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VSM: Why is Production Lead Time = sum(Days of Supply)?

Discussion in 'Lean, Six Sigma and DFSS' started by reynald, Sep 12, 2015.

  1. reynald

    reynald Member

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    Hi all,
    I saw this relationship on a training video.
    What is the logic behind this relationship?
     
    Last edited: Sep 12, 2015
  2. reynald

    reynald Member

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    Found the answer to this. Apparently the relationship is generalized from Queuing Theory, specifically Little's Law.
    This law states that

    L = λ W

    Where the variables may be interpreted as
    L = average number of WIP
    λ = average processing time
    W = average time spent of the material as a WIP

    Using these, you can derive
    L/ λ = W

    and (L/ λ ) is basically same as days of supply.
     
    Atul Khandekar likes this.

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