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New feature for Manufacturing module discussion
04-30-2012, 11:29 AM,
New feature for Manufacturing module discussion
Dear all:

I'd like to open a thread to discuss new feature needed for Manufacturing.

1) BOM version control.

BOM Plays a key role in ERP. It'll impact the result of MRP, the cost calculation of accounting, issuing material to production etc. So It is reasonable to store the version for the BOM. Then it'll bring more benefit to Engineering change and related issues management.

2)Klaus has some suggestion in another thread about MRP, and I just brought it here:

eoq: maybe this is a terminalogy problem.

item and stockmaster has an eoq.
purchase data has a minumum order quantity and leadtime.

leadtime from purchasedata (also for preferred supplier) is used, minumum order quantity from same table is ignored.

If we suggest PO's, either we ignore all info from purchase data, or we should use it.

I propose:

to use eoq as a quantity seen from my companies side (however the minumum order quantity is, I personally always want to order at least eoq

to use minimum order quantity on top of that: if eoq is smaller than minimum order quantity, use that in the proposal PO instead.

If you agree on this change, I can do it and submit it and change the wiki so others know how this is used.

another feature request: for MRP, one could add checkboxes:
x ... use supplier with fastest leadtime
x use supplier with lowest cost
x use supplier with lowest price
x use preferred supplier

That would help planning (e.g. it could show whether a project could be faster by choosing the supplier with the fastest leadtime).

Any comments are highly appreciated!

Best regards!


04-30-2012, 03:22 PM,
RE: New feature for Manufacturing module discussion
and a third one:

3) the MRP calculation takes the lead time from the purchdata table.
I think two questions are not considered:
3a) purchdata has an effective date which is not used in the sql for the levels table. In order not to blow up calculation: always use leadtime valid at time of MRP calculation? Leadtimes varying over time would be a pain... But we experience this, our supplier has lead times varying between 2 and 4 months.
3b) (at least I think that is an issue): what happens to MRP if there are multiple suppliers but none is preferred? Is the sql correct for that? Or does it just use the leadtime from the entry with the highest index for a given part, so it is neither the shortest nor the longest but random among the suppliers?


04-30-2012, 04:35 PM,
RE: New feature for Manufacturing module discussion
Dear all:

I've received a comments that for BOM control, the simplest way is to lock the BOM if there are WO issued according to it. And prepare s scripts to unlock it in Z_index.php.

Is it a smart idea?

Best regards!

05-06-2012, 08:23 AM,
RE: New feature for Manufacturing module discussion
I am quite nervous about this!

This is a complex area and multiple versions of BOMs will compound the complexity. We will not meet every manufacturers wants in relation to MRP and attempting to will make it VERY complex such that newer users of MRP discovering its potential will be put off/blown away with all the options around it - and with minimal documentation to describe what all the options do the chances of bringing users on board to this powerful feature are reduced.

A basic MRP offering is really good in my view. However, it must be approachable and usable by the majority of users. By having multiple BOM versions I can guaranttee a hornets nest of bugs will be introduced and this would have to be in a separate branch until it is debugged by those using it and driving it's development.

It seems from Klaus's postings in the bugs section it already has some shortcomings and these should be resolved first IMHO.

We allow for multiple BOM versions by date already. With existing components dropping out after the EffectiveTo date and new components coming in after the EffectiveAfter date. Engineering change orders are catered for in a rudimentary manner. I am not sure the MRP looks at the new version of the BOM for works orders released at later dates ... this would be a starting point.

We also allow for different versions of the BOM by location so that if the work order is made at a different location that location's BOM could be used. Again I am pretty sure the MRP does not cater for this.

The BOM is currently much more powerful than MRP calculations and we should work to improve the MRP to match the capabilities of the BOM before we reinvent new BOM functionality.
Phil Daintree
webERP Admin
Logic Works Ltd
05-07-2012, 03:10 PM,
RE: New feature for Manufacturing module discussion
yes, in principle, I agrre with Phil's comment.

I am trying to sort this out - we need a MRP solution, and at the moment, my candidates are frepple and weberp.

I am willing to add to the documentation parallel to what I discover about the functioning.

without digging into the code deeply another time, there might be the following issue with the effective dates:
1) Exson is right, I was too fast reading the code, and the creation of the levels table does include the effectiveto and from dates.
2) It may be that this is too 'late' in the code, because the primary tables are created from the BOM without reference to dates.

consider that BOM AB is outdated, but componnent ABB, which is part of AB, is not. At the moment, I am not quite sure whether looking at dates at the point where it is done now might mean that AB is excluded, but AB's components are already in the table and will be included? I am not sure about this, does anybody using this code know?



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