ISO9001 System Document Package (34) | Incoming Quality Control Work Instruction

Document Description: This work instruction is a lower-level supporting document for the "Procurement and External Provision Control Procedure" (the 16th document in the package) and the "Monitoring and Measurement Resources Control Procedure" (the 10th document in the package). It belongs to the third-level documents (work instructions) of the quality management system (QMS) and is used to implement the requirements of ISO 9001:2015, specifically clauses 8.4.2 "Control of externally provided processes, products, and services" and 8.6 "Release of products and services," at the IQC (incoming quality control) position. The second-level procedure documents address "who is responsible for procurement and the process for selecting and evaluating suppliers," while this work instruction answers "how to divide inspection batches, how many samples to draw, which items to inspect, what measuring tools to use, how to determine conformity, and what actions to take for nonconforming products." This document is applicable to all manufacturing enterprises that perform incoming inspection on raw materials, purchased components, subcontracted parts, packaging materials, and auxiliary materials. For service procurement (such as transportation and outsourced testing) and technical documentation, a simplified process of "document verification + validity confirmation" can be executed according to the classification criteria in section 4.3. This document can be directly published and used as a third-level document by the enterprise, with the organization name, department code, material category, and AQL values replaced by actual values.

1. Purpose

To standardize the company's incoming inspection (IQC) activities, clarify the division of inspection batches, sampling plans, inspection items, judgment criteria, status identification, and nonconforming product handling procedures, ensuring that materials that have not been inspected or are found nonconforming are not used in production, and preventing nonconforming purchased products from entering subsequent processes. This work instruction is specifically formulated for these purposes.

2. Scope of Application

2.1 This work instruction applies to the inspection and judgment activities of raw materials, purchased components, subcontracted parts, packaging materials, and auxiliary materials received by the company.

2.2 This work instruction covers the following stages: inspection application acceptance, inspection preparation, sampling, appearance/size/function/material inspection, judgment, status identification, nonconforming product handling, emergency release, data statistics, and feedback.

2.3 The following scenarios can be executed using a simplified process, but the simplification criteria must be approved by the quality department and recorded:

• Exempted from Inspection: Materials listed in the approved exemption list (such as standard fasteners, ordinary cardboard boxes) can be released based on the supplier's certificate of conformity and the completeness of packaging labels.
• Sampling with Each Batch: For materials where the supplier has provided a full inspection report and the historical pass rate is stable (no nonconformities in the last 10 batches), a relaxed inspection can be performed according to section 4.6.
• Service Deliverables: Acceptance can be done by verifying the delivery list, acceptance report, or capability validation results.

3. Responsibilities

3.1 Quality Department (IQC Team): Responsible for organizing and implementing incoming inspections, sampling, judgment, status identification, initial isolation of nonconforming products, filling out inspection records, and monthly data statistics. Responsible for compiling and maintaining the IQC inspection work instructions (SIP). Responsible for proposing reviews of the exemption list and relaxed inspection qualifications.

3.2 Purchasing Department: Responsible for communicating the company's inspection requirements and technical agreements to suppliers. Responsible for coordinating returns or replacements and claims for nonconforming batches. Responsible for incorporating IQC feedback quality data into supplier performance evaluations.

3.3 Warehousing Department: Responsible for receiving, temporarily storing, and inspecting materials upon arrival. Responsible for isolating and identifying un-inspected and inspected materials. Responsible for processing materials for storage or return based on inspection conclusions.

3.4 Technical Department / Engineering Department: Responsible for providing drawings, technical specifications, inspection standards, and key characteristic lists for purchased materials. Responsible for resolving technical disputes. Responsible for approving technical feasibility opinions for conditional acceptance.

3.5 Production Department: Responsible for tracing and tracking the use of materials released under emergency conditions. If any abnormalities are found during use, production should be immediately stopped and the quality department notified.

3.6 Management Representative / Quality Manager: Responsible for approving the exemption list, relaxed inspection qualifications, emergency release applications, and conditional acceptance conclusions.

4. Work Procedures

4.1 Inspection Preparation

4.1.1 The Quality Department should compile an "IQC Inspection Work Instruction" (SIP) for each major category of purchased materials. The content should include at least: material code and name, applicable drawings/standards, inspection items, technical requirements (nominal values and tolerances), inspection methods, measuring tools, sampling plans and AQL, judgment criteria, and record form numbers. The SIP should be co-signed by the Technical Department, approved by the Quality Manager, and updated when drawings or technical requirements change.

4.1.2 Before inspection, the inspector should confirm: the SIP being used is the current valid version; the drawings are the latest version; the measuring tools are within the calibration validity period and have no visible damage; the inspection environment (lighting, temperature, cleanliness, anti-static) meets the requirements.

4.1.3 Inspectors should be trained and qualified for their positions, possessing the necessary qualifications for the inspection items (such as non-destructive testing, electrical safety testing, material composition determination, etc., which require corresponding qualification certificates).

4.2 Inspection Application and Batch Division

4.2.1 Upon arrival, the Warehousing Department should verify the material name, specifications, quantity, batch number, and packaging completeness according to the delivery note, affix a "pending inspection" label, and store the materials in the pending inspection area. The inspection application form should be filled out and submitted to IQC.

4.2.2 Principles for dividing inspection batches:

• Materials from the same supplier, with the same material code, the same production batch number, and the same arrival date form one inspection batch.
• If a single delivery includes multiple supplier batch numbers, inspection batches should be divided by production batch number.
• If the same production batch number is delivered in multiple shipments, they can be combined into one inspection batch, but the quantity of each shipment must be noted in the records.
• Destructive testing, valuable materials, and key characteristics materials should be divided into inspection batches strictly and should not be combined.

4.2.3 Once inspection batches are divided, the batch size N should be recorded in the "Incoming Inspection Record" as the basis for calculating the sample size.

4.3 Determination of Sampling Plans

4.3.1 Conventional attribute sampling should be conducted according to GB/T 2828.1 (equivalent to ISO 2859-1): the inspection level is generally "General Inspection Level II," and the sampling plan type is "Normal Single Sampling Plan." The AQL value should be set based on the importance of the material, with the following suggested baseline (which can be adjusted by the enterprise according to industry and customer requirements and specified in the SIP):

4.3.2 Sampling table operations: Determine the sample size code based on the batch size N and inspection level, then determine the sample size n, acceptance number Ac, and rejection number Re based on the code and AQL. For example, for a batch size N = 1200 of an important material, the General Inspection Level II corresponds to sample size code J, and AQL 1.0 corresponds to n = 80, Ac = 2, Re = 3. This means that if there are ≤ 2 nonconforming items in 80 samples, the batch is accepted; if there are ≥ 3 nonconforming items, the batch is rejected.

4.3.3 Measurement inspection (continuous data) can be determined according to GB/T 6378 or using SPC methods (mean-range control chart, process capability index). Key characteristics should preferably be inspected using measurement sampling or 100% inspection, with actual measurement values recorded.

4.3.4 Exemptions from conventional sampling: Destructive test items (such as tensile, salt spray, and pressure resistance) are typically sampled 1 to 3 pieces per batch or at a specified frequency. Items requiring 100% inspection (such as key safety characteristics) are not subject to sampling plans and should be fully inspected.

4.3.5 Sampling should be random, covering different packaging units and different pallet layers. The supplier's representative should not be allowed to select or designate samples. If nonconforming items are found in the sample, the batch should not be re-sampled.

4.4 Implementation of Inspection

4.4.1 Appearance Inspection: Verify each item specified in the SIP (surface defects, burrs, scratches, deformation, rust, color differences, printing content, labels, and traceability codes).

4.4.2 Dimensional Inspection: Measure according to the nominal values and tolerances marked on the drawings. Critical dimensions, mating dimensions, and assembly interference dimensions must be inspected. Record actual measurement values, not just "conforming." Confirm that the measuring tool's resolution is better than 1/10 of the tolerance band width.

4.4.3 Function and Performance Inspection: Perform the items specified in the SIP (such as power-on testing, air-tightness testing, insertion and removal force, resistance, and insulation resistance).

4.4.4 Material and Compliance Verification: Verify the completeness and batch correspondence of material certificates, composition reports, RoHS/REACH declarations, etc. If necessary, send samples for inspection or use rapid testing equipment (such as an XRF spectrometer) for verification.

4.4.5 Packaging and Label Verification: Verify the quantity, label content (material code, batch number, production date, expiration date), moisture and anti-static protection, and damage from stacking and transportation.

4.4.6 Judgment: If all inspection items meet the requirements, the batch is judged as "conforming." If any item does not meet the requirements, the batch is judged as "nonconforming." For items that are on the borderline, re-verify the measurement system and operations, and then judge as nonconforming. The original data must be traceable to specific sample numbers.

4.5 Inspection Status Identification

4.5.1 After inspection, materials should be stored in designated areas and labeled accordingly:

• Pending Inspection: Yellow label, stored in the pending inspection area.
• Conforming: Green label, eligible for storage.
• Nonconforming: Red label, stored in the nonconforming product isolation area.
• Conditional Acceptance: Blue label or a label with "Conditional Acceptance (with conditions)" wording.

4.5.2 The label should include the material code, batch number, quantity, inspection date, inspector, and judgment conclusion. Un-inspected materials should not be moved out of the pending inspection area until a judgment conclusion is obtained.

4.6 Post-Judgment Handling and Relaxation/Intensification

4.6.1 Conforming: The inspector signs the conclusion in the "Incoming Inspection Record," and the Warehousing Department processes the materials for storage based on the record.

4.6.2 Nonconforming: Handle nonconforming batches as follows:

• Return: For batches that are entirely nonconforming or where nonconformities affect function and safety, the Purchasing Department should contact the supplier for returns or replacements.
• 100% Inspection and Sorting: If nonconformities can be sorted and the quality department assesses it as economically feasible, the sorting costs should generally be borne by the supplier. After sorting, the conforming items should be re-judged.
• Conditional Acceptance: If nonconformities do not affect the final product's function, safety, or regulatory compliance, conditional acceptance can be approved after technical review and authorization by the quality manager. Necessary compensatory measures should be taken for subsequent processes.
• Scrap: For materials that cannot be returned, sorted, or conditionally accepted, handle them according to the waste management regulations.

4.6.3 Relaxation of Inspection: If materials have passed 10 consecutive batches of normal inspection and the supplier's quality system is stable, the inspection level can be reduced to "General Inspection Level I" or the AQL value can be increased, with approval from the quality manager. If a nonconforming batch appears during the relaxation period, immediately revert to normal inspection.

4.6.4 Intensification of Inspection: If any of the following scenarios occur, perform intensified inspection (reduce the inspection level to III or lower the AQL value): two consecutive batches are rejected; the same nonconformity reappears; the supplier makes unauthorized changes to materials, processes, or production locations; the customer or regulations require intensified inspection.

4.7 Emergency Release

4.7.1 If production is urgently needed and there is not enough time to complete all inspection items, an emergency release can be applied for, provided that: the material is traceable (batch number and traceability code are clear); the un-inspected items do not affect product safety or regulatory compliance; there are clear measures for tracking and recalling the material during use.

4.7.2 The emergency release process is as follows: the Production Department submits an application → the Technical Department assesses the technical risks → the Quality Manager approves → the material is labeled with an "Emergency Release" label and registered in the "Emergency Release Application Form" with the batch number, quantity, un-inspected items, and usage process → IQC completes the inspection within 1 to 2 working days → if the supplementary inspection is nonconforming, immediately notify the Production Department to stop using, isolate, and recall the material already in production.

4.7.3 Emergency release should not be used for: safety characteristics, items with regulatory requirements, or items that the customer explicitly requires to be fully inspected.

4.8 Data Statistics and Feedback

4.8.1 IQC should compile monthly incoming inspection data into an "IQC Monthly Statistics Form," which should include at least: the number of inspection applications, the number of conforming batches, the number of nonconforming batches, the batch conformity rate, the distribution of defects by nonconformity type, and the list of involved suppliers.

4.8.2 Suppliers with a batch conformity rate below 95% or with two or more similar nonconformities in a month should receive a "Corrective Action Request" from the quality department and be included in the supplier performance evaluation. If a supplier has three consecutive months of nonconformities, the Purchasing Department should initiate a re-evaluation of the supplier's qualifications.

4.9 Flowchart (Text Version)

Material arrives → Warehouse verifies delivery note/quantity/batch number, affixes "pending inspection" label, and stores in pending inspection area → Fills out inspection application form and submits to IQC → IQC confirms SIP, drawings, and calibration status of measuring tools → Divides inspection batches (determines batch size N) → Determines n/Ac/Re according to GB/T 2828.1 (or items specified in the SIP) → Random sampling → Appearance/size/function/material/packaging inspection → Judgment → ① Conforming → Green label → Storage (record in "Incoming Inspection Record") ② Nonconforming → Red label → Isolation → Return/100% inspection and sorting/conditional acceptance/scrap (record in "Nonconforming Product Handling Form") ③ Production urgency → Emergency release application → Assessment → Approval → Labeling and registration → Usage tracking → Supplementary inspection → Conforming closure/Nonconforming recall End of month: Compile data → Supplier performance evaluation → Promote supplier improvement.

5. Related Records

5.1 "Incoming Inspection Record" (QR-IQC-01)

Field List: Record number, arrival date, supplier name, material code, material name, specifications, supplier production batch number, company batch number, delivery quantity, inspection batch size N, sample size n, Ac/Re, inspection items, technical requirements, actual measurement values (item by item), measuring tool number, inspection conclusion (accept/reject), nonconforming description, inspector, reviewer.

Filling Instructions: The actual measurement values must be filled in, not just "OK/conforming." If the batch is rejected, specify the nonconforming items and actual measurement values in the "nonconforming description" field. The measuring tool number must correspond to the actual tool used.

Example Row:

5.2 "IQC Inspection Work Instruction (SIP)" (QR-IQC-02)

Field List: Material code, material name, process/station, sequence number, inspection item, technical requirement, inspection method, measuring tool, sampling plan (inspection level/AQL), record form, version number, compiler/reviewer/approver.

5.3 "Nonconforming Product Handling Form" (QR-IQC-03)

Field List: Form number, material code and name, supplier, batch number, batch size, nonconforming quantity, nonconforming description, defect classification (critical/severe/minor), technical review opinion, handling method (return/100% inspection and sorting/conditional acceptance/scrap), responsible department, approver, verification of handling results, closure date.

5.4 "Emergency Release Application Form" (QR-IQC-04)

Field List: Application number, material code and name, batch number, quantity, applying department, application reason, un-inspected items, risk assessment conclusion, usage process, traceability measures, approver, completion date of supplementary inspection, supplementary inspection results, closure confirmation.

5.5 "IQC Monthly Statistics Form" (QR-IQC-05)

Field List: Statistical month, supplier name, number of inspection applications, number of conforming batches, number of nonconforming batches, batch conformity rate, defect type distribution, number of corrective action requests issued, suppliers requiring re-evaluation.

6. Related Documents

6.1 "Procurement and External Provision Control Procedure" (the 16th document in the package, corresponding to clause 8.4) 6.2 "Monitoring and Measurement Resources Control Procedure" (the 10th document in the package, corresponding to clause 7.1.5) 6.3 "Identification and Traceability Control Procedure" (the 18th document in the package, corresponding to clause 8.5.2) 6.4 "Nonconforming Product Control Procedure" (the 22nd document in the package, corresponding to clause 8.7) 6.5 "Nonconformity and Corrective Action Procedure" (the 27th document in the package, corresponding to clause 10.2) 6.6 "Process Inspection Work Instruction" and "Finished Product Inspection Work Instruction" (corresponding documents in the 35th and 36th documents of this series) 6.7 GB/T 2828.1 "Sampling Inspection Procedures for Attribute Data - Part 1: Sampling Plans Indexed by Acceptable Quality Level (AQL) for Lot-by-Lot Inspection"

Usage Instructions

1. How to Modify According to Enterprise Reality

1. Material Categories and AQL Values: The classification table in section 4.3.1 is a general benchmark. Enterprises should adjust it based on their product characteristics and customer requirements. Industries such as automotive, medical devices, and aviation often have stricter customer-specific requirements (CSRs), which should be followed and sourced in the SIP. The determination of AQL values should be based on evidence (customer requirements, historical quality levels, severity of consequences) and not simply copied from industry peers without validation.

2. Inspection Items and Sampling Plans: Treat the SIP as a "living document," with one for each major category of material. If the enterprise does not yet have an SIP, use drawings and the "Incoming Inspection Record" as a temporary solution, but first clarify the essential inspection items and judgment criteria to avoid inspectors deciding what to inspect based on experience.

3. Organization and Positions: In small and medium-sized enterprises, the IQC and process inspection roles can be combined, but key characteristic inspections should have a reviewer. For third-party logistics or outsourced warehousing, the responsibilities for isolating the pending inspection area and submitting inspection applications should be clearly defined in the service agreement to prevent materials from being used without inspection.

4. Industry-Specific Requirements: For enterprises involving food contact materials and electronic/electrical products, add RoHS/REACH/FDA/LFGB compliance verification requirements in section 4.4.4. For enterprises involving pressure vessels and fire protection products, add verification of the validity of mandatory certification certificates and type test reports.

2. Audit Focus Points

• Whether the sampling plan is specified in the document and actually implemented, and whether the randomness of sampling can be verified.
• Whether the inspection records include actual measurement values and not just "conforming"; whether the records and judgment conclusions are consistent.
• Whether the measuring tools used are within the calibration validity period and whether the calibration status labels are clear.
• Whether the inspectors have the necessary qualifications for their positions, and whether special projects have corresponding qualification certificates.
• Whether there is an approved exemption list and basis for exempted materials, and whether it is regularly reviewed.
• Whether emergency release has an application, assessment, approval, tracking, and supplementary inspection closure.
• Whether conditional acceptance has been technically reviewed and approved by the authorized person, and whether the impact on the final product has been assessed.
• Whether nonconforming materials are actually isolated and whether they are managed separately from conforming materials.
• Whether IQC data is used for supplier performance evaluation and whether measures have been taken and verified for nonconforming suppliers.

3. Common Errors

1. Sampling Based on Experience: The document specifies GB/T 2828.1, but in practice, "5 pieces per batch" or "check one box" is used, and no sampling basis can be provided during audits.
2. Unplanned Adjustments: After nonconformities are found in the sample, the batch is re-sampled, or the supplier selects the sample before submission, which compromises the representativeness of the sample.
3. Recording Only Conclusions: The inspection record only has a "conforming" checkmark, without actual measurement values, making it impossible to verify the judgment process or provide data for supplier improvement.
4. No Approval for Exemptions and Relaxations: "Long-term no issues" is used as a reason for exemption, without an approved exemption list, approval records, or regular reviews.
5. Tool Issues: Using measuring tools that are overdue for calibration, have insufficient resolution, or are damaged, leading to unreliable measurement results.
6. Emergency Release as a Routine: Emergency release is approved casually, without supplementary inspection or traceability records, becoming a way to bypass inspection.
7. Disconnection Between Judgment and Handling: The inspection record shows nonconformity, but the material is still used in production, making the isolation area ineffective and the nonconforming product handling form long un-closed.
8. Data Not Closed-Loop: The IQC statistics form is compiled monthly, but the data is never converted into corrective action requests or supplier re-evaluation inputs, and is only used for reporting.

Incoming inspection is the first gate of the quality defense. Accurate judgment, clear records, and effective handling are essential for compliance.

Knowledge code: 2.3.1

Version: v20260809

Author: QTank QTank is dedicated to providing systematic professional knowledge, methodologies, and practical tools to quality management practitioners, helping enterprises continuously improve their quality capabilities.