Slide 1

Descriptive Analysis Using Minitab

Slide 2

S/N Ratio

Slide 3

Note

The Nominal is Best (default) S/N ratio is good for analyzing or identifying scaling factors, which are factors in which the mean and standard deviation vary proportionally. Scaling factors can be used to adjust the mean on target without affecting S/N ratios.

Slide 4

Larger the better (golf ball case)

You manufacture golf balls and are working on a new design to maximize ball flight distance. You have identified four control factors, each with two levels:

Core material (liquid vs. tungsten)Core diameter (118 vs. 156)Number of dimples (392 vs. 422)Cover thickness (.03 vs. .06)

You also want to test the interaction between core material and core diameter.

Slide 5

The response is ball flight distance in feet. The noise factor is two types of golf clubs: driver and a 5-iron. You measure distance for each club type, resulting in two noise factor columns in the worksheet. Because your goal is to maximize flight distance, you select the larger-is-better signal-to-noise (S/N) ratio .

Slide 6

1   Open the worksheet GOLFBALL.MTW. The design and response data have been saved for you.

2   Choose Stat > DOE > Taguchi > Analyze Taguchi Design.

3   In Response data are in, enter Driver and Iron.4   Click Analysis.5   Under Fit linear model for, check Signal-to-noise ratios

and Means. Click OK.6   Click Terms. 7   Move the term AB to Selected Terms by using the arrow

keys or double-clicking it. Click OK.8   Click Options. 9   Under Signal to Noise Ratio, choose Larger is better.

Click OK in each dialog box.

Slide 7

Data

Material(KOLOM A)

Diameter(KOLOM B)

Dimples(KOLOM D)

Thickness (KOLOM E)

Driver(Ulangan 1)

Iron(Ulangan 2)

Liquid 118 392 0.03 247.5 234.3

Liquid 118 422 0.06 224.4 214.5

Liquid 156 392 0.03 59.4 49.5

Liquid 156 422 0.06 75.9 72.6

Tungsten 118 392 0.06 155.1 148.5

Tungsten 118 422 0.03 39.6 29.7

Tungsten 156 392 0.06 92.4 82.5

Tungsten 156 422 0.03 21.9 18.6

Slide 8

Slide 9

Mean o

f SN r

atios

TungstenLiquid

42

40

38

36

34156118

422392

42

40

38

36

340.060.03

Material Diameter

Dimples Thickness

Main Effects Plot (data means) for SN ratios

Signal-to-noise: Larger is better

Slide 10

Material

15611848

44

40

36

32

TungstenLiquid

48

44

40

36

32

Diameter

MaterialLiquidTungsten

Diameter118156

Interaction Plot (data means) for SN ratios

Signal-to-noise: Larger is better

Slide 11

For this example, because your goal is to increase ball flight distance, you want factor levels that produce the highest mean. In Taguchi experiments, you always want to maximize the S/N ratio. The level averages in the response tables show that the S/N ratios and the means were maximized when the core was liquid, the core diameter was 118, there were 392 dimples, and the cover thickness was .06. Examining the main effects plots and interaction plots confirms these results. The interaction plot shows that, with the liquid core, the flight distance is maximized when the core diameter is 118.   

Based on these results, you should set the factors at:

Material LiquidDiameter 118Dimples 392Thickness .06

Slide 12

Predicted values :S/N Ratio    53.6844   Mean     276.263  

Factor levels for predictions Material   LiquidDiameter   118Dimples        392   Thickness      0.06

    Interpreting the results For the factor settings you selected, the S/N ratio is predicted to be 53.6844 and the mean (the average ball flight distance) is predicted to be 276 yards. Next, you might run an experiment using these factor settings to test the accuracy of the model.

Slide 13

Slide 14

Interpreting the Results - Predicting Results

The predicted results for the chosen factor settings are: S/N ratio of 33.8551, mean of 17.5889, and standard deviation of 0.439978. Next, you might run an experiment using these factor settings to test the accuracy of the model

The predicted values for the standard deviation and log of the standard deviation use different models of the data.

Slide 15

Latihan

Diketahui karakteristik kualitas bersifat larger-the-better. Respon adalah pull-off force yang akan dimaksimumkan. Buatkan grafik respon dari SN ratio untuk keempat factor yang dicobakan serta tentukan nilai prediksi SN.

Slide 16

Factors and Levels for Tube

Control Factors Levels

A. Interference Low Med High

B. Wall Thickness Thin Med Thick

C. Insertion Depth Shal. Med High

D. % adhesive Low Med High

Noise Factors Levels

E. Time 24 h 120 h

F. Temp 72F 150F

G. RH 25% 75%

Slide 17

  Control Factors Noise

Treatment Combination A B C D E1F1G1 E1F2G2 E2F1G2 E2F2G1

1(A1B1C1D1) 1 1 1 1 15.6 19.9 19.6 20

2(A1B2C2D2) 1 2 2 2 15 19.6 19.8 24.2

3 1 3 3 3 16.3 15.6 18.2 23.3

4 2 1 2 3 18.3 18.6 18.9 23.2

5 2 2 3 1 19.7 25.1 21.4 27.5

6 2 3 1 2 16.2 19.8 19.6 22.5

7 3 1 3 2 16.4 23.6 18.6 24.3

8 3 2 1 3 14.2 16.8 19.6 23.3

9 3 3 2 1 16.1 17.3 22.7 22.6