KEVOS® MAKEOS · Manufacturing
Rotary Axis Feed Plan (Inverse-Time Feed and Axis Rate Limits)
For this combined linear and rotary move, what inverse-time feed gives my cutter feed, do the rotary and linear axes stay within their rate limits, and what feed is actually achievable?
Feed plan for a 4th-axis or rotary-table move: arc length at the cutting radius, path length at the cutter, block time and inverse-time F value for the wanted feed (as the inverse time feed tool), the rotary rate in degrees per minute and the linear axis rate, checked against the machine’s axis rate limits, with the largest achievable cutter feed and its inverse-time value if a limit governs.
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How this tool works
Inputs, units and where to find them
| Input | Unit | Typical source |
|---|---|---|
| Move | choice | Kind of move. |
| Linear length of the move | mm | Linear travel of the move. |
| Rotary angle of the move | ° | Rotation of the move. |
| Cutting radius on the rotary axis | mm | Radius on the part where the cutter works. |
| Wanted feed at the cutter | mm/min | Feed you want at the cutter. |
| Machine limits | ||
| Largest rotary axis rate | °/min | Highest rate the rotary axis can move at in feed moves. |
| Largest linear axis feed | mm/min | Highest feed the linear axis allows. |
Method and formulas
- Arc = π r × angle ÷ 180; path = linear, arc or √(linear² + arc²); block time = path ÷ feed; F = 1 ÷ time (as the inverse time feed tool).
- Rotary rate = angle ÷ time; linear rate = distance ÷ time.
- Achievable feed = wanted feed × the smallest of 1, rotary limit ÷ rotary rate and linear limit ÷ linear rate.
- Example: program F3.7361 (inverse time); the rotary axis turns at 336.25 °/min, within its 2000 °/min limit.
Limitations
- Constant feed through the block; acceleration at block ends is not included.
- Cutting radius taken as constant over the move.
- Example values are illustrations. Replace them with values for your actual task.
Typical uses
- Program a wrapped or helical rotary move
- Check a rotary feed against the axis limit
- Find why a rotary move runs slower than programmed
Who it is for
- CNC programmers
- Machinists
- Manufacturing engineers
What you get
- Path length, block time and inverse-time F
- Rotary and linear axis rates
- Achievable feed
Interpreting the result
- Near the centre of rotation the rotary rate limit rarely matters; far out it often sets the feed.
References
- Machinery’s Handbook, 29th edition (Industrial Press, 2012), printed pp. 1288–1289. Topic reference; no source tables or recommended settings are reproduced.
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Open the Rotary Axis Feed Plan (Inverse-Time Feed and Axis Rate Limits) calculator
