How to set up part traceability: audit-ready shop records

Traceability means you can look at a part and answer, with documents: what material was it made from, on which machine, by whom, when, and which measurement approved it? General quality management standards require this "where it is a requirement"; in aerospace, defense, medical and automotive, customer specifications usually spell it out in detail. This article covers the links in the chain, what an audit really checks, where paper breaks down and how to set up digital records.

What traceability is, and what it is not

Traceability works in two directions:

• Forward tracing: Which parts were made from this material lot, and which customers received them? You need this when a supplier says "that lot was defective."
• Backward tracing: Which lot, work order and inspection report did this part in the customer's hands come from? You need this when the customer says "the part failed."

Both directions draw on the same records; only the starting end differs.

Traceability is not engraving a serial number on every part (some jobs need it, most only need lot-based tracking), filming the whole process or being forced to buy separate software. A well-run paper system also gives you traceability; the problem is that paper breaks down as you grow.

General quality management standards require outputs to be identified and, where traceability is required, unique identification to be controlled and recorded. Sector-specific standards and customer specifications go further: the product must be identifiable throughout its life, parts traceable to a batch, nonconforming product identified and records retained. In short, the general standard asks "can you do it?" and the customer specification says "show me."

The chain: from certificate number to shipment

A complete traceability chain has seven links. Each link must connect to the one before it; if the chain breaks anywhere, you have no traceability.

Link	Record	Connected to
1. Raw material receiving	Supplier, material, lot or heat number, certificate (3.1)	Purchase order
2. Material cutting	Blanks cut from which lot for which work order	Work order + lot
3. Production record	Machine, operator, date, quantity, program revision	Work order
4. Tools and gauges	Critical cutting tools, gauge calibration status	Production record
5. Inspection and first article	Dimensions checked, values, who approved	Work order + part
6. Nonconformance	Scrap or rework, reason, disposition	Work order + part
7. Shipment	Quantity per work order, delivery note, recipient	Work order + customer order

The work order number is the backbone of the chain. It appears on every record; whichever end a query starts from, it reaches the work order, and from there every other link.

The material certificate (usually EN 10204 3.1) starts the chain and is the document most often lost. Scan it at receiving and file it against the lot number; in an audit, "where is the material certificate for this part?" should take 30 seconds.

What an audit really checks

Knowing what the auditor does tells you what to record. A typical quality audit tests traceability like this:

1. The auditor picks a shipped batch, usually at random, sometimes from a job with a customer complaint.
2. Delivery note to work order: "Which work order did this shipment come from?"
3. Work order to raw material: "Which lot, where is its certificate, does it match the material ordered?"
4. Production record: "Which machine, which operator, which program revision?"
5. Inspection record: "Is there a first article inspection, are critical dimensions recorded, is the gauge calibrated?"
6. Nonconformance, if any: "Was there scrap, are the reason and disposition recorded?"
7. Then in reverse: "Which other jobs came out of this lot?"

If this trail is complete in 15 minutes, you have traceability. If three binders get opened, an operator is called over and someone says "somebody else kept the records back then," the auditor writes a finding. Usually the record exists; nobody can find it.

Auditors also check retention. In aerospace, customer contracts often require 10 years or more, some programs the life of the part. For paper binders that is a serious physical burden; for digital records it is a setting.

When paper breaks down

Paper traceability works with few work orders, a single shift and one or two people with strong record-keeping discipline. It breaks down when:

• Lots get mixed. With two lots of the same material in stock, nobody notes which one was cut. The first link breaks and the rest of the chain is worthless.
• Records get lost. A note on the back of a drawing, an oily form, a certificate that slipped out of a binder.
• Cross-queries are needed. On paper, "which jobs came out of this lot?" means opening every work order one by one. Nobody does it.
• Revisions change. Paper rarely states which drawing or program revision a part was made to. If the customer changed the revision, the batch made to the old one cannot be found.
• It depends on one person. When the person who runs the system leaves, the order of the binders leaves too.

The break usually shows up during an audit or a customer complaint: the most expensive moment.

How to set up digital records

Digital traceability does not need an expensive system; it needs the seven links above kept in one place, tied to the work order. The setup order:

Step 1: Put the work order at the center

Every record links to a work order. The work order number is unique and appears on the printed traveler, the inspection report and the delivery note.

Step 2: Receive raw material by lot

Record every material receipt with supplier, material, lot or heat number and the certificate file. At cutting, select a lot for the work order. With two lots in stock at once, separate them physically (labels, shelves) as well as in the record.

Step 3: Add the revision to the production record

Along with machine, quantity and scrap, the production record includes the drawing and program revision. Usually the revision is selected when the work order is opened and the operator only confirms it.

Step 4: Tie inspection to the part

First article inspection and in-process checks go into an inspection report linked to the work order. Gauge calibration records live separately, and a warning appears for any gauge that is close to its due date or overdue.

Step 5: Record nonconformances

A scrap or rework record links to the work order with the reason, the disposition (scrap, rework, use as is) and, where relevant, root cause analysis. Auditors ask for this record separately.

Step 6: Ship from the work order

The shipment record holds how many pieces from the work order went to whom on which delivery note, tying the last link back to the first.

With these six steps in place, the auditor's seven-question trail is answered from one screen: open the work order, and material lot and certificate, production record, inspection report, nonconformance and shipment appear together. The cross-query ("what came out of this lot?") becomes a filter.

Record retention and backups

Digital records carry their own risk: servers fail, data gets deleted, and auditors ask about it. Regular, restore-tested backups are as basic as protecting paper binders from fire. With a cloud-based system, ask the provider for its backup policy and data retention period in writing; with your own server, put backups on a schedule.

Related articles: Quality records in a CNC shop: inspection, NCR, calibration, 7 ways to reduce scrap rate in a CNC machine shop.

Frequently asked questions

Is part-level traceability mandatory for every shop?

Not always; general quality standards require traceability "where it is a requirement." That requirement comes from a customer contract, a legal regulation or the organization's own decision. Customers of aerospace, defense, medical and automotive suppliers usually require it.

Serial number or lot number?

For most machined parts, lot-based tracking (by work order batch) is enough: the part is traced by its work order number. For critical parts (flight safety, pressure vessels), the customer requires a serial number on every part, which is then linked to the work order and the lot. The customer specification states which is needed.

How long should records be kept?

General quality standards set no fixed period; the organization decides. In practice the customer contract and legal requirements set it: 10 years is common in aerospace, some programs require the life of the product. Read the contract and write the retention period into your quality manual.

Do existing paper records need to be digitized?

Usually not. From the switchover date, new work orders are kept digitally; old records stay on paper for their retention period. For ongoing or repeat jobs, the latest revision and lot can be carried over; entering the whole archive is rarely worth it.

Spindeo's Traceability & Stock package keeps material receiving by lot number, production records by work order and shipments in the same chain; the inspection reports, calibration and nonconformance records in the Quality package connect to that chain.