• Operator is the technician operating the welding machine. Two technicians typically operate the machine.
 • Speed (in rpm) is the speed at which the part rotates under the beam.
 • Current (in amps) is a current that affects the intensity of the beam.
 • Mode is the welding method used.
 • Wall Size (in mm) is the thickness of the part wall.
 • Geometry indicates whether the joint is a single-bevel joint or a double-bevel joint.
 • Material is the type of material being welded.
Notice that three of these factors are continuous: Speed, Current, and Wall Size. Four are categorical: Operator, Mode, Geometry, and Material. Each of these categorical factors has two levels.
 • Find which factors affect the depth of the weld.
 • Quantify those effects.
 • Find specific factor settings that predict a weld depth of 0.17 inches with a tolerance of ±0.05 inches.
 1 Select DOE > Classical > Screening Design.
 2 In the Responses panel, double-click Y under Response Name and type Depth.
 3
 4 Click under Lower Limit and type 0.12.
 5 Click under Upper Limit and type 0.22.
 6 Leave the area under Importance blank.
 •
 • To enter the factors automatically, use the Weld Factors.jmp data table:
 1 Select Help > Sample Data Library and open Design Experiment/Weld Factors.jmp.
 2 Select Load Factors from the Screening Design red triangle menu. Proceed to Choose a Design.
 1 Type 3 in the Add N Factors box and click Continuous.
 2 Double-click X1 and type Speed.
 3 Use the Tab key to move through the rest of the values and factors. Make the following changes:
 a. Change the Speed values to 3 and 5.
 b. Change X2 to Current, with values of 150 and 165.
 c. Change X3 to Wall Size, with values of 20 and 30.
 4 Type 4 in the Add N Factors box and select Categorical > 2 Level.
 5 Double-click X4 and type Operator.
 6 Use the Tab key to move through the rest of the values and factors. Make the following changes:
 a. Change the Operator values to John and Mary.
 b. Change X5 to Mode, with values of Conductance and Keyhole.
 c. Change X6 to Geometry, with values of Double and Single.
 d. Change X7 to Material, with values of Aluminum and Magnesium.
Responses and Factors Outlines for Weld Experiment
 1 Click Continue.
 2 (Optional) From the Screening Design red triangle menu, select Set Random Seed, type 12345, and click OK.
 3 Accept the default selection to Choose from a list of fractional factorial designs and click Continue.
 4
Design List for Two Continuous Factors and One Categorical Factor
 5 Click Continue.
In the Output Options outline, note that Run Order is set to Randomize. This means that the design runs will appear in random order. This is the order you should use to conduct your experimental runs.
Completed Screening Design Window
 6 Open the Aliasing of Effects outline under Display and Modify Design.
Aliasing for an Eight-Run Fractional Factorial Design
Recall that you selected a Resolution 3 design (see Design List for Two Continuous Factors and One Categorical Factor). In a Resolution 3 design, some main effects are confounded with two-way interactions. The Aliasing of Effects outline indicates that, for this Resolution 3 design, every main effect is completely confounded with three two-way interactions. If you suspect that two-way interactions are active, this is a poor design. For a description of confounding, see Two-Level Regular Fractional Factorial.
 7 Click Make Table.
The Design Data Table
 – The table uses the names for the responses, factors, and levels that you specified.
 – The Pattern column shows the assignment of high and low settings for the design runs.
 – This fractional factorial design is a Resolution 3 design. It enables you to study the main effects of seven factors in eight runs.
 1 Open your Screening Design window. If you have closed it, then run the DOE Dialog script in the Design Data table.
 2 Click Back.
 3 Click Continue.
 4 (Optional) From the Screening Design red triangle menu, select Set Random Seed, type 12345, and click OK.
 5 (Optional) From the Screening Design red triangle menu, select Number of Starts, type 50, and click OK.
 6 In the Choose Screening Type panel, select the Construct a main effects screening design option.
 7 Click Continue.
Under Number of Runs, the selected option is Default with the number of runs set to 12. Keep this setting.
 8 Click Make Design.
Main Effects Screening Design
 9 Open the Design Evaluation outline and then open the Color Map on Correlations outline.
Color Map on Correlations for 12-Run Main Effects Screening Design

Help created on 9/19/2017