Working part cutting edge size calculation
1.1.1 Calculation of cutting edge size of blanking concave and punch die
The shape of the part is a square, relatively simple, suitable for separate processing. The characteristic of separate processing is that it is necessary to compare the conditions of [δ_d＋δ_p]≤Z_max—Z_min
.
After the cutting edge of the blanking die is worn, the size of the blade only changes, and all of them increase. The cutting edge size is generally calculated according to Equation 5-7.
A_A=（A_max-x△）₀⁺δ_d  （Equation 5-7）
  
After the blanking die cutting the edge wears, the edge size changes only one change, and all become smaller. The size of the cutting edge is generally calculated according to Equation 5-8.

B_A=（B_min+x△）δ_p⁰ (Equation 5-8)

Where   A_max—The maximum distance between the die edges perpendicular to the feeding direction;
B_min—The minimum distance between the punch edges perpendicular to the feeding direction.;
       x — convex and concave mold wear coefficient;
       △— Blade manufacturing tolerances;
1)Calculation of cutting edge size of convex and concave die
The basic size    30_-0.1^+0.1, R5 is converted to R5⁰_-0.22 at IT13 level. Check table 5-4

x₁=1;X_2=0.5

δ_p１＝-0.017 ; δ_d１＝0.025_;δ_p2＝-0.012　；　δ_d２＝0.017 ;

Check: 1----│δ_p１│＋│δ_d１│=0.042mm＜2x（Z_max－Z_min）;

2----│δ_p２│＋│δ_d２│=0.029mm＜2x（Z_max－Z_min）;

Both satisfy the condition of│δ_p│＋│δ_d│≤2x（Z_max－Z_min）_n.

1----- 30_-0.1^+0.1

D_d１=（30.1－0.2×1）₀δ_d１=29.9₀^+0.025(mm)

D _p１ =（30.1－0.2×1-0.246x2）δ_p１⁰ =29.408_-0.017⁰(mm)

Convert D_d１、D _p１to integer size:

D_d1=29.9^-0.02₀  D_d2=29.41⁰_-0.02
2------R5⁰_-0.22
D_d１=（5－0.5×0.22）₀δ_d１=4.89₀^+0.017(mm)
D _p１ =（5－0.5×0.22－0.246x2）δ_p１⁰=4.398_-0.012⁰(mm)
Convert D_d2、D _p2 to integer size:

D_d2=4.89^+0.020₀   D _p１=4.40⁰_-0.01

2）Calculation of cutting edge size of punching convex die
The precision of the part is not high, it is IT13 grade, the basic size of the hole isΦ40⁰_-0.039, the life of the die should be considered when determining the edge clearance, so a larger clearance should be taken. The results are as follows:

Zmax=0.360mm    Zmin=0.246mm    δ_p＝-0.014 ； δ_d＝0.02_;

So Z= Zmin=0.246mm

Check: 1----│δ_p│＋│δ_d│=0.034mm＜2x（Z_max－Z_min）;

 Cutting edge size of punching punch   d_P=（B_min+x△）δ_p⁰

then d_P =(9.961+05x0.039) _-0.014⁰＝9.98_-0.014⁰

Cutting edge size of punching die  d_d=（B_min+x△＋Zminｘ2）_０δ_d

　　　　　　　Then d_d＝（9.961+05x0.039+0.236x2）=10.47₀^0.02

Convert it to an integer size: d_P＝9.98_-0.014⁰         d_d＝10.47₀^0.02

Table 5-4 Coefficient X

Thickness t(mm)	Non-circular			Round
	1	0.75	0.5	0.75	0.5
	Workpiece tolerance △/mm
1 1~2 2~4 ＞4	＜0.16 ＜0.20 ＜0.24 ＜0.30	0.17~0.35 0.21~0.41 0.25~0.49 0.31~0.59	≥0.36 ≥0.42 ≥0.50 ≥0.60	＜0.16 ＜0.20 ＜0.24 ＜0.30	≥0.16 ≥0.20 ≥0.24 ≥0.30

Table 5-5  manufacturing deviation of convex and concave die during regular shape blanking (mm)

Basic size	Punch deviation dT	Concave die deviation dA
≤18	0.020	0.020
＞18～30	0.020	0.025
＞30～80	0.020	0.030
＞80～120	0.025	0.035
＞120～180	0.030	0.040
＞180～260	0.030	0.045
＞260～360	0.035	0.050
＞360～500	0.040	0.060
＞500	0.050	0.070