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Table 8 Design of punch and die according to the best draw ratio (2.4) and inflow angle (9\(^\circ\))

From: Deep Drawing Process Using a Tractrix Die for Manufacturing Liners for a CNG High-Pressure Vessel (Type II)

Stage

Dimension of die

Draw ratio and reduction ratio of cross-sectional area

1st stage

Deep drawing

\({D}_{0}\) = 1,129 mm

\({\mathrm{d}p}_{1}\) = 470.51 mm

\({\mathrm{d}i}_{1}\) = 490.51 mm

\({D}_{0}/{\mathrm{d}p}_{1}=2.4\)

\({A}_{1}=\frac{\pi }{4}\left({{\mathrm{d}i}_{1}}^{2}-{{\mathrm{d}p}_{1}}^{2}\right)\) = 15,095.7 mm2

2nd stage

Redrawing

\({\mathrm{d}p}_{2}\) = 332.5 mm

\({\mathrm{d}i}_{2-1}\) = 352.5 mm

\({\mathrm{d}}_{\mathrm{p}1}/{\mathrm{d}}_{\mathrm{p}2}=1.42\)

\({A}_{21}=\frac{\pi }{4}\left({{\mathrm{d}i}_{2-1}}^{2}-{{\mathrm{d}p}_{2}}^{2}\right)\) = 10,760 mm2

Ironing 1

\({\mathrm{d}i}_{2-2}\) = 346.7 mm

\({A}_{22}=\frac{\pi }{4}\left({{\mathrm{d}i}_{2-2}}^{2}-{{\mathrm{d}p}_{2}}^{2}\right)\) = 7,574.9 mm2

\({RA}_{Ironing,22}=1-\frac{{A}_{2-2}}{{A}_{2-1}}=29.6\%\) (< 35%)

\({RA}_{total,2}=1-\frac{{A}_{2-2}}{{A}_{1}}=49.8\%\) (< 50%)

3rd stage

Ironing 2

\({\mathrm{d}p}_{3}\) = 332.5 mm

\({\mathrm{d}i}_{3-1}\) = 341.9 mm

\({A}_{31}=\frac{\pi }{4}\left({{\mathrm{d}i}_{3-1}}^{2}-{{\mathrm{d}p}_{3}}^{2}\right)\) = 4,979 mm2

\({RA}_{Ironing,3-2}=1-\frac{{A}_{3-1}}{{A}_{2-2}}=34.3\%\) (< 35%)

\({RA}_{total, 3}=1-\frac{{A}_{31}}{{A}_{22}}=34.3\%\) (< 50%)