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4.5 Scanning, Databases & MES Links

Scanning and data integration are where physical marks become actionable traceability. This is the digital backbone that transforms a barcode into an audit trail. By wiring readers directly to your MES (Manufacturing Execution System), you create a continuous record from the raw panel to the final shipped box—turning an RMA into a quick database lookup instead of a costly physical investigation.

4.5.1 The Scan Gate Lineup: Where to Collect Data

You don't need a scanner at every machine, but you must have scanners at the minimum points required to bind the product's identity to its key process events.

A. Reader Lineup (Hardware)

  • Fixed-Mount 2D Imagers: Use these at automated stations (like stencil print or pick-and-place inflow) that demand speed and consistency. They capture the Panel or Unit ID instantly as the board passes.
  • Handheld 1D/2D Scanners: Ideal for manual processes (rework cells, debug benches, final pack-out). They offer flexibility where the operator controls the timing.

B. Minimal Scan Points (The Required Gates)

Wire these scan points into the MES route so the system forces the right action at the right time:

Scan Point

Item Scanned

Purpose

Panel-In (Start of SMT)

Panel Barcode (on the rail)

Starts Genealogy: Binds the Work Order (WO) to the physical panel.

After Marking (Laser/Label)

Unit 2D Code

Binds Identity: Verifies the new Unit SN is readable and writes the first critical record to the database.

Depanel/Breakaway

Panel ID, then individual Unit SNs

Splits the Record: Creates the "Panel – Units" split record in the database.

Test (ICT/FCT)

Unit SN

Records Verdict: Writes the pass/fail, test limits, and firmware version to the unit’s record. Fails automatically open repair tickets.

Final Pack-Out

Unit SN – Box Label

Closes the Loop: Links the individual unit(s) to the final customer shipping ID/Box ID.

4.5.2 Data Architecture: MES, APIs, and the Core Model

Traceability only works if the scanned data instantly updates a central system (MES/ERP). This requires a clean, simple relational database model and clear communication protocols.

A. The Few Tables That Matter

Your system needs to be relational, linking every event back to the single source of truth: the Unit Serial Number (SN).

Object

Primary Key(s)

Joins To

Purpose

Unit

SN

PanelID, BOMRev

The star of genealogy; holds core identity and configuration.

Panel

PanelID

WO, Units

Bridges line scans before depanel splits the product flow.

ScanEvent

(SN/PanelID, Timestamp)

Unit/Panel

Records the physical who, when, and where of every scan.

TestResult

(SN, Station, Run)

Unit

Stores every test pass/fail, measurement, and repair hook.

MaterialLot

LotID

Unit

Tracks critical component lots (BGA, FETs) when required for full genealogy.

B. API Patterns (How Stations Talk)

Automated stations and scanners communicate with the MES/ERP using clear, lightweight commands (APIs) to ensure data is consistent and sequenced correctly:

  • POST /scan {code, station, op, timestamp}: The basic log event. MES uses this to validate the station and advance the Work In Progress (WIP).
  • POST /test-result {sn, station, verdict, params}: Logs test results and, on a 'FAIL' verdict, auto-opens a repair ticket for the unit in the repair loop.
  • GET /label-data?sn=...: Returns the customer-facing fields (SN, BOM rev) from the ERP for printing final box labels.

4.5.3 Guardrails and Closure: Making Bad Data Hard

Traceability systems are useless if the data is faulty. You must build quality checks (guardrails) into the system to prevent bad data from being logged.

A. Data Guardrails

  • Grade Before Accept: The marking station must grade the code quality (Chapter 4.4). If the grade is poor, the MES must block WIP until a clean code is applied.
  • Duplicate & Format Checks: MES must reject reused SNs, wrong BOM revisions, or scans that are out of sequence based on the active production operation (e.g., rejecting a 'Depanel' scan if the unit hasn't passed 'Test' yet).
  • Store-and-Forward: Scanners must buffer data if the network connection temporarily drops, then replay the logs once the connection returns. This prevents operators from resorting to paper or shadow spreadsheets when the network blips.

B. "Board to Box" Proof (Closing the Loop)

The ultimate proof of a clean traceability system is the ability to instantaneously generate a complete unit history from the final shipping label.

  • Given a customer return (SN or Box ID), the system should be able to pull, in seconds: the WO, the SMT line, every test log (ICT/FCT), any rework/repair notes, and the final box/shipment data.
  • This means the MES and ERP are successfully linked: the ERP handled the shipment, but the MES provided the entire build and test history. This instantaneous lookup is the fundamental ROI of your traceability system.


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