---
title: "Manufacturing execution system and automation"
subject: "Computer Aided Design"
chapter: 6
key: "semester_4/computer_aided_design:manufacturing-execution-system-automation"
source: https://www.bctengineer.com/q/semester_4/computer_aided_design/manufacturing-execution-system-automation
site: BCT Engineering
---

# Manufacturing execution system and automation

Computer Aided Design · Chapter 6: CAM and Recent Technology

- Asked in: year not given, 5 marks
- Video: [MES | SolidWorks CAD | Operational Functions Allocation for Establishing a Production Process Chain](https://www.youtube.com/watch?v=i_S2ktannbk) — Laplanda Tech
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_4/computer_aided_design/manufacturing-execution-system-automation
- Whole chapter: https://www.bctengineer.com/md/semester_4/computer_aided_design/chapter-6

## Question

What is a manufacturing execution system (MES)? Explain its functions and how it fits between the enterprise planning level and the shop floor control level.

## Short answer

A manufacturing execution system (MES) is a real-time computer system that tracks and controls shop floor production, scheduling jobs, allocating resources, collecting data, and managing quality. It bridges ERP (enterprise planning) and machine-level control (PLC/SCADA), distributing work orders and returning performance data.

## Answer

A **Manufacturing Execution System (MES)** is a computer system that tracks, controls and documents the conversion of raw materials into finished goods on the shop floor in real time. It sits between the planning system (ERP) and the control systems on the machines (PLC, SCADA, CNC).

#### Position in the automation hierarchy
```text
 Level 4  ERP / business planning (orders, finance)
              |        ^
              v        |  orders, status
 Level 3  MES - execution, scheduling, tracking
              |        ^
              v        |  work orders, data
 Level 2  SCADA / cell control
 Level 1  PLC / CNC / robot controllers
 Level 0  Sensors and actuators, machines
```

#### Main functions
1. **Detailed scheduling** of operations on machines and sequencing of jobs.
2. **Resource allocation and status:** machines, tools, labour and material.
3. **Dispatching production units:** releasing work orders to cells.
4. **Document control:** drawings, NC programs, work instructions delivered to the right machine.
5. **Data collection:** actual times, quantities, scrap, downtime.
6. **Quality management:** inspection data, SPC, traceability (lot and serial numbers).
7. **Maintenance management** and performance analysis (OEE).
8. **Product tracking and genealogy.**

#### Role in CAD/CAM
CAD/CAM supplies drawings, process plans and NC programs to the MES, which distributes them (DNC) and returns as-built data. MES gives automation its information backbone and supports CIM and smart-factory systems.

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. What is an MES?
   A. A system that tracks, controls and documents conversion of raw materials to finished goods on the shop floor in real time
   B. An accounting package for payroll
   C. A CNC controller
   D. A CAD drawing editor
   Answer: A. MES manages execution on the shop floor in real time. (Key point: MES definition)

2. Where does the MES sit?
   A. Below sensors and actuators
   B. Between ERP planning (level 4) and shop-floor control such as SCADA, PLC and CNC
   C. Above ERP
   D. Only inside the PLC
   Answer: B. MES is level 3: it receives orders from ERP and sends work orders down, returning status. (Key point: Position in hierarchy)

3. Which is a function of an MES?
   A. Setting company tax policy
   B. Detailed scheduling, dispatching, document control, data collection, quality traceability
   C. Designing 3D parts
   D. Manufacturing sensors
   Answer: B. MES covers scheduling, resource allocation, dispatching, documents, data collection, quality, maintenance and tracking. (Key point: MES functions)

## Related in other subjects

- [GPSS manufacturing shop, conditional transfer](https://www.bctengineer.com/question.md?key=semester_8%2Fsimulation_and_modeling%3Agpss-manufacturing-shop) — Simulation and Modeling, chapter 9
- [Enterprise management system and benefits](https://www.bctengineer.com/question.md?key=semester_8%2Finformation_system%3Aems-with-example-benefits) — Information System, chapter 3
- [System call; read() execution](https://www.bctengineer.com/question.md?key=semester_6%2Foperating_system%3Asystem-call-read-example) — Operating System, chapter 1
- [Automation with a contactor](https://www.bctengineer.com/question.md?key=semester_6%2Fswitchgear_and_protection%3Acontactor-automation) — Switchgear and Protection, chapter 4