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Rotating assets: the parts you swap, repair and reuse

CMMS Maintenance

Two pellet mill ring dies and three roller shells, with a shaft, a gear shaft, a roller bearing and a pump impeller in front of them.

Most parts in a plant are used up or thrown away. A few are not. A pellet die in an animal feed mill wears down, comes off the press, is reworked in the workshop and goes back on, several times in its life. Maintenance software calls a part like this a rotating asset. To know how much life it has left, the record has to follow the die through every swap and every repair.

A die swap, recorded on the work orderA worn die comes off the press and a spare goes on. The work order cannot close until the swap is recorded. The worn die goes to the workshop with a repair-or-scrap job of its own, and comes back to the store when it is fixed. Every die keeps the tons it has run and the presses it ran in.Work order: change the diecannot close untilthe swap is recordedSpare die goes onfrom the storeWorn die comes offto the workshopRepair or scrapa job of its own,opened automaticallyBack in the storeready for the next swapEvery die keeps its historytons run, presses, repairs
A die change, from the press to the workshop and back to the store, with its history kept at every step.

A rotating asset is a spare that comes back

A plant keeps three kinds of part, and only one of them returns from the machine.

ConsumableSpare partRotating asset
What happens to itUsed up in operationFitted once, thrown away when wornSwapped out, repaired, fitted again
ExamplesLubricant, filters, welding rodsMost bearings, seals, fuses, beltsPellet dies, rolls, molds, spare pumps and motors
What the record tracksQuantity on the shelfQuantity on the shelfEach unit by name: where it runs, how much it has run, every repair

A bearing leaves the shelf, goes into a machine and drops out of the record. A die stays the same die through every swap and every repair, so its record has to stay with it.

Rotating assets are in almost every plant

  • Pellet mill dies and rollers, in animal feed, aquafeed, pet food, fertilizer, and wood and biomass pellet plants.
  • Roller mill rolls, reground between runs, in flour mills, sugar mills and cement plants.
  • Rolls in steel, aluminum and paper mills.
  • Punches and dies on tablet presses, in pharmaceutical and supplement plants.
  • Extrusion dies, stamping dies and molds, in food, plastics, automotive and tire plants.
  • Pumps, motors and gearboxes kept as spares and swapped in when one fails.

Each one is expensive, wears with use, is repaired several times, and runs in more than one machine.

Take the pellet die in a feed mill. The Feed Pelleting Reference Guide puts it plainly: “The cost of a die is a major operating expense associated with the pelleting process.” Dies “can easily weigh hundreds of kilograms”, so a change is a planned job with a crew. The same guide asks for the record: “Keep accurate and complete records on all die specifications and tonnage to help evaluate die performance.”

How maintenance software handles rotating assets today

Enterprise systems track them. IBM Maximo calls them rotating assets, and SAP calls the repair cycle refurbishment of repairable spares. Both are built for large enterprises, and SAP’s maintenance module comes as part of its ERP rather than on its own. We think a plant is better served by software built for the work it does.

Mid-market CMMS tools usually leave it to a workaround. MaintainX is one example. Asked how to track cutting blades that rotate between two extruders, its Community Team suggested making each blade a sub-asset of an extruder and recording its state with custom statuses. Moving a blade then means editing its Parent Asset field on the asset record, away from the work order.

That record stays right only if someone remembers to update it:

  • Nothing on the work order asks which part came off and which went on.
  • The job closes either way, whether or not anyone edited the asset.
  • A status set by hand is only as current as the last person who set it.
Where a swap gets recordedWith a sub-asset workaround, the work order closes on its own and the swap waits for someone to edit the asset record later, if they remember. In Koidra CMMS the swap is recorded on the work order, the job cannot close without it, and the worn part gets its own repair-or-scrap job.Koidra CMMSWork order: change the dieSwap recorded on the jobwhich came off, which went onJob closedRepair-or-scrap jobfor the worn dieSub-asset workaroundWork order: change the bladeJob closedSomeone edits the asset recordlater, if they remember
With the workaround, the swap waits for someone to remember it. In Koidra CMMS, the job cannot close without it.

How Koidra CMMS tracks a rotating asset

The steps below follow one die change on Koidra’s demo plant: ring die RD-07 comes off Pellet Press 2, and spare RD-12 goes on.

The part is an asset of its own. It has its own record and QR label, and knows the machine it is mounted in. A spare sits in the store or the workshop.

The record of ring die RD-07: its QR code for the asset label, and its parent asset, Pellet Press 2.

Ring die RD-07 knows the press it runs in.

The work order cannot be completed until the swap is recorded. The procedure for a die change, a roll change or a pump swap asks for it, so the record is never left for later.

The work order "Change ring die on Pellet Press 2" with no asset moves yet, and Complete greyed out beside "Record the asset swap".

Complete stays greyed out until the swap is on the job.

The technician records the swap on the job. It says which part came off, which went on, and where the old one goes. Only the parts mounted in that machine are offered to take off, and only spares to put on.

The Replace asset dialog: ring die RD-07 comes off, ring die RD-12 goes on, and the old one is stored at the Workshop.

RD-07 comes off to the workshop; spare RD-12 goes on.

Every move stays on the job and in the part’s history. Each one shows who made it and when.

The work order's asset moves: RD-07 from Pellet Press 2 to the Workshop, and RD-12 from no parent to Pellet Press 2, each with the time and the technician.

Both moves, timed and signed, on the work order.

The worn part gets a job of its own. “Repair or scrap” is filed at the workshop and linked to the job that took it off.

The completed die change, with one corrective action: "Inspect Ring Die RD-07: repair or scrap".

The die change is done, and RD-07 waits for the workshop’s verdict.

How much each part has run, from the machine’s own counter

With DataPilot reading the machine’s counter, every rotating asset shows how much it has run: the tons through a press, for example, as a lifetime total and one line per machine, from the day it went on to the day it came off. Nobody copies numbers from the control room into a notebook, and a counter that resets at a swap is handled.

Ring die RD-07's usage: 1510 t in its lifetime, 1080 t on Pellet Press 5 from 15 to 21 October and 430 t on Pellet Press 2 from 22 to 25 October.

RD-07 has run 1510 t across two presses.

Wear becomes a number you can manage. You can see when a part is due for repair, compare one supplier’s parts with another’s, and compare how fast each machine wears them.

Wherever a part is swapped, repaired and fitted again, the record has to follow it. To see how rotating assets fit with work orders, preventive maintenance and spare parts, explore Koidra CMMS.

See Koidra on your own plant data

Bring a week of readings from one line. We will show you what the platform sees, what it would have flagged, and what it would have scheduled.

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