A ball nose end mill cuts with a spherical tip. At shallow axial depths of cut (ap), the actual cutting diameter is smaller than the nominal tool diameter. Using the nominal...
Let our engineers find the right factory for your specs. 100% Quality Guaranteed.
Request a Proposal βA ball nose end mill cuts with a spherical tip. At shallow axial depths of cut (ap), the actual cutting diameter is smaller than the nominal tool diameter. Using the nominal diameter for speed calculations at shallow ap leads to incorrect SFM.
At a 0.1 mm depth of cut with a 10 mm ball mill, the effective cutting diameter is only ~2 mm. Using the full 10 mm diameter in SFM calculations gives 5Γ the correct surface speed β the tool rubs instead of cutting.
Surface finish depends on step-over and tool diameter. Theoretical cusp height = step-overΒ² / (8 Γ D). For Ra < 0.8 Β΅m with a 10 mm ball mill, step-over should be under 0.5 mm. Use smaller step-overs for finishing.
Ball nose end mills are inefficient for roughing because the centre of the tool has zero surface speed (it rubs, not cuts). For roughing, use a bull-nose or square-end tool; reserve ball mills for 3D contour finishing.
Enter the nominal tool diameter and the axial depth of cut. The calculator shows the effective cutting diameter and the corresponding surface speed. Use the effective diameter to set correct RPM for shallow finishing passes.
Continue with closely related tools from the machining calculator library.
Use the calculator freely. If the result points to a tooling or process problem, we can source the exact carbide tooling you need from vetted factories in China. Compare factory-direct pricing.
Before you commit to a spec, it helps to know what the market pays for it. These are real, publicly listed factory prices — not a quotation, and not a guess.
We source the tool families below direct from vetted Chinese factories, matched to the material and tolerance you just worked out. Every batch ships with its material certificate and dimensional record.
Explore more precision machining tools and calculators
CUTTING 3D SURFACES? Effective diameter is the number to quote against, and it is frequently got wrong. See how we confirm geometry before an order.
Tell us the part material, lot size, and target price. We’ll match a verified China factory and return a quotation within 48 hours.