Manufacturing2 min read
Manufacturing ERP Guide: BOMs, MRP, Shop Floor and Costing
A practical guide to manufacturing ERP: modelling BOMs and routings, making MRP trustworthy, shop-floor data capture, costing, quality and traceability.
Industry · Manufacturing
Manufacturing ERP that planners, buyers and accountants all trust
Most manufacturers we meet are not short of software. They have an accounting package, a spreadsheet that plans production, another that tracks stock, a whiteboard on the shop floor and a purchasing process that lives in one buyer's inbox. Each works in isolation. Together, they produce late orders, emergency buys and margins nobody can explain.
- M01Manufacturing (MRP)
- M02Inventory
- M03Purchasing
- M04Sales
- M05Accounting
- M06Quality
Context
ERP in manufacturing
A manufacturing ERP replaces that patchwork with one model of the business: what you sell, what it is made of, how it is made, what it costs, and what needs to happen next. The hard part is not installing it — it is modelling BOMs, routings and costing in a way that reflects the shop floor without burying planners in data maintenance.
01Operational challenges
What usually breaks before the ERP project starts
01
Planning in spreadsheets
Production plans built manually each week from sales orders and gut feel, with no visibility of component shortages until a job is already on the floor.
02
BOMs that do not match reality
Engineering changes made on drawings but not in the system, so material requirements and costs are calculated from outdated recipes.
03
Unknown true cost
Standard costs set years ago, labour and overhead absorbed by rule of thumb, and no comparison of actual to standard by job.
04
Emergency purchasing
Buyers react to shortages with expedited freight and premium prices because demand never reached them in time.
02Core flows
How the ERP should handle each part of the business
- Sales flow
- Quotes are priced from current BOM cost plus margin rules, with available-to-promise dates based on stock, open production and lead times. Confirmed orders create demand that flows straight into planning, and customer-specific configurations generate their own BOM variants rather than manual notes.
- Procurement
- MRP turns demand into purchase proposals using supplier lead times, minimum order quantities and reorder rules. Buyers work an exception list — late suppliers, price variances, shortages — instead of scanning every open order. Blanket orders and vendor price lists keep pricing consistent.
- Inventory
- Raw materials, sub-assemblies, WIP and finished goods are tracked by location, with lots or serials where traceability matters. Components are reserved against manufacturing orders, and consumption is recorded at the operation or on completion, depending on how accurately the floor can report.
- Warehouse
- Receipts can route through quality inspection before stock becomes available. Components are picked to production staging areas against manufacturing orders, and finished goods are put away or sent straight to shipping for make-to-order work.
- Manufacturing
- Multi-level BOMs, routings with work centres and capacities, and manufacturing orders broken into work orders. Operators clock on and off operations from a tablet, record scrap and complete quality checks. Planners see a schedule by work centre and can reschedule when a machine goes down.
- Accounting
- Perpetual inventory valuation posts material, labour and overhead to WIP and finished goods as production happens. Variances between standard and actual cost are captured per order, so finance can see which products or work centres consistently overrun.
- CRM
- Sales sees order status, production progress and promised dates without phoning the plant. Opportunities for engineered or custom products carry the specification that engineering needs to quote, reducing the back-and-forth before a price goes out.
03Industry workflows
Workflows specific to manufacturing
01
Engineering change control
BOM and routing revisions tracked with effective dates, so new orders use the new version while work in progress finishes on the old one.
02
Make-to-order and make-to-stock
Different replenishment routes per product: stocked items replenish by reorder rules, configured items create manufacturing orders directly from the sales order.
03
Subcontracted operations
Components sent to a subcontractor for plating, heat treatment or assembly, with the subcontract cost added to the product and the stock at the subcontractor tracked.
04
Rework and scrap
Non-conforming parts routed to rework orders or scrapped with a reason code, so quality costs appear in reporting rather than disappearing into overhead.
04 — Reporting
Reports that should come out of the system, not a spreadsheet
- Material shortage report by manufacturing order and required date
- Work centre load versus capacity by week
- Actual vs standard cost by product and order
- On-time delivery against promised date
- Scrap and rework by reason, product and work centre
- Inventory value by category, including slow-moving and obsolete stock
05 — Compliance
Compliance considerations
Requirements depend on what you make. ISO 9001 environments need controlled documents, traceable non-conformances and calibration records. Customers in automotive or aerospace may require lot genealogy and first-article inspection records. The ERP should hold quality checks, lot and serial history and change records so audits are answered from the system rather than from filing cabinets.
Regulatory requirements vary by jurisdiction. We configure the system to support your obligations; confirm specific rules with your auditor or compliance advisor.
06 — Integrations
Systems the ERP needs to talk to
Common integrations include CAD or PLM systems for BOM imports, machine monitoring for actual run times, carrier platforms for shipping, eCommerce or EDI for customer orders, and BI tools for management reporting. BOM import from engineering is the one we see most often requested — and most often done badly, with no revision control.
07AI opportunities
Where AI is genuinely useful here
Practical uses that sit on top of clean ERP data. None of them replace getting the core transactions right first.
01
Supplier document capture
Read supplier confirmations, invoices and certificates of conformance, and match them to purchase orders and receipts automatically.
02
Demand pattern alerts
Flag customers whose ordering pattern has shifted so planners review forecasts before shortages appear.
03
Quote assistance
Draft quotes for repeat or similar products by finding past jobs with comparable specifications and actual costs.
08ERP modules
Modules a typical deployment includes
- M01Manufacturing (MRP)
- M02Inventory
- M03Purchasing
- M04Sales
- M05Accounting
- M06Quality
- M07Maintenance
- M08PLM
09Roadmap
Implementation roadmap
- 01
Model products and processes
Clean item master, multi-level BOMs and routings for the top products by volume, with work centres and realistic times.
- 02
Core transactions live
Sales, purchasing, inventory and accounting go live with manufacturing orders, before detailed work-order tracking.
- 03
Shop-floor execution
Work orders, operator interfaces, scrap recording and quality checks introduced work centre by work centre.
- 04
Planning and costing maturity
MRP tuned with real lead times and safety stock; actual-versus-standard analysis reviewed monthly.
- 05
Continuous improvement
Maintenance scheduling, machine data integration and advanced reporting.
10Common mistakes
Mistakes we see repeatedly
01
Routings too detailed to maintain
Twenty operations per part with second-level timing looks precise but nobody keeps it current. Start with the operations that matter for capacity and cost.
02
Turning on MRP with bad data
MRP is only as good as lead times, stock accuracy and BOMs. Running it on dirty data produces nonsense proposals and destroys trust on day one.
03
Ignoring the shop floor
If reporting production takes operators longer than before, they will stop doing it, and WIP and costs become fiction.
04
Costing configured by IT alone
Costing method and overhead absorption are finance decisions. Get them wrong and every margin report is wrong.
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FAQ
Frequently asked questions
Do we need work orders or just manufacturing orders?
If you need to schedule capacity by machine or measure labour per operation, work orders help. Simple assembly with one or two steps often works fine with manufacturing orders alone, which keeps shop-floor reporting light.
Can the ERP handle both make-to-stock and make-to-order?
Yes. Replenishment routes are set per product, so stocked items and configured items can coexist in the same plant.
How accurate does inventory need to be before go-live?
Accurate enough that MRP proposals make sense. We usually recommend a full count of components shortly before cutover and cycle counting from day one.
Can we track lots and serial numbers?
Yes, on components and finished goods, with upstream and downstream traceability reports for recalls and customer queries.
Similar industries
Industries with related workflows
Metal FabricationJob-shop ERP for quoting, nesting-driven material planning, routings, heat numbers and job costing.Plastic ManufacturingERP for injection moulding and extrusion: resin and regrind, tooling, cavities, cycle times and scrap.FurnitureConfigurable products, panel and timber planning, finishes, delivery scheduling and showroom sales.
Next step
Running production on spreadsheets and experience?
We will map your shop floor onto an ERP model and show you where it fits — and where it needs care.