CNC common calculation formula

1. Calculation of trigonometric functions

1.tgθ=b/a ctgθ=a/b
2. Sinθ=b/c Cos=a/c

2. Calculation of cutting speed
Vc=(π*D*S)/1000
Vc: line speed (m/min)

π: pi (3.14159)

D: tool diameter (mm)
S: speed (rpm)

3. Calculation of feed amount (F value)
F=S*Z*Fz
F: Feed amount (mm/min)

S: speed (rpm)

Z: number of blades
Fz: (actual feed per edge)

4. Calculation of residual material height
Scallop=(ae*ae)/8R
Scallop: residual material height (mm)

ae: XY pitch (mm)

R tool radius (mm)

5. Calculation of material escape hole
Φ=√2R2

X, Y=D/4
Φ: escape hole diameter (mm)

R tool radius (mm)

D: tool diameter (mm)

Six, the calculation of the amount of material
Q=(ae*ap*F)/1000
Ｑ: Feed amount (cm3/min)

ae: XY pitch (mm)

ap: Z pitch (mm)

7. Calculation of feed per blade
Fz=hm * √(D/ap )
Fz: Implemented feed per blade hm: Theoretical feed per blade ap: Z pitch(mm)
D: blade diameter (mm)

8. Die edge processing method
Cutting edge processing depth = plate thickness – cutting edge height + drill tip (0.3D)
D means tool diameter

9. Drilling time formula
T(min)=L(min)/N(rpm)*f(mm/rev)
=πDL/1000vf
L: Hole length

N: Number of revolutions

f: Feed amount coefficient
D: Drill diameter

v: cutting speed

Drill coefficient table fz

diameter mm

Feed mm/rev

1.6~3.2

0.025~0.075

3.2~6.4

0.05~0.15

6.4~12.8

0.10~0.25

12.8~25

0.175~0.375

over 25

0.376~0.625

10. Calculation formula of tube teeth
1 inch = 25.4mm = 8 points

Eleven, horsepower (gun drill)
W=Md*N/97.410
W: required power (KW)
Md: Torque (kg-cm)
N: number of revolutions (r.p.m)

12. The torque calculation formula is as follows:
Md=1/20*f*ps*r2
f is the feed rate mm/rev coefficient
r is the radius of the drill bit (mm)
α: cutting resistance ratio ps. In small feed, the general steel is 500kg/m㎡; the general cast iron is 300kg/m㎡;

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