Page 80 - How To Implement Lean Manufacturing

Lean Manufacturing Simplified 61

nearly all the 20 Lean tools require an understanding of, and reduction of, variation to
work.
Stability

OEE OEE stands for Overall Equipment Effectiveness and is the primary measure of
production effectiveness. It can be used for value stream or individual work station
performance evaluation. Good value stream OEE is one of the key precursors to the
implementation of Lean and is the product of three important operational parameters.
These are:
• Equipment availability
• Quality yield
• Cycle-time performance
To calculate OEE, you will need five parameters. First is the planned production
time for the line. Second is the unplanned line downtime. Third is the line cycle time, or
cycle time, of the bottleneck. Fourth is the total production including scrap, and fifth is
the total amount of salable product. Let’s say we have the following data:
• Planned production time is 20.5 hours. It is 24 hours less 1 hour per shift for
lunch and breaks, and less one-half hour for planned preventive maintenance.
• Unscheduled downtime was 1.5 hours.
• Design cycle time is 30 seconds per piece.
• Actual total production was 2020 pieces with 50 rejects, yielding 1970 pieces of
salable product. This then allows us to calculate:
• Availability = Total uptime divided by total planned uptime = A = (20.5 – 1.5)/
20.5 = 0.927
• Quality Yield = The total of salable production units divided by the total
production = Q = 1970/2020 = 0.975
• C/T Performance = Total units produced, good and bad, divided by the volume,
which should have been produced during the actual uptime at the design
cycle time = P = 2020/[(20.5 – 1.5) × (3600/30)] = 0.886
• OEE = A × Q × P = 0.801

This is a way to express how our production facility is performing, and then priori-
tize our problems and allocate our resources. In this example, OEE is 80 percent. The
losses can be stated as about 2.5 percent due to quality issues, 7.3 percent losses due to
availability issues, either materials delivery or machinery downtime, and we are losing
11.4 percent due to the line not performing at the design cycle time. It is a very good
picture of plant performance and allows management to focus on the appropriate goals
for improvement.

MSA MSA stands for measurement system analysis. It is the statistical calculation
of the variation in the measurement system and applies to both attribute and vari-
ables data. MSA must be done on all measurement systems. The most common use
of MSA is as a precursor to doing a capability study on a product characteristic or a