I. Trigonometric calculation
1.tgθ=b/a ctgθ=a/b
2.Sinθ=b/c Cos=a/c
II. Calculation of cutting speed
Vc＝(π D S)/1000
- Vc: linear speed (m/min)
- π: Circumference (3.14159)
- D: Tool diameter (mm)
- S: Rotational speed (rpm)
III. Feed calculation (F value)
F＝S Z Fz
- F: Feed rate (mm/min)
- S: Rotational speed (rpm)
- Z: Number of blades
- Fz: (actual feed per blade)
4. Calculation of residue height
Vieira＝(ae*ae)/8R
- Scallop: Residue height (mm)
- ae: XY pitch (mm)
- A: Tool radius (mm)
V. Hole calculation
Φ＝√2R2
XY＝D/4
- Φ: Diameter of slug holes (mm)
- A: Tool radius (mm)
- D: Tool diameter (mm)
SAW. Calculation of material intake
Q＝(ae app F)/1000
- Q: The amount of material removed (cm3/min)
- ae: XY pitch (mm)
- ap: Z pitch (mm)
VII. Calculation of feed rate per blade
Fz＝hm * √(D/ap )
- Fz: Actual feed per blade
- hm: theoretical advance per blade
- ap: Z pitch (mm)
- D: Blade diameter (mm)
VIII. Cutting-edge processing method
Tool depth = plate thickness – tool height + drill tip (0.3D)
- D: Knife diameter
IX. Drilling Time Formula
T(min)=L(min)/N(rpm)*f(mm/rev)＝πDL/1000vf
- L: Total length of the perforation
- N: Number of turns
- f: feed volume factor
- D: Drill diameter
- v: Cutting speed
fz drilling factor table
| Dia. millimeters | Feed knife 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 |
| >25 | 0.376~0.625 |
X. Formulas for calculating pipe teeth
1 inch = 25.4 mm.
XI. Power (gun drill)
- W = Md*N/97,410.
- W: Required power (KW)
- MD: torque (kg-cm)
- N: Number of revolutions (rpm)
XII. The formula for calculating torque is as follows.
- Md=1/20*f*ps*r2
- f is the feed coefficient mm/rev.
- r is the drill radius (mm)
- α: cutting resistance ratio ps. in small feed, general steel 500kg/m²; general cast iron 300kg/m²
