In this example, 50 capacitor units are tested at three temperatures (85o, 105o, and 125o Celsius) for 1500 hours. The results are recorded in the Capacitor sample data table. The resulting model is used to predict the fraction of the population that is failing at 100,000 hours at normal use temperature of 25o Celsius.
Select Help > Sample Data Library and open Design Experiment/Capacitor
Click the green triangle to run the Fit Life by X table script.
Click 105 above Temp and change it to 25.
Click 750.5 above Hours and change it to 100,000.
Distribution Profiler for Capacitor Model
Based on your current study, the predicted fraction of the population that fails at 25o at 100,000 hours is 0.00358, with a confidence interval of 0.00056 to 0.02268. You want to estimate the failure fraction more precisely. To decrease the width of the confidence interval, augment your study with additional tests.
Select DOE > Special Purpose > Accelerated Life Test Design.
Select Design for one accelerating factor and click Continue.
Enter Temp for Factor Name.
Enter 5 for Number of Levels.
Enter 25 for both Low Usage Condition and High Usage Condition.
Click Continue.
Ensure that Weibull is selected as the Distribution Choice.
Under Prior Mean, enter the acceleration model parameter estimates from the Fit Life by X Estimates report, found in the Weibull Results report on the Statistics tab.
Parameter Estimates and Fitted Model from Weibull Results Report
For the Weibull distribution, JMP uses a parameterization that depends on a location parameter μ and scale parameter σ. In terms of the usual α and β parameterization, the scale parameter is σ = 1/β. See JMP’s Weibull Parameterization.
Under Diagnostic Choices, enter 100,000 for both boxes for Time range of interest. Leave the Probability of interest value set to 0.1.
Enter 250 for Number of units under test.
Completed Design Details Window shows the completed Accelerated Life Test Plan outline.
Completed Design Details Window
Click Continue.
To account for the units at each setting of Temp in the previous experiment, enter the following under Candidate Runs.
From the ALT Plan red triangle menu, select ALT Optimality Criterion > Make Probability I-Optimal Design.
Click Make Design.
Optimal Design
50 units at 85o. Since the previous experiment already tested 50 units at 85o, no additional units are needed.
89 units at 90o. The next experiment will test 89 units at 90o.
50 units at 105o. Since the previous experiment test 50 units at 105o, no additional units are needed.
0 units at 110o. The next experiment will not test any units at this level.
61 units at 125o. Since the previous experiment test 50 units at 125o, 11 additional units are needed.
Distribution Profiler for Temp = 25 and Time = 100000

Help created on 9/19/2017