Re: den.list-d Digest V2002 #45 - Inventory

[DirkandKaren@aol.com]

<In-process inventory is "just in case" inventory.  As the
<probability of the up-stream and down-stream units operating properly
<increased, the need for "just in case" inventory diminished.  The fifty
<percent inventory reduction was a natural consequence of the process change
<that improved reliability.  Inventory was planned as a consequence, but
<never the focus of an overt program.


In-process inventory may not be "just in case inventory" but rather an 
unintentional result of a poorly designed manufacturing process. 

There is at least one more process factor that can cause in-process inventory 
other than machine reliability. The interaction of process step cycle times 
can cause in-process inventory. If the cycle time of successive operations do 
not support each other, then in-process inventory is the result. In Lean 
Manufacturing, this overt process improvement approach concentrates on Takt 
Time. Machines can be 100% reliable but there still can be a tremendous 
amount of in-process inventory if step 1 is a 5 second cycle time where step 
2 is a 10 second cycle time. This assumes the process is linear in design and 
there is only one processing location for step 2. 

Regards, Dirk van Putten
dirkandkaren@aol.com

[Moderator's Note:  Takt Time (from the German word for pace) relates to making a process
flow based on customer demand (oversimplified)  When I first show people Takt Time - I use
Deming's Production Viewed as a System...  lots of "Hmmmmm" follows.