Manufacturing and MRP Start With the Data, Not the Software
An MRP run is only as good as the bills of material and routings behind it. Most manufacturing implementations that fail, fail on BOM accuracy. The software was fine. The structures were wrong, the scrap factors were guessed, and the planner stopped trusting the suggestions in week three. Cleaning the BOMs is the real project. Everything on this page assumes you do that first.
50+ ERP and software projects. Zero failed projects since 2021.
The data decides whether any of this works
A planning engine is a few hundred lines of arithmetic. It is not the hard part. The hard part is that it runs against every BOM line and every routing operation you own, and it has no way of knowing which ones are wrong. Get the structures right and the module pays for itself. Get them wrong and you have bought an expensive way to generate shortages.
Cleaning the BOMs is the project, not a task inside it
Multi-level structures with real sub-assemblies, phantom assemblies for groupings that are never stocked, scrap and yield factors held at component level rather than smeared across the whole BOM, alternate components for when the first choice is unavailable, and engineering change control so a revision is dated, approved and traceable instead of edited in place by whoever opened the record last. That last point matters more than it sounds. If a BOM can be quietly changed, you can never explain why a work order from March consumed something different from one in June.
- Scrap and yield at component level, because 2% on a gasket is not 2% on a casting.
- Phantom assemblies for groupings that exist on paper and never in stock.
- Change control with effective dates, so old work orders still make sense.
MRP is not a scheduling tool, and saying so early saves the project
A routing holds operations in sequence, each on a work centre, each with a setup time and a run time per unit. Work centres carry an hourly capacity and a cost rate. The standard planning run then ignores all of it and schedules against infinite capacity, offsetting only by lead time. That is why a plan can look perfectly clean on screen and still be undeliverable on the floor. MRP tells you what is needed and when. It does not know that the CNC cell is already booked solid for eleven days. If you need finite scheduling, that is a separate capability, and pretending the standard run does it is how a plan loses credibility with the people running the machines.
- Setup time and run time held separately, or batch sizing is meaningless.
- Lead time offsets are what make or break the schedule, so keep them honest.
- Finite scheduling sits above the MRP run, not inside it.
Six areas, and the first two carry the other four
Planning, execution, costing and subcontracting all read from the same bills of material and routings. That is why we set those up first and refuse to shortcut them, even when a client would rather see a demo of the planning run.
Plan to produce, from demand to finished goods
Five steps. Each one writes a record the next one reads, which is the whole reason the module exists.
What we set up when you hand us this module
BOM structure and clean-up
Every BOM loaded, levelled, checked against a physical build, with units of measure, scrap factors and alternates corrected before the planning run is switched on.
Routings and work centre master
Operations sequenced, setup and run times captured from observation rather than memory, and each work centre given a capacity and an hourly cost rate.
Planning run configuration
Lead times, lot sizing rules, planning horizon, run frequency, and the regenerative versus net change pattern that suits your order book.
Engineering change control
Revision numbering, effective dates, an approval route and a where-used view, so a change can be traced and old work orders still reconcile.
Costing model and variance reports
Standard cost rolled up from BOM and routing, overhead absorption basis agreed with finance, and variance reporting your controller can actually explain.
Operator training and floor documents
Role-based training for planners, storekeepers and operators, plus the job cards, issue slips and confirmation screens the floor will use every shift.
What a properly set up MRP actually buys you
What this connects to
Manufacturing sits between the stock ledger underneath it, the inspection points inside its own routing, and the scheduling layer above the planning run.
Why manufacturers hand us this module
Manufacturing and MRP questions
What does an MRP run actually do?
How accurate do our bills of material need to be before MRP works?
Does MRP schedule against our real capacity?
Can the module handle make to order and engineer to order?
How does subcontracting work in the module?
How is production cost variance calculated?
Get an Honest Read on Your BOMs
Book a free consultation. We will look at a sample of your bills of material and routings, tell you how far they are from the accuracy MRP needs, and give you a straight view on whether the planning run or the shop floor data capture is the bigger job in your plant.
Book a Free Consultation →No commitment. A practical first look at your manufacturing data, whichever ERP you end up running it on.
What Is Inside the Manufacturing and MRP Module
The structures that hold your product, the run that turns demand into orders, and the records that tell finance what a job actually cost. Written for planners, production managers and controllers rather than for a feature checklist.
From the bill of material to the closed work order
Bills of material that survive being questioned
Multi-level BOMs with real sub-assemblies, phantom assemblies for groupings you never stock, scrap and yield factors at component level, and alternate components so a planner can substitute without rewriting the structure. Engineering change runs through revisions with effective dates and an approval route, plus a where-used view that shows every parent an item appears in before anyone signs the change off. A costed roll-up shows what a design decision is worth before it reaches the floor.
- Component level scrap, not one blanket percentage per BOM.
- Revisions dated and approved, never edited in place.
- Where-used lookup before a change is released.
A planning run whose suggestions a planner will act on
Demand from sales orders and forecast, netted against stock on hand and confirmed incoming supply, exploded through every BOM level and offset backwards by lead time. A regenerative run weekly with a net change run daily is the pattern that suits most order books, because the full rebuild keeps the plan honest while the daily pass catches yesterday's orders without an hour of processing. Lot sizing rules, planning horizon and safety settings are configured per item class rather than globally, and every suggestion is reviewed before release.
- Regenerative weekly, net change daily, tuned to your order pattern.
- Lead time offsets kept honest, since they decide the whole schedule.
- Suggestions reviewed and released by a planner, not auto-firmed.
What the job consumed, and what it cost you
Material issued against the order or backflushed on completion, which is safe only where stock accuracy is already high and scrap is recorded honestly. Operations confirmed at the work centre in a few seconds, because operators will not use anything slower. Scrap and rework captured with a reason code. Work in progress valued while the order is open, then cleared when finished goods are received at a calculated cost, with the variance against standard split into material price and usage, labour rate and efficiency, and overhead absorption.
- Backflushing offered as a judgement call, with its risks named.
- Scrap and rework recorded against a reason, not written off silently.
- WIP value visible while the order is still open.
Everything the module puts in your hands
Costed multi-level BOM
Every level exploded, with material, labour and overhead rolled up so you can price a change before committing to it.
Routing and work centre master
Operations in sequence with setup and run time split, each work centre carrying an hourly capacity and a cost rate.
MRP suggestion list
Proposed purchase and production orders with required dates, a pegging view back to the demand, and exception messages for dates that no longer hold.
Work order pack
Job card, material issue slip, operation confirmation screen and rework route, designed for a few seconds of operator time per step.
WIP and variance reporting
Work in progress by order and by work centre, with closed order variance split into material, labour and overhead for your controller.
Subcontract tracking
Material held at the supplier in its own location, ageing visible, and the processed item received back with the service cost added in.