Feed rate is how fast the table moves, in inches per minute. It is built from the chip each tooth should take, how many teeth there are, and how fast the spindle turns.
What the variables mean
| Symbol | Meaning |
|---|---|
| IPM | Feed rate (inches per minute) |
| RPM | Spindle speed |
| Chip load | Feed per tooth (inches) |
| Flutes | Number of cutting edges |
Worked example
FAQ
Does the feed rate formula change between drilling, turning, and milling? The underlying math is similar, but inputs differ: milling uses chip load times flute count times RPM, while drilling and turning typically use feed per revolution times RPM, since those operations don’t have multiple engaged cutting edges the way a mill does.
What happens if programmed feed rate exceeds the machine’s rapid rate? Most controls simply cap the actual feed at the machine’s maximum programmable feed rate, silently running slower than commanded, which can produce a longer cycle time than expected without any error being raised.
Skip the arithmetic with the Feed Rate Calculator in Feeds & Speeds.