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Value Stream Mapping

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  • #48240

    corona91719
    Participant

    I am attempting to create a VSM and have a question regarding cycle times. When attempting to calculate a cycle time for a part that comes through receiving, do I just count the time the part physically takes to be received or do I include the time it sits waiting to be received as well. For example: A part arrives at the dock but sits as other parts are being received. Does this time get counted as cycle time?
    Thanks 

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    #161831

    Chad Taylor
    Participant

    In General the part is not technically waiting until it is physically received as inventory. If this shipment is already considered inventory and is simply a transfer of inventory, then the whole time would be counted. The reason I say this is if a shipment arrives late in the afternoon and does not get Physically Received until the next day, obviously a long wait time, but the actual act of receiving may only be a few minutes.
    Chad Taylor

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    #162139

    Big Al
    Participant

    My initial question would be where does the process for which you are preparing the VSM start and finish?  Is “waiting to be received” within the boundaries?  If yes, then it needs to be included.  Is it also likely that the time it (and other parts) sit waiting to be received represent a significant portion of the process cycle time you are trying to evaluate?  If it is significant, then the waiting time needs to be quantified and reviewed to determine whether it can be reduced.  You may also want to check with your accounting types to determine who owns the inventory at that point.  I would also go as far as to question how much of the receiving process is value added?  If receiving includes inspection, counting and moving product around, it may have a number of non value added elements.   Hope this helps.  

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    #162143

    EdG
    Participant

    If you refer to the “Current State Map” section of Learning to See, in the example the authors show inventory triangles between each process step and preceeding the first process step in the example.  (Look at page 33 for the final sample)
    I would recommend you use that to account for the parts awaiting “their turn for Recieving”.  In this fashion, the parts awaiting recieving are not apart of the recieving cycle time.  However the time duration for a part to make it through recieving from when it arrives “at the dock” is dependent upon the Recieving process step’s cycle time.  I.E: If recieving’s cycle time is 5 minutes and the “inventory” prior to recieving is 1,000 parts then their is 5,000 minutes of inventory (or ~3.5 days of inventory assuming continuous 24 hr operations).  Meaning that after arriving at the dock, that part will take ~3.5 days before it is actually recieved into the plant.
    Hope that this suggestion helps some.

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    #162145

    Ron
    Member

    Cycle time is defined as the time it takes to complete the cycle. I assumethat your step in the value stream map would be simply receiving. If this is correct then your cycle time would be from the time the trucl backs up to the dock until you complete this step in the process which is normally logging it into your computer inventory system.

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    #162148

    jcampagna
    Participant

    The whole point of VSM is to help identify areas of waste or where value is not being added.  The parts waiting on the dock is a time where no value is being added.  This is certainly a time to be measured.  The benifit for knowing this time is to determine if this is an area where you need to make improvement.  Parts waiting on the dock are parts that could be used in a value adding process.

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    #162151

    JJ
    Participant

    Ron,
         Once the item / product hits the dock, it part of the complete measuring process. Think of it as FOB destination, you own it when the trucker arrives at the dock.
    JJ

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    #162156

    ALain
    Participant

    Total cycle time is the total elapsed time, exluding non-business hours. For example, the business closes at 5h00PM and reopens at 8h00AM. If the part arrives at 4h00PM and is physically received at 9h00AM the next morning, cycle time is 2 hours.

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    #162159

    Ron
    Member

    You must separate “cycle time” from “waiting time.”  This is the true point of VSM.
    So, if the “value add” time, in this case the time to actually receive the product, is 3 minutes and the product waits for 1 hour before receiving and then another 2 hours after it is received we have VA = 3 minutes and NVA = 3 hours (180 minutes). 
    This gives us a PCE (process cycle efficiency) of 3 min / 180 min = 1.6%.
    As another commented mentioned you draw these waiting times using a triangle symbol of some people use tombstone looking symbols. 
    Your goal would then be to see how to eliminate this waiting time, or at least radically reduce it.
    There are many good VSM books available (Learning to See is just one of them).  Go to Amazon and do a search.  Pick up a couple of them and you will be good to go.
    Hope this helps.

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    #162161

    Perryman
    Participant

    I agree with Chad’s logic but you have to also consider the question from the customer perspective.  Why are you doing this project in the first place?  In my experience, it is probably because the “customer” is waiting too long for whatever it is that is coming through the receiving door.  They don’t care if it is sitting on the dock or in process, they just want the part or product.  If this is so, you have to set your process limits accordingly, otherwise you might miss the boat.
    Good luck,
    Patch

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    #162167

    BTDT
    Participant

    Corona91719:You have identified a very important aspect of a project; the operational definition of “received.”During the Define phase, you should have determined with the team when the stopwatch starts for, “receiving.” It depends on the project scope, who owns the process at the handoff, etc.In a practical manner, I would include the time spent waiting on the dock before it is logged as received. There is too much slack in this area of the process to ignore. If this is vague, it allows too much finger pointing to occur while you are identifying delay in the process.The example I like to use is how tax returns are classified as late or on time. The IRS uses the postmark as the cutoff. The IRS has not received the return, but the taxpayer can not recall the mail. If delivery to the IRS is a problem, it is not the fault of the taxpayer. Everyone involved agrees to this definition and the stakeholders adapt their behaviour to accomodate this.Cheers, BTDT

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    #162169

    EdG
    Participant

    All, Take a quick look at this.  As both Ron and I were trying to explain, it hope this picture helps eliminate confusion…
    That first inventory triangle, that is your “stuff at the loading dock” awaiting their turn to be received.  The first process block, that is your Receiving Process step (with all information ONLY pertaining to the process of receiving an item).  The time-line portion below the first inventory triangle is how you will account for all of the WAITING time that the items must endure prior to actually being received.
    I hope that this helps.
    Good luck…

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    #162175

    Mike Carnell
    Participant

    Patch,
    Is this the same Patch that posted from Canada?
    Regards

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    #162177

    Perryman
    Participant

    Hi Mike,
    Been a while.  We should get back in touch.
    514.873.7414

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    #162179

    Brandon
    Participant

    Corona – go to lean.org – you’ll find more info on Lean than you can ever use.

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    #162184

    Mike Carnell
    Participant

    Patch,
    I will give you a call. I am headed for Mexico this afternoon and will try you in between flights.
    Good to see you are still around.
    Regards

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