# Calculation of cutting edge size of stamping die

Working part cutting edge size calculation
1.1.1 Calculation of cutting edge size of blanking concave punch die
The shape of the part is a relatively simple square, suitable for separate machining. The feature of the separate processing is that it is necessary to compare the conditions of [δd + δp] ≤ Zmax-Zmin.

After the cutting edges of the blanking die wear, only the size of the blades changes and all of them increase. The cutting edge size is generally calculated according to Equation 5-7.
AA = (Amax-x △) 0 + δd (Equation 5-7)

After the cutting edge of the blanking die wears, the edge size changes only once and everything becomes smaller. The cutting edge size is usually calculated according to Equation 5-8.
BA = (Bmin + x △) δp0 (Equation 5-8)

Amax-Maximum distance at the end of the mold perpendicular to the feed direction.
Bmin-Minimum distance between punch edges perpendicular to the feed direction.
x –Concavo-convex mold wear factor.
1) Calculate the convex and concave cutting edge sizes
The base size is 30-0.1 + 0.1 and R5 is converted to R50-0.22 at IT13 level. Checklist 5-4
x1 = 1; X2 = 0.5
Δp1 = -0.017; δd1 = 0.025; δp2 = -0.012; δd2 = 0.017;

Check: 1 —- │ δp1 │ ＋ │ δd1 │ = 0.042mm <2x (Zmax－Zmin);

2 —- │ δp2 │ ＋ │ δd2 │ = 0.029mm <2x (Zmax－Zmin);

Both satisfy the conditions of │ δp │ ＋ │ δd │ ≤ 2x (Zmax－Zmin) n.

1—– 30-0.1 + 0.1

Dd1 = (30.1-0.2 × 1) 0δd1 = 29.90 + 0.025 (mm)

D p1 = (30.1-0.2 × 1-0.246×2) δp10 = 29.408-0.0170 (mm)
Convert Dd1, D p1 to integer size:

Dd1 = 29.9-0.020 Dd2 = 29.410-0.02
2——R50-0.22
Dd1 = (5-0.5 × 0.22) 0δd1 = 4.890 + 0.017 (mm)
D p1 = (5-0.5 × 0.22-0.246×2) δp10 = 4.398-0.0120 (mm)
Convert Dd2, Dp2 to integer size:

Dd2 = 4.89 + 0.0200 D p1 = 4.400-0.01

2) Calculation of the cutting edge size of the punching punch
The accuracy of the parts is not high, it is IT13 grade, the base size of the hole is Φ400-0.039, and it is necessary to take a larger gap because the service life of the mold needs to be considered when determining the edge clearance. I have. The results are as follows.
Zmax = 0.360mm Zmin = 0.246mm δp ＝ -0.014 ； δd ＝ 0.02;
So Z = Zmin = 0.246mm

Check: 1 —- │ δp │ ＋ │ δd │ = 0.034mm <2x (Zmax－Zmin);

Cutting edge size of punching punch dP = (Bmin + x △) δp0

After that, dP = (9.961 + 05×0.039) -0.0140 = 9.98-0.0140

Cutting edge size of punching punch dd = (Bmin + x △ ＋ Zminx2) 0δd

After that, dd = (9.961 + 05×0.039 + 0.236×2) = 10.470.02

Convert it to integer size: dP = 9.98-0.0140 dd = 10.4700.02