3.3 Component genealogy

Genealogy is the forensic DNA of your product. While “Traceability” tracks where a unit went, “Genealogy” records exactly what it is made of. In the event of a component failure (e.g. a bad batch of capacitors), a robust genealogy tree allows you to surgically recall only the 500 affected units, rather than the 50,000 produced that month.

The genealogy hierarchy

Data must be linked hierarchically, not flatly. A parent-child relationship tree must be built by the Manufacturing Execution System (MES) that traverses from the final shipping box all the way down to the raw material provider.

Level 1: the product (finished good)

Entity: The Top-Level Assembly (TLA).
Key: Serial_Number (System SN).
Contains: Housing, Accessories, and the PCBA.

Level 2: the PCBA (the brain)

Entity: The Printed Circuit Board Assembly (PCBA).
Key: PCBA_ID.
Link: The PCBA_ID is scanned into the System_SN at Final Assembly.

Level 3: the panel (the array)

Entity: The manufacturing frame containing multiple PCBAs.
Key: Panel_ID.
Logic: Components are placed on the Panel. Upon depaneling, the MES should “clone” or inherit the component links to every individual PCBA_ID.

Level 4: the reference designator (RefDes)

Entity: The specific physical location on the circuit board (e.g. C14, U20, R4).
Key: Ref_Des (Reference Designator, e.g. C14, R20) + Timestamp.
Logic: The Splice Resolver. When a reel runs out in the middle of populating a board (e.g. Reel A empties at C10, Reel B starts at C11), this level captures exactly which Lot went to which specific reference designator. Without this precision, you cannot establish the true boundary between two lots on the same board.

Level 5: the feeder / setup (the source)

Entity: The slot on the SMT machine.
Key: Slot_ID + Feeder_ID.
Logic: The machine tracks which Reel was mounted on Slot 4 at the exact time of placement.

Level 6: the supplier lot (the root)

Entity: The raw material package (Reel, Tray, Bag).
Key: Manufacturer_Lot_Number + Date_Code.
Constraint: It must be ensured that no material enters the floor without a Unique Internal ID (UID) linked to this vendor data.

Capturing the link: the SMT interlock

The weakest link in genealogy is the human operator loading the machine. If they load Reel A but the system thinks it is Reel B, your genealogy is corrupt.

The validation logic (replenishment event)

Scan Slot: Operator scans the Machine Feeder Slot barcode.
Scan Part: Operator scans the Reel/Component barcode.
MES Check:
- When the Component Part Number matches the Active Recipe for that Slot, the system permits the load.
- When there is a mismatch, the system should trigger an interlock to stop the machine and sound an error alarm.
Binding: The MES records: Time_Start, Slot_ID, Reel_UID.
Exhaustion: When the reel is empty (calculated by Component Count), the MES automatically closes the binding.

Handling bulk & consumables (time-based traceability)

Not everything has a barcode. Solder paste, adhesive, and screws are often “Bulk Consumables.” You cannot link a specific application of adhesive to a specific board via serial number.

Strategy: Temporal Windowing

Logic: The “Active Window” of the material must be recorded.
Input: Operator scans Solder Paste Pot ID at 08:00 (Start) and 12:00 (End).
Inference: Any board processed through that Screen Printer between 08:00 and 12:00 is linked to that Solder Paste Pot ID.
Resolution: Granularity is lower (Batch Level), but coverage is 100%.

”Forbidden” actions

It is highly recommended to police the following behaviors to preserve data integrity:

Splicing without Scanning: Operators typically splice a new reel to an old tape to keep the machine running.
- Rule: Splicing requires a mandatory scan of the new reel.
- Risk: If missed, the system attributes the new components to the old (empty) lot.
Tray Refills:
- Rule: Trays (e.g. for ICs) should be treated as independent “Lots.” A half-full tray must not be topped up with parts from a different lot. The tray must be completely cleared before loading the new parts.

Final Checkout: Component genealogy

Category	Metric / Control	Threshold / Rule
Hierarchy	Depth	Full linkage: Product → PCBA → Panel → RefDes → Slot → Reel → Supplier Lot.
Validation	Material Interlock	Machine creates “Stop” error if scanned reel ≠ Recipe Part Number.
Splicing	Scan Discipline	100% of splices require a validation scan before the splice enters the head.
Inheritance	Panel Split	Genealogy data transfers from Panel ID to Circuit ID automatically.
Bulk	Temporal Link	Paste/Glue linked via Time Windows (Start/End times).
Integrity	FIFO	The MES assumes First-In-First-Out for feeder consumption.
Recall	Search Speed	Ability to execute a query like “Where used: Lot A123” in < 5 minutes.