Published 8 October 2026 · 7 minute read
An aerospace customer finds a void in a cured panel and traces it back to your prepreg. The question that lands on the quality manager's desk is short: which rolls could have the same problem, and what went into them? If the answer takes two days of pulling paper travelers, shift logs and PLC trend exports, the plant has traceability on paper but not in practice.
AS9100D clause 8.5.2 asks a manufacturer to identify its outputs and keep what it needs to trace them. On a composite line the unit that matters is the one that ships and gets cut: for a prepreg treater that is the roll. This article uses a prepreg line as the worked example because the details are concrete, but it is one example. A layup kit, an autoclave cure load or a filament-wound part raises the same questions with a different unit.
A useful roll record answers an auditor's or a customer's question without anyone opening a second system. In practice that means:
That last point is the one most systems skip, and it is the one an experienced auditor probes. A blank alarm section can mean the roll ran clean or that the alarm log was offline. Only one of those is evidence.
Most plants that have any electronic traceability have it per job: this work order consumed these lots and produced this quantity. That is a good start and it is not enough for composites.
A job on a treater can run a full shift. In that time the resin film lot may change twice, the line may stop for a web break and restart, and a zone temperature may drift and recover. A per-job record tells you which lots were used somewhere in the job. It cannot tell you which lots are in roll 7, or whether roll 7 was the one made during the drift.
The consequence shows up at the worst moment. When a supplier notifies you of a bad resin lot, a per-job record puts every roll in the job on hold. A per-roll record puts on hold only the rolls that contain the lot. The same applies in reverse: when a customer reports a defect in one roll, a per-roll record shows the conditions for that roll, not an average over eight hours. This is the same principle behind batch tracking and material genealogy in general, applied at the granularity a composite customer actually uses.
Composite lines are built to run continuously, which is where traceability usually breaks. A turret letoff lets the operator load the next roll of film or paper and splice it in without stopping. That is good for throughput and awkward for records, because the output roll that spans the splice contains two input lots.
The right answer is simple to state: the record keeps which lot fed which stretch of the roll, and a roll that spans a splice lists both lots. Getting there in practice takes two things:
Without both, the plant ends up assigning the whole roll to whichever lot was scanned first, which is a guess written down as a fact.
Prepreg and many film adhesives have a limited life at room temperature. A lot that comes out of the freezer, waits beside the line through a long stop and goes back in has used part of that life. If out-time is tracked on a clipboard, nobody can show later that the material in a given roll was within limits when it was used.
Treat take-out and return as recorded events on the lot, with the out-time used and remaining. Then the check at the letoff can refuse a lot that is over its limit, and the roll record can show that every input lot was within out-time and shelf life. A lot whose out-time history is unknown should block release of the rolls it fed, not be assumed fine.
Traceability is only as good as the search. The questions come in several shapes: a roll ID from a customer complaint, a job number from a production meeting, a material lot from a supplier notice, a recipe and a date range from an auditor. All four should open the same records. A search that silently truncates its results is worse than none, so a bounded search should say when it was cut short.
Retention matters too. Clause 7.5 covers documented information, and aerospace customers often set retention periods well beyond a typical IT default. Records nobody can delete, a declared retention period, and an audit trail of every change are what make the roll record usable years later.
The prepreg roll is one example. The same record works with each industry's own unit:
What counts as one unit, which signals matter and which limits apply are decided for each line. The AS9100 manufacturing overview walks through the full flow.
In PulseMQ the record is built automatically from the PLC. A small edge gateway reads the line, and when a roll closes PulseMQ writes a permanent record with everything listed above: recipe and revision, critical parameters against limits with a verdict, the lots per letoff position including splices, the operator who took the job, alarms and downtime, and a data-integrity line. Lab results are added to that record with the instrument used. A "Find a roll" box takes a roll ID, a job number, a material lot, a recipe or a date.
The record is what Quality signs when it releases the roll, and what the certificate of conformance is generated from. How that release works, and why a rejected roll can never ship, is covered in who can release a nonconforming roll. If a quality problem needs a cause rather than a trace, the same records feed golden run comparison, and stops recorded against each roll tie into downtime tracking.
PulseMQ keeps the evidence for clause 8.5.2 and 7.5. It does not certify a plant: certification stays with the manufacturer and its registrar, and PulseMQ is qualified on your own line during a pilot.
Design partner program. We are looking for composite and AS9100 manufacturers to pilot PulseMQ on one line: we connect to your PLC and qualify the records on your own process.
See the design partner programWhat does AS9100D clause 8.5.2 ask for on a composite line?
Clause 8.5.2 asks the manufacturer to identify its outputs and keep the information needed to trace them. On a prepreg line the practical unit is the roll: each roll needs its own identity and a record of the material lots, recipe and process conditions behind it.
Why trace per roll instead of per job?
A job can run for a whole shift and change material lots, recover from stops and drift several times. A per-job record answers which lots were used in the job, not which lots are in a given roll. A per-roll record narrows any investigation, hold or recall to the rolls that were actually affected.
Do release liners and poly film need lot tracking?
Anything that touches the product is worth tracking by lot. Release paper and poly film are in contact with the resin film, so a contaminated or out-of-specification liner lot can affect the rolls it was used on. Tracking them like any other input makes that question answerable.
Does a traceability system make a plant AS9100 compliant?
No. Certification belongs to the manufacturer and its registrar. Software can keep the records an auditor asks for under clauses such as 8.5.2 and 7.5; whether the plant meets the standard is decided in its own audit.