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QFD vs Pugh Matrix

Six Sigma – iSixSigma Forums Old Forums General QFD vs Pugh Matrix

This topic contains 3 replies, has 2 voices, and was last updated by  Michael Schlueter 15 years, 11 months ago.

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  • #32299

    Mannu Thareja
    Participant

    Hi,
    Could any one please compare the QFD and Pugh Matrix with an example?
    I am little confused… It seems to be same to me…
    Regards,
    Mannu

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    #86107

    Michael Schlueter
    Participant

    Hi Mannu,
    QFD basically evaluates different views by matrices. You can start at a vague top-level and can deploy its messages downstream into concrete design-, process- and other requirements. The outcome from one matrix serves as input for the next lower level of detail. Hence the name Quality -> Function -> Deployment.
    The most prominent matrixis the matrix “house of quality”, which compares customer requirements with technical parameters. It translates the “voice of the customer” into the “language of the engineer”.
    E.g. for a car a customer may require “the doors close easily”. An engineer would translate this requirement into several technical parameters, like “closing force”, “size of the door lock” etc. This makes the vague statement more quantifiable.
    One should keep in mind that these technical parameters must hold for any design implementation. In other words: they are independent from concrete solutions, engineers may or may not have in mind.
    This concretisation is one of the next steps in Pugh concept selection. You can re-use the data from a previous matrix, like the house-of-quality. In the Pugh-matrix you will compare how effectively different design alternatives will satisfy the stated requirements.
    You can Pugh-compare the “voice of the customer” with design alternatives (design concepts). You can Pugh-compare the technical requiremetns with design alternatives.
    E.g. we have the following desingn alternatives for the door handle:

    A: snap-mechanism   (taken as reference)
    B: vacuum mechanism
    C: magnetic mechnism
    Now compare (in form of a matrix) which design concept will be better than the reference (+), equal to it (=) or worse (-). This way you visualize advantages and disadvantages and can select the most suitable concept for further implementation. Many times you can even come up with a (few) better alternative(s) from this considrations.
    E.g.
    “doors close easily”   A: ref.  B: +   C: +
    closing force 1N          A: ref   B: –   C+
    etc.
    Eventually concept C has more advantages than disadvantages over the reference A. Then you can hand over this taks to the next design team, asking: “elaborate a magnetic closing mechanism with … as boundary conditions; look into the house-of-quality, if you want to understand how important this device is for the overall success of the project”. (There you will also find benchmark data from your market place and an importance rating by your customer.)
    Best regards,
    Michael Schlueter

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    #86112

    Mannu Thareja
    Participant

    Hi Michael,
    Thanks for the great answer.
    That means QFD is generally used at the requirement stage, to choose the best set of requirements.
    Whereas Pugh matrix is used at the deployement stage, i.e. to select the best method which can be cover all the requirements selected by QFD.
    Like u gave an example, “the doors close easily” – This is the requirement. And by QFD, we select the best parameters which fulfill the requirements. eg, “cosing force”, “size of the door lock”.
    And in Pugh matrix we select the best technique which suits the parameters (from QFD) more than anyone.
    Am I on right track? Please let me know and correct me if i am wrong.
    Regards,
    Mannu
     
     
     
     

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    #86132

    Michael Schlueter
    Participant

    Hi Mannu,
    You did provide a great summary to my many words.
    Regards, Michael Schlueter

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