a. Simatic IT
b. Customised OEE measurement solutions
Acronym for Overall Equipment Efficiency.
Best practices metric for identifying, monitoring and improving the efficiency of a
Consistent and proven way to measure the effectiveness of Lean manufacturing,
six sigma, TPM etc.
Breaks down the most common causes for loss of productivity into 3 simple
Identifying the 3 OEE factors:
1. Availability: In order to determine the availability of a machine, the Operating time needs to be established.
Planned Production Time = Plant Operating Time - Planned Shutdown
Operating Time = Planned Production Time - Down Time Loss
Availability = Operating Time / Planned Production Time.
Availability is also called Utilisation in some literature.
Down Time Loss includes any changeover time, equipment failures, material shortages, operator absence etc.
2. Performance: Accounts for the speed loss or capacity loss. If a machine runs at a lower speed as compared to its nominal speed, this results in Performance Loss. Performance loss is the ratio of Net Operating Time to Operating Time, where Net Operating Time = Operating Time - Speed Loss.
Performance = (All Parts/Operating Time) / Std. Rate
Or= (Std Cycle * All Parts) / Operating Time
Since Std. Cycle = 1 / (Std Rate).
Performance is also known as % Std. Rate.
3. Quality: Accounts for quality related rejects.
Quality related rejects reduce the net operating time to what is called as Fully Productive Time. The fully productive time is responsible for producing good quality parts.
Quality is the ratio of fully productive time to Operating time. This is measured as-
Quality = (All parts -Reject) / All parts.
Quality is also known as Yield.
OEE is therefore calculated as
OEE = Availability * Performance * Quality
OEE = (All Parts -Reject) * Std. Cycle / Planned Production Time
OEE = (All Parts - Reject) / (RunTime + DownTime) * Std. Rate)
Why invest in OEE monitoring:
Quantifies the losses occurring in plant.
Generates Efficiency report elucidating the losses happening per batch, per machine, shift wise etc.
Identifies the major reasons for Down Time Loss and Rejects.
The identification of major causes for down time loss leads to plan Preventative Maintenance
Programme and generates a pointer towards the appropriate Automation system.
Helps the management to benchmark its facility with the best in that class.
Provides the management with a correct perspective into Operations.
Managing OEE: A WORD OF CAUTION:
Installing an OEE system is easy but to develop a culture of OEE consciousness is the most difficult part.
Managing OEE: Why does it fail?
Management handling of shop floor operators.
OEE measurement relies on Operator entering the correct Down Time Reason or Reject reason. This also exposes the operator to the plant manager and makes the operators vulnerable.
OEE sponsor moving on to a different role.