in the case of the blue dyes, we assumed that the
brainstorming sessions led to the conclusion that,
apart from the main effects, only two of the
interactions, namely the dye and electrolyte
concentration as well as the electrolyte concentration
& temperature, have been significant. This led to
seven degrees of freedom which required the Taguchi
L8 scheme.
Table 1 shows twelve runs for red dyes with the
conditions of the variables stated as a coded factor
value whose real amount is shown in Table 2.
The samples were dyed in a Polymat (AHIBA1000)
laboratory dyeing machine. Each dyeing (run) was
carried out with hard water (Block 1) as well as soft
water (Block 2). So a total of 24 dyed samples were
prepared for each red dye. The dyeing was started at
room temperature with the dye bath containing the
required amount of dye. The dye bath temperature
was raised to the final value in 20 minutes and then
the electrolyte was added to the dye bath. The dyeing
continued at the final temperature for the required
amount of time (Table I and II). At the end of the
dyeing, the samples were thoroughly rinsed in water
(40 °C) and finally dried