# Essential CNC Calculation Formulas You Should Know

Looking to take your metalworking skills to the next level? Look no further than MachineMfg’s comprehensive guide to CNC calculation formulas.

Whether you’re a seasoned pro or just starting out, our expertly curated collection of formulas and insights will help you get the most out of your metalworking machines.

From calculating cutting speeds and feed rates to determining torque and horsepower requirements, our guide has everything you need to take your metalworking game to the next level.

So why wait? Dive into our guide today and start honing your skills with the best in the business.

## I. The calculation of trigonometric

1.tgθ=b/a      ctgθ=a/b

2.Sinθ=b/c      Cos=a/c

## II. Calculation of cutting speed

Vc＝(πDS)/1000

• Vc: linear velocity (m/min)
• π: Circumference (3.14159)
• D: Tool diameter (mm)
• S: Rotational speed (rpm)

## III. Calculation of the feed (F-value)

F＝SZFz

• F: Feed rate (mm/min)
• S: Rotational speed (rpm)
• Fz: (actual feed per blade)

## IV. Calculation of residue height

Scallop＝(ae*ae)/8R

• Scallop: Residue height(mm)
• ae: XY  pitch(mm)

## V. Calculation of slug holes

Φ＝√2R2

X. Y＝D/4

• Φ: Diameter of slug holes(mm)
• D: Tool diameter (mm)

## VI. Calculation of material intake

Q＝(aeapF)/1000

• Q: The quantity of material taken(cm3/min)
• ae: XY  pitch(mm)
• ap: Z  pitch(mm)

## VII. Calculation of the feed rate per blade

Fz＝hm * √(D/ap )

• Fz: Actual feed per blade
• hm: theoretical feed per blade
• ap：Z  pitch(mm)

## VIII. Die cutting edge processing method

Tooling depth = plate thickness – tool height + drill tip (0.3D)

• D : Knife diameter

## IX. Drill drilling time formula

T(min)=L(min)/N(rpm)*f(mm/rev)＝πDL/1000vf

• L: Full length of the drilling
• N: Number of turns
• f: feed volume factor
• D: Bit diameter
• v: Cutting speed

Drill factor table fz

## X. Formulas for calculating pipe teeth

1 inch = 25.4 mm.

## XI. Horsepower (gun drill)

• W = Md*N/97.410.
• W: Power required (KW)
• Md: torque (kg-cm)
• N: Number of rotations (r.p.m.)

## XII. The formula for calculating torque is as follows.

• Md=1/20*f*ps*r2
• f is the coefficient of feed mm/rev.
• r is the drill radius (mm)
• α: cutting resistance ratio ps. at small feed, general steel 500kg/m²; general cast iron 300kg/m²