🔩 Turning / Longitudinal
-- seconds / -- min
⚙️ Milling (Face / Slot)
-- seconds / -- min
🕳️ Drilling
-- seconds / -- min
⚡ Formulas: Turning = (L×passes)/(N×f) | Milling = (L+approach)/Vf × passes | Drilling = (depth/(N×f)) × holes
Turning, milling & drilling cycle time calculations
Machining time is the time the cutting tool is actually in contact with the workpiece. It does not include setup time, tool change time, or loading/unloading — those are handled separately in a process sheet.
The basic formula for turning is: T = L / (f × N), where L is the cutting length (mm), f is feed rate (mm/rev), and N is spindle speed (RPM). For a 200mm shaft at 0.2 mm/rev feed and 500 RPM, that's 200 / (0.2 × 500) = 2 minutes per pass.
For milling, the formula becomes: T = L / Vf, where Vf is the table feed rate in mm/min. Add approach and overtravel distances (typically 5–10mm each side) to get the total cutting path length.
| Operation | Formula | Key Variable |
|---|---|---|
| Turning | L / (f × N) | Feed per rev |
| Milling | L / Vf | Table feed rate |
| Drilling | (D/2 + depth) / (f × N) | Approach distance |
| Grinding | Passes × L / Vt | Number of passes |
Practical note: Always add 15–20% to your calculated machining time for actual production planning. Tool wear, coolant checks, and minor adjustments are real and affect throughput. Machining time calculators give you the theoretical minimum — your process sheet should reflect reality.