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Manufacturing software is the group of systems a plant uses to plan, run, maintain and check its production. Five systems cover most of the work: ERP for orders, material and cost, APS for the sequence of orders on the machines, MES for what happens on the shop floor, CMMS for maintenance and QMS for quality processes. Each one answers a different question. The tables below show which system to look at first for a given problem, and which system should own which data.
What each system is for
The ISA-95 standard describes a plant in levels. Level 4 covers the activities of running a business and includes ERP systems. Level 3 covers manufacturing execution systems (MES) and other systems that manage manufacturing operations. ISA-95 deals mainly with the interface between these two levels. APS, CMMS and QMS serve planning, maintenance and quality, and they exchange data with both ERP and MES.
| System | Question it answers | Typical records | Time scale |
|---|---|---|---|
| ERP (enterprise resource planning) | What do we sell, buy and make, and what does it cost? | Customer orders, bills of materials, routings, purchasing, stock, costs | Days to months |
| APS (advanced planning and scheduling) | In which order, on which machine and when can the orders run, given capacity, material and setup? | Order sequence, finite capacity plan, setup sequence | Hours to weeks |
| MES (manufacturing execution system) | What is happening on each machine and order right now, and why did it stop? | Machine states, stop reasons, quantities, scrap, order progress, OEE | Seconds to one shift |
| CMMS (computerized maintenance management system) | Which asset needs which maintenance work, and what was done on it? | Maintenance work orders, inspection plans, asset history | Days to years |
| QMS (quality management system) | Do processes and products meet requirements, and what happens when they do not? | Documents, audits, complaints, nonconformities, corrective actions, training records | Weeks to years |
In German-speaking plants, software for inspection planning and measured quality data is often called CAQ. It overlaps with the QMS and connects to the MES at the inspection station.
Which system solves which problem
A software project should start with a problem, not with a category. The table maps common plant problems to the system that holds the missing information. The last column names the sign that a different system is the real gap.
| Problem in the plant | Look first at | Why | Sign that the gap is elsewhere |
|---|---|---|---|
| Orders ship late although the machines look busy | MES | The plan assumes capacity that stops, slow running and scrap take away. Only shop-floor data shows where the time goes. | Actual times match the plan, but the sequence is poor: then APS |
| The weekly plan breaks down every day because of setups and shared tools | APS | Finite capacity and setup sequence are what APS calculates. An ERP plan with infinite capacity cannot do it. | The plan uses standard times that are far from reality: then MES first, to get real cycle and setup times |
| Nobody can name the OEE or the three biggest stop reasons | MES | Stops, counts and reasons have to be recorded at the machine while they happen. | Data exists but sits in several spreadsheets: then the gap is reporting, not capture |
| The same breakdown returns, and the repair history is on paper | CMMS | Asset history, work orders and inspection plans are maintenance records. | Breakdowns are known only from what operators remember: then MES stop data first |
| Spare parts are missing when a machine fails | ERP or CMMS | Spare part stock and purchasing are material management. | The parts exist but nobody knew the machine was due: then maintenance planning in the CMMS |
| A customer complaint needs a documented cause and fix | QMS | Complaint, root cause, corrective action and the check of its effect are a quality workflow. | The cause cannot be found because order, shift and machine data are missing: then MES |
| Order costs are wrong, and material consumption is unknown | ERP | Cost calculation and stock live in the ERP. | The ERP numbers are right but the feedback from the shop floor is late or typed by hand: then MES |
| Scrap rises and nobody knows on which machine or shift | MES | Scrap by reason, machine and shift has to be booked where it occurs. | The reasons are known, but actions are not followed up: then QMS |
How the systems pass data
The five systems work as a chain. A production order follows this path:
- ERP creates the order with material, quantity and due date.
- APS places it in a sequence on a machine, based on capacity, setup and material.
- MES runs it on the shop floor and records start, stops, quantities and scrap.
- MES reports quantities, scrap and times back to the ERP, which books stock and costs.
- CMMS receives runtimes and breakdowns as triggers for maintenance work.
- QMS receives nonconformities and starts the formal follow-up.
Each step only works if one system is the master for each piece of data. If stop reasons are kept in two lists, one in the MES and one in the CMMS, the reports of production and maintenance will disagree, and both teams will defend their own number.
| Data object | Master system | Who reads it |
|---|---|---|
| Material master, bill of materials, routing | ERP | APS, MES |
| Order sequence and planned start times | APS (or ERP if there is no APS) | MES, ERP |
| Machine state, stop reasons, actual quantities and scrap | MES | ERP, APS, CMMS, QMS |
| Asset history and maintenance work orders | CMMS | MES (planned maintenance stops) |
| Spare part stock | ERP | CMMS |
| Nonconformities, complaints and corrective actions | QMS | MES, ERP |
Where the lines blur
The categories overlap. Several ERP vendors sell production, quality and maintenance modules. Several MES include inspection at the workstation or simple maintenance triggers. Some suites combine several categories in one product. This does not remove the questions in the first table. It moves them inside one vendor. The interface still has to be configured, and someone still has to decide which module is the master for each data object.
A practical test is the time scale. A module that books data once per order or once per shift cannot replace a system that records machine states in seconds. A system built for planning weeks ahead does not show why a machine stopped five minutes ago.
Mistakes when choosing manufacturing software
- APS before real times. An APS schedules with the cycle and setup times it is given. If these come from old ERP routings and differ from the shop floor, the schedule is wrong from the first hour, and planners go back to the spreadsheet.
- OEE from ERP bookings. ERP feedback arrives at the end of an operation or shift. Short stops are never booked, so the availability and performance in the ERP look better than they are. See MES vs. ERP.
- Two masters for the same data. Stop reasons, scrap reasons or asset names kept in two systems drift apart over time, because each team maintains its own list.
- Buying by feature list. A long feature list says little about which question the system answers well. Start with the problem table above, and test the system with your own data.
In which order to add the systems
The order follows the data flow, not a fixed rule:
- ERP first, because orders, material and invoices need it.
- MES next, because every later step needs real times, stops and scrap from the shop floor.
- APS once real cycle and setup times exist, and once sequencing is the main cause of late orders.
- CMMS when the number of assets, work orders and inspection plans is too large to manage in a list.
- QMS as a formal system when customers, audits or certification require documented quality processes.
The broader software stack, including SCADA and control systems, is explained on production software. For planning tools in detail, see production planning software.
What SYMESTIC contributes
SYMESTIC, the cloud-native MES, covers the MES layer in this chain. It detects stops automatically, records stop reasons, quantities and scrap and rework by reason, and supports quality inspection at the workstation. It connects to the ERP, for example SAP, Microsoft Dynamics NAV, Business Central or InforCOM, via REST API and webhooks. Other systems such as QMS, CAQ, APS, WMS or PLM connect via the REST API.
For maintenance, SYMESTIC sends alarms by push message or e-mail, shows MTBF and MTTR and plans maintenance intervals by operating hours. The data can be handed to maintenance software via the REST API. SYMESTIC is not a CMMS, and spare parts stay in the ERP. More on the MES platform and on MES-ERP integration.
Sources
Related: MES software compared · MES vs. MOM · ISA-95 · CMMS · APS
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In manufacturing IT since 1989, previously head of the industry division at STERIA for process control systems and MES. Founded SYMESTIC in 1999. Dipl.-Ing. in communications engineering and electronics.
- Manufacturing Execution Systems (MES)
- OEE & Production KPIs
- Shopfloor Management
- Cloud-native Manufacturing Software
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All articles by Uwe Kobbert