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MRP and obsolete items
09-05-2012, 11:56 AM
Post: #1
MRP and obsolete items
Hi all:

MRP demand calculation includes obsolete items (which I think is wrong).

Scenario:
ItemA has a BOM with 1 x ComponentA, 5 x ComponentB
Sales of ItemA = 10 units in 6 months
Current ItemA stock = 0
Current ComponentA stock = 0
Current ComponentB stock = 0

Has been flagged as obsolete recently (after stock = 0).

Run MRP for 6 months period, and the result will show a shortage of 10 ComponentA and 50 ComponentB, because they are needed to produce 10 ItemA.

I think it's wrong because ItemA is now flagged as obsolete. If so, should not be taken into consideration.

So, in MRP.php should:
1) line 248, include the stockmaster.discontinued = 0 condition

2) line 272, include the stockmaster.discontinued = 0 condition

3) line 314, include the stockmaster.discontinued = 0 condition

Not sure about the SQl in line 294, as these are the explicit demands made by the user...

Is it ok?

MRP is quite complex, so would like the POV of others developers before doing these changes.

Regards,
Pak Ricard
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09-05-2012, 06:36 PM
Post: #2
RE: MRP and obsolete items
Hi Tim:

Preventing an obsolete item being added to a BOM is a very good idea (and very simple to implement), but we should be able to mark an item as obsolete without loss of information (deleting its BOM). We keep BOM's for obsolete items to keep full track of them (how we produced them and costs involved).

My POV is we should just prevent obsolete items to be taken into consideration. Or is there any other simpler way to do it?

Regards,
Pak Ricard
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09-06-2012, 06:46 AM (This post was last modified: 09-06-2012 06:47 AM by phil.)
Post: #3
RE: MRP and obsolete items
I think if an item is obsolete then it is important also to remove it from any bills of materials - and the business would need a "heads up" that they will need a substitute in future. The warning should pop up IMHO when attempting to flag as obsolete only when the substitute has replaced all usage should the flag for obsolete be allowed to be set. If it is not done this way the MRP will calculate and the businsess will still be short of components to make what it needs to.

Goodness, does this mean Timmy and I are on the same page?

Phil Daintree
webERP Admin
Logic Works Ltd
http://www.logicworks.co.nz
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09-06-2012, 09:30 AM
Post: #4
RE: MRP and obsolete items
Hi:

I fully agree obsolete items shouldn't be a part of a BOM. This should be controlled at Stocks.php when changing the flag.

But my original worries were a bit different. The question was if obsolete items should be filtered out on MRP calculation, as now they are included on the demands side (as example, if there has been a sale of the item before the obsolete flag but inside the period of MRP calculation).

Regards,
Pak Ricard
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09-08-2012, 11:29 AM
Post: #5
RE: MRP and obsolete items
Coded and submitted. MRP now excludes obsolete items from demand side.

Sure we still need to work on control of change of the obsolete flag, but that's another issue ;-)

Pls check!

Regards,
Pak Ricard
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09-08-2012, 02:38 PM
Post: #6
RE: MRP and obsolete items
Hi Ricard,

I am not too sure about excluding the demand for these obsolete items where they are required for a work order:

Code:
prnMsg(_('Loading requirements from work orders'),'info');
    flush();
    // Definition of demand from SelectProduct.php
    $sql = "INSERT INTO mrprequirements    (part,
                                         daterequired,
                                         quantity,
                                         mrpdemandtype,
                                         orderno,
                                         directdemand,
                                         whererequired)
                               SELECT worequirements.stockid,
                                    workorders.requiredby,
                                    qtypu*(woitems.qtyreqd - woitems.qtyrecd) AS netqty,
                                    'WO',
                                    woitems.wo,
                                    '1',
                                    parentstockid
                                FROM woitems
                                    INNER JOIN worequirements
                                        ON woitems.stockid=worequirements.parentstockid
                                    INNER JOIN workorders
                                      ON woitems.wo=workorders.wo
                                      AND woitems.wo=worequirements.wo
                                      INNER JOIN stockmaster
                                        ON woitems.stockid = stockmaster.stockid
                                WHERE workorders.closed=0
                                    AND stockmaster.discontinued = 0";

I think this is dangerous and we need to ensure that no works orders are released containing the obsolete items as components - we need to have the BOM changed before the flag is changed.... I guess there could still be released works orders with these components in the requirements until the work order is complete.

Bit confused by this, but an uneasy feeling. Appreciate any other feedback on this one.

Phil Daintree
webERP Admin
Logic Works Ltd
http://www.logicworks.co.nz
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09-08-2012, 06:29 PM
Post: #7
RE: MRP and obsolete items
Hi Phil:

Appreciate your POV, and now I think the real question here is the definition of obsolete item.

In our case we use the flag obsolete as "item that currently we don't stock, we don't need and we don't want to stock or use again". In this scenario, the demands for obsolete items make no sense.

In our daily use it is incorrect to flag an item as obsolete if still in use for any reason (stock not 0, WO's or PO's running), so that's why in my logic it should be the way I coded it.

Any way it will not disturb me a second if you want these lines removed on WO's demands. The only mod that we really need is the one referring to demand due to past sales.

Maybe before flagging an item as obsolete webERP should check few thinks (as it does in many other flags or deletions).

We use a batch script to detect and flag obsolete items but it's highly personalized, I don't think will be useful for the community.

What about if I comment these WO lines until we all get to a final decision?

Regards,
Pak Ricard
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09-09-2012, 01:39 PM (This post was last modified: 09-09-2012 01:40 PM by phil.)
Post: #8
RE: MRP and obsolete items
But if you has sales orders out there and a customer expecting these to turn up, much better IMHO to phone the customer and let em know they won't get these obsolete items now - and cancel the sales order. With the demand appearing on the MRP this would be a useful flag to identify orders entered against the wrong item, but now you have lost this alert as they just don't appear on the MRP and you have an increasing volume of orders placed against obsolete items with no alert as to the problem?

Sorry to pour cold water on this - just trying to think about the practicalities and issues that may arise from this change. My feeling is this may not be a good idea. Interested to see how it works for you in your business - but you don't make stuff so maybe we back out the WO requirements change in the interim anyway? If that's ok with you?

The more important changes I would have thought would be the checks on changes to the obsolete flag which we seem all to agree on.

Phil Daintree
webERP Admin
Logic Works Ltd
http://www.logicworks.co.nz
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09-09-2012, 08:47 PM (This post was last modified: 09-09-2012 09:06 PM by PakRicard.)
Post: #9
RE: MRP and obsolete items
Yes, Phil, I think we should work and focus on the obsolete flag setting conditions.

If you have ANY outstanding sales order, WO or even PO against the item, it should be current not obsolete.

The question can be seen as: If MRP is used for planning purposes: Does it have any sense to plan on obsolete items? We should flag them as obsolete when they are obsolete, not before!!!

I can't understand your point of how you can have an increasing volume of sales on an obsolete item (probably we use a different definition of obsolete or language issue here). If you are selling it, producing it, stocking it, etc... to webERP purposes should be current, not obsolete. Again, this is true if we all use the same definition of obsolete item.

Regards,
Pak Ricard
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