Common calculation formulas for CNC machining

　1. Trigonometric function calculation

1.tanθ=b/a θ=tan-1b/a

2.Sinθ=b/c Cos=a/c

　　 2. Calculation of cutting speed for cavity machining

Vc=(π*D*S)/1000

Vc: linear velocity (m/min) π: circumference ratio (3.14159) D: tool diameter (mm)

S: Speed (rpm)

Example. Use Φ25 milling cutter Vc to be (m/min)25 to find S=?rpm

Vc=πds/1000

25=π*25*S/1000

S=1000*25/ π*25

S=320rpm

　　 Three, the calculation of the cavity processing feed (F value)

F=S＊Z＊Fz

F: Feed rate (mm/min) S: Rotation speed (rpm) Z: Number of blades

Fz: (actual feed per edge)

Example. A standard 2-flute end mill cuts a workpiece at a speed of 2000rpm), and find the feed (F

Value)? (Fz=0.25mm)

F=S＊Z＊Fz

F=2000*2*0.25

F=1000(mm/min)

　　 Fourth, the calculation of the residual material height

Scallop=(ae*ae)/8R

Scallop: residual material height (mm) ae: XYpitch (mm) R tool radius (mm)

Example. Φ20R10 refined 2 blades, the pre-residual height is 0.002mm, what is the pitch?

few? mm

Scallop=ae2/8R

0.002=ae2/8*10

ae=0.4mm