Crusher maintenance and liners: wear parts by crusher type, the closed side setting, routine checks, and planning liner changes from measured wear
How to maintain jaw, gyratory, cone and impact crushers: the wear parts of each, why the closed side setting drifts as liners wear and how to hold it, the routine checks by interval, planning liner changes from tonnes and measured wear, what fails and the response, and working safely inside a crusher. With a cone crusher cross-section.
Key takeaways
- Crusher maintenance is mostly wear management. Liners, dies, blow bars and mantles wear by design, and the job is to measure the wear, hold the setting and change the parts on a plan rather than after failure.
- In a cone crusher the closed side setting opens as the liners wear, so product coarsens unless the setting is measured and reset. Logging it each shift shows the wear rate as well as holding the product size.
- Liner life is best tracked in tonnes, not weeks, and liner changes planned from measured wear. Scanning the worn profile shows where wear concentrates and whether the liner design suits the feed.
- Choke feeding a cone crusher, centred feed and tramp metal removal ahead of the crusher do more for liner life and reliability than any inspection.
- Lubrication is the other half. Oil temperature, pressure, flow and cleanliness are watched every shift and trended, because bearing and bushing failures are the long outages.
A secondary cone crusher's product is coarsening over a few weeks, and the screens downstream are overloading with oversize. The setting has not been measured since the last liner change because the hydraulic adjustment shows the setting it was set to, not the gap the worn liners actually leave. When it is finally measured the closed side setting has opened by several millimetres, and the scan at the next liner change shows the wear concentrated in a band halfway up the chamber, the sign of a crusher that was not running choke fed.
This guide covers crusher maintenance: the main crusher types and their wear parts, the closed side setting and why it drifts, the routine checks, planning liner changes from measured wear, what fails and how to prevent it, and working safely inside a crusher. It sits beside the guides to fixed plant maintenance in mining and conveyor belt tracking. The manufacturer's manual sets the limits, values and methods for each crusher.
The setting, and why it drifts
In a cone crusher the mantle gyrates inside the concave, and the gap between them at the bottom of the chamber opens and closes once each turn. The smallest gap is the closed side setting, which largely sets the product size. As the mantle and concave wear, both surfaces move back and the gap opens, so the crusher is adjusted to bring the setting back.
The adjustment system can only report where it has been set. The gap the worn liners actually leave has to be measured, traditionally by lowering a lead plug through the chamber while running and measuring how thick it comes out, under the manufacturer's procedure. Logging the measured setting and the adjustment made each shift gives the wear rate for free, and a rising rate is the earliest sign that something has changed in the feed.
The control screen shows the setting the crusher was set to. Only a measurement shows the gap the worn liners leave.
Crusher types and their wear parts
Each kind of crusher wears differently and has different weak points. Jaw and gyratory crushers do the primary work on large rock, cone crushers the secondary and tertiary reduction, and impactors suit softer rock and shaping. The wear parts are consumables, and the spares and critical spares holding for each crusher should be set from their life and lead time.
| Type | Where it is used | Wear parts | What to watch |
|---|---|---|---|
| Jaw crusher | Primary crushing of hard, abrasive rock | Fixed and moving jaw dies, cheek plates, toggle plate and seats | Die wear at the bottom of the chamber, toggle plate condition, bearing temperature, flywheel and belt condition |
| Gyratory crusher | High tonnage primary crushing | Mantle, concaves, spider cap and arm guards, spider bushing | Concave and mantle wear, main shaft position, spider bushing lubrication, eccentric and hydraulic support |
| Cone crusher | Secondary and tertiary crushing | Mantle and bowl liner or concave, feed plate, backing material where used | Closed side setting as liners wear, choke feeding, tramp release events, lube oil condition |
| Horizontal shaft impactor | Softer rock, recycling, some secondary duties | Blow bars, impact aprons or curtains, side liners | Blow bar wear and turning, rotor balance, apron gaps |
| Vertical shaft impactor | Shaping and sand making in tertiary duties | Rotor tips and wear plates, anvils or rock shelves | Rotor tip wear, rotor balance and vibration, feed distribution |
Routine checks
Most crusher problems give warning in the lubrication system, the setting or the sound, and the people best placed to notice are the operators. Their checks belong in the operator rounds, with readings recorded rather than ticked, so a slow rise in oil temperature or setting change shows up as a trend.
| Interval | Who | What |
|---|---|---|
| Each shift | Operators | Lube oil temperature and pressure, return oil flow, unusual noise or vibration, choke level in a cone crusher, spillage and blockages |
| Each day or week | Operators and maintainers | Closed side setting measured and logged, filter differential pressure, hydraulic system, drive belts and guards, liner bolts and wedges where fitted |
| By tonnes or weeks | Maintainers and reliability engineer | Liner wear measured or scanned, lube oil sample for analysis, tramp metal events reviewed, bearing and drive condition trended |
| Each liner change | Maintainers | Seating surfaces, backing and fit, feed plate, bushings and seals inspected while the chamber is open, with the worn liner profile recorded |
Planning liner changes
Liner changes are the largest planned job on most crushers and usually set the length of the crushing circuit's shutdown. Planning them from measured wear rather than the calendar avoids both changing liners with life left in them and running them through. Liner life is tracked in tonnes crushed for each set, with the feed source and setting recorded, so the next change can be forecast from the current wear rate.
Scanning the worn liner profile in 3D, during an inspection or at the change, shows exactly where the wear is. Comparing scans across changes shows whether the liner design suits the feed, and helps the supplier adjust the profile. It is the same laser scanning used to measure chute and liner wear elsewhere in the plant. The change itself is a shutdown job with heavy lifts, special tools, backing material curing times on some designs, and a sequence worth rehearsing in the job pack.
What fails, and the response
Liner wear is expected. The failures that cost most are the ones that damage parts behind the liners or take out a bearing: liners run through, tramp metal, and lubrication failure. Each has a clear warning and a clear prevention.
| Failure | How it shows | Response |
|---|---|---|
| Liners worn past their limit | Product coarsening, throughput falling, setting that cannot be held | Change planned from measured wear, not run to failure. Worn through liners damage the seats behind them |
| Uneven liner wear | Wear concentrated in one band or one side of the chamber | Choke feed a cone crusher, centre the feed, and match the liner profile to the feed size |
| Tramp metal | Tramp release or overload trips, chipped liners, broken toggle plates or shafts | Magnets and metal detectors ahead of the crusher, and their rejects reviewed |
| Lubrication failure | Rising oil temperature, falling pressure, contaminated oil, bearing or bushing damage | Oil condition trended against ISO 4406 cleanliness codes, filters and coolers maintained, interlocks tested |
| Loose liner fastening | Knocking, liners moving, cracked backing | Torque or wedge checks after the first hours of a new set, and at each inspection |
| Drive and structure | Belt slip, motor faults, cracks in frames and mounts | Vibration and current trended, non-destructive testing of high stress areas at shutdowns |
Working inside a crusher
Crusher maintenance carries high consequence hazards: material hung up in the chamber or the feed hopper that can fall, hydraulic pressure and accumulators, flywheels that can turn, heavy lifts and confined spaces. Work inside a crusher is done under the site's isolation and permit arrangements, with the chamber and feed confirmed clear and stored energy released and verified. The Safe Work Australia model Code of Practice for managing the risks of plant sets the general duties, and the manufacturer's procedures set the specific steps.
Where crusher maintenance goes wrong
- The setting read from the control screen instead of measured, so product coarsens unnoticed.
- Liner changes on the calendar, wasting life in some sets and running others through.
- A cone crusher run below choke level, wearing the liners in a band.
- Magnets and metal detectors ahead of the crusher left unserviced.
- Lube oil readings ticked rather than recorded, so trends are invisible.
- Worn liners thrown away without measuring or scanning the profile.
- Liner bolts or wedges not rechecked after the first hours of a new set.
Common questions
What does crusher maintenance involve?
Daily checks of the lubrication system, setting, feed and noise. Measuring liner or die wear and resetting the crusher to hold product size. Planned liner changes based on measured wear and tonnes. Oil analysis and condition monitoring of bearings and drives. Removing tramp metal before it reaches the crusher. And inspections of the frame, drive and seating surfaces when the chamber is open. The balance between them depends on the crusher type and duty.
What is the closed side setting on a cone crusher?
The closed side setting, or CSS, is the smallest gap between the mantle and the concave during each gyration, at the bottom of the crushing chamber. It largely sets the product size. As the liners wear, the gap opens, so the setting is measured and adjusted, often each shift, to hold the product. The open side setting is the largest gap, on the opposite side of the gyration.
How often should crusher liners be changed?
When measured wear reaches the limit set for that liner, rather than on a fixed calendar. Liner life varies with the rock's abrasiveness, the feed size and the setting, so it is tracked in tonnes crushed and confirmed by measurement or scanning as the change approaches. Running liners past their limit risks wearing through to the seats behind them, which turns a liner change into a major repair.
Why are my cone crusher liners wearing unevenly?
The common causes are a crusher that is not choke fed, so the chamber runs partly empty and wears in one band, feed landing off centre so one side does more work, feed that is too fine or too coarse for the liner profile, and segregated feed with fines on one side. Scanning or measuring the worn profile shows the pattern, which points to the cause.
What are crusher wear parts?
The parts that contact the rock and wear by design. In a jaw crusher, the fixed and moving jaw dies and the cheek plates. In gyratory and cone crushers, the mantle and the concaves or bowl liner. In impact crushers, the blow bars, impact aprons, rotor tips and wear plates. The toggle plate in a jaw crusher is also replaced regularly, because it is designed to fail first if uncrushable material enters.
Key terms
Plain-language definitions from our glossary for the concepts this article leans on.
Standards and further reading
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