Metso MP Series Cone Crushers — Liner Selection, Wear Parts and Common Faults

1. What the MP series is for

MP800, MP1000 and MP1250 are the high-power end of Metso's cone range: more installed power, a larger eccentric throw and a chamber designed to take a coarse secondary feed and still make a fine product in one pass. In a plant they usually replace two stages — which is exactly where most of the parts problems start, because the machine is asked to do a reduction ratio it was not bought for.

Compared with an HP machine, the MP runs a bigger throw at a similar setting. That means the liner sees a longer stroke, the eccentric and head bushings see higher unit load, and the oil system has less tolerance for contamination.

2. Wear parts that actually move

• Bowl liner and mantle. The biggest spend. 18% Mn for hard rock, 22% Mn where abrasion dominates. Chamber choice runs from coarse to extra fine; the MP will happily take a coarse feed and make a fine product, which is why the "correct" liner is often coarser than the operator expects.
• Head ball and socket liner. The MP carries the crushing load through a head ball rather than a flat head seat. When the head ball runs dry or gets grit, the whole rotating assembly starts to bind and the symptom appears as heat and current, not as a wear mark.
• Eccentric and head bushings. Bronze. These are the honest indicators: a bright band on one side means the machine has been running off-centre, usually from a badly levelled installation or a loose frame bolt.
• Clamping and adjustment cylinders. Hold the setting under load. Seal failure shows as a setting that drifts during a shift.
• Feed cone, distributor plate and arm liners. Cheap parts that protect expensive castings, and the first place segregation shows.

3. Chamber selection

Three variables decide the chamber: top size, product target and how well the feed is screened.

1. Top size drives the opening. An MP with a coarse chamber will take a large feed but produce a coarse product; if the product target is fine, the load moves to the next stage.

1. Reduction ratio per pass has a ceiling. Pushing an MP to do more reduction than its chamber was designed for gives a poor shape, a hot machine and a short liner life. The cost per tonne goes up even though the tonnage goes up.

1. Packing is the warning sign. When the chamber packs, the machine is being fed material it cannot evacuate fast enough — too fine a feed, too wet a feed, or a setting too tight for the throughput.

4. Common faults

Oil temperature climbing after a few hours

Check in this order: oil level and suction strainer; dust seal condition (grey or black oil means fines are getting in); cooler fouling; oil viscosity against ambient temperature. On an MP, high oil temperature is contamination far more often than a pump problem.

Head ball / socket running hot

Symptom: heat at the top of the machine, sometimes a smell, current creeping up under steady load. Causes: lubrication to the head ball starved, grit in the socket, or the head not seated correctly after a rebuild. This is the failure that quietly destroys a head.

Eccentric bushing wear on one side

Installation geometry. Check frame level, frame bolt torque and whether the machine sits on a foundation that has settled. A crusher that runs off-centre wears every bushing unevenly, and no bronze grade compensates.

CSS drift under load

Clamping cylinder seal leakage or accumulator charge loss. On control-equipped machines the fault code points at the symptom; the cause is usually a seal kit, not the control system.

Chamber packing

Feed too fine, feed too wet, or throughput pushed past the chamber's evacuation capacity. Fix the feed before touching the setting.

Tramp release nuisance trips

Accumulator pre-charge wrong, or the release valve set too light. A machine that trips on every bucket of hard rock is protecting itself from a feed problem, not from tramp iron.

5. Maintenance that pays

• Weekly: oil level and pressure, return oil temperature trend, dust seal inspection, head ball temperature by hand (carefully) after shutdown, clamping cylinder for external leaks.
• Monthly: oil sample — iron and silicon tell you more than colour; accumulator pre-charge; frame bolt torque; liner wear measured at fixed points.
• Every liner change: inspect head ball and socket, check the seating surfaces, and re-torque the head nut after the first eight hours of running.

Two numbers belong on a board next to the machine: the closed side setting and the ammeter reading at normal load. Every fault above announces itself as a deviation from one of those two before it announces itself as a breakdown.

6. Matching parts to the machine

MP parts are the ones most often bought from a photograph alone, and the ones where that fails most often. We work from the part number on the worn component, the machine serial, and the critical dimensions measured on the old part. Where a liner profile was revised during production, the serial is what resolves which revision the machine was built to.