- Maintenance · CMMS
- Operations Manager, CFO / Finance, Plant / Operations Director, IT Director / CTO
- Manufacturing, Logistics and warehousing, Public sector
Spare parts inventory management: stock enough, and know where each part went
In short
Spare parts inventory management is deciding which parts to keep, how many, where, and recording which machine each part was used on. The aim is to avoid two costs: downtime while waiting for a missing part and money tied up in parts that never move. Rank parts by machine criticality and lead time, set minimums, count regularly and link every issue to a work order. Remanently CMMS records which machine and action a part was used for, while the warehouse module keeps stock, location and batch.
Two ways to get it wrong
Maintenance teams fail on spare parts in two opposite ways. In the first, the part is not there. A machine waits for three days for a bearing that costs a few dollars. In the second, the shelves are full of parts that nobody has used in years, bought "just in case" or left over from a machine that was sold.
Both come from the same cause: nobody knows what was used, for which machine and how often. Without that knowledge, stock decisions are guesses. The rest of this page replaces guesses with a routine.
Decide which parts belong in stock
Not every part deserves a place on the shelf. Sort them by two questions: how badly does the machine's stop hurt, and how long does it take to get the part?
| Short lead time | Long lead time | |
|---|---|---|
| Critical machine | Keep a small stock of fast-moving parts | Keep stock, even if it moves rarely |
| Non-critical machine | Buy when needed | Decide case by case; accept the wait or hold one unit |
The top right corner is the expensive one: a rarely used part with a long lead time on a machine you cannot do without. That is where stock is justified even if the part sits for years.
Set minimums with real data
- List parts per machine. Start with the critical machines. Use manuals and the technician's own list of what usually fails.
- Check consumption. How many were used in the last year, and on which machines? Closed work orders with parts are the source.
- Note the lead time. Days from order to delivery, including approval.
- Set a minimum. Enough to cover usage during the lead time, plus a small margin for critical items.
- Define a reorder trigger. When stock falls to the minimum, someone is notified and orders.
An illustration with made-up numbers: a belt is replaced about 3 times per year on a machine, and the lead time is two weeks. Usage during lead time is far below one, so a minimum of one on the shelf covers it. For a part used 30 times per year with a lead time of two weeks, the minimum should be around two or three.
Link each issue to the work
A part that leaves the shelf without a note is lost information. For every issue, record which machine and which work order it served. Three things follow from this record: the next stock decision rests on real usage, the cost of the repair includes the part and the machine's history shows what was replaced and when.
That last point helps with repeat failures. If the same bearing was replaced three times in a year on one machine, the part is not the problem; something around it is. The work order template includes a place for parts used for this reason.
Keep the physical stock honest
- Locations. Every part has a shelf or bin, labeled. A technician should find it without asking.
- Counts. A short cycle count of critical parts each month is better than a full count once a year.
- Returns. A part taken but not used goes back and is recorded.
- Dead stock review. Once a year, list parts with no movement and decide: keep, sell, or write off. Write-off follows your accounting rules; ask the accountant.
- Obsolete machines. When a machine is retired, check its parts. They may fit another machine or not.
Who decides what
The maintenance manager proposes which parts to hold and the minimums. The warehouse keeps the stock and the locations. Finance sets the limit on money tied up and asks for the dead stock review. The plant director approves stock for critical machines, because it is a business decision about risk. IT checks that the parts list and the asset list use the same machine names.
A monthly routine that keeps it working
- Review the parts that dropped below the minimum and confirm orders were placed.
- Check closed work orders for parts used that were not recorded, and fix the habit with the technician.
- Count five to ten critical parts on the shelf against the records.
- Look at one machine with repeat failures and ask whether the right part is stocked.
- Note parts that were bought urgently, and decide whether they should now be stocked.
Half an hour with the maintenance manager and the person who runs the stock room is enough. The value is not in the meeting itself but in the habit of looking at real usage.
How Remanently splits the job
Two questions are separate. The warehouse answers what do we have, where is it and what was issued. The maintenance side answers which machine and which action a part was used for. In the Remanently set, the warehouse module (WMS) holds availability, location, batch and movement of parts, while Remanently CMMS gives the part its context: the machine, the action and the history of cost and work. A repair order can be linked with the availability of the part, so the information does not stop at "issued from the warehouse". You do not have to implement the warehouse module and Asset Management together with CMMS right away; you can start with CMMS and connect the next process when you need it.
For the module, see Remanently CMMS. The sibling guides are maintenance management software, reactive maintenance and the CMMS software hub.
Frequently asked questions
What is spare parts inventory management?
It is deciding which maintenance parts to keep, in what quantity and where, and recording which machine and work each part was used for.
Which parts should I stock?
Parts for critical machines, especially those with long lead times. Cheap, quick-to-buy parts for non-critical machines can be bought when needed.
How do I set a minimum level?
Take usage per period from closed work orders, multiply by the lead time and add a small margin for critical items.
Why link parts to work orders?
It tells you the real cost of a repair, shows which parts a machine consumes and reveals repeat replacements that point to a deeper cause.
How does Remanently CMMS handle spare parts?
A part taken from the warehouse can be linked to a specific machine and action. Stock, location and batch stay in the warehouse module, and CMMS holds the usage context.
Link parts to repairs on your own machines
Book a short demo and we will show how a part issued for a repair lands in the machine's history, using your own equipment.