1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.
Dismiss Notice
You must be a registered member in order to post messages and view/download attached files in this forum.
Click here to register.

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

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

Tags:
  1. reynald

    reynald Member

    Joined:
    Jul 31, 2015
    Messages:
    19
    Likes Received:
    24
    Trophy Points:
    2
    Location:
    Manila, Philippines
    Hi all,
    I saw this relationship on a training video.
    What is the logic behind this relationship?
     
    Last edited: Sep 12, 2015
    reynald, Sep 12, 2015
    #1
  2. reynald

    reynald Member

    Joined:
    Jul 31, 2015
    Messages:
    19
    Likes Received:
    24
    Trophy Points:
    2
    Location:
    Manila, Philippines
    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.
     
    reynald, Nov 18, 2015
    #2
    Atul Khandekar likes this.