Optimizing Bearing Lubrication with LUBExpert

Why calendar-based greasing fails

At a mining and processing plant, a factory or a power station, bearings in conveyors, crushers, pumps and fans are usually greased on a schedule: every N weeks, with a fixed dose. That ignores how much grease is actually left in the bearing.

As a result, some bearings get grease they do not need and are overfilled. Excess grease raises friction and temperature and damages seals. Others run short between scheduled points and wear faster. Both mistakes shorten bearing life. See the article on over-greasing for the consequences.

What ultrasound adds

Friction in a rolling bearing produces ultrasound. When grease runs short, the signal level rises. When grease reaches the raceways, friction and the signal drop. If greasing continues after that, the signal starts rising again: the bearing is overfilled.

This is the principle behind SDT's LUBExpert. The LUBESense1 sensor attaches to the grease nipple or grease gun and stays in place while the technician greases. The instrument works in the 36.1–40.7 kHz band and measures the signal in dBµV.

Greasing with LUBExpert

1. Route. The list of bearings due for greasing is loaded from Ultranalysis Suite 3. The instrument guides the technician through the asset tree.
2. Grease type and capacity. The assistant shows the grease type and the bearing's maximum grease capacity.
3. Half-shots. After each shot LUBExpert recalculates the friction level. While friction falls, it asks for more.
4. Stop. When friction reaches its minimum and stabilises, the instrument tells the technician to stop.
5. Result. Each job closes with a GOOD, BAD or SUSPECT rating. Grease quantity, temperature (built-in IR pyrometer) and the result go to UAS3.

If friction does not drop or rises after greasing, the problem is not the dose. The bearing is most likely developing a defect and should go for diagnostics, for example with the SDT340 or vibration analysis.

Building a condition-based programme

Step	What to do
1. Start with critical points	Bearings whose failure stops the line: conveyor drives, mills, main pumps
2. Create records in UAS3	Bearing type, grease grade, capacity, current interval
3. First round	Grease with LUBExpert, record the actual dose and result
4. Review intervals	From history: where grease is needed less often than scheduled, and where more often
5. Extend coverage	Add the remaining bearings as the team gets used to the method

UAS3 generates Work Orders for each shift and a Shopping List of how much of each grease to take on the route. Technicians flag skipped points with a reason, so it is clear what was missed and why.

Practical points

• Training. The method is simple, but results depend on technique: sensor on the nipple, even shots, pauses between them.
• One grease per bearing. Mixing incompatible greases undoes precise dosing. See the article on grease incompatibility.
• Permanent points. For hard-to-reach or hazardous locations SDT offers LUBExpert ON-GUARD with permanently mounted sensors.
• Condition data. With the Dynamic option the instrument records the signal, so the lubrication team collects bearing condition data on the same round.

Savings

The benefit comes from lower grease consumption, fewer bearing replacements and fewer unplanned stops. How large it is depends on the number of points and current practice. The article on the economics of condition-based greasing shows how to calculate it for your site. KEG TRK quotes LUBExpert and training on request.