Your inspection log shows ten parts scrapped. The scale ticket from the same batch records discarded trim that never became a part. Manufacturing scrap rate can mean the share of units scrapped or the share of material input discarded. Choose the denominator that answers the question you need to act on, then name it in the report.
For a closed batch, divide scrapped units by unique units entering the measured process to see how many pieces you lost. Divide discarded material weight by material input weight to see how much feedstock left as waste. Keep the process and batch boundaries fixed (including which material returns count as reusable).
Choose between units lost and material discarded
A unit-based rate answers whether a work order or operation lost more pieces. Count unique pieces entering the stated process, including pieces that end up scrapped there. If you count at a downstream inspection station, a part scrapped upstream is outside that denominator. Put the operation in the metric name so reviewers can tell those rates apart.
A weight-based rate helps a material owner investigate how much stock was lost at cutting, forming, or later rejection. Weigh the input charged to the measured batch and the material discarded inside the same boundary. Use net weights (subtract the tare, or the weight of the empty container) and the same unit on both sides. The EPA’s materials-flow method separates material flows from waste flows so waste that never became a finished part can still be measured.
Write down how you treat offcuts returned to usable stock and material sent out for recycling. A discard rate can include material sent out of the process even when it has resale value. A report on unrecoverable loss may use a different category. Preserve the recorded disposition so changing that policy does not change the old scale ticket.
Calculate both rates for one closed batch
Suppose a line charges 1,000 kilograms of sheet metal to one closed batch that produces 500 traceable pieces entering its finishing and inspection process. Of those, 460 pass the first inspection, 30 fail and pass after rework, and 10 are scrapped. The weight view covers the batch from cutting through final disposition. No material is left in the line and there are no other losses in this teaching example.
| Final destination | Piece count at finishing and inspection | Material weight across the batch |
|---|---|---|
| Accepted on first pass | 460 | Included in accepted material |
| Accepted after rework | 30 | Included in accepted material |
| Total accepted output | 490 | 900 kg |
| Parts discarded after final decision | 10 | 20 kg |
| Trim discarded at cutting | Outside the piece count | 65 kg |
| Reusable offcuts returned to stock | Outside the piece count | 15 kg |
The unit scrap rate at finishing and inspection is 10 ÷ 500 × 100 = 2%. The material discard rate is (20 + 65) ÷ 1,000 × 100 = 8.5%. The weight reconciles to 1,000 kilograms across accepted parts, discarded material, and reusable offcuts. The reusable 15 kilograms remain outside the discarded numerator under this example’s policy.
First-pass yield is 460 ÷ 500 × 100 = 92%. ASQ’s quality glossary measures first-pass yield against quality requirements before actions such as rerunning or repair. The thirty pieces that needed rework missed first-pass yield and still reached accepted output. To investigate why they needed a second pass, preserve the initial inspection outcome as described in First pass yield.
Keep rejection and disposal as separate events
Oracle’s production quantity reporting supports separate rejected, completed, and scrap quantities and captures a scrap reason. Use the same separation in your report. A rejected item may sit on hold, return from rework, or end as scrap. Link the final disposition to the original inspection so one rejected piece with a scrap ticket appears once in the scrap count.
Use a stable plant, work-order, operation, lot or serial key and record the source transaction ID, disposition time, material and unit, measured amount, and reason. Keep the scale-ticket ID and tare for weight records. If several orders share a bin and the tickets establish the bin weight but cannot allocate it, report the bin total with its scope and leave the order split unknown. Assigning all the weight to the last order makes the arithmetic work and gives the wrong team a loss to explain.
When you compare product groups or shifts, calculate the combined rate from the sum of their numerators and denominators at the same process boundary. A simple average gives a small run as much influence as a large one. Trace a high numerator back to material lots and operations before assigning a cause. Lot traceability describes how to preserve those links when a lot splits across orders.
Keep the inspection time and the disposal time when a reject crosses a reporting cutoff. A batch view follows the original pieces through final disposition, while a waste pickup log follows the date the bin left the facility. The two reports can assign the same loss to different weeks.
Check a scrap export against its source fields
Use a supported source in Permute to see whether the export retains disposition, weight, and work-order references.
Where Permute fits in scrap reporting
Permute is the context layer we sell between production records and the AI tools people use. We can bring together a supported ERP export, inspection data, and scale records, then connect the rows through work-order, lot, or transaction identifiers where those keys exist.
We keep the unit and weight definitions separate. The stated boundary and disposition rules can feed the same report each week, with pending rejects and missing lot links visible in the results.
A quality manager can ask which batches lost the most material and get the supporting weights and dispositions they are authorized to see. The answer can distinguish a batch tied to scale tickets from a bin total that has no order allocation.
Keep disposition authority with the plant
We read connected records. We do not write back into the system of record, decide whether a part can be reworked, or set how scrap is valued. Use the plant’s approved quality and accounting procedures for those decisions.
Choose the loss measure that matches the investigation
A unit-based manufacturing scrap rate follows pieces through final disposition. A weight-based rate follows input material and can capture trim that never became a piece. In the sheet-metal batch, both rates reconcile because the boundaries, reusable returns, and rejected pieces are accounted for. Keep first-pass yield separate so a successful repair remains visible in the quality history without increasing scrap.
Trace a scrap variance with Permute
Bring a disputed batch, its disposition history, and any scale tickets to review how the records can be connected.
Questions about what belongs in scrap
How should I report a batch with parts still on hold?
Show the confirmed scrap and the unresolved quantity with the cutoff. If you publish a provisional rate, keep its status visible until the final dispositions are known.
What if the discarded weight is higher than the material input?
Check whether the bin included other batches, whether the ticket is gross weight, and whether all charged inputs were captured. Keep the mismatch open until both weights cover the same boundary.
Should planned trim count as scrap?
Include it when the measure is total material discarded and it meets the stated disposition rule. Track planned trim separately if the team also needs to isolate avoidable defects.