Design of Experiments Project Summary Version 3
Jayden Stout, Afeez Kareem, Brent Edgerton
Introduction:
We are working on batteries. The new batteries are good but have issues we want to characterize.
Many of the issues are caused by grain size (sort of, eventually). For that reason, measuring the grain
size is important.
Methods:
We will be making four batches using two inputs in a standard 22 design. Each batch will contain 18
samples, 12 of these will be used for this classwork. From those twelve samples they will be “charged”
with 6 levels of current (two replicates at each current level). The variables can be organized in a table
as follows:
Low Pressure
High Pressure
Low Power
Batch 1 (Samples 1-12)
Batch 3 (Samples 25-36)
High Power
Batch 2 (Samples 13-24
Batch 4 (Samples 37-48)
The powers will be 100 or 400 W. The pressures will be 3.75 or 11.25 mTorr. The currents will be 0.5,
1.0, 1.5, 2.0, 2.5, or 3.0 mA/cm2. The average grain size is expected to be less than 100 um2 in all cases.
Lurking variables include: deposition thickness, image analyzer (as in, the operator of the image
scanning software), time between first and second depositions, solvent thickness, and distance between
sample and source during electroplating. There are others, but these are obvious. They are being
controlled in most cases by meticulous attention to detail and manufacturing sameness across all steps
with very detailed standard operating procedure documents. The operator in question is being tracked
and can be checked after the fact to identify sources of bias. Any operator work is reversible so issues
with the operator can be fixed after the fact (as in, after the semester is over and the research is no
longer for the class).
The total samples will be 48 and the 2*2*6 design will require 24 runs to complete the experiment. We
therefore will have a full experiment with 2 replicates.
Results:
We will use a linear regression to explore how, for each batch, current has an effect. We will also use
ANOVA to explore if one batch differs from another. We are curious about interactions between batch
and current- which current/batch combination is best?
The final plots in the presentation will resemble the interaction plots. We can place current on the X
axis, size on the Y axis, and provide a line for each batch. It will be noted which batches had which input
parameters.