OEE Analysis

preventive maintenance

OEE Analysis at Toyota Motor Manufacturing company

OEE can be analyzed with True Downtime Cost in mind.

"A reply to one readers inquiry for help doing an OEE analysis of a well-established automotive industry automotive plant, Toyota Motor Manufacturing."

This article is about measuring overall equipment effectiveness as a basis for increasing the productivity of manufacturing process. It is delivered as a reply to one of our readers. He was doing a three month research at the Toyota Motor Manufacturing Indonesia and focused on a production line of it's stamping plant.

The question was "where should I start to analyze the examined data (OEE, availability, performance rate, and quality rate figures also all the losses) and how to analyze them?"

Don's Reply:

First of all, the purpose of OEE is to benchmark either equipment utilization or production efficiency or both.

See http://www.downtimecentral.com/oee_teep.htm

For OEE or any benchmark to be a tool, it must be acted on. I like to use the terminology, �Closed Loop�. :>) You take the lines first OEE measurements, maybe several for accuracy. Either Daily, weekly or monthly with the best being automated collection of data daily, then averaged for weekly, monthly, annual.

The start of constant improvement:

Now for the acting on OEE information. You must first make the daily or weekly OEE number know to all involved. Not just management, but the operators too. A campaign to Improve (make the OEE percentage higher) must be implemented from top management on down to line supervisors.

What must be done:

You analyze each of the three OEE factors individually to see how to improve the OEE. (Availability, Performance Rate, and Quality) This should be done by a TEAM made up of operators, maintenance, engineering and management.

For each of the three factors, the team brain storms one the most cost effective ways to improve (Minimum cost with maximum gain in percentage.) The you start with changes to which every factor (Availability, Performance Rate, and Quality) has the greatest opportunity for improvement and the lowest cost and work your way up the list implementing the recommended changes and recalculating the OEE after each change.

For example:

Before any change, you find 50% Availability (0.5) X 70% Performance Rate (0.7) X 20% Quality Reject Rate (results in 80%(0.8) acceptable) = 28%OEE

If you calculate Availability on a 24/7 time table (equipment utilization method), increasing availability may be a simple as increasing from a two shift operation to a 3 shift operation. Which in the above example would result in about a 16% increase in availability which would bring our OEE up to 37%

If you calculate Availability on a scheduled time table (operating efficiency method), increases in percentage are smaller. It may be reducing excessive downtime by increasing PMs or making parts more available to feed the line or reducing change over time for products. You may see only a 1% or 2% increase in availability.

Your team may decide that the operating seep of the machine is the first factor to work on because it is the most cost effective. In the above example the line is only running at 70% of it�s designed capacity. You may have the OEM come in and tune it up for free, and see a 10% increase in the Performance Rate factor. There by increasing the OEE from the first measured 28% to 32%.

After both the above factor changes where implemented, the total OEE would be 42.2% OEE. That�s a 14% increase on Return On Investment (ROI) for company stock holders.

The same would be for the third factor, Quality. The team may find adding an extra employee pre-inspecting raw material feed to the line increases the quality factor of OEE by 7%. The increased company profit amortized over a year, this may justify the additional quality employee.

I could go on with hundreds of examples, but don�t have the time. Just remember, no body is perfect, so your should never reach 100% OEE. The goal is through constant improvement to keep striving to get close and closer to 100% OEE. The closer you get the smaller the percentage gains will be.

Implementation should start with the machine, line, facility in a company that measures the lowest OEE but shows the greatest opportunity for improvement with the lowest cost to implement that improvement. Until you have worked your way thru the entire company. So the start is to measure all OEE for all equipment, Lines, Facilities in the company so you can see the big picture as to where the best place to focus improvement is.

When you are analyzing cost to implement improving OEE and savings seen by improved OEE, TDC is a valuable tool to realize more accuracy and reality in coast analysis.


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