How buyers identify a spare part

It is 19:20 on a Friday. A seal has failed on a ten-year-old filling machine, production is standing, and the maintenance technician is holding a torch and a photocopied drawing from the 2014 manual. They do not know your article number. They will never know your article number. Everything about a spare parts shop follows from that.

The five ways a buyer arrives

There are exactly five things a buyer can bring you, and each one needs different data behind it. Build them in the order your service desk's call log tells you to, not in the order they appear here.

Machine type or series

The cheapest path to build and the least precise. The buyer picks their machine from a list, or types the type designation from the plate, and reaches the parts list for that series. It works when your machines are catalogue products built to a small number of specifications. It fails, confidently and expensively, when they are not — a series-level parts list shown to the owner of a special build produces orders for parts that do not fit their machine.

Where you cannot be exact, say so on the page. "Parts list for FS-200, series build. If your machine has a serial number beginning FS200-2011 or earlier, please check the drawing." A hedge the buyer can act on beats a wrong answer.

Serial number

The path that actually solves the problem, and the one that requires real data. The buyer types the serial from the type plate; you resolve it to their machine, in the configuration in which it left your factory, and show the parts list for that machine.

This depends on you having an as-built record per machine — not a parts list per model. Machine builders usually have this somewhere, in the ERP order archive or in a service database, and it is usually in worse shape than anyone expects. Getting it out is the longest lead time in the project. Start it on day one.

Two things make this path dramatically better for very little effort. Put a photo of where the type plate is next to the input field — a technician on a ladder with a torch should not have to guess. And accept the serial number in every format anyone has ever written it: FS200-2014-0871, FS200 2014 0871, FS2002014871. Rejecting a serial because of a hyphen is a lost order.

Drawing position

The buyer is looking at a drawing — yours, in the manual — and can name the position. This is the fastest path for anyone who has the paperwork, and it is the path exploded drawings turn into clicking rather than typing. It requires that your position numbers are stable, published, and the same in the drawing, the manual and the shop. See Exploded drawings and hotspots.

Old or superseded part number

The buyer has an invoice from 2014 and types 4711-A. You stopped making 4711-A in 2019; it was replaced by 4711-B, which was replaced last year by 4711-C.

A shop that returns "no results" for 4711-A has told the buyer, at 19:20 on a Friday, that they should phone somebody else. A shop that returns 4711-C with the line "4711-A was replaced by 4711-B and is now supplied as 4711-C" has done something no catalogue can do, and the buyer will remember it. This costs you a supersession chain and nothing else, and it is the highest-return item in the whole area.

Competitor part number

The buyer pulls out the failed part and reads the number stamped on it — and it is not yours, because the machine is not yours, or because a previous repair used a third-party part. A cross-reference table turns that number into your equivalent.

This is data you have to build or buy rather than derive, and it is the one identification path that wins business rather than serving it. Treat it as a commercial project, not a data-migration task, and be precise about what "equivalent" means: interchangeable, technically equivalent, or functionally similar are three different promises.

Discontinued must never be a dead end

Parts are superseded constantly, and supersession is a chain, not a pair. 4711-A → 4711-B → 4711-C. If you only model one hop, the buyer arriving with a 2014 invoice reaches a part you also no longer make, which is a slower way of failing.

Three rules that hold up in practice:

1. Always resolve to the end of the chain, and show the path you took. The buyer needs to see that you understood their number.
2. Never delete a superseded part record. Disable it for ordering, keep it findable. Deleting it destroys the only bridge between the customer's paperwork and your current catalogue — and it breaks the order history of everyone who ever bought it.
3. Say what changed when it matters. "Successor 4711-C has a 14 mm bore instead of 12 mm; requires adapter AD-14." A silent substitution that needs an adapter is a wrong-part return with extra steps.

Handle the reverse direction too. A buyer who bought 4711-C should be able to see that it replaces 4711-A and 4711-B, because that is how they confirm they have found the right thing.

Compatibility is data, not prose

"Passend für FS-200 Serie" in a description field cannot be filtered, cannot be checked, and cannot answer the question a buyer is actually asking, which is "will this fit my machine?".

Compatibility as data means an explicit relationship between a part and the machines it fits, qualified where necessary by a serial-number range or a build date. Once it exists, three things become possible that prose never allows: the part page can list the machines it fits, the machine page can list its parts, and the shop can warn a buyer whose registered machine is not in the list before they order. See Compatibility and fits-with.

How this works in the Revenue Cloud

Every identification path above resolves to catalogue data you already know how to model.

• Machines and series are reference entities — a machine_series entity with records for FS-200, FS-300, each carrying its own attributes: build years, type-plate photo, manual. Machines that need to be associated with parts are modelled as products instead, because associations connect products to products; the trade-off is set out in Compatibility and fits-with.
• Parts lists are quantified associations — see Bills of material and assemblies.
• Supersession chains are an association type such as replaced_by, kept strictly one-way so the direction of time survives, with replaces as its mirror.
• Cross-references are an association type too — or, where the competitor part has no record of its own, a searchable multi-value attribute on your part.
• Exploded drawings are assets in a drawing asset family, carrying a drawing number and a revision.
• Old part numbers, competitor numbers and type designations all need to be findable by the search index, which is a decision you make in Index configuration. An identification path that the search box cannot answer is a path that does not exist.

Next

• Bills of material and assemblies — the structure underneath every path here.
• The buyer's path: find a spare part — the same five paths, from the buyer's side.