Lars, Thanks for the answer. I hope there is no problem if I ask a few questions. I understand all you wrote.
1. Just as in your example, a customer buys a combination of "rolls". And the sales order has that detail. So I have to setup manufacturing of all the rolls in the order. So I have to create a UoM called "Rolls 50 m". Is this similar to what you did or do you sell mts (or yards, etc.)?
2. When I setup a manufacturing order for a roll, when and where do I regsiter the actual length in a roll?
3. When you say that I will see each lot number individually, that will appear as a list in the "detail operations" tab, correct? If so, the "Done" column should show the real length in meters, right?
THANKS

1. Do NOT create such UoM. Your rolls are not exact 50 m. That kind of UoM will not work. That UOM in the sales order is transferred to the delivery. It would have worked if they where 50 M. Enter the sales order in M. It is simple, and it works.
2. You register the manufacturing order fot the total M you need. Then when you confirm, you confirm one and one lenght. Set up a workcenter and an operation in the BOM. Then the registration of each roll will flow very good. This video here show how the registration flow. With one exception: You must enter the lenght of each lot number, before you confirm.
https://www.youtube.com/watch?v=nPxnl82eZ6A

3. One manufacturing order can only make one Lot number. So each time you confirm a lenght from work order view, Odoo create a new manufacturing order in the background.
In the inventory you will see each lot number with the lenght, and in the delivery you will see in the detailed view the lot number and qty for each lot number.

Another tip for: Use product packaging. You find it in Inventory->Condifuration.
There you can set a quantity in a roll. Using that, will warn yyou if the total order quantity is not a factor of packaging.

Hi Lars. I'm working on the last point you mentioned about using packaging. Can you explain a bit more about how to use it? It's not clear to me.

Packaging in sales. I made two screenshost that I hope tell you more than what I can describe for packages in Sales. One how to define a sales package for a product. You can also do it in the inventory tab in the product.
To activate this you need to go to settings in Inventory and sales and click on packages.

The Odoo help is found here:
https://www.odoo.com/documentation/14.0/applications/inventory_and_mrp/inventory/management/products/usage.html#packages

https://drive.google.com/file/d/1-bxtjixPfyllxy0EhEJgrpgmlZNB5NYx/view?usp=sharing

https://drive.google.com/file/d/1-gweFFGCUHWk1tz3NK-tY32mIszwdbqO/view?usp=sharing

Hi gain Lars. I want to understand better your directions. I have not been able to make this work like you say. In step 2, you say: "Then when you confirm, you confirm one and one lenght". I have not been able to make this work. When I create the MO, I only have the MO for the total, for example 200 m. I can't create four 50m work orders. Can you tell me how to create mulitple WOs from a single MO? Thanks.

Hell Manuell.
It is correct that the initial manufacturing order and work order is the full planned quantity. But as you confirm one part quantity with lot number, Odoo will automatic create a new manufacturing order and work order in background. I have a video that show the sequence and how it works.
https://drive.google.com/file/d/1-iuukpnL9Z1-SgjmnF4Id4AmhBzTyF2I/view?usp=sharing

Hi Lars. Would you be willing to consult on a project? If so, how can I reach you?

Hey Manuel
Yes I can provide some consultant service. Please send an email to lars.aam@vikenfiber.no

Hi Lars, sent you an email. Let's get in touch.