How Scrap Works in Production Routings in Business Central

Among the lesser-known properties of production routings in Business Central are the Scrap Factor % and Fixed Scrap Quantity fields found on the routing lines.

Many consultants ignore them completely, while others use them assuming they work the same way as BOM-level scrap.

In reality, their behavior is quite different and, without some hands-on testing, far from intuitive.

The question we're asking is: what impact do they have and, more importantly, which production scenarios do they actually cover?

Let's look at two separate cases.

With the Routing Link Code

When we link components to a specific routing operation via the Routing Link Codefield, we're telling the system that those specific components are consumed at that operation. In the example below, at operation 10 (painting) we consume the table top (to be painted) and the wood stain.

At the BOM or single-item level we haven't defined any scrap yet.

Let's now enter a Scrap Factor % of 10% on operation 10 of the routing.

Let's create a production order for 10 tables and look at the result on the generated components.

The system increased the requirement of all components linked to operation 10 by 10%: against a theoretical consumption of 2 liters of wood stain, the expected requirement rises to 2.2 liters, and in the same way one extra table top is needed compared to the theoretical calculation.

If we also add a further 10% scrap to the wood stain at BOM level, the system works in two steps: it first calculates the consumption including the routing scrap, then applies the BOM scrap percentage to that resulting value.

But what happens if, instead of the percentage, we set the Fixed Scrap QuantitySince this is a fixed quantity rather than a percentage, the first question to ask is: what unit of measure does that value refer to? In our BOM, after all, the table top is managed in pieces, while the wood stain is managed in liters.

To find out, let's produce 100 tables and see what happens.

What did Business Central do?

The answer is fairly simple, even if not entirely intuitive: by entering a fixed quantity on the routing line we are telling the system that at operation 10 there is a fixed consumption of 1 extra table compared to what was planned and, as a result, all requirements for the components linked to that operation are calculated as if we had to produce 101 tables instead of 100.

In fact, Business Central calculates a requirement of 101 table tops and 20.2 liters of wood stain.

Without the Routing Link Code

If components are not linked to a specific routing operation, the system increases the requirements of all components always in proportion to the increase in the parent item. In the example below, still producing 100 tables, but removing the link code from both the routing and the BOM, we also get an increase in the requirement for the table legs.

Naturally, if the scrap factor is entered on more than one operation at the same time, the system will increase the requirements proportionally for each of them.

Conclusions

The scrap factors entered on the production routing, whether fixed or percentage-based, increase the requirement of the parent item and, as a result, that of the components linked to that operation — or of all components, if no link is defined.

This feature is useful in scenarios where a machine involved in the production process requires an additional consumption of pieces, either fixed or as a percentage, of the parent item to be produced. Here are three typical real-world examples:

• Destructive test/trial piece: before starting series painting, the operator paints one test piece to calibrate color and thickness; that piece is scrapped once per order, whether 10 or 1,000 tables are produced.

• Machine setup/start-up: the machine "consumes" one piece to reach operating speed — for example, the first pieces coming out of a mold or a spray-painting line are often out of tolerance until the process stabilizes.

• Mandatory quality sampling: internal or industry regulations may require sampling one piece per batch for destructive testing (e.g., paint adhesion testing), regardless of order size.

© 2022–2026 Marco Francesco Ferrari. All rights reserved.