§ 18
How large will the comb be, and what speed should I use with the ball mill?
Answer: In fine milling of a surface with a ball mill cutter, each pass leaves a small ridge. Ridge height depends on the ball's radius and the side offset (stepover). At the same time, the ball cutter only cuts with a smaller diameter when the cutting depth is small, so the number of revolutions must be worked out from the effective diameter. The calculator gives the ridge height, the stepover that gives a desired ridge height, and the number of revolutions for your cutting speed.
Kamhøjde h = R − √(R² − (stepover ÷ 2)²), R = Dc ÷ 2
Stepover for ønsket h = 2 × √(h × (Dc − h))
Effektiv diameter De = 2 × √(ap × (Dc − ap)) ved ap < Dc ÷ 2
n = Vc × 1000 ÷ (π × De)
| Symbol | Meaning | Unit |
|---|---|---|
| dc | Ball mill diameter Dc | mm |
| stepover | Lateral shift between tracks | mm |
| ap | Depth of cut ap | mm |
| kam_maal | Desired ridge height | µm |
| vc | Cutting speed Vc (datasheet) | m/min |
| = | Scallop height at selected step-over | µm |
| = | Stepover that gives desired ridge height | mm |
| = | Effective cutting diameter at ap | mm |
| = | Revolutions at effective diameter | o/min |
Does not apply when
The calculator's own default values inserted. The figures are calculated with exactly the formula the tool uses.
Substituted
Giver
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Ved finfræsning af formværktøjer, matricer og 3D-flader med kuglefræser skal du vælge sideforskydning (stepover) efter den overflade, kunden kræver. Samtidig skærer kuglen kun med en lille diameter ved lille skæredybde, så omdrejningstallet skal regnes ud fra den effektive diameter.
Du finfræser en formhalvdel i værktøjsstål med en Ø10 mm kuglefræser, stepover 0,5 mm og ap 0,3 mm. Kunden vil have en kamhøjde under 3 µm. Vc er 200 m/min.
It means: Kamhøjden er 6.25 µm. For 3 µm skal stepover være 0.346 mm. Effektiv diameter er 3.41 mm, og n er 18,660 rpm.
Detaljer i formen fræses med en Ø6 mm kuglefræser, stepover 0,2 mm og ap 0,15 mm ved Vc 150 m/min.
It means: Kamhøjden er 1.67 µm. Den effektive diameter er 1.87 mm, så n skulle være 25,485 rpm. Er det over spindlens maks., må Vc ned.
Halv stepover giver en fjerdedel af kamhøjden.
Effektiv diameter er mindre end Dc.