4.4 Incoming quality interface

The receiving dock is the firewall of the factory. If defective material crosses this line, the cost of quality explodes by 10x (at board test) or 100x (in the field). The Incoming Quality RequirementsControl (IQC) team is the operational arm of the Supplier Quality organization. This chapter defines the rules of engagement for inspection, the sampling logic that governs lot acceptance, and the binary triggers for quarantine.

The IQC Mandate (Rules Owned by SQ)SQE)

WhatThe IQC Inspector does not invent the rules; they execute the legislation written by the Supplier Quality Engineer (SQE).

• The Inspection Plan: Every Part Number (PN) must checkhave a defined Inspection Plan in the ERP/QMS system.
  • Standard: If no plan exists, the default is "Identify & Count" (Verification of MPN, Quantity, and howDamage).
  • Critical: SQFor definesTier it:1 COA/CofCparts, acceptance,the traceabilitySQE fields,must labeldefine rules,specific moisture/ESDCritical packagingto acceptance,Quality quarantine(CTQ) triggers,dimensions sampling(e.g., plan"Measure selection.
    Pin Pitch with Caliper").
• Documentation Hygiene:
  • CoC (Certificate of Conformance): Mandatory for every shipment. Must state adherence to the specific drawing revision.
  • CoA (Certificate of Analysis): Required for raw materials (Solder Paste, Chemicals, Metal). Must show actual test data (e.g., Viscosity, Tensile Strength).
  • Failure: Missing CoC/CoA = Automatic Rejection. The lot cannot be received into stock.

Sampling and Acceptance Criteria Standard(AQL)

We do not guess; we use statistics. The Dannie Operating System utilizes ANSI/ASQ Z1.4 (equivalent to ISO 2859-1) for attribute sampling.

• Sampling Plan:
  • Normal: Level II.
  • Reduced: Level I (Only for "Dock-to-Stock" candidates).
  • Tightened: Level III (For new suppliers or probation status).
• Acceptance Quality Limit (AQL):
  • Critical Defect (Safety/Functional): AQL 0.01. (0 defects allowed).
  • Major Defect (Fit/Form/Function): AQL 0.4.
  • Minor Defect (Cosmetic): AQL 1.0.
• The "Zero Defect" Goal (c=0):
  • For high-reliability sectors (Auto/Med), we often adopt c=0 sampling, where any defect in the sample rejects the entire lot, regardless of AQL tables.

Defect Classification

Inspectors must categorize findings to determine the severity of the rejection.

1. Critical (Stop Ship):
   • Definition: Hazardous or renders the unit totally dead.
   • Example: Wrong MPN, Mixed parts in reel, Cracked PCB, ESD bag puncture.
2. Major (Production Stopper):
   • Definition: Likely to cause failure or reduce usability.
   • Example: Bent pins, Oxidized leads (solderability), Wrong package size.
3. Minor (Process Indicator):
   • Definition: Deviation from standard but does not affect function.
   • Example: Slight discoloration, Scratched label (readable).

Switching Rules (Dynamic Control)

The singlerigor placeof thatinspection defines:adjusts samplingautomatically methodbased on supplier performance history.

• Normal to Tightened:
  • Trigger: 2 out of 5 consecutive lots rejected.
  • Action: Move to Level III inspection. SQE notified immediately.
• Tightened to Normal:
  • Trigger: 5 consecutive lots accepted.
  • Action: Return to Level II.
• Normal to Reduced (AQLDock-to-Stock):
  • Trigger: or10 internal),consecutive tightened/normal/reducedlots switchingaccepted rules,+ whatApproved countsSupplier as a defect, defect classificationStatus (critical/major/minor)Grade A).
  • Action: Skip-Lot inspection (1 in 5).

Final Checklist

IQC Element	Standard	Risk of Failure
Missing Plan	Default to "ID & Count"	Critical defects missed
Missing CoC	Block Receipt	Untraceable material
Sampling	ANSI/ASQ Z1.4	Statistically invalid acceptance
Rejection	Entire Lot (No Sorting)	"Cherrry picking" bad lots
ESD/MSL	Check Bag Integrity	Latent field failures
Switching	Auto-Triggered	Inspecting good suppliers too much

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