FREE CNC TOOL · Cutting parameters
Cutting Speed / RPM / Feed Calculator
Enter cutting speed and cutter diameter to get the spindle RPM; then enter flute count and feed per tooth to get the feed rate. All calculations run in your browser—nothing is uploaded.
The calculated result is a theoretical starting point. For real machining, follow your tool supplier's catalog values and have shop-floor staff refine them with a test cut, accounting for machine rigidity, tool overhang, workholding and coolant conditions.
Formula notes
Vc is the surface (peripheral) speed at the cutting edge (m/min); it drives tool life and cutting temperature. fz is the thickness each edge bites into the material (mm/tooth); it drives chip load and surface quality. Pick Vc by material to get the spindle speed, then pick fz by tool and rigidity to get the feed—that is the standard workflow for milling parameters.
Cutting speed reference for common materials (carbide tooling, milling)
| Workpiece material | Vc reference range (m/min) | Notes |
|---|---|---|
| Aluminum alloy (6061 / 7075) | 200 – 500 | Good chip evacuation allows higher; watch for built-up edge |
| Carbon steel (S45C, etc.) | 80 – 200 | Adjust for hardness; use the upper end with coated tools |
| Tool/mold steel (quenched & tempered) | 60 – 150 | The harder the material, the lower the value |
| Stainless steel (304 / 316) | 60 – 150 | Work-hardening sensitive; don't run the feed too low |
| Titanium alloy (Ti-6Al-4V) | 30 – 80 | Poor heat conduction; use heavy coolant, low RPM and high feed |
| Copper / brass | 150 – 400 | Sticky—keep a sharp cutting edge |
| Engineering plastics (POM / acrylic) | 200 – 500 | Low melting point; watch chip evacuation and heat |
Ranges are compiled from the intervals commonly used in tool supplier catalogs and are only a starting-point reference; brand, coating and flute geometry vary widely, so follow the catalog for the tooling you actually use.
FAQ
What if the calculated RPM exceeds the machine's limit?
Run at the machine's top spindle speed and the effective Vc drops—small-diameter tools are already at a disadvantage on low-RPM machines. You can choose a lower Vc, pick a larger-diameter tool, or accept lower efficiency; the key is to recompute the feed from the actual RPM while keeping fz unchanged.
What feed per tooth fz should I use?
General end mills for roughing are commonly 0.03–0.15 mm/tooth (depending on cutter diameter and material); use the lower end for finishing. Larger diameter and better rigidity allow a larger value; too small actually generates friction heat and accelerates wear (especially on stainless steel).
Can AI pick these parameters for me automatically?
Yes—this is exactly how BestAI CAM works: once your in-house tool library (diameter, flute count, recommended parameters) is on file, AI automatically applies your shop-verified parameters when generating G-code instead of using generic values; the machinist still signs off before running. See Making cutting parameters intelligent.
Further reading: The three cutting variables and AI parameter generation · End mill selection guide · Choosing cutting fluid | More tools: Tap drill chart · Metal weight calculator
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