Re: Shop Order Days Mystery Analysis -- BPCS-L

E-mail from Al Macintyre at Tim's PC at work.
____________________________________________
From: Stephen Bos <steveb@dayspring.com>
>We have stepped through the scheduling engine (SFC739) - arduous task - and
>are very confused about something.  It would seem that as the program loops
>from one operation to the next, regardless of work center correlation, the
>hours of capacity remaining from the previous operation's work center
serves
>as the basis for the next operation's hours remaining of capacity.  Maybe I
>am completely missing something, but to my simple mind this makes no sense
>at all.  The previous operation's work center capacity remaining is
>irrelevant to the next work center's capacity.  Can anyone shed some light
>on this for me?  Each of our work centers has a variable amount of standard
>capacity and these remainder hour quantities leave us with partial days
>which are apparently rounded up to whole days.  I think that is why we end
>up with 5 days of operation queue.
____________________________________________

There are times that fractions need to be rounded up (e.g. material
consumption) & times they need to be netted.  Often it is not clear whether
the programmer's understanding of this reality matches that of the end
users.  There are times I think programming standards ought to include at
beginning or end of a report which rounding rule was used here, and possibly
put that into system parameters for an application, so SSA clients have the
power to second-guess programmers on which rounding rule to use in which
circumstances.

Decimal Places & Unit of Measure Conversion Capabilities usually have been
sufficient for our purposes, but we have had troubles dealing with our
extruded wire.  We put it onto reels like 100,000 feet on a machine that
will only need 10,000 feet, but the fact that the reel is being used one
place means that it is not available to be used some place else & this is
not the only raw material in lots of similar magnitude.  Our production
handling of extruded wire has to go down to like 15/32 of an inch, and it
pricing it at 29 cents per foot is not competitive - we have to have more
decimal places than that.  Depending on where we incorporate unit of measure
conversions, there can be different hassles for different people, and
inappropriate rounding.

Inaccuracies in reporting material consumption & scrap can lead BPCS to
assume inaccurate on-hand material & generate flawed shop order
requirements.  This netting is hated by some of our people.  I do not know
if capacity has a similar risk of flawed reporting being a weak link in the
logic.  I do know that misconceptions in our system parameters can & have
screwed up our shop orders in the past.

There are a lot of variables for the BPCS detective.

Is there any pattern to the scenarios of extra days "thrown in?"
This might point you at one of the BPCS calendars (MRP120 SFC140 DRP150)
or at flawed engineering data (work centers, BOM, routings),
or an inconsistency in how your people are releasing orders (SFC500 MRP540
JIT540).

Do you have a check list of what people are supposed to do at the various
steps, for example we run CAP160 before we run CAP500.

When you find an order with extra days "thrown in" are you able to view the
story on earlier production of the same order & was the pattern consistent
for the part, with other concurrent parts scheduled just fine.  That would
point finger of suspicion at the engineering rules for the parts that went
haywire.

When you find orders with extra days "thrown in" are they the same days for
all those orders, in which those parts were scheduled just fine on other
days?  That would point finger of suspicion at one of the BPCS calendars.
____________________________________________
Al Macintyre
Central Industries of Indiana, Inc.
We Harness Quality
www.cen-elec.com
(812) 421-0231
(812) 424-6838 fax

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