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Parts & BOMs - Something I am missing?
04-29-2015, 08:43 AM (This post was last modified: 04-29-2015 08:51 AM by janb.)
Post: #1
Parts & BOMs - Something I am missing?
In our company we hardly produce nothing from raw materials, only occasionally.
Most of our parts is either bought or produced by external companies. We do most assemblies into finished products.

Some BOMs can become quite big, 500-700 single items.
In practice most of the parts is parts of sub-assemblies, down to 7 levels mixed with fasteners for mounting and subs.
..and i thought i could do this in weberp as well.

My first approach was to use Assembly Items and realized that that was a bad idea. In my head an Assembly is an assembly of items to a product in a practical aspect.
Changing Assemblies to Manufactured instead was the only option left.
This part seems to work quite well (if it is correct).

My next approach was to use Phantom in our master BOM trying to keep track of both subassemblies, sequences and fasteners for mounting subassemblies in a logic order.
The reason for using Phantom was to tie mounting items to the same level as the sub-assembly in our master-bom. Seems also to be a good idea, this gave me a quite pretty and understandable bom list!

The problem i discovered today was that Phantom Items shows up in "List Components Required" reports as shortage. I thought Phantoms should be treated as a container of Items in BOMs? ..not as an item itself in reports?
Is this a bug in the report or is it my approach that is wrong?
I must say I am really confused!

The next problem i saw in the same report is that Items used in a Manufactured "Assembly" shows up both as shortage for the parts but not for the "assembly" itself.
I will try to explain:
IF i am using lets say 10 Items in a Manufactured "Assembly", makes a Work Order for 5 assemblies, gets the finished assemblies back, items are auto-issued from stock, and i have 5 sub-assemblies ready for the master assembly.
All single items (parts) are correctly drawn from stock an my sub-assemblies rises with 5 in stock.
The report "List Components Required" show all 5 assemblies available, but 5x10 parts used as shortage.

I am now in a situation where i am very unsure of my approach to how this should be done in weberp. Am i doing this completely wrong?
I am absolutely not an ERP expert but trying to learn while walking.
Anyone that can telling my what i am doing wrong?

JanB
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04-29-2015, 06:59 PM
Post: #2
RE: Parts & BOMs - Something I am missing?
Hi, JanB,

Your concept about Assembly is wrong. You can read the manual about the definition of Assembly and its properties. Manufactured instead of assembly should be used in you scenario.

And the phantom is a logic unit only and there is no physical one available. It seems a bug if there shortage report has this kind of item. I'll find sometime to check.

Thanks and best regards!

Exson
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04-29-2015, 11:52 PM (This post was last modified: 04-30-2015 02:05 AM by janb.)
Post: #3
RE: Parts & BOMs - Something I am missing?
Hi Exson and thank you for your reply

Yes, I have understood that Assembly in this concept is wrong, I have already changed to Manufactured. (that's why "assembly" is in double quotas)
..but still, when both Phantom and Manufactured/Bought items shows up as shortage, then I start to be confused.

If we ignore the Phantom for now, let me try to explain more clearly:

This is a simple list of a Manufactured Item tree:

  1. 50001 M ManufacturedItem1 (0 items in stock)
    1. 10001 B BoughtItem1 (1 item for build, 10 items in stock)
    2. 10002 B BougthItem2 (1 item for build, 10 items in stock)
    3. 10003 B BougthItem3 (1 item for build, 10 items in stock)


All parts are either Bought or Manufactured

If i have 0 Items left in stock of item 50001 the "List Components Required" shows correct shortage qty for all items.
If i creates a WO of lets say 4 items of 50001 with auto-issued 1 pcs of all parts beneath, all items is correctly drawn from my stock when returned (6 items left of all 1000*, and +4 pcs of 50001 in stock.

When i now run the report "List Components Required" for a higher level where 50001 is a part (1pcs) it shows:
    50001 (Build qty: 1, Shortage -3) - Correct, it's in stock
    10001 (Build qty: 1. Shortage -5) - Not Correct (its a part of 50001 in stock)
    10002 (Build qty: 1. Shortage -5) - Not Correct (its a part of 50001 in stock)
    10003 (Build qty: 1. Shortage -5) - Not Correct (its a part of 50001 in stock)

Edit:
A little bit more complicated situation occurs when i want to use let say 4 items of 50001 but only have 3 of them in stock.
..or when the same part participating in several different parent items.
The correct report should then only show shortage for items in the missing parent item?
..as well as shortage for the missing parent item it self?

The problem is that i am not sure we have built up this ERP correctly and therefore i want to be 100% sure before i flag this as a misleading report leading to serious consequences when we start purchasing parts based on this.
Another question i have asked my self about is how MRP treating this, which i don't have had time to analyze yet.
I want to be sure the base is correct before starting on that chapter.

JanB
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05-03-2015, 05:56 AM
Post: #4
RE: Parts & BOMs - Something I am missing?
After testing and looking into the "List Components Required" code i suspect this report for not support nested BOMs.
..and maybe it never was the intention to have support for nested BOMs in WebERP at all (?)
That's probably the reason i got Phantom items in there as well.
Well, fair enough.
I'm in a situation that i absolutely need nested bom's for keeping my assemblies (as manufactured parts) in order with their own bom's in my master-bom.
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05-03-2015, 08:16 PM
Post: #5
RE: Parts & BOMs - Something I am missing?
Hi, JanB,

What's version are you using?
Did you check the MRP report if the demand and supply is right?

Best regards!

Exson
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05-03-2015, 09:25 PM (This post was last modified: 05-03-2015 10:49 PM by janb.)
Post: #6
RE: Parts & BOMs - Something I am missing?
webERP version 4.12.2
Have done some patches as well from svn where necessary.
(but don't have the rev. for you just now)

Edit:
..sorry, have not checked the MRP report yet, planning to do that later today or maybe to morrow.
I made a new test company yesterday with some relevant data to make it easier to check but have to do some serious thinking/testing to get this right.

Btw. I have written a script that seems to work quite well giving me shortage for both single items and parents.
I haven't tested it with all possible variations for qty's , the challenge is to ensure qty's is split where it's on the "edge" for build / on hand where qty pass zero within a parent with childs.
It seems i can't send you an PM or e-mail?
Thought maybe you would be interesting having a look? It's quite different from the original script without temp tables.
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05-04-2015, 06:48 AM
Post: #7
RE: Parts & BOMs - Something I am missing?
I'd be keen to have a look

submissions@weberp.org

many thanks

Phil Daintree
webERP Admin
Logic Works Ltd
http://www.logicworks.co.nz
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