Page 101 - TPM A Route to World-Class Performance

82 TPM-A Route to World-Class Performance

Performance = operating speed rate x operating rate
Ideal cycle time actual cycle time x output
- - X x 100%
Actual cycle time operating time
Ideal cycle time is the cycle time the machine was designed to achieve at
100 per cent. Output is output including defects. Operating time is total
available time minus unplanned stoppages (i.e. available time).

total output - number of defects
Quality = x 100%
total output
OEE calculation for welding cell
Calculation of OEE can best be demonstrated by using the values in Figure
5.3. The roman numerals refer to the columns in the figure.
Average OEE calculation
111 - IV - 1980 - 50
Availability = - - 100 = 97.5%
I11 1980
-
V x VI11 - 2498 x 0.5
Performance = 100 = 64.7%
I11 - IV 1980 - 50
V - VI - VI1 - 2498 - 0 - 0
Quality = 100 = looyo
V - 2498
Average OEE = 0.975 x 0.647 x 1.000 x 100 = 63.1%

Best of best (target) OEE calculation
The best of best calculation uses the best scores in the period from each
column. This gives us a theoretical achievable performance if all of these best
scores were consistently achieved. It is our first target for improvement.

Best of best OEE = 1.000 x 0.877 x 1.000 x 100 = 87.7%
Question What is stopping us achieving the best of best consistently?
Answer We are not in control of the six big losses!
The best of best calculation generates a high confidence level, as each value
used of the three elements (availability, performance, quality) was achieved
at least once during the measurement period. Therefore, if control of the six
big losses can be achieved, our OEE will be at least the best of best level.
We can now start putting a value to achieving the best of best performance.
TPM potential savings for achieving best of best

Cycle time A = 30s
Number of men B = 2
Allowance in standard hours
(lunch breaks, technical allowance, etc.) C = 11%