3.1 Traceability Standards (IPC-1782)

Traceability is not an archive of what happened; it is the active defense against liability. In the event of a field failure, your ability to surgically recall only the granularityaffected units—rather than the entire month's production—determines whether the recall costs $50,000 or $5,000,000.

We adopt IPC-1782 (Standard for Manufacturing and Supply Chain Traceability of yourElectronic dataProducts) determinesas the scopearchitectural baseline.

The Four Levels of your recall. If your traceability is weak, you recall 100% of production. If it is robust, you recall the 0.1% actually affected. Adopt the IPC-1782 standard to define the "Resolution" of your data, transforming traceability from a cost center into an insurance policy.

Defining the Traceability Level (IPC-1782 Tiers)

Do not apply the"Nuclear sameGrade" data burdentraceability to a $5cable toytie. andBalance arisk $5,000vs. pacemaker.cost Theusing the IPC-1782 standardhierarchy. defines four distinct levels of granularity. SelectDefine the level basedfor onevery risk,BOM not convenience.item.

Level 1: Basic1 (Lot Traceability)

• Scope:Basic): LinksLot/Batch WorkTraceability. Order to Material Lot Code.
• Granularity: "This batch of 1,000 units mightTarget: containPassives capacitors(Resistors, fromCapacitors), ReelMechanicals A."(Screws, Housings).
• Use Case:Record: Consumer"Lot ElectronicsA123 (Mouse,was Keyboard),used Cables.
• Risk:on HighLine Recall1 Scopebetween (Entire08:00 Batch).and 12:00."

Level 2:2 (Process): Sequence Traceability.

• Target: PCBs, Standard (Serialized Assembly)
  • Scope: Links Serial Number (SN) to Work Order + Test Results.ICs.
  • Granularity:Record: "Unit SN-SN:123 passed testSolder onPaste DateInspection X.at 09:05." (Components are still Batch-level).
  • Use Case: White Goods, Industrial Controllers.

  Level 3: Advanced3 (Component Serialization)

  • Scope:Component): LinksSerialized SerialMatching. Number
    • Target: High-value silicon (SN)CPU, toFPGA), KeyWireless ComponentModules, Lots.Batteries.
    • Granularity:Record: "UnitChild SN-SN:ABC was placed on Parent SN:123 containsat CPURef LotDes Y and Memory Lot Z.U4."
    • Use Case: Automotive (Safety Critical), Medical Class II.

    Level 4: Precision4 (FullParametric): Process Traceability)Data.

    • Target: Safety-critical joints, Torque specs, Press-fit force.
    • Record: "Screw J1 tightened to 4.5Nm with angle 12°."

    Minimum Viable Record (The Data Payload)

    For every production event, the MES must commit a transaction containing these five immutable dimensions. If any dimension is missing, the record is legally void.

    1. Who (Actor)

    • Scope:Field: LinksUser_ID
    • Requirement: SNMust map to Componenta Lotsspecific human or service account. "Admin" is forbidden.

    2. What (Subject)

    • Field: Unit_Serial_Number (The Parent) + Process ParametersComponent_Lot_Or_SN (Torque,The Temp, Time)Child).
    • Granularity:Requirement: "UnitThe SN-123Parent containsSN CPUis Lotthe Y,Primary solderedKey atof 245°Cthe forGenealogy 30s."Tree.

    3. Where (Location)

    • Field: Resource_ID (Machine) + Slot/Feeder_ID.
    • Use Case:Requirement: Aerospace,Granularity Medicalmust Classmatch IIIthe risk. Knowing it was "On the SMT Line" is insufficient; we must know it was "Feeder Slot 4, Nozzle 2."

    4. When (Implantables)Timestamp)

    • Field: UTC_Timestamp.
    • Requirement: Synchronized via NTP (See Chapter 2.4). Resolution: Milliseconds (YYYY-MM-DD HH:MM:SS.ms).

    Selection5. How (Context)

    • Field: Process_Outcome (Pass/Fail) + Parametric_Data (Volts, Temp, Torque).
    • Requirement: Link to the specific Recipe_ID used.

    The Linkage Keys

    The database schema must enforce referential integrity. A collection of logs is not traceability; a Linked Graph is traceability.

    • The Golden Thread: Every child component record must have a Parent_ID field pointing to the PCBA or Sub-assembly.
    • The Work Order Bridge: Every Parent_ID must link to a Work_Order_ID. This connects the physical unit to the financial ERP record.
    • The Material Bridge: Every Component_Lot must link to a Goods_Receipt_ID. This connects the shop floor usage back to the Supplier Invoice.

    Validation Logic

    • If ProductComponent LiabilityX Costis > Production Costscanned → AdoptThen LevelCheck: 3Is orComponent 4.X valid for this BOM?
    • If Regulatory Requirement (FDA/IATF) existsValid → FollowThen theCreate mandatedLink: LevelINSERT INTO Genealogy (Parent, Child, Time) VALUES (...).

    TheRetention Chain of CustodyRequirements (ForwardBusiness & Backward)Rules)

    AThe traceabilityretention system must answer two specific questions instantly. If it takes > 1 hour to query, itperiod is broken.dictated by the product class and liability profile, not by disk space.

    Forward Traceability (Containment)

    • Question:Consumer Class: "WeWarranty foundPeriod a+ bad1 Reel of Resistors (Lot 999). Where are they?"Year.
    • Action:Industrial/Medical: InputProduct LotLifecycle 999+ →10 OutputYears List(Statute of Parent Serial Numbers.Repose).
    • Goal:Aerospace/Automotive: Quarantine specific units before they ship.

    Backward TraceabilityPerpetual (Root Cause)

    • Question: "Unit SN-123 failed in the field. How was it built?"
    • Action: Input SN-123 → Output BillLife of Materials (Lots) + Process History.
    • Goal: Identify the common factor (e.g., all failures used Lot 999)Vehicle).

    Pro-Tip: Test your "Recall Velocity" annually. Give a Lot Number to the Quality Engineer and measure how many minutes it takes to generate the list of affected Serial Numbers. Target: < 15 minutes.

    Data Retention & Immutability

    Data that expires before the warranty does is useless. Data that can be edited is fraudulent.

    Retention Policy

    • Standard:Rule: Product Lifetime + 2 Years (or 7 Years for Tax/Audit).
    • Medical/Aero: Indefinite (or 15+ Years).

    Immutability Logic

    • If a record is written → It is Read-Only forever.
    • If a correction is needed → Append a new record.
    • Storage: Use WORM (Write Once, Read Many) storage or Blockchain-verified logs for Level 4 systems.

    The "Genealogy" Tree Structure

    Traceability data is hierarchical. The MES must buildprevent aany parent-childmanual relationshipdeletion treeof asrecords thethat producthave movesnot downmet thetheir line.defined retention policy.

    Structure

    • Root: Finished Good SN.
      • Branch 1: PCB SN.
        • Leaf: CPU Lot.
        • Leaf: Capacitor Reel.
      • Branch 2: Housing Lot.
      • Branch 3: Firmware Version.

    Assembly Logic

    • If Sub-Assembly (Branch 1) is scrapped → Invalidate the Parent.
    • If Sub-Assembly is swapped (Repair) → Update the Tree instantly.

    Final Checklist

    Category	Metric / Control	Threshold / Rule
    StrategyGranularity	IPC Level Selection	LevelAll defined per Product Family (L1-L4)
    Speed	Query Latency	Forward/Backward Trace Report < 15 Mins
    Scope	Components	Critical Components (ClassCPU, A)Battery) tracked= toLevel Lot/SN3 (Serialized).
    Integrity	EditThe Access5 Dimensions	0Records Usersdrop haveif "Update/Delete"Who, permissionWhat, onWhere, TraceWhen, Logsor How is missing.
    ProcessTime	Parameter LinkSync	LevelTimestamps 4must linksbe ProcessUTC Dataand (Temp/Torque)NTP to SNsynced.
    ValidationLinkage	MockGraph RecallCheck	Perform100% 1of MockSerial RecallNumbers perlink Yearto a Work Order.
    ArchiveSuppliers	BackupInbound	Off-siteNo ImmutableLot Backupentering verifiedthe quarterlyfloor without a Date_Code and Manufacturer record.
    Audit	Retrieve Time	"Reverse Genealogy" (Component → Finished Goods) query < 5 minutes.