How is cutting time calculated?

Cutting time equals the total cutting toolpath length divided by the feed rate. If a part has 40 inches of cuts at 20 inches per minute, the cutting time is 2 minutes. The tool sums all cutting moves you enter.

Why include rapid traverse time?

Rapids are non-cutting moves between features and to and from tool-change positions. On long programs the rapid time adds up, so dividing total rapid distance by the rapid rate keeps the estimate honest for scheduling and quoting.

How long is a tool change?

It varies by machine. A fast carousel changer may take 2 to 4 seconds, while older or umbrella changers can take 6 to 10 seconds. Enter your machine's measured time per change and multiply by the number of changes in the program.

Is this estimate accurate enough to quote from?

It is a solid rough estimate based on programmed motion. Real cycle time can run longer due to feed-rate overrides, acceleration and deceleration on short moves, and dwell or probing. Add a small contingency for quoting.

Does it account for acceleration and deceleration?

No. The model assumes moves run at the programmed feed and rapid rates. On parts with many short, sharp moves the machine never reaches full speed, so add 5 to 15 percent for accel and decel losses on complex programs.

CNC Machining Cycle Time Estimator

A quick, defensible cycle-time number is the backbone of any machining quote and of realistic machine scheduling. This estimator sums the time a CNC actually spends moving: cutting at feed, rapid traversing, changing tools, and dwelling. It does not need a postprocessor or simulation, only a few figures you can read off the program or the slicer.

How it works

Time is distance over speed for each motion type, plus fixed times for tool changes and dwells:

cut time     = cutting path length / feed rate
rapid time   = rapid distance / rapid rate
change time  = number of tool changes × seconds per change
dwell time   = total programmed dwell
total cycle  = cut + rapid + change + dwell

Feed and rapid rates are typically in inches (or mm) per minute, so lengths in inches (or mm) give minutes directly. Tool-change and dwell times are added in seconds and converted.

Example and notes

A part with 60 in of cuts at 25 IPM takes 2.4 min to cut. Add 30 in of rapids at 400 IPM (0.075 min), 5 tool changes at 4 s each (0.333 min), and 2 s of dwell (0.033 min), giving about 2.84 min, or 2 min 51 s, per part. Multiply by your machine’s hourly rate for a labour-and-machine cost, and by order quantity for total run time. Because the model assumes full programmed feed and rapid, add 5 to 15 percent on parts dominated by short moves where the machine cannot reach commanded speed.