CNC Lathe Cycle Estimator

Estimate roughing, finish-pass, spring-pass, rapid motion, and spindle response for OD/ID turning.

Inputs

Keep the core cut inputs visible, then open the machine-model sections only when you want to tune the estimate more closely.

OD turning reduces the outside diameter from stock to target.
Saved Machine Presets Keep your actual machine-motion model locally in the browser.
Save the rapid and spindle-motion model for your actual machine. Built-in presets stay read-only.
Machine Motion Model Rapid travel, acceleration, and spindle ramp assumptions.

Use separate rapid assumptions for roughing versus finishing, and include spindle ramp time so short-cycle estimates stay realistic.

Overall axis rapid for non-cut positioning.
Effective axis accel for retract and return motion.
Total retract + return + re-approach distance for roughing passes.
Used for finish and spring passes, which are usually shorter and tighter.
RPM per second between passes. Set to 0 if you want to ignore spindle ramping.
Raises modeled rapid time to reflect smoother servo motion.
Rough Spindle Control
Rough CSS and finish CSS both honor this clamp. Clamped rows are called out in blue.
Optional Finish Pass

Leaves finish stock after roughing, lets you choose finish CSS or fixed RPM independently, and can add one spring pass with zero additional DOC.

Uses the finish spindle mode, finish feed, and finish rapid travel with zero additional stock removal.
Estimator Assumptions
Rapid Rate is machine rapid traverse (non-cut move speed), usually from X/Z axis spec lines.
Rough / Finish Rapid Travel are separate reposition assumptions for roughing versus finishing and spring passes.
Rapid Acceleration is effective axis acceleration during rapid; use machine data if available, otherwise tune from observed cycle time.
Spindle Accel / Decel models RPM changes between passes so short parts do not look artificially fast.
Bell-Curve Factor models servo accel/decel smoothing: 1.00 = ideal trapezoid, 1.10 to 1.25 is typical.
G50 Max Spindle RPM clamps CSS RPM: Effective RPM = min(Commanded RPM, G50 Max RPM). Clamped passes are called out in blue.

In-cut formula: RPM = (12 x SFM) / (pi x pass midpoint diameter), Time(min) = Length / (IPR x RPM), diameter step per pass = 2 x DOC(radial).

Results

Cycle Summary
Pass counts and total cycle
Passes
0
Rough Passes
0
Finish Passes
0
Spring Passes
0
Total Time (min)
0.000
Total Time (sec)
0.0
Removal & Motion
Cutting, rapid, and spindle model
Cut Time (min)
0.000
Finish / Spring Cut (min)
0.000
Rough Rapid (min)
0.000
Finish Rapid (min)
0.000
Spindle Time (min)
0.000
Avg Pass (sec)
0.0
Spindle & Clamp
Observed from the modeled passes
Average RPM
0
Min RPM
0
Max RPM
0
Clamp Passes
0
Clamp Time (min)
0.000
Peak Cmd RPM
0
Diameter Profile
Approximate pass-by-pass reduction
Rough pass Finish pass Spring pass G50 clamp active
This estimator calculates cutting, rapid reposition, and modeled spindle ramp time. Tool change, indexing, probing, coolant dwell, and load/unload are not included.
Detailed Pass Table Per-pass RPM, clamp state, cut time, rapid motion, and spindle ramp.
Pass Type Start Dia (in) End Dia (in) DOC Radial (in) Feed (IPR) RPM Cmd RPM Used Clamp Cut (sec) Rapid (sec) Spindle (sec) Total (sec)