A key KPI for a FUSE program is Overall Equipment Effectiveness (OEE) which measures the efficiency and productivity of equipment and production processes.
Definition of OEE
OEE is a percentage that represents the proportion of truly productive manufacturing time. It takes into account three main factors:
- Availability: The ratio of Run Time to Planned Production Time. It takes into account any events that stop planned production for an appreciable length of time.
- Performance: Anything that causes the manufacturing process to run at less than the maximum possible efficiency when it is running.
- Quality: Manufactured material that do not meet quality standards, including materialthat require rework and reprocessing.
The formula for calculating OEE is:
OEE = Availability × Performance × Quality
Components of OEE
Availability
Availability measures the percentage of scheduled time that the equipment is available to operate. It accounts for downtime losses.
Availability = Run Time / Planned Production Time
Performance
Performance compares the actual output of equipment to its theoretical maximum output at optimal speed.
Performance = (Ideal Cycle Time × Total Count) / Run Time
Quality
Quality represents the percentage of released material produced out of the total material produced.
Quality = Good Count / Total Count
Importance of OEE
OEE is crucial for several reasons:
- It provides a comprehensive view of manufacturing productivity.
- It helps identify losses and areas for improvement.
- It serves as a benchmark for comparing performance across different equipment or production lines.
- It supports continuous improvement initiatives.
Interpreting OEE Scores
While OEE scores can vary by industry, generally:
- 100% OEE is perfect production
- 85% is considered world-class
- 60% is fairly typical
- 40% is low but not uncommon for companies just starting to measure OEE
Benefits of Tracking OEE
- Identifies hidden capacity in manufacturing operations
- Reduces manufacturing costs
- Improves quality control
- Increases equipment longevity through better maintenance practices
- Enhances decision-making with data-driven insights
Improving OEE
To improve OEE, manufacturers can:
- Implement preventive maintenance programs
- Optimize changeover procedures
- Enhance operator training
- Use real-time monitoring systems
- Analyze root causes of downtime and quality issues
- Implement continuous improvement methodologies
By focusing on OEE, manufacturers can significantly enhance their productivity, reduce waste, and improve their bottom line. It’s a powerful metric that provides actionable insights for optimizing manufacturing processes.
The Effectiveness of the OEE Metric
Utilizing the rubric:
| Attribute | Meaning | Score | What this means in My Organization |
| Relevance | How strongly does this metric connect to business objectives? | 5 | Empirically Direct – Data proves the metric directly supports at least one business objective – the ability to meet client requirements |
| Measurability | How much effort would it take to track this metric? | 3 | Medium – Data exists but in a variety of spreadsheets systems, minor collection or measurement challenges may exist. Will need to agree on what certain aspects of data means. |
| Precision | How often and by what margin does the metric change? | 5 | Once we agree on the metric and how to measure it, it should be Highly Predictable |
| Actionability | Can we clearly articulate actions we would take in response to this metric? | 4 | Some consensus on action, and capability currently exists to take action. This metric will be used to drive consensus. |
| Presence of Baseline | Does internal or external baseline data exist to indicate good/poor performance for this metric? | 3 | Baseline must be based on incomplete or directional data. Quite frankly, the site is just qualified and there will be a rough patch. |
This tells me this is a strong metric that requires a fair amount of work to implement. It is certainly going into the Metrics Plan.
A Deeper Dive into Equipment Availability
Equipment availability metric measures the proportion of time a piece of equipment or machinery is operational and ready for production compared to the total planned production time. It is a key component of Overall Equipment Effectiveness (OEE), along with Performance and Quality.
This metric directly impacts production capacity and throughput with a high availability indicating efficient maintenance practices and equipment reliability. This metric helps identify areas for improvement in operations and maintenance.
Definition and Calculation
Equipment availability is expressed as a percentage and calculated using the following formula:
Availability (%) = (Actual Operation Time / Planned Production Time) × 100
Where:
- Actual Operation Time = Planned Production Time – Total Downtime
- Planned Production Time = Total Time – Planned Downtime
For example, if a machine is scheduled to run for 8 hours but experiences 1 hour of unplanned downtime:
Availability = (8 hours – 1 hour) / 8 hours = 87.5%Types of Availability Metrics
Inherent Availability
This metric is often used by equipment designers and manufacturers. It only considers corrective maintenance downtime.
Inherent Availability = MTBF / (MTBF + MTTR)
Where:
- MTBF = Mean Time Between Failures
- MTTR = Mean Time To Repair
Achieved Availability
This version includes both corrective and preventive maintenance downtime, making it more useful for maintenance teams.
Achieved Availability = MTBM / (MTBM + M)
Where:
- MTBM = Mean Time Between Maintenance
- M = Mean Active Maintenance Time
Factors Affecting Equipment Availability
- Planned downtime (e.g., scheduled maintenance, changeovers)
- Unplanned downtime (e.g., breakdowns, unexpected repairs)
- Equipment reliability
- Maintenance strategies and effectiveness
- Operator skills and training
Improving Equipment Availability
To increase equipment availability, consider the following strategies:
- Implement preventive and predictive maintenance programs.
- Optimize changeover procedures and reduce setup times.
- Enhance operator training to improve equipment handling and minor maintenance skills.
- Use real-time monitoring systems to quickly identify and address issues.
- Analyze root causes of downtime and implement targeted improvements.
- Incorporate fault tolerance at the equipment design stage.
- Create asset-specific maintenance programs.
Relationship to Other Metrics
Equipment availability is closely related to other important manufacturing metrics:
- It’s one of the three components of OEE, alongside Performance and Quality.
- It’s distinct from but related to equipment reliability, which measures the probability of failure-free operation.
- It impacts overall plant efficiency and productivity.
By focusing on improving equipment availability, manufacturers can enhance their overall operational efficiency, reduce costs, and increase production capacity. Regular monitoring and analysis of this metric can provide valuable insights for continuous improvement initiatives in manufacturing processes.
To generate an equipment availability KPI in process manufacturing, you should follow these steps:
Calculate Equipment Availability
The basic formula for equipment availability is:
Availability = Run Time / Planned Production Time
Where:
- Run Time = Planned Production Time – Downtime
- Planned Production Time = Total Time – Planned Downtime
For example, if a machine is scheduled to run for 8 hours, but has 1 hour of unplanned downtime:
Availability = (8 hours – 1 hour) / 8 hours = 87.5%
Track Key Data Points
To calculate availability accurately, you need to track:
- Total available time
- Planned downtime (e.g. scheduled maintenance)
- Unplanned downtime (e.g. breakdowns)
- Actual production time
Implement Data Collection Systems
Use automated data collection systems like machine monitoring software or manufacturing execution systems (MES) to capture accurate, real-time data on equipment status and downtime.
Analyze Root Causes
Categorize and analyze causes of downtime to identify improvement opportunities. Common causes include:
- Equipment failures
- Changeovers/setups
- Material shortages
- Operator availability
Set Targets and Monitor Trends
- Set realistic availability targets based on industry benchmarks and your current performance
- Track availability over time to identify trends and measure improvement efforts
- Compare availability across equipment and production lines
Take Action to Improve Availability
- Implement preventive and predictive maintenance programs
- Optimize changeover procedures
- Improve operator training
- Address chronic equipment issues
Use Digital Tools
Leverage technologies like IoT sensors, cloud analytics, and digital twins to gain deeper insights into equipment performance and predict potential failures.
Planned Production Time
Planned production time is the total amount of time scheduled for production activities, excluding planned downtime. It represents the time during which equipment or production lines are expected to be operational and producing goods. It can be rather tricky to agree on the exact meaning.
Calculation
The basic formula for planned production time is:
Planned Production Time = Total Time – Planned Downtime
Where:
- Total Time is the entire time period being considered (e.g., a shift, day, week, or month)
- Planned Downtime includes scheduled maintenance, changeovers, and other planned non-productive activities
Components of Planned Production Time
Total Time
This is the full duration of the period being analyzed, such as:
- A single 8-hour shift
- A 24-hour day
- A 7-day week
- A 30-day month
Planned Downtime
This includes all scheduled non-productive time, such as:
- Preventive maintenance
- Scheduled breaks
- Shift changes
- Planned changeovers between batches
- Cleaning and sanitation procedures
Considerations for Batch Manufacturing
In batch production, several factors affect planned production time:
- Batch Changeovers: Time allocated for switching between different product batches must be accounted for as planned downtime.
- Equipment Setup: The time required to configure machinery for each new batch should be included in planned downtime.
- Quality Checks: Time for quality control procedures between batches may be considered part of planned production time or planned downtime, depending on the specific process.
- Cleaning Procedures: Time for cleaning equipment between batches is typically considered planned downtime.
- Material Handling: Time for loading raw materials and unloading finished products between batches may be part of planned production time or downtime, based on the specific process.
Example Calculation
Let’s consider a single 8-hour shift in a batch manufacturing facility:
- Total Time: 8 hours
- Planned Downtime:
- Scheduled breaks: 30 minutes
- Equipment setup for new batch: 45 minutes
- Cleaning between batches: 15 minutes
Planned Production Time = 8 hours – (0.5 + 0.75 + 0.25) hours
= 8 hours – 1.5 hours
= 6.5 hours
In this example, the planned production time for the shift is 6.5 hours.
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