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Inconsistency for MRP suggested WO's and MRP suggested PO's concerning their dates??
11-25-2014, 07:48 AM
Post: #1
Inconsistency for MRP suggested WO's and MRP suggested PO's concerning their dates??
A long time ago I sent in a patch for the following problem.
I just tested 4.11.5 and saw that it is not included.

In short: all dates are planned for the due date of the parent WO. But if I want to work for the WO, it is too late if I receive the constitutent parts on its due date. I rather need them on its start date (or sometime in between start and due date).

How do those people using MRP live with this problem, what is your workaround?
For us, it makes MRP suggested workorders and MRP suggested PO's unusable. Or maybe I just don't understand the correct way to go.

In detail:
Create a WO for AA, start Dec. 1st, due Dec. 31st.
BOM for this item AA has WO for item AB
BOM for item AB requires BB (purchased).

*Display MRP suggested WO: it gives date for WO for AB as Dec. 31st. But ??, that is the required date for AA. That cannot work in praxis if I start the child WO at the due date of parent WO.

*Display MRP suggested PO: it recommends PO for item BB for WO AB on Dec. 31st. But ??, that is the due date for the WO, isn't that too late for purchasing a BOM component for this WO?

It seems all dates are planned for the due date of the parent WO. Shouldn't they be planned for the start date of the WO?

Question: does anybody use this for actual time planning of purchases and WO start?
And if you do: how do you do it, what workarond do you use?


If child WO's and PO's are planned for the start date of the PO, I can still shift them to later time. If they are planned for the due date, I don't have the start date of the parent WO in that window, so I don't know when really to procure the PO or child WO.



My proposal (and the patch I submitted) is:

--suggest PO's and WO's for the start of the parent BOM, not for the due date of the parent WO. At the due date, the WO must be finished, so I definitely have to buy the PO items and start the child WO before the due date.
--even better:
* for purchases, include the lead time and shift recommended purchase date accordingly
* for child WO's, use a lead time. (One could set up the BOM item in addition as 'purchased' from my own company, and then I would have a field where to put my internal lead time for this type of WO).

--even more enhancement for planning: for each item in a BOM, add a field for the typical day number (either from start, or from end of the WO) when the item is needed.

Background: we do specialty equipment with delivery times of up to 6 months. Constitutent items are never on stock. To control money flow in a time where down payments are low, procurement should be as late as possible but still in time not to block the WO. We need a way to know when to buy or when to start a child WO.



any help is appreciated,

Klaus
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02-07-2015, 07:07 AM
Post: #2
RE: Inconsistency for MRP suggested WO's and MRP suggested PO's concerning their dates??
Hi Klaus,

I started with webERP 4.11.5 this year and I've just seen your topic about the MRP generated dates.

I have the same problem, simply the leadtime is not calculated to the manufactured items.

If an item is purchased and part of a manufactured item, that is part of another manufacutred item then sold, the lead time is calculated only for the purchased item. Buying of the purchased items, you will receive the material the day of sale.

Example for tree level of BOM:
buy.....(lead time).....manufacturing, manufacturing, sale.

instead of
buy.....(lead time).....manufacturing.....(lead time).....manufacturing.....(lead time).....sale.

At the moment I have to remember at which BOM level is the item and anticipate the buying estimating a week for every level down.

Another solution for this problem will be appreciated.

Regards
Giusba
Italy
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02-08-2015, 07:38 PM
Post: #3
RE: Inconsistency for MRP suggested WO's and MRP suggested PO's concerning their dates??
I did a fix for this a long time ago but it wasn't accepted into the code.

At the moment, I am off to a business trip and have no time to pull it.
I think I submitted it as requested in the wiki at that time (submit to developer list or a special email, I don't remember), so it may not be publicly availabe in the forums or on nabble.
You can search for my posts here or on nabble, maybe it is there as well.

Klaus

(02-07-2015 07:07 AM)giusba71 Wrote:  Hi Klaus,

I started with webERP 4.11.5 this year and I've just seen your topic about the MRP generated dates.

I have the same problem, simply the leadtime is not calculated to the manufactured items.

If an item is purchased and part of a manufactured item, that is part of another manufacutred item then sold, the lead time is calculated only for the purchased item. Buying of the purchased items, you will receive the material the day of sale.

Example for tree level of BOM:
buy.....(lead time).....manufacturing, manufacturing, sale.

instead of
buy.....(lead time).....manufacturing.....(lead time).....manufacturing.....(lead time).....sale.

At the moment I have to remember at which BOM level is the item and anticipate the buying estimating a week for every level down.

Another solution for this problem will be appreciated.

Regards
Giusba
Italy
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04-30-2015, 09:50 PM
Post: #4
RE: Inconsistency for MRP suggested WO's and MRP suggested PO's concerning their dates??
Hi Klaus,

I tryed to find a field where the leadtime (or something similar) could be stored, but I haven't found it.

The only field containing something similar is the "Lead Time" in Supplier Purchasing Data, but it exist only for purchased items and for maintained suppliers.

I don't know how MRP can calculate the requirement date without a leadtime for each stock item.

Giusba
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05-13-2015, 01:23 AM
Post: #5
RE: Inconsistency for MRP suggested WO's and MRP suggested PO's concerning their dates??
I submitted a fix to the developer list a very Long time ago.

Unfortunately, at the Moment, I do not find the code.

Maybe Phil can see/find what I submitted?

best regards,

Klaus

(02-07-2015 07:07 AM)giusba71 Wrote:  Hi Klaus,

I started with webERP 4.11.5 this year and I've just seen your topic about the MRP generated dates.

I have the same problem, simply the leadtime is not calculated to the manufactured items.

If an item is purchased and part of a manufactured item, that is part of another manufacutred item then sold, the lead time is calculated only for the purchased item. Buying of the purchased items, you will receive the material the day of sale.

Example for tree level of BOM:
buy.....(lead time).....manufacturing, manufacturing, sale.

instead of
buy.....(lead time).....manufacturing.....(lead time).....manufacturing.....(lead time).....sale.

At the moment I have to remember at which BOM level is the item and anticipate the buying estimating a week for every level down.

Another solution for this problem will be appreciated.

Regards
Giusba
Italy
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