A CNC control keeps its own running totals of time, and they answer different questions. Read side by side, they show how much of a machine’s day actually goes into making chips.
The three clocks
Power-on time
- Counts while…
- the control is switched on
- Answers
- How long was the machine available?
Operating time
- Counts while…
- a program is running in automatic mode
- Answers
- How long was it running jobs?
Cutting time
- Counts while…
- the axes are feeding into material
- Answers
- How long was it actually removing metal?
| Counter | Counts while… | Answers |
|---|---|---|
| Power-on time | the control is switched on | How long was the machine available? |
| Operating time | a program is running in automatic mode | How long was it running jobs? |
| Cutting time | the axes are feeding into material | How long was it actually removing metal? |
Each one sits inside the one above it, so the order never changes: power-on ≥ operating ≥ cutting. Names differ between control makers — you may see “run time”, “automatic operation time” or “feed time” — but the three ideas are the same.
Reading the gaps
One machine over one 8-hour shift (illustrative numbers):
Power-on time
- Minutes this shift
- 480
Operating time
- Minutes this shift
- 330
Cutting time
- Minutes this shift
- 210
| Counter | Minutes this shift |
|---|---|
| Power-on time | 480 |
| Operating time | 330 |
| Cutting time | 210 |
- Power-on minus operating = 150 min the machine was on but not running a program: handling, setup, waiting for material or an operator, breakdowns.
- Operating minus cutting = 120 min running a program but not cutting: rapids, tool changes, probing, dwells. This is the gap program optimization attacks.
The first gap is a floor problem; the second is a programming problem. One total “machine hours” number hides which one you have.
Using the counters in practice
The counters are lifetime totals, so they only become useful as differences — this shift minus last shift. Writing them down by hand rarely survives a month.
On controls that expose these timers over the network, ThingConnect reads the operating and cutting counters directly and records them per machine, so the gaps above are worked out per shift without anyone visiting the timer screen. Cutting time also feeds tool life tracking, since a tool wears while cutting, not while the machine is merely switched on.