In this guide 6 sections
Most machine shops should start with ERP, because quotes, orders, purchasing and costing need one record before shop floor tracking can feed it. Add MES when late jobs or unknown machine status cost you more than the planning gaps do. Small shops often cover both with one tool.
What each system holds
ERP is the office record. It holds customers, quotes, purchase orders, bills of material, stock, invoices and the ledger link, and it answers what you promised, what you bought and what you owe.
MES is the floor record. It holds the operation queue, setter and operator logins, cycle times, scrap counts, inspection results and machine status. The supervisor sees what is running now and what happened overnight.
The two overlap at the work order. Vendors argue there.
- ERP: quote, order, purchase, stock, invoice, cost
- MES: dispatch, booking, downtime, scrap, first-off sign-off
- Shared: work order, routing, operation, due date
Why planning data usually comes first
A tracking system with no clean routings has nothing to track against. If operations, machine rates and material codes live in five spreadsheets, MES will faithfully record the chaos on every shift. Fix the master data first.
Costing is the next reason. The owner wants to know whether a job paid. That needs material, outside processing such as heat treatment or plating, and spindle hours gathered under one job number, which only a commercial record can hold.
Customers push the order too. Drawing revisions, material certificates, certificates of conformance and delivery dates all live in the commercial record, and they must be right before anything reaches the floor.
When floor tracking cannot wait
Some shops feel the floor pain first. Jobs vanish between turning and milling, setters wait for a fixture nobody can find, and the planner asks three different people where batch forty-one has gone. It is a bad morning.
If that is your week, a light execution layer helps early. Barcoded job travellers, operation scans and a status board need little master data, and they give the planner a live queue within days of switching on.
Keep the scope small. Bookings, stops and quantity are enough to begin. Full machine integration can come later.
A sensible order for a growing shop
Under about a dozen machines, one tool with quoting, work orders, simple shop booking and costing is usually enough. That holds whether the floor runs VMCs, turning centres or Swiss-type lathes. Do not buy two systems to solve a problem that one can handle.
As machines, shifts and customers grow, split the roles. The planning system keeps orders and cost, while the execution layer reads from it and writes actuals back, so ask each vendor how the handoff works field by field.
Agree who is master for routings and who owns part revisions. Two masters drift apart. Put dates on each stage, and leave a gap between them. A shop that adds booking terminals during a peak month will blame the software for what is really timing.
- Stage one: quotes, orders, purchasing, work orders
- Stage two: booking at the machine, downtime reasons, scrap
- Stage three: machine signals, tool life, finite scheduling
- Review the plan after each stage
Questions that settle the choice
Ask where the work order lives and how a change of due date travels from the sales desk to the setter at the machine. Ask how many taps a booking takes. Ask how rework and partial deliveries are handled.
Then list the three reports your owner reads every week and check that each one can be produced without exporting to a sheet. Where a report needs both systems, ask who builds it and who maintains it.
Finally, write your own rule for what must be true before the second system arrives. Make it measurable. Date it.
ERP and MES scope comparison grid
Functions run down the left side of a single sheet: quoting, purchasing, routings, work orders, booking, downtime, inspection, scrap, costing and invoicing. Three columns follow: needed now, needed in a year, and which system owns it. Beneath the grid, a strip lists the handoff fields agreed between planning and the shop floor, such as work order number, operation, due date and actual hours.
Open a blank worksheet to printQuestions owners ask
Is MES only for large factories?
No. Execution tracking helps any shop with several machines and shifts. A small shop may get it as a module inside its planning tool rather than as a separate product.
Can a spreadsheet stand in for either one?
For a time, yes. It breaks when two people edit the same file, or when revisions and traceability start to matter. That is the moment to move.
Who should own the routings?
One person, usually the process planner or production head. Everyone else requests changes through them. Shared ownership is how stale cycle times creep in.
What if the vendor sells both?
Ask whether they share one database and one work order. If they are two products stitched together, treat them as two purchases and test the handoff.