I don't believe there is a perfect solution.  You need to explore 
alternatives, do some testing, determine which is best fit to your needs.
Needs vary with company, but something that has been important to us is 
simplicity of procedures.  We need our people to get practiced at doing 
things a certain way.
If they have to remember ...
if this set of circumstances we are to do things one way
if that set of circumstances we do things some other way
with a bunch of different scenarios
then there is high risk that some scenarios will get done a way that is 
right in some circumstances, but the wrong way for that scenario
plus the process of figuring out which alternative way to use, that can 
introduce inefficiency, slow down into clerical work
We better off having some system of coding such that when the orders are 
entered to customer orders, forecast, the independent demand ... that is 
correct, then everything else falls into place..
I think managing the purchasing consolidation is the easiest.
You can have thousands of different items for many different customers & 
internal all aiming at same component used ordered from some supplier in 
the BOM.  The MRP will calculate for you what quantity of the componenent 
needs to be ordered.  The PUR process does not need to know why we ordering 
this part on behalf of what end items, MRP aggregates or consolidates the 
needs for you.
Likewise production of sub-components & sub-assemblies does not need to 
know why this or that part being made for what end customer or for OUR end 
item #s ... you do the work efficiently through MRP netting.  We have in 
our routing instructions, which prints on the labor tickets, where the part 
is to go after completion, or what is to be done next, to expedite movement 
through the factory.  A copy of the labor ticket becomes an inventory tag 
... what this is, where it goes next, what needs to be done with it.
We also have a miniature BOM where-used printed on the labor ticket, so if 
the part is a common, it is showing the non-commons that use the part, that 
have current requirements.  Supervisors of final part assembly have an 
inquiry ... they can key in some part that we are about to start work on 
... the screen tells them which components are not yet ready, and where in 
the factory they supposed to get ready.
We accomplish this by thinking through how to structure BOM and routings, 
not just how to make the parts, but how to track the parts needs.
A potential challenge comes when you have parts in inventory, and in 
production, that are physically identical but identified with different 
item #s.  It is very easy for a worker to go get the materials that 
physically are exactly what's needed, but end up with transactions that are 
for a different item #, leading to inaccuracies, when you need BPCS to 
aggregate quantities of what's physically identical.  This is one reason 
why we went to commons.   We use our # system and customer # system only 
for parts that are truely unique.  We are able to sort descriptive info 
from item master and routings to identify where there are different items 
that are physically identical.  Then we replace them with a system of part 
#s based on what's in common identical.
Thus we have several different part # logic systems.
* item #s based on OEM where the parts are truely unique
* item #s based on our internal, also unique
* item #s describing physical characteristics of parts that are common to 
multiple places
* codes on ends of item #s to identify special handling, with respect to 
pricing, QC etc.
We also use some fields of item master that BPCS does not use, to flag some 
items as needing special handling.  For example, we have identified some 
bottlenecks in our factory, where we want to keep the work going through 
there busy all the time, never idle, and sometimes prioritize what parts 
are going through there.  So we have a code to identify parts that at some 
point in their production will be going through a particular bottleneck, 
and print that on reports showing lists of items in production, to let 
certain people know to watch out, make sure these parts not fall behind 
because of that bottleneck.
Al Mac
BPCS nerd
Thanks, Al.  I'm mulling all if this over - there is a lot to it!
Don
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