how to calculate cnc turning cycle time

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Calculating CNC turning cycle time is key to estimating job duration, cost, and machine utilization. Here’s a simple breakdown of how to calculate CNC turning cycle time:

???? Basic CNC Turning Cycle Time Formula

Cycle Time (min) = Cutting Time + Non-Cutting Time

Let’s break that down.

???? 1. Cutting Time (CT)

For straight turning operations:

CT = (L + A) / (f × N)

Where:

L = Length of the cut (in mm or inches)
A = Approach/retract length (usually 2–5 mm extra)
f = Feed rate (mm/rev or in/rev)
N = Spindle speed (RPM)

Example:

Turning a 100 mm long part
Feed rate = 0.2 mm/rev
RPM = 600
Approach = 3 mm

CT = (100 + 3) / (0.2 × 600) = 0.858 minutes (about 51.5 seconds)

⚙️ 2. Non-Cutting Time

This includes:

Tool changes
Part loading/unloading
Spindle acceleration/deceleration
Rapid positioning

Estimate based on your machine setup or use the machine’s control software for precision.

Rough average: 0.5–2 minutes per part

???? Full Cycle Time Example

Let’s say:

Cutting time = 0.86 min
Non-cutting time = 1.2 min

Total Cycle Time = 0.86 + 1.2 = 2.06 minutes per part

Multiply by the number of parts to get total production time.

????️ Pro Tip

For multi-tool operations (facing, OD turning, grooving, threading), calculate cutting time for each step separately and add them all up.

You can also use CAM software (like Mastercam or Fusion 360) to simulate the entire program and get an accurate cycle time estimate.

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HOW TO CALCULATE CNC TURNING CYCLE TIME

how to calculate cnc turning cycle time