5.6 Kitting, FIFO & Shortage Management

Pick by variant, issue by FIFO, control substitutes, and keep line-side supermarkets calm.

Kitting is the quiet choreography that turns a BOM (bill of materials) into the exact parts and lots a build needs, right when it needs them. It anchors to a fixed snapshot of the BOM/AVL (approved vendor list) so late changes don’t leak in unnoticed. FIFO (first in, first out) for components and FEFO (first expiry, first out) for chemistries keep age and shelf life honest, while MSDs (moisture-sensitive devices) stay sealed or in dry storage to protect floor life. Calm, labeled supermarkets prevent “mystery bins” and wandering reels. When reality bites—missing parts or alternates—structured substitutions and clear triage (DNS: do-not-start; BT: build-through) keep WIP from ballooning. The result is smooth loading, traceable consumption, and kits that close cleanly without surprises.

5.6.1 Purpose & scope

Turn a BOM into the right parts, right lots, right place, right time—without starving the line or growing mystery bins. This covers kit creation, supermarket control, FIFO/FEFO rules, substitutions/deviations, shortage triage, and kit close-out for PCA, THT add-ons, and box-build.

5.6.2 Kit fundamentals (how a good kit looks)

Locked to a snapshot: Kit ties to BOM/AVL + revision at pick time; ECNs after pick trigger kit review/freeze.
Traceable lots: Each line item has UID + lot/date code; no “loose” handfuls.
One lot per feeder (preferred). If mixing lots for passives is allowed, one lot per position and log both lots in MES.
MSDs controlled: MSD reels/trays stay sealed or in DRY-CAB until load (5.4). Don’t stage MSD kits early.
ESD right: All parts travel in shielding totes/bags with UID visible (5.3).
Chemistries separate: Paste/flux are not inside kits; issued by FEFO and tracked per 5.5.

5.6.3 Picking rules (accuracy beats speed)

Verify the order: WO, variant, rev, quantity, due date.
Scan to pick: Every UID is scanned; MES validates PN ↔ location ↔ lot and warns on wrong rev or off-AVL.
FIFO for parts / FEFO for chemistries:
- Components, PCBs, hardware → FIFO by received date (unless engineering requests a specific lot).
- Paste/flux/adhesives → FEFO (5.5).
Count and confirm: Use scales/counters for reels/tubes; record issued qty and expected remainder.
Label the kit: Kit card lists WO, variant, rev, all UIDs, MSD status, and staging location (LINE-SMKT shelf/bin).

Accuracy target: ≥99.8% line items right, 0 wrong PN to line.

5.6.4 Line-side supermarkets (calm, not crowded)

Min/Max: For high-runners, set min–max by usage/takt; kanban two-bin works well for screws, labels, and fixtures.
Shelf discipline: One PN per slot, lot tags face out; no gray bins or “misc” shelves.
Color & zone: Color code by product family/variant; post a simple map on the endcap.
Aging control: If a kit sits >24–48 h unstarted, return MSDs to DRY-CAB or reseal (5.4) and re-validate before release.

5.6.5 Substitutions & deviations (no “close enough”)

Use AVL first. If an alternate is on the AVL, MES should accept it automatically.
Not on AVL? Raise a Deviation/Waiver with PE/QE sign-off (and Design if electrical). Check: form/fit/function, derating, test limits, labels, and compliance (RoHS/REACH).
Document the decision: Ticket ID on the kit card; tag feeders loaded with deviated parts; ensure test recipes don’t mis-bin the change.
Close the loop: If deviation becomes permanent, push an ECN and update AVL/BOM.

5.6.6 Shortage management (avoid starving the line)

Do-Not-Start (DNS): If critical items are missing (ICs, boards, unique connectors), DNS the WO. Don’t start partials that will clog WIP.
Build-through list: If only non-blocking items are missing (screws, shields), you may BT with QE/ME approval and a clean re-touch plan.
Visual board: Maintain a Shortage Board (digital/physical) showing WO, PN, qty missing, ETA, owner, escalation level.
Hot lots: Mark expedited receipts with a HOT tag tied to the shortage ticket; route straight to LINE-SMKT.

Triage categories

A (Critical): Unique IC, PCB, high-value module → DNS.
B (Conditional): Mechanical/hardware that can be installed later → BT with plan.
C (Cosmetic/pack): Labels, manuals → may ship hold; coordinate with 26.3.

5.6.7 Loading & consumption (clean hand-off to the machines)

Scan to load: Feeders only accept UIDs on the kit card; MES ties UID ↔ feeder ↔ program.
Backflush/consume: As placement proceeds, consumption decrements by verified part count (machine count or scale).
Reel splits & splicing: When splicing, label new tail with the same UID plus -A/-B suffix; scan the splice. No naked tail pieces.

5.6.8 Returns & reconciliation (close the kit cleanly)

End of run: Count back reels/tubes/trays; scan back to stock; update remaining qty.
MSDs: Reseal with fresh HIC/desiccant or park in DRY-CAB; update floor-life per 5.4.
Scrap jars/tubes that violated open-time/expiry rules (5.5).
Variance ticket: Any mismatch opens a ticket; recount once; if still off, QE investigates (lot split, feeder loss, or pick error).

5.6.9 Metrics that keep you honest

Kitting accuracy (%) = right line items / total line items.
On-time kits (%) to requested start.
Shortages per WO and DNS hours (lost time).
Supermarket service level (%) (stockouts vs demand).
Kit age (days) from pick to start.
Substitution rate (%) and deviation lead time.

Review weekly; fix the biggest pain first.

5.6.10 Acceptance cues (fast table)

Checkpoint	Accept	Reject
Kit card	WO/variant/rev + all UIDs present	Handwritten notes; missing lots
FIFO/FEFO	Components by FIFO; chemistries by FEFO	“Newest first”; expired mid-run
MSD control	Reels sealed or in DRY-CAB until load	MSDs staged open overnight
Shelf discipline	One PN per slot; labels out; no gray bins	Mixed PNs; unlabeled cups
Substitutions	AVL or approved deviation attached	“Looks same” swap with no record
Returns	Count-back scanned; MSDs resealed/parked	Loose remainders; no timer update

5.6.11 Common traps → smallest reliable fix

Trap	Symptom	First move
Early kitting of MSDs	HIC wet, floor-life wasted	Pick MSDs closest to start; use DRY-CAB staging
Partial start on critical shortage	WIP pile, rework later	DNS until criticals arrive; BT only with plan
Lot mixing in one feeder	Traceability headache	One lot per feeder; if mixed passives allowed, log both
Decanting without labels	“Mystery bin” finds	No decanting; if required, print child UID referencing parent
Paste inside kits	Expired on arrival	Issue chemistries separately by FEFO
Unplanned substitutions	AOI/test false fails	Deviation + test library update before load

5.6.12 Pocket checklists

Before picking

WO/variant/rev confirmed; AVL current
MSDs planned to pick near start time

During pick

Scan every UID; FIFO/FEFO observed
Kit card printed; shielding totes; MSDs sealed

At line release

Substitutions/devs attached; feeders labeled
MSD floor-life sufficient for shift + buffer

Close-out

Count-back scanned; MSDs resealed/DRY-CAB
Variance ticket opened if counts don’t match

Bottom line: Kitting is quiet choreography. Pick to a locked BOM/AVL, move parts by FIFO (FEFO for chemistries), protect MSD time, and escalate shortages cleanly. Do that, and supermarkets stay calm, feeders stay full, and builds start on time—without surprises.