BOM Software for Indian Manufacturers: What to Look For

Why the BOM matters more than any other module

In a manufacturing business, almost every number comes out of the bill of materials. Purchase requirements are the BOM multiplied by the order. Stock issues are the BOM multiplied by the work order. Product cost is the BOM rolled up with current rates. If the BOM is wrong, or out of date, or kept in a spreadsheet the system cannot see, every downstream number is wrong with it — confidently and silently.

That is why the BOM is the first thing to test when you evaluate a manufacturing ERP in India, and why a weak BOM module cannot be compensated for by strength anywhere else.

A real example: a Y-type strainer

Take a cast Y-type strainer — a typical product for an Indian process-equipment shop. Even a simplified version is three levels deep:

Y-Strainer 50NB (finished good)
├── Body, machined              × 1
│   ├── Body casting (CF8)      × 1   scrap 3%
│   └── Machining               — operation, in-house
├── Cover, machined             × 1
│   └── Cover casting (CF8)     × 1   scrap 3%
├── Screen assembly             × 1
│   ├── SS304 perforated sheet  × 0.18 kg   scrap 8%
│   └── Rolling + welding       — operation, job worker
├── Gasket                      × 1
└── Studs + nuts M12            × 4 sets

Now add what happens in real life: the screen supplier changes the mesh size, engineering issues a revision, some orders already in progress must finish on the old screen and new orders must use the new one. The casting comes from a foundry that also machines some bodies for you as job work. That is the level of complexity BOM software has to handle on a normal Tuesday.

Eight things BOM software must do

1. Explode to any depth

Sub-assemblies inside sub-assemblies, expanded automatically with quantities multiplied down each level. If the software makes you raise a separate production entry for each level by hand, it is storing a BOM, not using one.

2. Control revisions with ECOs

Every change should carry an engineering change number, a reason and an approval, with effective-from and effective-to dates. A work order should pick the revision in force on its date — automatically. Without this, the answer to "which drawing was this batch built to?" is whoever remembers.

3. Carry scrap and yield per line

Castings get rejected; sheet gets trimmed. A scrap percentage on the component line should increase the material requirement, so the store issues what the job really consumes and the cost reflects it. One blanket wastage figure for the whole product hides where the loss is.

4. Attach a routing

A BOM says what a product is made of. A routing says how: the sequence of operations, each tied to a work centre, a machine or a subcontractor. Software that stores BOMs without routings can tell you material cost and nothing else.

5. Refuse circular references

An assembly that contains itself — usually by accident, three levels down — will break cost rollups and explosions. Good software rejects it when the BOM is saved, not when a work order fails.

6. Compute cost live, never freeze it

A BOM should describe what the product is, not what it cost on the day someone typed it in. Cost should roll up from current material rates and current operation rates, so an old revision never quotes last year's steel price.

7. Handle consumables sensibly

Welding rod, cutting oil and grinding discs are consumed but not counted per unit. They still belong in the cost, typically as a configurable percentage, rather than being forgotten or forced into fake per-piece quantities.

8. Model parallel operations

The body and the screen can be made at the same time; final assembly waits for both. A routing that can only be a straight line misrepresents lead time for anything with sub-assemblies.

What is specific to India

Three things matter more in Indian shops than in the markets most BOM software is designed for:

Job work is part of the routing. Plating, heat treatment, rolling and machining are routinely sent to job workers under Section 143. The BOM and routing should know which step is subcontracted, so the challan, the return deadline and the per-unit charge follow from it. (See our Section 143 guide.)
Labour is often paid per piece. An operation on the routing needs to be costable per piece, per hour, at a fixed rate or as a subcontract — not just per hour. Our piece-rate costing article shows what the wrong mode does to a quote.
The books usually stay in Tally. BOM software has to produce stock and cost figures your CA can carry into Tally cleanly. (More on that in Tally vs manufacturing ERP.)

Questions to ask in a demo

Bring one of your own real assemblies — not the vendor's sample data — and ask:

Load this three-level BOM and explode it for an order of 40. Show me the purchase requirement.
Issue a revision to one sub-assembly. Show me that open work orders stay on the old one.
Put a 5% scrap on this casting. Show me the material issue change.
Mark this operation as sent to a job worker. Show me the challan and the return date.
Change the rate of one raw material. Show me the product cost update without re-saving the BOM.
Try to add the top assembly as a component of itself. What happens?

A system that handles all six on your own data in a single demo has a real BOM engine. One that needs "a configuration session" for half of them does not — whatever the brochure says.

These are the six we ask people to test us on, too. The BOM module is described in full on the NextGenManager features page.

BOM software for Indian manufacturers: what to look for