A manufacturing execution system (MES) is software that tracks and directs work on the shop floor as it happens: which job is on which machine, what has been made, by whom, from which material, and whether it passed inspection. If an ERP is the record of the business, an MES is the record of the floor, minute by minute.
This guide explains what an MES does, how it differs from ERP, what it needs in order to work, where it fits well and where it struggles, the alternatives for smaller manufacturers, and the questions to ask before you buy one.
What an MES does
- Dispatching: sending jobs to machines and people in the right order, with the right drawing and work instructions at the station.
- Production tracking: recording when each operation starts and finishes, and how many good and rejected pieces it made.
- Material and traceability: recording which batch of material went into which job, so a part can be traced back to its heat or lot.
- Quality data: inspection results recorded at the station, with alerts when a dimension drifts.
- Machine performance: running, idle and breakdown time, often summed up as OEE (overall equipment effectiveness).
- Labour: who worked on what, and for how long.
- Documents: the current drawing revision and instructions at every station, so nobody works to an old copy.
MES vs ERP
The two are often confused because both touch production. The difference is in timescale and purpose:
- An ERP plans and records the business: orders, purchases, stock, invoices and accounts. It works in days and weeks.
- An MES runs the floor: which job is where, right now, and what happened at each operation. It works in minutes and hours.
- In the ISA-95 standard, widely used to describe how factory software fits together, ERP sits at level 4 (business planning) and MES at level 3 (manufacturing operations). The machines and their controls sit below, at levels 0 to 2.
- Many companies run both: the ERP releases the production order, and the MES tracks how it's carried out and reports the finished quantity back.
We've written more about this split in your ERP is great at history.
What an MES needs to work
- Data at every station: terminals, tablets, barcode scanners or connections to the machines, and a reliable network across the floor.
- Master data: routes, operations, standard times, bills of material and drawings for every product, kept up to date.
- Discipline: every start, stop, quantity and rejection recorded when it happens.
- An owner: someone who keeps the master data right and fixes problems quickly.
- Time: setting it up, training people, and running it alongside the old way until everyone trusts it.
None of this is a reason not to buy one. It's the real cost, alongside the licence, and it's what decides whether the system is still in use in month six.
Where an MES fits well, and where it struggles
An MES tends to fit well where:
- Products follow repeating routes, at volume.
- Customers or regulations demand detailed traceability, as in automotive, pharmaceuticals, medical devices or food.
- Machines can be connected, so much of the data is captured automatically.
- There are people to own the system and its data.
It tends to struggle where:
- Every job takes its own route, as in a job shop or a build-to-drawing fabricator.
- Much of the work happens outside, at job workers for plating, heat treatment or grinding.
- The changes that matter arrive by WhatsApp, email or phone, and never reach the system.
- Every extra minute of data entry falls on operators who are already busy.
Alternatives for a smaller manufacturer
- A sheet and barcodes: one row per job, one column per stage, and a barcode on every job card scanned at each stage. The bulk barcode generator prints the labels from your job list.
- Your ERP's production module: good for production orders, material issues and finished goods; less suited to a live view of the floor.
- A simple shop-floor app: job status updated from a phone, without the full depth of an MES.
- A custom system built around your flow: your stages, your job cards and your outside processes, with updates captured where they already happen. More on this in what's the best software for tracking work in progress.
Questions to ask before you buy an MES
- Which problem will it solve first, and how will we measure it?
- Can it handle our routes, including jobs that skip a stage, repeat one or go outside?
- Who records each event, on what device, and how many seconds does it take?
- What master data does it need from us, and who will keep it up to date?
- Can we start with one area of the floor before rolling it out everywhere?
- How does it exchange data with the software we already use?
- What happens when the network drops?
- Can we try it on our own jobs before we commit?
- Who supports us after go-live, and how quickly?
Quick answers
What is the full form of MES?
Manufacturing execution system: software that tracks and directs work on the shop floor as it happens.
Is MES the same as ERP?
No. An ERP plans and records the business over days and weeks; an MES runs the shop floor minute by minute. Many companies use both, connected.
What's the difference between MES and SCADA?
SCADA monitors and controls machines and processes directly: temperatures, pressures, motors and alarms. An MES works one level up, with jobs, orders, materials and people, and often takes some of its data from SCADA.
Does a small manufacturer need an MES?
Usually not as a first step. If your routes repeat and you need detailed traceability, it can pay off. If every job is different and the real updates live in WhatsApp and phone calls, start with something lighter that fits how your jobs move, and grow from there.
What does an MES measure?
Typically job status, quantities made and rejected, machine running and idle time (often as OEE), material used, labour time and quality results, all recorded when they happen. Our production lead time calculator shows the kind of question that data answers: how much of a job's life is spent waiting.
Where to start
Before you look at any MES, write down what you can't see today and need to: the oldest open job, the queue at the bottleneck, the jobs out at job workers, the drawing revision on the floor. Then ask where that information lives now. If the answer is WhatsApp, Excel and people's memory, the first step may be bringing it into one place around how your jobs already move, which is the work we do at Wisemove. If that sounds like your floor, book a call with us.