Help Manual

Contents






Sigma Magic Help Version 15

Quality Function Deployment (QFD)

Overview

Quality Function Deployment (QFD) is a structured approach to define product, manufacturing, or service requirements based on Voice of the Customer needs (VOC). It translates qualitative user needs into quantitative parameters that can be used to design quality into subsystems, parts, and manufacturing processes. It helps the company focus on the characteristics of the product or service from the market viewpoint. QFD is used in a wide variety of consumer products and services.

This tool can be added to your active workbook by clicking on Project and then selecting QFD Analysis.

Inputs

Click on Analysis Setup to open the menu options for this tool. A sample screenshot of the menu is shown below. inputs
1
Num Needs: Specify the number of customer needs. This dictates the number of rows of the QFD.
2
Num CTQs: Specify the number of CTQs. This dictates the number of columns of the QFD.
3
Weights Scale: Specify the scale to use for the weights for the relative importance of the VOC needs. The available options are:
OptionDescription
AnyWeights can take any integer value greater than or equal to 0.
0-10Weights can take any integer value between 0 and 10. This is the default setting.
0-100Weights can take any integer value between 0 and 100.
4
Correlations Scale: Specify the scale to use for the correlation between the VOC needs and CTQs. The available options are:
OptionDescription
AnyThe correlation scale can take any values greater than or equal to 0.
0-10The correlation scale can take any value between 0 and 10.
1,3,9The correlation scale can only take values 1, 3, or 9. This is the default setting.
1,3,5,9The correlation scale can only take values 1, 3, 5, or 9.
5
QFD Type: Specify the type of QFD you would like to create. The options available are:
OptionDescription
Standard QFDAll houses of the QFD are displayed.
QFD without RoofShow QFD without roof but with competition house.
QFD without CompetitionDisplay QFD with roof but without the competition house.
Basic QFDDisplay QFD without roof and without competition house.
6
View Example: Click on this button to open the example file. You can view the example to get an idea of how to fill out this tool or you can use the example as a starting point and modify it to meet your project needs.
7
Help Button: Click on this button to open the help file on this topic.
8
Cancel Button: Click on this button to exit without saving any changes.
9
OK Button: Click on this button to save changes and update your analysis results.

Worksheet

Enter the following information in the worksheet:
  • List all the customer needs in left side of the QFD matrix
  • Specify the importance ratings for each of the customer needs
  • List all the Critical to Quality (CTQ) on the top of the QFD matrix
  • Enter the correlation between the customer needs and the CTQs on a 0-1-3-5-9 scale
  • Enter the competitive ratings for our product/processes and suppliers on the right hand side of the QFD matrix
  • Enter the correlation between different CTQs in the roof of the QFD matrix
  • Specify the targets and specifications at the bottom on of the QFD matrix
  • Finally, specify the risk of meeting the CTQs on a scale of 1-10 at the bottom of the QFD matrix

Charts

If you click on the Charts button, you will see the following dialog box. Charts
1
Title: The system will automatically pick a title for your chart. However, if you would like to override that with your own title you can specify a title for your chart here. Note that this input is optional.
2
Sub Title: The system will automatically pick a subtitle for your chart. However, if you would like to override that with your own subtitle you can specify a subtitle for your chart here. Note that this input is optional.
3
X Label: The system will automatically pick a label for the x-axis. However, if you would like to override that with your own label for the x-axis you can specify a different label here. Note that this input is optional.
4
Y Label: The system will automatically pick a label for the y-axis. However, if you would like to override that with your own label for the y-axis you can specify a different label here. Note that this input is optional.
5
X Axis: The system will automatically pick a scale for the x-axis. However, if you would like to override that with your values for the x-axis, you can specify them here. The format for this input is to specify the minimum, increment, and maximum values separated by a semi-colon. For example, if you specify 10;20 then the minimum x-axis scale is set at 10 and the maximum x-axis scale is set at 20. If you specify 10;2;20, then the x-axis increment is set at 2. Note that this input is currently disabled and you will not be able to change this setting.
6
Y Axis: The system will automatically pick a scale for the y-axis. However, if you would like to override that with your values for the y-axis, you can specify them here. The format for this input is to specify the minimum, increment, and maximum values separated by a semi-colon. For example, if you specify 10;20 then the minimum y-axis scale is set at 10 and the maximum y-axis scale is set at 20. If you specify 10;2;20, then, in addition to minimum and maximum values, the y-axis increment is set at 2. Note that this input is optional.
7
Horizontal Lines: If you want to add a few extra horizontal reference lines on top of your chart you can specify the values here. The format for this input is numeric values separated by semi-colon. For example, if you specify 12;15 then two horizontal lines are plotted at Y = 12 and Y = 15 respectively. Note that this input is optional.
8
Vertical Lines: If you want to add a few extra vertical reference lines on top of your chart you can specify the values here. The format for this input is numeric values separated by semi-colon. For example, if you specify 2;5 then two vertical lines are plotted at X = 2 and X = 5 respectively. Note that this input is optional.

Verify

If you click on the Verify button, the software will perform some checks on the data you have entered. A sample screenshot of the dialog box is shown in the figure below. Verify The objective of this analysis as well as any checks that are performed is listed in this dialog box. For example, the software may check if you have correctly specified the input options and entered the required data on the worksheet. The results of the analysis checks are listed on the right. If the checks are passed, then they are shown as a green-colored checkmark. If the verification checks fail, then they are shown as a red-colored cross. If the verification checks result in a warning, they are shown in the orange color exclamation mark and finally, any checks that are required to be performed by the user are shown as blue info icons.

Outputs

Click on Compute Outputs to update the output calculations. A sample screenshot of the worksheet is shown below. outputs CTQ importance vs. Risk chart is created in the output area. The QFD matrix also lists the relative importance of each of the CTQs. The conclusion box shows a summary of the number of CTQs with high risk and high importance.

Notes

Here are a few pointers regarding this analysis:
  • To perform a multi-level house of quality or for CTQ cascade, you can insert several QFD worksheets in your Excel workbook. The output of the first QFD becomes an input to the second QFD worksheet and so on. The QFD tool remains the same for all the worksheets.
  • You can determine risk based on several factors: If it is a new technology or involves a significant expenditure of resources it could be considered high risk. Anything that may cause you to feel that you may have a problem with delivering the CTQ could be considered high-risk.