5.2 Environmental Controls

~~Run~~

Environmental ≤10%control RHis drythe cabinets,invisible stableshield temp/RH,that keeps components reliable long before they reach the soldering iron. Moisture and groundedstatic floors/shelvingare fromsilent storeskillers, tocreeping line.
in
Environmentalunnoticed controlsuntil keepthey cause latent failures, costly rework, or field returns. By defining clear storage zones, locking down humidity and temperature setpoints, and grounding every surface, the factory builds a climate of predictability. The discipline is simple but powerful: when environments remain boring, production lines stay calm and parts safesurvive from moisture and static, plain and simple. Dry cabinets at ≤10% RH (relative humidity) pause the moisture clock for MSDs (moisture-sensitive devices), and grounded floors/shelves prevent ESD (electrostatic discharge). Clear zones—REC-STAGE, CMP-STORE, LINE-SMKT—match signage and MES so items only move under the right rules. Basic logs and alarms catch drifts early, keeping climates boring and builds predictable.
intact.

5.2.1 Purpose & scope

Define where material may live—from docks to finished-goods—and what controls apply so moisture and static never get a head start. We use clear area names that match signage and MES locations.

5.2.2 Storage areas & setpoints (post this on the wall)

Area (MES code)	What belongs here	Temperature	Humidity	Key rules
Inbound Staging (REC-STAGE)	Pallets just received; unopened cartons only	Ambient	Ambient	Transit only. No opening or kitting. Target ≤1 h, max 4 h to next area. If carton damaged → NG-QUAR. Paste/flux go straight to CHEM-COLD.
Bulk Parts Warehouse (BULK-PARTS)	Unopened cartons of components, mechanicals, enclosures, cables	Ambient (kept out of heat sources)	Ambient (dry, roofed)	Cartons stay sealed. No MBB opening. If ambient >30 °C or RH >70% for >8 h, move sensitive lots to CMP-STORE. Time limit per policy (e.g., ≤14 days) before put-away to controlled store.
Component Store (CMP-STORE, EPA)	Opened/partial packs; any MSD; kitting stock	20–26 °C (±2 °C)	≤60% RH room; ≤10% RH in dry cabinets	ESD floors/shelves/carts. All MSDs in dry cabinets. Opening MBBs, HIC reads, relabeling, and put-away happen here. Room & cabinet loggers required.
Line-Side Supermarket (LINE-SMKT, EPA)	Kits for current/next shift; feeder banks nearby	20–26 °C	≤60% RH room; ≤10% RH in any local cabinet	Issue shift demand + buffer. For pauses: cabinet-park feeder+reel or reseal (5.4). Keep away from ovens/doors.
Dry Cabinets (DRY-CAB)	Point storage for MSDs/PCBs	Room temp	≤10% RH (≤5% best)	Pauses moisture clock (5.4). Recover ≤10 min after door close. Local display + independent logger.
Chemistry Cold Chain (CHEM-COLD)	Solder paste, flux, adhesives/coatings	Per label (typ. 0–10 °C)	—	Separate from components. Logged temps. No MSDs inside. Follow 5.5.
Quarantine / MRB Staging (NG-QUAR)	Suspect/damaged/expired/unknown lots; returns	As CMP-STORE if components; as CHEM-COLD if chemistries	As CMP-STORE	Caged/segregated. ESD-safe. No issue picks. All moves via MRB ticket. Time-limit (e.g., ≤5 business days) to disposition.
Finished Goods Warehouse (FG-WH)	Packed, sealed finished units and spares	15–30 °C preferred	≤70% RH preferred	Palletize per 26.4. ESD not required for sealed goods. Open RMAs/returns go to NG-QUAR, not FG-WH.

5.2.3 Movement rules (keep the chain unbroken)

REC-STAGE → CMP-STORE/BULK-PARTS: pallets closed; no opening at the dock. Timestamp moves in MES.
BULK-PARTS → CMP-STORE: before kitting or any MBB opening. Sensitive items (high-value ICs, BGAs, optics) should not linger in BULK-PARTS—move within policy window.
CMP-STORE ↔ LINE-SMKT: use shielding totes/bags with UID visible (5.1). MSD exposure clock runs per 5.4.
Any area → NG-QUAR: red tag + photo + ticket; segregate by lot; no mixed storage.
CMP-STORE/LINE-SMKT → DRY-CAB: when pausing MSDs; verify ≤10% RH and recovery ≤10 min.

5.2.4 Dry cabinet essentials (wherever they sit)

Door discipline: <30 s per open; don’t prop.
Recovery: RH back to ≤10% in ≤10 min; if not, take cabinet out of service and evaluate contents with 5.4.
Loading: Leave air gaps; no wet items inside.
Monitoring: Local display + independent logger (≥hourly).
Calibration: RH sensors verified annually; sticker next due date.
Ownership: Name on the cabinet; owner keeps logs and responds to alarms.

5.2.5 ESD surfaces, shelves & carts (make ground obvious)

Floors/mats/shelves/carts are dissipative and bonded; verify continuity monthly.
Totes/bags: Shielding for travel; pink bags only as inners inside a shield.
Access testers at CMP-STORE and LINE-SMKT doors (see 5.3).

5.2.6 Alarms, excursions & what to do

DRY-CAB >10% RH >60 min: Tag cabinet OUT OF SERVICE. Quarantine contents by location; decide bake/reset per 5.4. Fix cabinet; document.
CMP-STORE/LINE-SMKT env out of range: Pause issues; cover WIP; fix HVAC; record duration/peak; QE decides extra checks or controlled bakes for exposed MSDs.
BULK-PARTS heat/humidity event: If ambient exceeds thresholds, relocate sensitive cartons to CMP-STORE and note event in receiving/storage log.
CHEM-COLD temp drift: Hold chemistries; assess with 5.5 (lot disposition).

5.2.7 Acceptance cues (fast table)

Checkpoint	Accept	Reject
REC-STAGE	Sealed cartons moving promptly	Open reels; kitting activity at dock
BULK-PARTS	Cartons sealed; away from heat/moisture; dwell within limit	MBB opened; pallets lingering weeks; roof leaks
CMP-STORE env	20–26 °C, ≤60% RH; logs complete	Drifts with no record/action
DRY-CAB	≤10% RH, recovers ≤10 min; logger OK	Stuck high; door propped; no independent log
LINE-SMKT staging	Closed shielding totes; away from ovens/doors	Open reels on bare table in hot drafts
NG-QUAR	Segregated, labeled, ticketed; no picks	Mixed with good stock; unlabeled “mystery” items
FG-WH	Only sealed finished goods; pallets stable	Loose RMAs stored with shippable stock

5.2.8 Common traps → smallest reliable fix

Trap	Symptom	First move
“Quick peek” at the dock	Moisture clock started in ambient	Ban opening in REC-STAGE; train & sign the rule
Using BULK-PARTS as long-term store for MSDs	HIC shows wet on first open	Time-limit ambient storage; route MSDs to CMP-STORE
Pink bags for travel	ESD escapes	Require shielding totes/bags for all moves
Overpacked dry cabinets	Slow RH recovery	Reduce load; service seals; owner checks weekly
Returns dumped in FG-WH	Good stock contaminated	Route all RMAs to NG-QUAR only
No logs for excursions	Can’t prove control in audit	Independent loggers + weekly review sheet

5.2.9 Pocket checklists

REC-STAGE / BULK-PARTS

Cartons sealed; no opening or kitting
Dock→store move ≤1 h (≤4 h max) logged
Sensitive lots not baking in heat; paste/flux to CHEM-COLD ≤15 min

CMP-STORE / LINE-SMKT

Room 20–26 °C & ≤60% RH; logs OK
MSDs in DRY-CAB; recovery ≤10 min
Grounded floors/shelves/carts; shielding totes in use

NG-QUAR

Segregated cage/shelves; red tags + photos + MRB ticket
No picks; time-limit to disposition

FG-WH

Only sealed finished goods; RMAs routed to NG-QUAR
Pallets stable; no overhang; environment reasonable

~~Bottom~~

Strictly line:following Usearea REC-STAGErules, setpoints, and BULK-PARTSmovement onlydiscipline asensures sealed,MSDs short-stayand waypoints;chemistries doremain realstable, workwhile ESD threats are neutralized. With environments under control, materials arrive at the line in CMP-STOREperfect condition, safeguarding quality and LINE-SMKTextending underproduct EPA rules; let DRY-CAB carry the moisture load; keep NG-QUAR truly isolated; and treat FG-WH as ship-ready only. Keep environments boring—and parts will be perfect when the process begins.
reliability.