND E XPERIMENTAL PROCEDURE
Abbreviations:
Die semi angle alpha “α”,
Cross-sectional area reduction “r”,
Friction coefficient “µ”,
Initial diameters “di”
Diameter of stabilizing zone “df”,
Back tension “Fb”
Drawing force “F”,
Tensile strength “σ t ”,
Break Point Load “L”,
Elongation “δ”,
Elongation Percentage “Δ%”
A typical drawing die consists of four main regions (i)
a bell shaped entrance zone for proper guidance of work
piece, (ii) a conical working zone, (iii) a straight and short
cylindrical zone for adding stability to the operation that is
bearing and (iv) a bell shaped exit zone.
I. INTRODUCTION
Drawing is a metal forming process for production of
bars, rods and wires particularly used in the electrical
conductor, binding wires, electronics, cable transport,
sports and automotive sectors. The process consists of
reducing the cross-sectional area by pull the wire through
series of dies while the volume remains the same stated by
K. Yoshida (2000), and Morton et al. (1999). In the wire
drawing process the material is pulled through a die with a
hole by the means of tensile force applying to the exit side
of the die. The products manufactured by this process are
called wire stated by Deant (1995). Copper is the most
commonly used materials for the production the wires.
Copper is the preferred and predominant choice in the
electrical industry because of its high thermal and electrical
conductivity. Set of dies are required for the production of
the fine wire, for the reduction in the stages and forces.
Material should flow properly in the die in order to reduce
defects and improve surface quality which depends upon
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© 2012 AMAE
DOI: 03.MES.2012.2. 512
Fig 1. Parameters used in wire drawing (Ghosh and Malik 2010)
The final size of product is determined by the diameter of
stabilizing zone (d f), the other important die dimension
being the half cone angle (α). Sometimes a back tension Fb
is provided to keep the input work piece straight. The
workload, i.e., the drawing force F, is applied on the exit
side. A die can handle jobs of different initial diameters
(di) which in turn, determines the length of the job-die
interface.
Drawing force is minimum when α = 60 that is F = 1791.3N.
So absolute drawing angle α is 60.
So we design the die for: Half Cone Angle ‘α’ = 60
Cone Angle ‘2α’ = 120
Bearing length H” 2.6mm
Back relief Angle = 600
Full Paper
Proc. of Int. Conf. on Recent Trends in Mechanical, Instrumentation and Thermal Engineering 2012
Fig 2 Design of die of Diameter2.6
Fig 6 Design of die of Diameter 3
Fig 3 Design of die of Diameter2.7
Fig 7 Design of die of Diameter 3.1
In this experiment the drawing of wire is mostly done in
steps of reduction of 0.1 mm, 0.2 mm and 0.3 mm in diameter.
For this experiment the lathe machine is used for the
drawing of these wires. The final diameter of the all wires
is 2.6mm of each step of 0.1mm, 0.2mm, and 0.3mm.
Reductions of diameter of wires are shown in table 1.
T ABLE I: STEPS
OF REDUCTION
Fig 4 Design of die of Diameter 2.8
III. PROCEDURE
Firstly make the one end of wire to 3.0 mm diameter by
grinding it, so that it can pass through die of 3.1 mm bore.
Pass it through die of size 3.1mm. Hold die in the jaw and
gripped the wire with a fixture as shown in figure 8.
Fig. 2.4
Fig 5 Design of die of Diameter2.9
© 2012 AMAE
DOI: 03.MES.2012.2.512
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Full Paper
Proc. of Int. Conf. on Recent Trends in Mechanical, Instrumentation and Thermal Engineering 2012
T ABLE III: FORCE
REQUIRED TO
0.2 MM
REDUCTION
T ABLE IV: FORCE
REQUIRED TO
0.3 MM
REDUCTION
Fig 8 Wire Passed Through Die and Gripped In Fixture
By providing the longitudinal feed to the carriage, pull the
wire from the different die according to the step reduction
and results in reduction of diameter.
Fig 9 Drawing of Wire
IV. RESULTS
The required force to draw the wire from initial
diameters di to diameter of stabilizing zone d f is derived
from the relation as shown below
F = σxf* Af
From the above relations, the required forces were calculated
for each step reductions 0.1mm, 0.2mm and 0.3mm shown in
table 2, table 3 and table 4 respectively.
TABLE II: FORCE REQUIRED
TO
Fig10 Required force for each reduction
Graph shows by increasing the step reduction diameter
(0.1mm, 0.2mm and 0.3mm) the required drawing force increases
and it is cleared that force required is maximum when step of
reduction is 0.3mm.
0.1MM REDUCTION
A. Mechanical Analysis of wires
After performing various tests on all wires following
results are obtained shown in table 5.
T ABLE V: MECHANICAL ANALYSIS OF
© 2012 AMAE
DOI: 03.MES.2012.2.512
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STEPS OF DIFFERENT WIRES
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Proc. of Int. Conf. on Recent Trends in Mechanical, Instrumentation and Thermal Engineering 2012
Fig 11 shows the variation of tensile strength of wire with
the different reduction of wire. It shows that by increasing
the reduction diameter of the wire from 0.1mm to 0.2mm
and 0.2mm to 0.3mm results in improve the tensile strength
of wire.
Obtaining elongation were 2.56mm, 2.36mm; and 2.05mm
by the number of steps i.e. 6, 3 and 2 respectively. It is cleared
that by increasing number of steps of drawing elongation of
wire increase.
Percentage elongation of wire decreases from 12.80%,
11.80%; and 10.25% by decreasing the reduction in steps
of 6, 3; and 2 respectively.
The Break point loads were recorded as 228, 232; and
236 Kgs at the number of steps reductions of 6, 3; and 2
respectively. Conclude that by increasing number of steps
of drawing Break Point Load of wire increases.
The tensile strength for number of reduction step of 6,
3; and 2 were observed as 421, 429; and 436N respectively.
Concluding that with decrease in no of steps of drawing
tensile strength of wire increase.
 By increasing the step reduction diameter of 0.1mm,
0.2mm and 0.3mm reduction in the steps from 6, 3 and 2
respectively. It is observed that the required drawing force
increases with increasing reduction diameter and force
required is maximum when step of reduction is 0.3mm.
Fig 11 Tensile Strength during Step reductions
Figure 12 shows that by increasing the reduction diameter of
the wire from 0.1mm to 0.2mm and 0.2mm to 0.3mm results in
decreases the elongation of wire.
REFERENCES
[1] Magalhaes F.C, Pertence A.E.M, Campos H.B et al (2012) “
Defects in axisymmetrically drawn bars caused by longitudinal
superficial imperfections in the initial material” Journal of
Materials Processing Technology, Vol 212, 237-248
[2] Black J.T. And Ronald A. Kohser (2010) “Degarmo’s Materials
& Processes in Manufacturing” Tenth Addition.
[3] DEAN T A (1995), “A profile of the market for cold forging”,
International Congress on Cold Forging. Sollhul, UK, 17"27.
[4] Ghosh Amitab and Malik Ashok Kumar (2010) “Manufacturing
Sciences” Second Edition, New Delhi.
[5] Kalpakjian Serope and Schmid Steven R. (2010),
“Manufacturing Engineering and Technology”, Fourth Edition,
Pearson, New Delhi.
[6] Lucca D.A. and Wright R.N. (1991), “Heating effect in the
drawing of wire and strip under hydrodynamic lubrication
conditions”, Tribological Aspects in Manufacturing, 54, 291–
313.
[7] Morton. J (1999), “Thomas Bolton & Sons and the rise of the
electrical industry”, Engineering Science and Education Journal,
vol-8, 5- 12.
[8] Nikkei-Mechanical (2000). “The motor efficiency competition”
Tokyo, Nikkei: 40-44.
[9] Norasethasopon S, and Yoshida K.,(2003), “Influence of an
inclusion on multi-pass copper shaped wire drawing by 2D
finite element analysis”, Wire Journal International. Eng. 279–
292
[10] Yoshida. K (2000), “FEM analysis of wire breaks in drawing
of superfine wire with an inclusion”, Wire Journal International,
102–107.
Fig 12 Final Elongation during step Reduction
Fig 13 shows the variation break point load of wire with the
different reduction of wire. It shows that by increasing the
reduction diameter of the wire from 0.1mm to 0.2mm and 0.2mm
to 0.3mm results in the increase of the break point load.
Fig 13 Break Point Load during step reduction
V. CONCLUSION
Result of wire drawing on the basis tensile strength of
wire, break point load, elongation, required drawing forces,
and diameter was examined experimentally and theoretically.
A number of conclusions were derived during the course of
investigation, as given below.
© 2012 AMAE
DOI: 03.MES.2012.2.512
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