RE: MRP Arguement

Al,

You are correct (assuming you are not using "shop order generate").   Demand
is pegged to one level up in the BOM.  The nice part about an MRP system is
until you hard allocate materials to a shop order, there is no link to a
parent and they can be applied however a Planner sees fit.  The bad part of
an MRP system is, without pegging up, you do not have a direct link to the
finished goods.

Hope this helps.

Kent Van Horn
Manufacturing Consultant

-----Original Message-----
From: owner-bpcs-l@midrange.com [mailto:owner-bpcs-l@midrange.com]On Behalf
Of MacWheel99@aol.com
Sent: Wednesday, August 30, 2000 12:02 PM
To: BPCS Users Discussion Group
Subject: MRP Arguement

We 405 CD users have been having an arguement about MRP Reschedule dates
that
perhaps someone else can weigh in on one side or another to help us out.

It is my contention that MRP reschedule dates only blow through the whole
BOM
when there is no firm planned order with a contrary story.

Co-workers are arguing that we can rely on MRP reschedule dates irrespective
of any dates maintained in Factory orders.

Let's suppose we have a Customer Order due end of October and zero Factory
Orders released   MRP500+600 regen will blow through BOM & correctly date
plan that we should assemble the end item (100 wire harness) within a few
days before the promised ship date, and a few days before that we should
complete the various sub assemblies (many wires), and some days before that
we should complete the individual wire leads, and the raw materials should
be
in house perhaps 10 days before end item promised to customer.

If customer order gets changed, so now it is due beginning of October & we
do
MRP500+600 regen, and no orders have actually been released other than the
original customer order, the reschedule dates will be recomputed on all the
BOM requirements, recommended shop orders & purchase orders, with the same
lead time logic, so that if we follow the MRP advised dates then we will get
the part shipped to customer on promised date with no material shortages &
no
expediting needed.

However, if before the due date on the customer order was pulled up, someone
had released a shop order due when MRP says it was due, we are now in the
situation of Customer order beginning of October, shop order that satisfies
the quantity of the customer order due end of October, with reccommended
reschedule date beginning of October.

All the sub-components & raw materials needed for that end item have their
MRP reccommended dates driven not by the customer order, whose quantity is
satisfied by the shop order that will be a month late, but by the shop
order,
so the sub-assemblies (many wires), individual wire leads, and raw materials
will all have MRP saying they are due as if the part is not needed until the
end of October.

So long as the shop order for the part says it is not due until the end of
October, this situation will not change, because human firm orders trump MRP
soft dates.

Now if someone does shop order maintenance to make the due date of the shop
order for the end item in agreement with the pulled up customer order due
date, then the MRP reschedule date reccommendations will drop down a level &
tell any orders needed to fulfill that item to be ready in sync with the due
date that was put in the shop order.

If there are no released orders, MRP will blow through BOM correctly
calculating everything we need, to once again be on the correct schedule to
meet our promise to our customer.

If an order has been released on any sub-component with a due date that was
valid before the customer order due date was pulled up, MRP reschedule date
reccommends that it also be pulled up, but MRP date projections stop at that
point & do not suggest that any orders to get the materials that
sub-assembly
shop order needs be pulled up, because BPCS is assuming that we know what we
are doing & are deliberately firm planning dates other than MRP
reccommendations.

Am I correct about all this, or are my co-workers correct that in this
respect I have got it wrong?

Al Macintyre  (c)¿(c)
MIS Manager Green Screen Programmer & Computer Janitor of BPCS 405 CD Rel-02
running on AS/400 V4R3 http://www.cen-elec.com Central Industries of
Indiana--->Quality manufacturer of wire harnesses and electrical
sub-assemblies
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