Six Big Losses in OEE Lean Tool Improve Productivity

Six Big Losses in OEE and TPM

→ The Six Big Losses are responsible for productivity. We have to eliminate these to improve productivity.
→ One of the major goals of TPM (Total Productive Maintenance) and OEE (Overall Equipment Effectiveness) is to reduce and eliminate Six Big Losses.

Classification of Big Losses:

Classification of Losses in OEE

[1] Availability Losses:

→ This includes equipment failures or unplanned stops, set-up and changeovers, planned stops, etc.
→ When we consider the availability of a process, it is a decision making parameter for understanding the reasons for that loss and to describe the time spent during unplanned stops.
→ Decreasing the time spent on unplanned events will increase the available running time for manufacturing.
→ Equipment failures or unplanned stops have a very severe impact on productivity.
→ Set-up and changeovers are also responsible for the biggest cause of downtime.
→ Changeovers are tackled with the help of using SMED (Single Minute Exchange of Dies) programs.
→ The main reason for long changeover times may be the main adjustments, tooling adjustments, warm-up time, cleaning, and quality inspections, etc.
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[2] Performance Losses:

→ This is due to machines or manpower are in ideal conditions, minor stoppages or small stops.
→ We can eliminate this loss by taking precautionary action like line balancing and bottleneck analysis.
→ On the other hand, we can prioritize the tasks by recording and analyzing the minor stoppages.
→ For Reduced speed, the common reasons consist of dirty machines, damaged equipment, lubrication, environmental circumstances, worker experience, and usual startup and shutdown techniques.
→ So we can improve productivity by identifying and eliminating the above causes.

[3] Quality losses:

→ This includes scrap, rework, and all types of non-conformity of the product.
→ However, being familiar with the quantity of the loss is not sufficient also we have to consider the quality of the loss for improving productivity.
→ For improving the product quality we have to analyze the defect generation during the machine startup and during manufacturing.
→ After analyzing the defect we can have an analysis of causes that are responsible for the defect generation. So by eliminating the causes, we can eliminate the defect.

Classification of Six Big Losses in OEE

  1. Breakdowns
  2. Setup and Adjustment
  3. Small Stops
  4. Reduced Speed
  5. Start-up Rejects
  6. Manufacturing Rejects
Classification of Six Big Losses

[1] Breakdowns:

→ The breakdown comes under the Category - Downtime.
→ Unplanned downtime elimination is critical.
→ Preventive maintenance is a key weapon to kill unnecessary breakdowns.
Root cause analysis can be done on severe breakdowns.
→ Timely validation of tools is also important in order to prevent unplanned downtime.
→ Prediction of an equipment failure is a key skill of engineering that helps a lot in the prevention of downtime.
➨ Examples of Breakdowns:
     ⇢ Tooling Failure,
     ⇢ Unplanned Maintenance,
     ⇢ Equipment Failure,
     ⇢ General Breakdowns, etc...

[2] Setup and Adjustment:

→ Setup and Adjustment come under the Category - Downtime.
→ It is generally called duration between the last good part produced before setup change and the first good part produced after the changeover.
→ Tracking of adjustment timing is very important in reducing this loss.
→ We can use the concept of SMED (Single Minute Exchange of Dies) for reducing the Setup and Adjustment timing.
➨ Examples of Setup and Adjustment:
     ⇢ Excess setup/change over timing,
     ⇢ Material shortage,
     ⇢ Operator shortage,
     ⇢ warm-up timing, etc...

[3] Small Stops:

→ Small Stops comes under the Category - Speed Loss.
→ Recording of this type of loss is very difficult.
→ Cycle time analysis to be used to identify this type of loss.
→ Activity wise actual-time monitoring and micro-mapping of this data help in the identification of small stops and speed reduction.
➨Examples of Small Stops:
     ⇢ Component jam,
     ⇢ Sensor blocked,
     ⇢ Delivery blocked,
     ⇢ Cleaning and Checking, etc...

[4] Reduced Speed:

→ Reduced Speed comes under the Category - Speed Loss
→ Recording of Reduced Speed is very difficult.
→ It can be recorded by Cycle time analysis.
➨ Examples of Reduced Speed:
     ⇢ Poor planning,
     ⇢ Machine wear and tear,
     ⇢ Operator inefficiency,
     ⇢ Under design capacity, etc...

[5] Start-up Rejects:

→ Start-up Reject comes under the Category - Quality Loss.
→ “First Time Right” concept to be adopted during each startup of production.
→ Effective use of production start-up check sheet can eliminate start-up rejects.
→ The process parameter setting plays a vital role in the manufacturing of the good part at the first time.
➨ Examples of the Start-up Rejects:
     ⇢ Damage,
     ⇢ Scrap,
     ⇢ Rework,
     ⇢ Incorrect assembly, etc..

[6] Manufacturing Rejects:

→ Manufacturing Reject comes under the Category - Quality Loss
→ It is related to the rejection during the manufacturing
➨ Examples of the manufacturing Rejects
     ⇢ Damage,
     ⇢ Scrap,
     ⇢ Rework,
     ⇢ Incorrect assembly, etc...

Benefits of Elimination of Six Big Losses:

→ It helps us to improve the process and product.
→ It reduces the_losses and improves the profit
→ Overall Equipment Effectiveness improves by reducing these losses.

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