Lubrication savings in money: a cement plant calculation before and after SDT

In How much money does precise lubrication save we covered what open sources show. Here we take the next step: a model enterprise, and a calculation in money of what changes before and after moving to condition-based lubrication with SDT ultrasound. The calculation is a model, but its benchmarks come from real SDT case studies.

Setup: the plant and assumptions

The plant is a model cement plant: crushers, mills, fans, conveyors, gearboxes. Cement was chosen because it has a lot of rotating equipment, dust and expensive stoppages.

Parameter	Value
Grease points (bearings)	600
Bearing failures in rotating equipment per year	24
Share of failures linked to lubrication	about 40%, so about 10 failures (sources give 36-80%; SKF's 36% refers to premature failures)
Greasing before	40 g per point, 13 times a year (every 4 weeks)
Grease price	10 dollars per kg

These inputs are invented for the calculation. Replace them with your own.

What real SDT case studies show

Benchmarks for the model come from SDT Ultrasound Solutions case studies:

• Paper mill. A dryer roll received 40 g every 4 weeks. After moving to ultrasound-guided lubrication the first shot was 20 g (50% less), the next 25 g. A bearing that had failed before the program cost 16,000 Canadian dollars (about 10,865 euros), plus 8 hours of labor and lost production during replacement. Full breakdown: paper mill case study with LUBEChecker.
• Cement plant, cooling fan. The schedule was 50 g every two weeks per bearing. After moving to condition-based lubrication the latest shots were 16 g and 14.4 g, 68-71% less. Two bearings with developing defects were replaced at a planned stop, avoiding an unplanned outage.
• Fans, norm-based greasing. The calculated amount was 13 g per bearing every 4,000 hours; measurement showed 5.2-6.5 g was needed, 50-60% less.
• Water treatment plant. One lubrication technician served about 700 bearings, 35-40 bearings per shift. In Q4 2020 against Q4 2019 bearing failures dropped noticeably and there were no lubrication-related failures. The case gives no money estimate.

What can be concluded: grease use falls 50-70%, and one serious failure costs on the order of 11,000 euros or more. Money itself is almost absent from the cases: a cost appears in only one.

The plant before

• Calendar greasing: 40 g per point every 4 weeks, 600 points, 13 visits a year.
• Annual use: 600 x 13 x 40 g = 312 kg, about 3,120 dollars.
• Some bearings get too much grease, some too little. In a study cited by SDT, about 70% of bearings were over-greased, 15% under-greased and only 15% greased correctly.
• Failures: about 10 of 24 are lubrication-related. They become known when the machine has already stopped.

The plant after

• Greasing by measurement: before and after each shot the operator sees the ultrasound level and decides whether grease is needed. The principle is in How often to grease bearings.
• Bulk points are covered by operators with LUBEChecker, critical assets by a specialist with the SDT340 in LUBExpert mode, hard-to-reach points by LUBExpert ON-GUARD.
• Bearings with a defect that grease does not cure show up in the data and are replaced at a planned stop.

The calculation in money: three scenarios

We run three cases to show the spread. The conservative scenario is deliberately milder than the real case studies.

Line	Conservative	Base	Optimistic
Grease use reduction	30%	50%	70%
Grease saving per year	936 dollars	1,560 dollars	2,184 dollars
Failures prevented per year	3	5	7
Cost of one failure	5,000 dollars	15,000 dollars	25,000 dollars
Failure saving per year	15,000 dollars	75,000 dollars	175,000 dollars
Total per year	15,936 dollars	76,560 dollars	177,184 dollars

The cost of a failure is the bearing and labor, downtime hours and collateral damage. In the paper mill case one such failure cost about 11,000 euros before counting lost production, so the base value of 15,000 dollars for a cement plant is not inflated.

Almost all the saving comes from failures: in the base scenario grease is 2% of the total. This is not a flaw of the method but a pattern: grease is cheap, stoppages are expensive.

Payback

SDT kit prices depend on configuration and delivery terms, so below is an illustrative program budget (equipment, training, implementation). It is not a price list or an offer.

Program budget	Conservative	Base	Optimistic
30,000 dollars	22.6 months	4.7 months	2.0 months
60,000 dollars	45.2 months	9.4 months	4.1 months

In the conservative scenario with the larger budget the program pays back in 3-4 years, which is a weak argument. So where stoppages are cheap and failures rare, condition-based lubrication is mainly about order and safety, not fast payback.

What the calculation leaves out

• Labor. Measuring before and after each shot takes time, so labor is treated as neutral. A gain is possible if visits to healthy machines are dropped, but a pilot must confirm it.
• Energy. Bearings over-filled with grease run hot and draw more power. The effect is usually small and counted separately.
• Safety and environment. Failures at height, grease leaks, disposal.
• Bearing life and spares. Fewer failures also mean fewer spare parts.
• Indirect production losses. If a stop disrupts shipments, a failure costs more.

How to carry the calculation to your plant

1. Take the bearing failure report for 2-3 years and mark which failures were lubrication-related.
2. For each failure work out the cost: bearing, labor, downtime hours x cost per hour, damage.
3. Measure annual grease use and number of visits.
4. Run a pilot on 20-30 bearings of different types and compare grease use and signal trends over 3-6 months.
5. Put the results into the table.

KEG TRK supplies SDT ultrasound equipment in Kazakhstan and can help calculate a pilot for your bearing fleet. Price on request.

Sources

• SDT Ultrasound Solutions. Success Stories: Precision Lubrication with LUBExpert (paper mill).
• SDT Ultrasound Solutions. Success Stories: Bearing Grease Management using Ultrasound.
• SDT Ultrasound Solutions. Success Stories: Time-Based greasing. Sure?
• SDT Ultrasound Solutions. Success Stories: Diagnosing Bearing Failure with LUBExpert Static and Vibration (cement plant).
• SDT Ultrasound Solutions. Success Stories: We succeeded, what is next? (water treatment plant).
• Reliability Solutions. The Real Cost of Poor Bearing Lubrication: https://reliabilitysolutions.net/articles/poor-bearing-lubrication-costs-downtime-energy-replacement/
• Calculation model: the authors' assumptions, not data from a specific plant.