Trace forward from a supplier's lot to every device that used it, and backward from a finished device to the exact lots of parts inside it. When a distributor flags a bad date code, you find the boards it went into. When a unit comes back from the field, you find where each of its parts came from, and when.
Traceability in PartsBox is built on lot control and serial numbers. Every build records the exact lots it consumed, and how much of each. That record is what makes the chain work in both directions:
The links are already there because the everyday operations created them: receiving an order linked it to the lot that arrived, and each build linked the lots it drew from. A lot's screen shows where it came from, which builds used it, and which sub-assembly parts contain it — the chain is a page, not an investigation.
A distributor emails: one date code of a voltage regulator may fail early. Find the lot — by its name, by the order it arrived on, or by scanning the reel's label. Its screen lists every build that consumed from it. Each build lists the devices it produced, and with serial numbers, each device is individually identified. In a few minutes you have the complete set of affected units and can quarantine what is still on the shelf by tagging the lot as unusable, so no new build touches it.
When you split a lot — cut a length from a reel, set part of a batch aside, or ship some to a contract manufacturer — each new lot keeps its link to the original. If a lot was itself produced by a build, as a sub-assembly part is, PartsBox follows the splits back to that build. However many times stock is divided, a lot still traces to where it started.
Put an ID Anything™ label on a built device or a storage bin, and a scan brings up the full history: the build, the lots it used, and where and when those parts were bought. Scanning works in the browser, so the person on the floor needs no special hardware.
For regulated work, this is the record an auditor asks for, and the audit trail makes it tamper-proof. Lot and build data is also available through the API, so you can feed an ERP or quality-management system from the same source.
Traceability comes from lot control and serial numbers, both on the Control plan. The immutable audit trail, which records every change for audits and US FDA 21 CFR Part 11, is on the Compliance plan.