3 Fundamentals of press design

336 Sheet metal forming and blanking
blank clearance u [mm]
H R
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
0
blanking plate
vee-ring plate
h R
H R
r
2 4 6 8 10 12 14 16
sheet metal thickness s [mm]
45°
45°
A
R R
45°
R
45°
R
45°
A
45°
r
0.1mm
standard
blanking
fine blanking
Fig. 4.7.7 Guideline values for vee-ring dimensions
Metal Forming Handbook / Schuler (c) Springer-Verlag Berlin Heidelberg 1998
Fig. 4.7.6
Guideline values for the blanking
clearances for standard
and fine blanking in function
of sheet metal thickness s
sheet metal
A HRR thickness
[mm] [mm] [mm] [mm]
2.8 - 3.2 2.5 0.6 0.6
3.3 - 3.7 2.5 0.7 0.7
3.8 - 4.5 2.8 0.8 0.8
sheet metal A HRR hRr thickness
[mm] [mm] [mm] [mm] [mm] [mm]
4.5 - 5.5 2.5 0.8 0.8 0.5 0.2
5.6 - 7.0 3.0 1.0 1.0 0.7 0.2
7.1 - 9.0 3.5 1.2 1.2 0.8 0.2
9.1 - 11 4.5 1.5 1.5 1.0 0.5
1 1.1 - 13 5.5 1.8 2.0. 1.2 0.5
13.1 - 15 7.0 2.2 3.0 1.6 0.5