By-products
In the “Manufacturing” module, by-products are implemented through Bill of Materials by-products.
From a user perspective this means:
- in a Bill of Materials you can specify not only components (what is consumed), but also by-products (what is additionally produced);
- when manufacturing order lines are generated, by-products automatically appear in output lines (and for unbuild — in material lines).
Where by-products are defined
By-products are defined in a Bill of Materials on the “Byproducts” tab.
Each line includes:
- Product (what is produced as a by-product), with the UoM, Barcode and ID reference columns;
- Qty — the norm for the Bill of Materials base quantity.
Example: if the Bill of Materials is defined for 1 unit of the item, then by-product quantity is the by-product norm per 1 unit.
How by-products are transferred to a manufacturing order
In the manufacturing order card, when you run the line generation action (“Create Lines”), the system:
- Takes the planned quantity (how much needs to be produced).
- Calculates component lines.
- Creates output lines:
- the main item;
- by-products from the Bill of Materials.
By-product quantity is calculated proportionally:
by-product norm × order quantity / Bill of Materials quantity
For example, if the Bill of Materials is defined for 10 units and the order is for 20 units, by-product norms are doubled.
Note: by-products are taken only from the order’s own Bill of Materials; by-products of nested intermediate Bills of Materials are not added.
By-products in unbuild (disassembly)
For unbuild, the logic is mirrored:
- Bill of Materials components become “output” (what is received);
- the source item becomes “material” (what is consumed);
- Bill of Materials by-products are added to materials, i.e. they are also consumed.
Practical meaning: by-products in unbuild are treated as additional losses/consumption that should be written off together with the unbuild.
How by-products affect costing
The order cost (the material write-off plus any additional cost components — see Costing) is distributed across output.
Important:
- by-product lines created from the Bill of Materials do not have a cost ratio filled in automatically;
- if cost ratios are not filled in, the total cost is assigned to the main item, and by-products get a zero share.
If you need part of the cost to be assigned to by-products:
- Fill in the Cost ratio on output lines in the manufacturing order.
- Recalculate/verify distribution.
For details about distribution see Costing: how it is calculated.
Recommendations for by-product accounting
- Separate “by-products” from “scrap”:
- by-products are an expected result of the process (for example, offcuts, recyclable material) that can be received into stock;
- scrap is an unplanned loss that is usually recorded by a separate Scrap document.
- Configure by-product items as separate items so they can be stored, written off, and analyzed.
- If the whole cost should stay on the main output item (by-products received "for free") — keep the default distribution. If the cost should be split between the main output and by-products — use cost ratios.
Typical mistakes
- By-products do not appear in the order — by-products are not filled in the Bill of Materials or line generation was not run.
- By-products appear but the quantity is wrong — check the Bill of Materials base quantity and the planned order quantity.
- By-products do not affect costing — this is expected with default distribution; fill in cost ratios on output lines.