Overall Equipment Effectiveness

From Elsmar Cove Quality Assurance and Business Standards Wiki

Overall Equipment Effectiveness - The overall performance of a single piece of equipment or even an entire factory, will always be governed by the cumulative impact of the three OEE factors: Availability, Performance Rate and Quality Rate.

OEE is a percentage derived by multiplication of the three ratios for the factors mentioned above. The OEE percentage is used for analysis and Benchmarking.

OEE = Availability X Performance Rate X Quality Rate

Availability - Percent of scheduled production (to measure reliability) or calendar hours 24/7/365 (to measure equipment utilization), that equipment is available for production.

Note: measures the percent of time that the equipment can be used (usually total hours of 24-7-365), divided by the equipment uptime (actual production).

Performance Rate - Percent of parts produced per time frame, of maximum rate OEM rated production speed at. If OEM specification is not available, use best known production rate.

Note: Performance efficiency is the percentage of available time that the equipment is producing product at its theoretical speed for individual products. It measures speed losses. (e.g., inefficient batching, machine jams)

Quality Rate - Percent of good sellable parts out of total parts produced per time frame.

Note: Determining the percent of the total output that is good. (i.e. all products including production, engineering, rework and scrap.)

Example: 50% Availability (0.5) X 70% Performance Rate (0.7) X 20% Quality Reject Rate (results in 80%(0.8) acceptable) = 30%OEE

The goal of measuring OEE is to improve the effectiveness of your equipment. Since equipment effectiveness affects shopfloor employees more than any other group, it is appropriate for them to be involved in tracking OEE and in planning and implementing equipment improvements to reduce lost effectiveness. Let’s look at some of the benefits of OEE measurement for operators and shift leaders or line managers.

We recommend that the operator collect the daily data about the equipment for use in the OEE calculation. Collecting this data will:

Teach the operator about the equipment. Focus the operator’s attention on the losses. Grow a feeling of ownership of the equipment.

The shift leader or line manager is often the one who will receive the daily operating data from the operator and process it to develop information about the OEE. Working hands on with the data will:

Give the leader/manager basic facts and figures on the equipment. Help the leader/manager give appropriate feedback to the operators and others involved in equipment improvement. Allow the leader to keep management informed about equipment status and improvement results.

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Elsmar Cove forum definition discussion thread: Overall Equipment Effectiveness (OEE)