OPENLOCK · PRACTICAL GUIDE
How can manufacturers connect demand, bills of materials, and inventory?
Manufacturers can connect approved demand to the applicable bill of materials, expand finished-product quantities into component requirements, and subtract eligible inventory and incoming supply. The useful output includes the source records, revision, dates, units, and unresolved exceptions behind each quantity.
Documented demonstration using synthetic data. This is the calculation used by the website’s local sourcing example. It does not connect to a customer system, run the developing OpenLock platform, or demonstrate customer results.
1. Establish the records and their meaning
| Source | Fields or decisions | Validation |
|---|---|---|
| Demand | Order ID and line, product, open quantity, due date, status, and unit. | Include only the approved scope; exclude canceled or already fulfilled quantities. |
| Bill of materials | Parent product, component, quantity per parent, unit, revision, and applicability. | Select exactly one applicable approved definition for each scoped demand line. |
| Inventory | Component, location, snapshot time, on-hand quantity, and exclusions. | Subtract reservations and exclude unusable or quarantined stock without double counting. |
| Incoming supply | Purchase-order line, component, open quantity, expected date, and status. | Count only approved, unreceived supply eligible for the need date; do not count it again after receipt. |
| Crosswalk & ownership | Source identifiers, shared identifiers, conversions, and business approver. | Review mappings; do not merge different parts just because descriptions are similar. |
A demand line may create several component lines. Keep the original order-line identifier so this intentional expansion can be distinguished from a duplicate join. When aggregating component requirements across orders, subtract shared available supply once for the agreed scope.
2. Reproduce the website calculation
The fixed example uses 1,200 finished kits and one approved bill of materials: one housing, two seals, and four fasteners per kit. All stock and receipts below are assumed eligible. Quantities are individual parts.
| Component | Per kit | Gross need | Eligible stock | Eligible receipts | Net to source |
|---|---|---|---|---|---|
| Housing | 1 | 1,200 | 150 | 100 | 950 |
| Seal | 2 | 2,400 | 300 | 500 | 1,600 |
| Fastener | 4 | 4,800 | 600 | 1,000 | 3,200 |
Gross need = finished kits × component quantity per kit
Net to source = max(0, gross need − eligible stock − eligible receipts)
For seals, 1,200 × 2 = 2,400 parts. Subtract 300 in eligible stock and 500 eligible incoming parts: 2,400 − 300 − 500 = 1,600 additional seals. The zero floor prevents a surplus from being described as a negative quantity to source.
Change the kit quantity in the local calculator. The table here and the calculator’s default values are generated from the same synthetic inputs. The fixed calculation remains readable without JavaScript.
3. Check what a total cannot tell you
An annual total is not a time-phased purchasing plan. Suppose 200 kits are due before any of the 500 incoming seals arrive. With all 300 stock seals still eligible, early need is 200 × 2 = 400 seals, leaving an early shortage of 100 seals. The annual net requirement of 1,600 does not reveal when that shortage occurs.
This simplified calculation assumes no finished-goods stock, safety stock, scrap, yield loss, or multilevel assemblies. It does not schedule lead times, allocate stock across competing demand, apply supplier minimums or lot sizes, approve substitutions, or handle changing revisions. Those requirements need additional data and tested planning logic.
4. Make the result reviewable
- Reconcile the included demand to the approved source export, with every excluded or unresolved line explained.
- Verify units and bill-of-materials applicability. Missing or ambiguous definitions should block a complete-scope answer.
- Check inventory freshness, location, usability, reservations, and receipt eligibility for the needed dates.
- Recompute selected totals independently and preserve the input snapshot, transformation version, and source identifiers.
- Test an unauthorized user, a duplicate source line, a late receipt, and a stale inventory snapshot. Confirm that restrictions and exceptions remain visible.
The accepted output is a requirements table with assumptions and exceptions, not an automatically approved purchase order. OpenLock’s intended contribution is the governed information behind that result; purchasing decisions and actions remain with the customer’s authorized process.
Use the readiness guide to define acceptance and the Managed DataOps guide to decide how the inputs and mappings will stay useful.