How much less does a machine have to stand before machine monitoring pays for itself? For the illustrative horizontal boring mill from our post on machine downtime tracking without a PLC, about 12 minutes a shift: an OEE improvement of just over 2 percentage points. With 13 minutes, monitoring pays back within three years.
The mill stands about 80 minutes a shift, as a boring mill measured in a published study did (Lahri and Pathak, 2015). An hour of the mill costs about 100 zł, and monitoring costs 550 zł a month at a published market price. Money is in złoty, as the plant is in Poland. The full calculation, with every input, is in the appendix at the end.
Two points of OEE pay for monitoring
| OEE improvement | Less standing still a shift | Payback |
|---|---|---|
| 1 point | 6.0 min | never |
| 2 points | 12.0 min | Month 41 |
| 2.17 points | 13 min | Month 22 |
| 3 points | 18.0 min | Month 9 |
One point of OEE is 1% of the planned production time: 36 hours a year on two shifts. That does not cover the subscription. From just over 2 points, monitoring pays back within three years, and from 3 points within the first year. Every payback here counts the subscription only; the staff's time and what the fixes cost come on top.
If the mill is the plant's bottleneck and its extra output can be sold, a recovered hour is worth its margin, not its cost: at 250 zł of margin an hour, less than one point pays back.
What the camera catches, and what each fix is worth
A dozen minutes a shift is little, but nobody logs them. Records kept by hand often leave out short stops (Muchiri and Pintelon, 2008), and even where OEE is measured automatically, almost half of the recorded losses could not be put down to a cause (Hedman et al., 2016). A camera aimed at the mill logs every stop with its time and duration, and its clip shows what happened at the mill meanwhile, such as the part being measured on its table. A cause outside the frame, such as a crane busy elsewhere or missing inserts, has to be found separately.
Examples of stops at a boring mill, and what fixing each is worth:
| Stop | What fixes it | Less standing still a shift |
|---|---|---|
| Waiting for the crane, with no part on the table | The crane booked for the mill's loads at set times | 10 min |
| Waiting for cutting inserts | Inserts and tools for the shift's jobs prepared before it starts | 5 min |
| Measuring the part again and again, with the spindle stopped | A measuring plan for each part, and the gauges kept at the mill | 8 min |
| A slow start of each shift | The handover done at the machine, with the next job ready | 10 min |
| All four | 33 min |
The minutes are examples; the log of stoppages gives the real ones. The wait for the crane and the slow start together, 20 minutes a shift, pass the break-even, and all four give back 33 minutes a shift. What each fix is worth in OEE points is in the appendix.
The camera does not raise OEE by itself. Hedman et al. (2016) note that, for those who decide on improvements, much of the improvement potential stays hidden when the causes of losses are not communicated. The camera shows which stop to fix first; the points come from fixing it.
Find your 13 minutes
The camera that finds them may already hang in the hall; if none sees the machine, we place one where it sees it best. Our machine monitoring reads running and idle time from camera images, with no connection to the controller and no sensors, and keeps a log of stoppages with time, duration and a clip:
- Send three stills from the camera that sees the machine to contact@blixild.com. This step is free.
- We reply whether running and idle time can be read from that view, and what the camera needs.
- Then a one-week pilot on one machine.
Stills with no people in them are enough for the first step. Using hall cameras for production control is workplace monitoring: in Poland, art. 22² of the Labour Code allows it where it is needed for production control, if that purpose is written into the collective agreement, the work rules or a notice, and the staff are told at least two weeks before it starts.
The place to start is one machine that is the bottleneck, like the boring mill here, because it sets how much the plant makes. Then put the plant's own figures into the OEE improvement ROI calculator: the payback month it gives is the number for the board. We can also help with the calculation, from the plant's own figures. This post's plant is illustrative, not measured: its machine is a boring mill as a published study measured one, its costs are the calculators' Polish worked examples adjusted for an old mill, and its monitoring is a published market price for a sensor subscription, not Blixild's price for the camera service.
Appendix: the calculation
The inputs
| Input | Value |
|---|---|
| Planned production time | 3,600 h a year: two shifts of 7.5 h, 5 days a week, 48 weeks |
| OEE now | 62%: availability 82%, performance 77%, quality 97.5% |
| Stops a shift | 80 min |
| Cost of one hour of the mill | 100.32 zł |
| Machine monitoring | 600 zł one-off and 550 zł a month |
| Time for the gain to build up | 6 months |
The current OEE is what Lahri and Pathak (2015) measured on a CNC table-type boring mill, observed for 40 hours; entered in the OEE calculator, it means 80 minutes of stops in a 450-minute planned shift. The hour comes from the machine hour rate calculator: operators and overheads are 90% of its cost; the old mill is entered at 200,000 zł with a salvage value of 100%, so no depreciation, on 70 m² of floor. The monitoring is one supplier's lowest price per machine, before VAT, for a cloud subscription with a sensor, as published in October 2026; the payback comes from the OEE improvement ROI calculator.
To check the hour, open the Polish machine hour rate calculator and change three of its example's inputs: purchase price 200,000 zł, salvage value 100%, floor area 70 m².
The break-even
One point of OEE is 36 hours a year, worth 3,611 zł at the cost of one hour. The subscription costs 6,600 zł a year and 600 zł at the start.
| OEE improvement | Less standing still a shift | Hours recovered a year | Value a year | After the subscription | Payback, counted over 5 years |
|---|---|---|---|---|---|
| 1 point, 62% to 63% | 6.0 min | 36 h | 3,611 zł | −2,989 zł | never |
| 2 points, 62% to 64% | 12.0 min | 72 h | 7,223 zł | +623 zł | Month 41 |
| 3 points, 62% to 65% | 18.0 min | 108 h | 10,834 zł | +4,234 zł | Month 9 |
| 5 points, 62% to 67% | 30.0 min | 180 h | 18,057 zł | +11,457 zł | Month 5 |
At exactly 2 points, monitoring pays back in month 41, in its fourth year; over the calculator's default three years the net gain is −237 zł, about even. From 2.03 points, 12.2 minutes a shift, it pays back within three years. To check it in the OEE improvement ROI calculator, enter 62% as the current OEE, 64% as the target, 100.32 zł as the value of a recovered hour, 600 zł and 550 zł as the costs, and 5 years as the horizon.
The price moves the break-even most. Published prices for monitoring one machine run from 349 zł to 908 zł a month (October 2026, before VAT, some without the hardware); with the same one-off cost and ramp, the break-even runs from 1.31 to 3.31 points, 7.9 to 19.9 minutes a shift. Staff time counts too: an hour a week on the log, at the operators' 90 zł an hour, adds 361 zł a month and lifts the break-even to 3.32 points, 19.9 minutes.
How the minutes are counted: one point is 4.5 minutes of fully productive time a shift. Cutting stops gives it at the measured performance and quality, 77% and 97.5%, so a point takes 6.0 minutes less standing still. That is the cautious count: short stops that nobody logs already lower the performance, and cutting those, at the ideal cycle, takes 4.6 minutes per point. A camera usually finds more stop time than a log kept by hand, so compare the minutes camera against camera, before and after a fix. At the cost of one hour, the recovered hours are capacity the plant already pays for, not cash.
The four fixes in OEE points
At the measured performance and quality, the four stops are worth 1.67, 0.83, 1.33 and 1.67 points of OEE, 5.50 together: 19,862 zł a year at the cost of one hour, with payback in month 5, before the cost of the fixes. In Lahri and Pathak's study, the mill stood 75 minutes in 40 hours for missing inserts alone, so 5 minutes a shift is a cautious figure. That leaves 47 minutes of other stops a shift, such as setups: availability rises from 82% to 89.6%, not to 100%.
On a bottleneck
On a bottleneck whose extra output can be sold, a recovered hour is worth its margin, not its cost: the contribution margin of what the mill makes in a fully productive hour, its selling price less its variable cost (OpenStax, 2019, 3.1). The margin is the plant's own figure; two examples:
| Value of a recovered hour | Smallest OEE improvement that pays back in 3 years | Payback at 2 points |
|---|---|---|
| 100.32 zł, the cost of one hour | 2.03 points | Month 41, after 3 years |
| 250 zł of margin | 0.82 points | Month 5 |
| 500 zł of margin | 0.41 points | Month 3 |
Sources
- Lahri, V., Pathak, P. (2015). A case study of implementation of overall equipment effectiveness on CNC table type boring & milling machine of a heavy machinery manufacturing industry. IOSR Journal of Mechanical and Civil Engineering, 12(5), 63-70. https://www.iosrjournals.org/iosr-jmce/papers/vol12-issue5/Version-5/K012556370.pdf
- Muchiri, P., Pintelon, L. (2008). Performance measurement using overall equipment effectiveness (OEE): literature review and practical application discussion. International Journal of Production Research, 46(13), 3517-3535. https://doi.org/10.1080/00207540601142645
- Hedman, R., Subramaniyan, M., Almström, P. (2016). Analysis of critical factors for automatic measurement of OEE. Procedia CIRP, 57, 128-133. https://doi.org/10.1016/j.procir.2016.11.023
- Franklin, M., Graybeal, P., Cooper, D. (2019). Principles of Accounting, Volume 2: Managerial Accounting. OpenStax, Rice University. Section 3.1, Explain Contribution Margin. https://openstax.org/books/principles-managerial-accounting/pages/3-1-explain-contribution-margin-and-calculate-contribution-margin-per-unit-contribution-margin-ratio-and-total-contribution-margin