Scrap Rate per Batch: The KPI Most Factory Owners Aren't Tracking

Most SME factories track scrap monthly. The accountant adds up the scrap material at month-end, divides by total material consumed, and writes a number on a report. That number is technically accurate and operationally useless — by the time you see it, the runs that caused it are weeks in the past, and the patterns inside it are completely hidden.

Scrap rate per batch is the same data, measured at the level where it can actually be acted on.

Why Per-Batch Beats Monthly

A factory might run 400 batches a month and average 3% scrap. That average hides everything that matters. Maybe 380 batches ran at 1% and 20 batches ran at 40% — same average, completely different problem. The 20 bad batches are where the money is being lost, and the only way to find them is to measure each one.

What to Capture

For every work order, log: total input material, total good output, total scrap output. The scrap rate is (scrap / input). Capture it the moment the batch closes — not at month-end. Attach it to the work order along with machine, operator, shift, and raw material lot. Those attached fields are what turn a number into a diagnosis.

The Patterns That Emerge

Once you've got per-batch scrap with context, the patterns reveal themselves within weeks. One machine consistently runs 2x the average. One operator's batches are clean when running familiar products and high-scrap on unfamiliar ones (a training opportunity, not a discipline one). One raw material supplier's lots produce more scrap than another's (a procurement conversation worth having). None of these are visible from a monthly total.

What to Do With the Data

Set a threshold — say 5% above your rolling baseline — and have any batch that exceeds it trigger a review. Not a punishment; a review. Five minutes of "what was different about this run?" within hours of it happening is worth more than a month-end report nobody reads. The goal is to build a feedback loop fast enough that the next batch benefits from what the last batch revealed.

The Cost You're Currently Eating

For a typical SME factory, the difference between measured-and-acted-on scrap and measured-only scrap is 20-40% of the total scrap cost. That's not a small line item — for many factories it's larger than the cost of the software that would surface it. The KPI is free to collect once your work orders are digital. Not collecting it is the expensive choice.