Taguchi method is based on performing evaluation or experiments to test the sensitivity of a set of response variables to a set of control parameters (or independent variables)by considering experiments in “orthogonal array” with an aim to attain the optimum setting of the control parameters. Orthogonal arrays provide a best set of well balanced (minimum) experiments [1]. Table 5.4.1 shows eighteen standard orthogonal arrays along with the number of columns at different levels for these arrays [1]. An array name indicates the number of rows and columns it has, and also the number of levels in each of the columns. For example array L₄ (2³) has four rows and three “2 level” columns. Similarly the array L₁₈ (2¹3⁷) has 18 rows; one “2 level” column; and seven “3 level” columns. Thus, there are eight columns in the array L18. The number of rows of an orthogonal array represents the requisite number of experiments. The number of rows must be at least equal to the degrees of the freedom associated with the factors i.e. the control variables. In general, the number of degrees of freedom associated with a factor (control variable) is equal to the number of levels for that factor minus one. For example, a case study has one factor (A) with “2 levels” (A), and five factors (B, C, D, E, F) each with “3 level”. Table 5.4.2 depicts the degrees of freedom calculated for this case. The number of columns of an array represents the maximum number of factors that can be studied using that array.