Straight talk on keeping plants running.

PREDICTIVE MAINTENANCE

Hearing a Bearing Fail Before It Does

Aurelia Maintenance Team · Field Notes

Every rotating asset makes a vibration signature — a specific pattern of frequencies tied to its bearings, shaft, and gearing. When a bearing starts to degrade, that signature changes long before the fault is visible, audible, or measurable any other way. Vibration analysis is the discipline of reading that change early enough to act on it.

A healthy bearing produces a fairly clean, low-amplitude vibration pattern. As a fault develops on the outer race, inner race, a rolling element, or the cage, it introduces a repeating impact at a frequency tied to that specific component and the bearing's geometry. A trained analyst — or, increasingly, an AI-driven monitoring system — can pick that signature out of the noise well before the fault is severe enough to affect the asset's running sound or temperature.

The same technique picks up shaft misalignment (both angular and parallel), rotor imbalance, and mechanical looseness or gear wear, which together with bearing faults account for the large majority of failure modes on rotating industrial equipment. Combined with thermal imaging, vibration monitoring is estimated to cover more than 80% of all rotating-equipment failure modes.

Why the early warning matters

Reliability engineers describe failure progression in stages. By the time a fault is audible or visible — what's sometimes called Stage IV — a reactive maintenance team is already too late to prevent an unplanned stop. Vibration monitoring typically catches the same fault at Stage III, while it's still a scheduled repair rather than an emergency one.

Sources: Oxmaint, "Vibration Analysis Guide: Predict Equipment Failures Early"

CONVEYOR MAINTENANCE

Six Ways a Conveyor Belt Fails — and How to Catch Them Early

Aurelia Maintenance Team · Field Notes

A conveyor system fails in a small number of predictable ways. Almost every belt stoppage we see on site traces back to one of the same six root causes — which means almost every one of them is catchable with a routine inspection, before it becomes a line stop.

• Belt mistracking. The belt drifts off centre, usually from misaligned idlers, uneven loading, or a frame that's shifted out of square. Left unchecked, it wears the belt edge and can pull the belt off the structure entirely.
• Belt slippage. The belt slips on the drive pulley from improper tension, a worn pulley lagging, or contamination on the pulley face — cutting throughput even while the motor keeps running.
• Tears and rips. Sharp or trapped material, or a seized roller acting like a blade under the belt, can open a tear that spreads with every pass.
• Splice separation. A poorly executed splice, or one pushed past its rated tension, is one of the more common causes of a sudden, total belt failure.
• Material carryback. Product that doesn't fully discharge sticks to the belt and builds up on return idlers and structure — adding load, mess, and eventually more mistracking.
• Seized rollers. A failed roller bearing or debris packed into the roller stops it turning; the belt then drags across a stationary roller instead of rolling over it, generating heat and accelerated wear.

Every one of these has an early tell — edge wear, a rising motor amp draw, a roller that's gone quiet or hot, material tracking to one side. Routine visual and thermal inspection catches nearly all of them while they're still a five-minute adjustment rather than a replaced belt.

Sources: Oxmaint, "Conveyor Belt Failures & Troubleshooting Guide for Manufacturing Plants"

LUBRICATION & RELIABILITY

The Silent Killer: Why Bearing Failures Start With Lubrication

Aurelia Maintenance Team · Field Notes

Ask most plant teams what kills a bearing and the answer is usually "it just wore out." The bearing manufacturers' own failure data tells a different story: the single largest cause of premature bearing failure isn't fatigue or age — it's lubrication.

SKF's widely cited breakdown of premature bearing failures attributes roughly 36% to lubrication-related causes, ahead of fatigue (34%), mounting and handling errors (16%), and contamination (14%). It's worth being precise about what that figure covers: these are shares of premature failures specifically — the roughly 10% of bearings that don't outlive the equipment they're fitted to — not all bearings in service. Using a broader definition of "lubrication-related" that folds in contamination and degradation of the oil film alongside selection and application errors, tribology literature puts the figure as high as 60–80%.

Contamination is a lubrication problem too

Water and particulate contamination in a lubricant do their damage quietly. A long-standing study on water-in-oil contamination found that water at just 100 to 400 parts per million measurably cut tapered roller bearing fatigue life — and that free or emulsified water can cut bearing life by roughly half. Particulate contamination works the same way: hard particles get pressed into the raceway under load, denting the surface and starting a fatigue crack that would never have formed in clean oil.

None of this requires exotic equipment to manage. Correct grease or oil selection for the load and speed, sealed or properly maintained relubrication points, and keeping contamination out of the lubricant in the first place close most of that 36% gap — which is exactly why lubrication management sits inside almost every reliability-centred maintenance program, rather than being treated as routine housekeeping.

Sources: Reliamag, "Bearing Failure Cause Statistics: What the Numbers Show" · SKF Bearing Grease brochure

WORKFORCE & TRAINING

Behind Every Millwright: A Trade Built on Three Disciplines

Aurelia Maintenance Team · Field Notes

Ask what an electrician does and most people can answer. Ask what a millwright does, and the honest answer is: a bit of everything a piece of rotating equipment needs. It's a trade built specifically to close the gap between mechanical, electrical, and instrumentation work — and in South Africa right now, it's also one of the hardest roles to hire for.

A millwright's apprenticeship covers installing, aligning, and repairing industrial machinery end to end: the mechanical drivetrain, the electrical panel that controls it, and increasingly the instrumentation that monitors it. That range is deliberate. A fault on a piece of rotating equipment rarely respects the boundary between disciplines — a vibration problem can be a bearing, a misaligned coupling, or a variable-speed drive fault, and a millwright is trained to work through all three instead of calling in a second contractor once the first diagnosis turns out to be wrong.

A shortage that's accelerating

South Africa's critical skills data shows the gap widening quickly rather than holding steady. In 2025, 22% of companies reported they could not recruit the artisans they needed — more than double the 10% who said the same in 2024. Millwrights, along with electricians, automation specialists, and instrumentation artisans, are named specifically among the trades in shortest supply. The engineering roles that sit alongside them — maintenance engineers, industrial engineers, mechanical and electrical engineering technicians — show the same trend: 38% of companies struggled to fill those roles in 2025, up from just 14% in 2018.

It's also the exact background Aurelia Maintenance was built around: Managing Director Louis Rossouw trained as a millwright before leading Ekhethelo Maintenance, and that multi-discipline grounding is a large part of why Aurelia can take on a plant's mechanical, electrical, and instrumentation problems as one job rather than three separate call-outs.

Sources: Polity.org.za, "Critical Skills Crunch Deepens in South Africa" (2025) · FundiConnect, "How to Become a Millwright in South Africa"