MRP issues

Hi Jim

MRP has a few issues here in that it does not take into account:

1. the fact that there may be W/Os in the past (last month, last week or
even yesterday) that are not completed. i.e. there may still be quantities
due on these w/orders.
2. the fact that some W/Os due in the future may have a quantity already
completed.

I did this about 2 years ago and I'm not in front of the box at the moment.
If you need more details you may email me privately (website address is at
the bottom).

The way we've handled this is as follows:
a. Assume your actual model is D1.
b. Setup a new model for the user to enter the forecast to model F1. 
c. Setup another new model X1 which will only hold the differences
calculated. 
d. Create a pgm that will add/subtract the data (taking account points 1 and
2 above) and put the differences (either positive or negative) in model X1.
The relevant past due (as per the limit set in 12/MRP) orders should also be
totaled into todays date (MRP doesn't look at anything before today). The
pgm should then run through and create a running total in your actual model
D1 from which your demand is produced. 
e. Before MPS/MRP day-end run, run this pgm. 
 
NOTE: If I remember correctly MRP regards a negative as an absolute value
(i.e. positive, as there can never be a negative demand) and thus creates a
demand. 

Therefore, when I say running total, I mean the running total (in model D1)
should be: 
Qty in F1 + Adj qty in X1 = Qty in D1
If the Qty in D1 is negative, zeroize Qty in D1 and add this negative qty to
the Adj Qty in D1 for the next (production) day. You may end up actually
creating records as well. Your actual demand should now be correct.

Hope this helps

Regards

Kit
www.support.changefit.com
 

> message: 1
> date: Mon, 12 Jan 2009 12:01:50 -0800
> from: "Jim Kerr" <JKerr-FaIC0pVkSM6w7v2zf2itdNJR4SXAr38/@public.gmane.org>
> subject: [SYSTEM21] MRP issues
> 
> I have two issues that have just come to light.
> 
> 
> 
> 1.	No MRP demand created for items on a bill of material where the
> parent does have a forecast demand. I've checked the production details
> and
> the item looks to be defined correctly. Other item on the BOM do show
> the
> necessary demand but a couple of items lower down the BOM are not
> showing
> demand.  What program do I need to look at that builds the MRP73 file ?
> 
> 
> 
> 2.	The MRP Planner report (MR045) all of a sudden has started
> showing
> duplicate entires for purchase orders. No surprise there as there are
> duplicate records in the MRP73 file. So again, where is the best place
> to
> look (program) that creates these MRP73 records. I think this isuue
> must be
> a bug, surely ?
> 
> 
> 
> Regards.
> 
> 
> 
> Jim Kerr.
> 
> 
> 
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