Table 4.1: Parameters used in deep drawing
Para
meter
Parameter Quantity/ Range
1 Punch Diameter, mm 80
2 Die inner diameter, mm 82.5
3 Blank Holder opening diameter, mm 96
4 Maximum blank Diameter (mm) 180
5 Minimum blank Diameter (mm) 100
6 Blank thickness (mm) 0.9
7 Punch Diameter (mm) 80
8 Die inner Diameter (mm) 82.5
9 Lubrication type MoS2
10 Punch nose radius (mm) 5.5 - 10.5
11 Die shoulder radius (mm) 5.5 - 10.5
12 Blank holder force (kN) 3 - 7
Table 4.2: Optimal parameters obtained through DOE
Process Parameter Level description Level
Punch nose radius, mm 5.5 1
Die shoulder radius, mm 5.5 1
Blank holder force, kN 7 3
The contribution of each highly influencing parameter using ANOVA is shown
in Table 4.3
Table 4.3 Contribution of optimal process parameters found in deep drawing
process
Process parameter Sum of squares S Si % of Contribution description
Punch nose radius, mm 0.505 33.25
Die shoulder radius, mm 0.417 11.52
Blank holder force, kN 0.839 55.23
172
Table 4.4 LDR found by traditional experimental method for aluminium at
different temperatures
Material Temperature (oC) LDR
Aluminium
R T 1.8325
100 1.855
150 1.900
200 1.938
Table 4.5 LDR found by traditional experimental method for copper at different
temperatures
Material Temperature (oC) LDR
copper
R T 1.8875
150 1.9563
Table 4.6 LDR found by traditional experimental method for aluminium and
copper at different temperatures
Material Temperature (oC) LDR
Aluminium
R T 1.8325
100 1.855
150 1.900
200 1.938
copper
R T 1.8875
150 1.9563
R T : Room temperature
The optimized process parameters are used for determination of LDR. The LDR
found through traditional method for aluminium and copper at different temperatures are
as shown in Table 4.6.
173
4.2 Rapid Determination of LDR
The experimental results revealed that the maximum punch load is linearly
proportional to the blank diameter and this concept is used for rapid nation of LDR. The
LDR calculations have been performed with the use of three deep draw tests. The test
results are used for finding LDR by rapid method of determination for aluminium and
copper different temperatures. Each test consists of two undersize blanks and one over
size blank. The maximum punch load has recorded and plotted on the graph for the
test conducted. The undersize blanks produced a successful cup and over size blank
produced a fractured cup. The oversize blank fractures due to excessive forming load
called critical punch load. The critical blank diameter has found by drawing a horizontal
line passing through the critical punch load (maximum punch load) that intersects with
the line passing through the maximum punch loads of two undersize blanks as shown in
the below Figures. The intersection point gives the maximum size of the blank that can
be successfully drawn without fracture. The Figure 4.1 to 4.7 gives the Critical diameter
for different conditions tested.
Fig. 4.1 Determination of critical diameter for AA6111 aluminum at room
temperature using three data points
174
Fig. 4.2: 146.6mm blank successfully drawn and testing the validity of rapid method of finding critical diameter
175
Fig. 4.3 Critical diameter for AA6111 aluminum cups drawn at 100oC using
three data points
Fig. 4.4 Determination of critical diameter for aluminium cups drawn at 150oC
176
4 RESULTS AND DISCUSSION
4.2 Rapid Determination of LDR
