Last week we talked about the cost of downtime. I don’t know about you, but I was shocked at just how expensive it can be. Then we’ll probably also agree that it makes the most sense to try to avoid it in any way you can. Today, we’re looking at some of the most common causes of downtime and what you can do to avoid them.

Tape retention

Belt failure can be caused by a number of reasons and can quickly stop production for a long period of time and become very costly. Let’s look at some of the most common reasons.

  • Skewed driving. When conveyor belts run crooked, there is a great risk of the rubber catching on the frame and starting to cut the steel profiles. Then it becomes both costly and dangerous. The wear and tear costs to repair and potential downtime awaits. There are many reasons why conveyor belts can go wrong; incorrect use of tensioning stations, misaligned return rollers, sticky rollers, etc. To avoid uneven driving, you should have a regular maintenance routine to prevent major problems. You should also consider using a belt tracker, a device that automatically centers the conveyor belt, or a guide roller that prevents the belt from slipping off the roller, or a guide roller that prevents the belt from slipping off the roller.
  • Metal parts. Rock bolts, blasting debris, tools and machine parts are things you definitely don’t want in your crusher. Metal debris can also do a lot of damage to your conveyor belt. To avoid this, it is fairly standard practice to use a metal detector. However, there is a downside to this solution, namely that the detector can be so sensitive that it stops the tape due to trivial objects such as tin foil or simply too much iron in the rock masses. If this becomes a problem that leads to many stops, it may make sense to install magnets on the conveyor belt as well. A magnet for the conveyor belt will in most cases be sufficient, but if you still experience problems, it may also make sense to look at a magnetic drum, which works like this.
It is very advantageous to use a magnetic drum after a top-mounted magnet.

By setting up a magnet before your metal detector, you can reduce downtime by up to 75%!

Magnet + metal detector = true

Warehouse breakdown

Roller bearing failure on a drive or reversing drum can also have many causes, and if you let it go too far, you’re looking at a very large repair.

  • Missizing. If you have a bearing that is too small for the task it is set for, the torque will be too great and the service life of the bearing will be drastically reduced.
  • Lubrication. It’s always a good idea to read the manual, even though it’s probably more tempting to throw it straight in the bin. Incorrect lubrication can have major consequences in the long term. For example, if you have too much lubrication on a high-speed bearing, the friction can be far too high, which will lead to excessive heat generation and breakdown in the long term. We know from science lessons at school that things that get hot expand. If too much oil heats up, there may be so little space for the balls in the bearing that the entire bearing raceway bursts. Boom, breakdown.

Everything that goes around goes around.

Says Professor Pukk. Translated for those of you outside Rogaland, this means that everything that goes around comes apart. It just doesn’t sound as good.


As mentioned, all moving parts are subject to wear and tear, and the gear is no exception. Here, too, there are many things that can go wrong, and we have chosen to look at a few examples below.

  • Missizing. As with the roller bearing, gears that are incorrectly dimensioned for the task are no good either. If you have an undersized gear, the high torque will lead to excessive load, which will reduce the service life of the gear.
  • Lubrication. Also in gear, proper lubrication is very important. Too little oil, too much oil, the wrong type of oil. All of these things can cause major problems in the long run. It is also important to check that there is no water in the oil. This can be caused by, for example, a leaking or missing gasket on the filler plug.
  • Air plugs. It is important that the vent plugs in the gearbox are open to avoid overpressure. Small parts often disappear, such as the cap on the vent plug in the gearbox. This can cause dust to enter the vent plug, clogging it and leading to overpressure. If the entire vent plug is missing or a tight plug has been fitted, oil may leak out into simmering rings. If the gearbox runs with overpressure and oil sweats out in the seals, there will eventually be too little oil on the gearbox, which of course leads to inadequate lubrication. Then there can be a high risk of breakdowns and downtime after a while.
We have developed a unique calculator that allows you to calculate the cost of downtime based on your specific crushed rock plant.

Screen cloth

Holes or densities in screen cloth can cause major problems and downtime.

  • Choose the right canvas. There are a number of different screen fabrics to choose from, both in different thicknesses and materials. Everything from modular fabrics to finger screens, Iseflex to side-tensioned/long-tensioned fabrics, rubber, PU (polyurethane) or the traditional steel fabric. Choosing the wrong one can quickly become expensive as it can lead to unnecessary maintenance.
  • Wear and tear. It is perfectly normal for moving parts to wear out. The viewing screen takes a beating when sharp stones “strut” across it day in, day out. What you want to avoid at all costs, however, is holes in the fabric. The sieve cloth’s task is to act as a large colander that only lets through the small parts you want, and then sends the larger parts on their way. If you get a hole in your screen cloth, larger fractions will pass through and the storage piles will become contaminated. This leads to downtime as you have to replace the cloth, as well as clean and re-crush the storage pile.

General tips and tricks

Good inspection routines and planned downtime for maintenance are very important to avoid unplanned downtime. You can anticipate many mistakes and avert major crises by having good routines in place. By replacing cheaper components more often, you can avoid breaking more expensive machines. It’s also a good idea to make sure that you have wearing parts in stock so that you don’t have to wait for delivery if you see that a part needs replacing soon.

We’ve said it before, but we’ll say it again. These are just a small selection of things that can go wrong. When there are a lot of moving parts, there are also a lot of things that can go wrong. However, there is still a lot that can be done to avoid this. Choosing the right equipment for the job, selecting innovative technology that can alert you to faults before they occur, and inspecting carefully and frequently can save you a lot of expense and headaches.


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