Calculating OEE (Overall Equipment Effectiveness) or overall machine effectiveness is a very important metric in industrial plants, especially in production lines that involve CNC (Computer Numerical Control) machines .
🏭 What is OEE (Overall Equipment Effectiveness)?
OEE is a measure used to assess the overall performance of machinery or production equipment, to see how well it is using its full production potential compared to the planned production time, in order to know the losses that have occurred and be able to make improvements.
OEE is calculated from three main components, all expressed as a percentage (ratio):
Availability Rate (A)
Performance Efficiency (P)
Quality Rate (Q)
🛠️ How to calculate OEE
The formula for calculating OEE is to multiply these three components together:
Where:
1. Availability (A)
It is a measure of how ready the machine is for actual use at the planned time by deducting the time the machine is downtime such as breakdowns, setup/adjustment, waiting for raw materials, etc.
2. Performance (P)
It is a measure of how fast a machine can work according to the standard it should be. It is done by comparing the number of pieces actually produced with the number of pieces that should be produced according to the standard speed (Ideal Cycle Time).
3. Quality rate (Quality - Q)
It is a measure of the quality of the product produced by comparing the number of standard products (Good Product) with the total number of products produced (Total Product).
🚀 How to increase overall machine effectiveness (OEE) on your CNC production line
Increasing OEE means reducing losses incurred in each of the key components:
1. Increasing the operating rate (Availability$\uparrow$)
Focus on reducing downtime losses
Reduce machine breakdowns: Use preventive maintenance (PM) and autonomous maintenance such as regular inspections and lubrication.
Reduce setup/adjustment time: Use SMED (Single Minute Exchange of Die) technique to reduce the time for changing dies/tools in CNC machines.
2. Improving the efficiency of the machine (Performance$\uparrow$)
Focus on reducing speed losses
Reduce slow idle times: Ensure that the CNC machine is operating at the feed rate and spindle speed specified in the standard (Ideal Cycle Time).
Reduce minor stops and idle times: Check for sensor problems, underfeeds, or chip jamming.
3. Increasing the quality rate (Quality$\uparrow$)
Focus on reducing waste (Quality Losses)
Reduce process rejects: Improve the accuracy of CNC machine settings, monitor tool condition, and control temperature/humidity appropriately.
Reduce Start-up Rejects: Thoroughly inspect the first-off part after tool set-up/change to ensure the correct part is obtained before full machine operation.
Implementing OEE in CNC production lines will provide managers and teams with a clear picture of waste, enabling them to prioritize and implement improvements effectively.
| Key indicators | OEE , Overall Equipment Effectiveness , Overall Equipment Effectiveness, Performance Measurement |
| OEE components | Availability (A) , Performance (P) , Quality (Q) , Operating rate, Operating efficiency, Quality rate |
| Calculations and formulas | OEE formula , how to calculate OEE, find APQ value |
| Losses | Downtime Losses , Speed Losses , Quality Losses , Six Big Losses, Machine Downtime, Waste |
| Improvements | Increasing OEE , reducing downtime, reducing waste, increasing productivity, improving efficiency |
| Related techniques | TPM (Total Productive Maintenance), SMED (Single Minute Exchange of Die), Preventive Maintenance |
| Environment | CNC production line , CNC machinery, industrial plant, Manufacturing, Industry 4.0 |
OEE
CNC production line
Efficiency enhancement
Availability Performance Quality
Factory KPI
Here are the four illustrations:
An infographic summarizing OEE and its three components (Availability, Performance, Quality) with formulas.
An illustration depicting "Downtime Losses" in a CNC line, showing a stopped CNC machine.
An illustration depicting "Speed Losses" with a CNC machine running slower than optimal or showing minor stops.
An illustration depicting "Quality Losses" with rejected parts next to a CNC machine.
Here is the first illustration:
1. OEE Overview Infographic
Here is the second illustration:
2. Downtime Losses Illustration
Here is the third illustration:
3. Speed Losses Illustration
Here is the fourth illustration:
4. Quality Losses Illustration
