Production Quality Control & Process Capability Checklist

This checklist is prepared to ensure quality control, process capability, and continuous improvement monitoring of production process. The goal is to establish repeatable quality, measurable performance, and Zero Defect culture in production.

Production Process Definition and Planning​

1. Is production process (Process Flow Diagram) created?​

A Production Process Flow Diagram (Process Flow Diagram – PFD) should be prepared for each product or module, covering all steps from raw material input to final packaging.

This diagram shows:

• Operation sequence
• Machine/equipment usage
• Control and measurement points
• Input/output parameters

PFD is the basic reference document for process analysis and risk assessment (PFMEA). It should be approved by quality team after each update and uploaded to ERP/PLM system.

2. Are responsibilities and control points determined for process steps?​

Responsibility for each step in production process should be clearly defined.

In this scope:

• Operator, technician, and quality control supervisors
• Inspection and test points
• Authorized approval authorities should be determined

At each control point, measured parameter, control frequency, and acceptance criteria (pass/fail limits) should be documented. This structure should be managed with "Process Control Plan" document. Mandatory step approval should be applied in ERP system against unauthorized process skip risk.

3. Are work instructions prepared for production stations?​

Work instructions (WI) explaining how operations should be performed should be created for each production station.

These instructions should include:

• Step-by-step assembly, test, or measurement procedure
• Tools, fixtures, and equipment to be used
• Visuals, torque values, and safety notes

Work instructions should be easily accessible by operator in the field (e.g., touch terminal or QR code). Revisions should be approved by production engineering and quality unit.

4. Are production parameters (temperature, time, torque, speed, etc.) defined and limit values determined?​

Parameters that should be kept under control at each process step (e.g., soldering temperature, screwing torque, pressing time) should be clearly defined.

For each parameter:

• Nominal value
• Upper/lower tolerance limits
• Measurement method and device
• Recording frequency should be specified

This data should be monitored with SPC (Statistical Process Control) system and deviations should be detected at early stage. Parameter limits should be based on process capability analysis (Cp/Cpk).

5. Is Production Readiness Review (PRR) performed?​

Production Readiness Review (PRR) or Pilot Run Approval should be conducted before production start.

This review verifies:

• All work instructions are completed
• Equipment calibrations are valid
• First Article Inspection (FAI) is successfully performed
• Material supply and stock levels are sufficient

PRR meeting report should be signed by quality team and archived as production start approval.

6. Is line balancing analysis performed?​

Line balancing analysis should be performed for production efficiency and bottleneck management.

Cycle time of each station should be measured, stations creating bottleneck in production flow should be identified. Results should be evaluated with Takt Time – Work Content comparison.

This analysis should be continuously updated in accordance with Lean Manufacturing principles. If necessary, process should be balanced with workforce or equipment redistribution.

Quality Plan and Control Points​

7. Is Quality Control Plan created?​

A Quality Control Plan (QCP / Control Plan) should be prepared for each production line or product family.

This plan should include following information for each process step:

• Process name and description
• Control method (visual, measurement, functional test, etc.)
• Measurement equipment to be used
• Control frequency (e.g., every 10 parts, start of shift, 100% test)
• Acceptance criteria (specification limits)
• Responsible person or station

Quality plan creates a common control standard between production and quality.

8. Are Critical to Quality characteristics (CTQ) defined?​

All critical quality characteristics (CTQ) that directly affect product's customer requirements should be identified.

CTQ examples:

• Voltage regulation tolerance ±2%
• Connection torque 0.7 ±0.1 Nm
• Soldering temperature 245 ±5 °C
• Connector alignment ±0.1 mm

These characteristics should be marked with special symbol (★) in process control plan and taken into statistical monitoring. "Measurement System Analysis (MSA)" verification should be performed for each CTQ value. This approach is the foundation of customer-focused quality culture.

9. Is PFMEA (Process Failure Mode and Effects Analysis) completed?​

PFMEA (Process Failure Mode and Effects Analysis) should be completed for each production line.

PFMEA identifies potential failure modes, their probabilities, and effects in advance and defines preventive actions.

Analysis content:

• Failure Mode
• Effect
• Occurrence (O), Severity (S), Detection (D) values
• RPN (Risk Priority Number) = O × S × D
• Preventive actions and responsibilities

Corrective/preventive actions (CAPA) should be applied for risks with RPN value of 100 or higher. PFMEA should be updated with each process change or new product introduction.

10. Is SPC (Statistical Process Control) application initiated?​

SPC (Statistical Process Control) should be applied to monitor variability in production.

X-bar / R control charts should be used for critical measurements; process stability should be monitored with Cp, Cpk target of 1.33 or higher.

Automatic warning system or quality approval should be activated when deviation is detected. SPC data should be recorded digitally (e.g., via MES or SCADA) and included in daily quality reports. This application prevents errors before they occur by early detection of process trends.

11. Are quality control forms (checklist, control card) accessible in production area?​

Required forms for each control point (visual control lists, measurement record forms, test result cards) should be easily accessible in production area.

Forms can be digital or printed, but always current revision should be used.

Form content:

• Date / shift / operator name
• Measurement results
• Approval signature / e-signature
• Notes or observations

These forms are basic documents for traceability in quality audits.

12. Is error classification (Critical / Major / Minor) defined?​

All production and test errors should be classified according to their impact:

• Critical: Error affecting safety or legal compliance (e.g., high voltage leaks)
• Major: Error affecting functional performance (e.g., communication failure)
• Minor: Visual or cosmetic defect (e.g., surface scratches)

This classification ensures both operators and quality engineers use common language. Corrective action times should be defined for each error type (e.g., Critical: shorter than 24 hours, Major: shorter than 72 hours). This approach facilitates root cause analysis in 8D problem-solving processes.

13. Are quality gate points positioned correctly in process (e.g., after AOI, ICT)?​

Quality control steps should be positioned at correct strategic points (Quality Gates) in production flow.

Example quality gates:

• AOI (Automated Optical Inspection) → After soldering
• ICT (In-Circuit Test) → Before function test
• Burn-in / stress test → After assembly
• Final QC → Before packaging

These gates prevent defective products from passing to next stage ("Containment Control"). "Stop-at-fail" principle should be applied at each quality gate and responsible person should be authorized. Quality gate points should be clearly marked on "Control Plan Layout".

Measurement Systems and Equipment Capability​

14. Is Measurement System Analysis (MSA / GR&R) performed?​

MSA (Measurement System Analysis) or GR&R (Gage Repeatability & Reproducibility) study should be performed for all measurement systems used in production.

This analysis verifies reliability and repeatability of measurement results.

Acceptance criterion: Total measurement variation should be less than 10% of total process variation.

Analysis results are classified as follows:

• Lower than 10%: Acceptable (Excellent)
• 10–30%: Conditional acceptance (Marginal)
• Higher than 30%: Not suitable (Unacceptable)

MSA reports should be renewed with each measurement device change or process revision.

15. Is calibration plan and labeling system created?​

Calibration plan should be created for all measurement devices, test equipment, and reference tools.

This plan should specify:

• Calibration period (e.g., 6 months / 12 months)
• Calibrating organization (accredited laboratory)
• Certificate number and validity date
• Calibration history and traceability code

Each device should carry calibration label: "CAL OK – Due Date: 2025-10-31"

Equipment with expired calibration should be automatically removed from production and system alert should be created.

16. Is preventive maintenance plan defined for critical equipment?​

Preventive maintenance plan (PM Plan) should be created for all critical equipment (press, soldering station, test fixture, mold, etc.) in production line that directly affects process quality.

Plan should include:

• Maintenance frequency (daily / weekly / monthly)
• Checklist and approval area
• Required spare parts list
• Authorized maintenance personnel

Maintenance forms after implementation should be signed and archived digitally. Preventive maintenance reduces downtime from equipment failures and increases OEE rate.

17. Is parameter tracking digital (IoT / MES integration) at soldering, pressing, welding, etc. stations?​

Process parameters at critical production stations (e.g., soldering, pressing, welding, screwing) should be monitored digitally.

Parameter examples:

• Soldering temperature and profile
• Press force and time
• Welding current / energy
• Torque value

This data should be recorded through IoT sensors or MES (Manufacturing Execution System) integration. Automatic warning system (threshold alarm) should be activated for instant deviations. This system forms the basis for real-time quality control (real-time SPC) and process traceability.

18. Are Equipment Qualification records (IQ/OQ/PQ) completed?​

New or revised production equipment should go through qualification tests before use:

• IQ (Installation Qualification): Verification that equipment is installed correctly and suitable for environmental conditions
• OQ (Operational Qualification): Testing that all functions of equipment operate at specified parameters
• PQ (Performance Qualification): Verification that consistent product quality is obtained under real production conditions

Each stage should be approved by quality unit and archived as "Equipment Qualification Report". This process is especially mandatory for medical, defense, or high-reliability products.

Production Quality Tracking and Records​

19. Is First Article Inspection (FAI) performed?​

FAI (First Article Inspection) should be performed on first production batch for new product, revised design, or after process change.

FAI verifies product's compliance with technical drawing and specifications.

Control scope:

• Dimensional measurements
• Electrical test results
• Material verification
• Visual quality control

FAI results should be documented in "FAI Report" format and signed by quality unit before Production Release.

20. Are yield and scrap rates monitored for production lines?​

Yield rate and scrap rate should be regularly monitored for each production line.

Yield rate: Yield (%) = (Valid product count / Total production count) × 100

Data should be reported on shift basis and trend analyses should be performed. Root Cause Analysis (RCA) should be initiated when scrap rate exceeds 2%. These measurements should be continuously tracked among production KPIs (OEE, FPY).

21. Are rework rate and causes analyzed?​

Rework operations should be tracked separately and causes should be recorded.

For each rework operation:

• Error type (e.g., solder deficiency, incorrect assembly, wrong component)
• Rework operation description
• Responsible operator
• Retest result should be recorded

When rework rate exceeds 1%, PFMEA and control plan should be reviewed. This analysis provides critical feedback for reducing quality losses and process improvement (Kaizen).

22. Is scope of AOI (Automatic Optical Inspection) and ICT (In-Circuit Test) defined?​

Test scope, limits, and evaluation criteria for AOI and ICT systems in production lines should be documented.

• AOI: Solder quality, component orientation, polarity, missing/incorrect assembly detection
• ICT: Electrical connection, resistance, capacitance, short circuit/open circuit tests

Test coverage (coverage %) should be calculated for each device and target should be 90% or higher. Test limits should be kept synchronized with design files (netlist, gerber, BOM). Test results should be automatically recorded in MES system.

23. Are Functional Test (FCT) statistics reported?​

Functional Test (FCT) results performed on each production batch should be statistically analyzed.

Basic metrics to track:

• Pass rate
• Average test time
• Test failure reasons
• Station-based error frequency

Data should be reviewed weekly by quality engineering team and deviations should be tracked with "Corrective Action Request (CAR)". This analysis verifies product's functional reliability and production process stability.

24. Is product serial number, test result, and revision relationship stored in production database?​

Each product's serial number (SN), test results, hardware/firmware revision, and production date should be associated in production database.

This relationship provides full traceability: SN → Test result → Revision → Operator → Date

These records should be stored digitally for 10 years and should be accessible in quality audits when necessary. Systematic traceability should be conducted through traceability matrix or MES database.

25. Are production process records (batch/lot, date, operator) traceable?​

Production records for each production batch (lot or batch) should be traceable backward.

Record system should include:

• Batch/lot number
• Production date
• Operator identity
• Material and component lots used
• Test station and results

These records should be kept centrally on ERP or MES system and should be automatically retrievable in quality inspections. Thanks to traceability, quick recall can be made in case of defect detection.

Process Capability and Improvement​

26. Is process capability index (Cp/Cpk) target 1.33 or higher?​

Process capability index (Cp/Cpk) should be calculated for all critical processes and should be at least at 1.33 level.

This value indicates that process can produce stable within specification limits.

Evaluation criteria:

• Cp lower than 1.00: Process inadequate
• 1.00 ≤ Cp lower than 1.33: Marginal
• Cp 1.33 or higher: Acceptable
• Cp 1.67 or higher: Excellent (Six Sigma level)

Cpk values should be automatically pulled from SPC system regularly and trend graphs should be shared in quality reports. Root cause analysis is mandatory when Cpk is lower than 1.33 in critical processes.

27. Are process variability sources (Machine, Material, Method, Operator, Measurement) analyzed?​

Source of variability observed in production should be analyzed through 5M approach (Machine, Material, Method, Man, Measurement).

Each variation factor should be examined separately:

• Machine: calibration, maintenance history, parameter deviation
• Material: supplier variation, moisture content, batch difference
• Method: non-compliance with work instruction, step skipping
• Operator: training level, fatigue
• Measurement: equipment sensitivity, environmental effects

These analyses should be supported with "Ishikawa (Fishbone) Diagram" and "Pareto Analysis". Obtained results should be fed back to PFMEA and control plan.

28. Are Poka-Yoke (error prevention) solutions applied in critical processes?​

Poka-Yoke (error proofing) methods should be applied at critical assembly and test points.

These systems aim to prevent error before it occurs.

Example applications:

• Shape/position guides preventing incorrect part placement
• Torque sensor screw systems
• Barcode verification (part-to-process match)
• Connection direction control sensors

Poka-Yoke solutions should aim to prevent rather than detect defective production and should work integrated with test stations. Each solution should be tracked on "Mistake-Proofing Register".

29. Are production improvements (Kaizen, 5S, TPM) conducted systematically?​

Kaizen (continuous small improvement) culture should be systematized in production processes.

Each team should report at least one Kaizen activity monthly.

With 5S (Seiri, Seiton, Seiso, Seiketsu, Shitsuke) applications, work area should be standardized; with TPM (Total Productive Maintenance) program, equipment efficiency should be monitored.

Results should be measured with:

• OEE increase (%)
• Scrap rate reduction (%)
• Ergonomics and safety scores

All improvement activities should be tracked in "Continuous Improvement Log" document.

30. Are error root cause analyses (8D, 5Why) regularly applied?​

Root cause analysis should be performed with 8D (Eight Disciplines) or 5Why (Five Whys) methodology for each detected quality problem.

8D stages are:

1. Problem definition
2. Team formation
3. Immediate corrective action
4. Root cause analysis
5. Permanent corrective action
6. Verification
7. Prevention
8. Success sharing

Analysis results should be recorded in Corrective and Preventive Action (CAPA) system and closure time should be tracked.

31. Are error rates (DPMO, PPM) reported monthly?​

DPMO (Defects Per Million Opportunities) and PPM (Parts Per Million) rates, which are statistical indicators of production quality, should be calculated monthly.

Formula examples:

• DPMO = (Total defect count / (Unit × opportunity count)) × 10⁶
• PPM = (Defective part count / Total production) × 10⁶

These metrics are the basis of process capability (sigma level) and customer satisfaction KPIs. Reports should be regularly shared in quality meetings, action plan should be prepared for deviations. Target: DPMO lower than 3000 (≈ 4 Sigma) / PPM lower than 5000.

Production Change Management​

32. Is ECO (Engineering Change Order) process integrated with production?​

ECO (Engineering Change Order) process applied for design or process changes should work integrated with production planning and quality teams.

Each ECO should include following information:

• Change definition and justification
• Affected product/version list
• Effectivity date
• Responsible engineer and approval chain
• Required test / validation steps

ECO system should be connected to PLM (Product Lifecycle Management) or ERP infrastructure and production should not start without change approval.

33. Are revision changes reflected timely to production documents?​

Each engineering change should be transferred to production documents in controlled and timely manner.

Documents to be updated:

• Schematic and PCB files
• BOM (Bill of Materials)
• Work Instructions
• Test plans
• Quality control forms

Only "latest released revision" documents should be accessible in production area. Revision lock or automatic archive should be applied on document management system (DMS) to prevent accidental use of old versions. Revision transition dates should be recorded in "Change Implementation Log" document.

34. Does change require production re-qualification after change?​

After each engineering or process change, re-qualification may be required depending on change type.

Following evaluations should be made in these cases:

• Does it affect product function? → FAI / FCT repetition required
• Did material change? → Material certification repetition
• Did production line/equipment change? → OQ / PQ validation

35. Is impact of changes on quality reflected to PFMEA?​

Potential impact of each engineering change on quality should be reflected to PFMEA (Process Failure Mode and Effects Analysis) document.

Change can reduce, increase existing process risks, or create new risks.

Therefore:

• Related row in PFMEA should be updated
• New RPN values should be calculated
• New preventive actions (CAPA) should be assigned if necessary

These updates should be checked as closure condition of ECO approval. Thus, engineering changes keep not only design but also risk management system dynamically updated.

Supply and Process Audits​

36. Are supplier process audits planned?​

Process audits (Supplier Process Audit) should be conducted systematically for all strategic suppliers.

Audit plan verifies supplier's production process quality, capacity, and sustainability criteria.

Audit scope:

• Material traceability
• Calibration and maintenance processes
• Trained personnel availability
• Process control plan and SPC applications
• Product shipment quality (PPM, OTD rates)

Supplier audit plan should be prepared annually and should be applied at least once a year for high-risk suppliers. Audit results should be entered into "Supplier Scorecard" system and used in score-based performance evaluation.

37. Is internal process audit frequency defined (e.g., twice a year)?​

Internal process audits should be conducted systematically in production facility.

Recommended minimum frequency: twice a year or after each major process change.

Audit plan should cover assembly, test, maintenance, quality control, and warehouse processes.

Each audit should include:

• ISO 9001 and customer requirements compliance
• Operator work instruction compliance
• Accuracy of process control forms
• Calibration labels and record update

Audit calendar should be published by quality management, findings should be tracked on "Internal Audit Log".

38. Are audit findings tracked through CAPA system?​

All nonconformances detected in audits should be recorded in CAPA (Corrective and Preventive Action) system and tracked until closed.

For each finding:

• Nonconformance definition
• Root cause analysis (5Why / Ishikawa)
• Corrective action plan
• Responsible person and target closure date should be determined

CAPA statuses (open / in-progress / closed) should be regularly reviewed in quality meetings.

39. Are audit results reported periodically to management?​

All supplier and internal audit results should be periodically presented in Management Review meetings.

Report content:

• Audit scope and dates
• Detected nonconformances (Critical / Major / Minor)
• Unclosed actions
• Continuous improvement recommendations
• Trend analyses (nonconformance type / frequency)

These reports should be presented to management committee at least once a year and decisions should be recorded in "Management Review Minutes" document.

Product Approval and Shipment Quality​

40. Is Final Quality Control (Final QC) procedure written?​

Final Quality Control (FQC) process performed before product shipment should be defined with written procedure.

This procedure should cover:

• Functional tests (FCT)
• Visual inspection
• Label and packaging control
• Document verification (certificates, test reports)

All checks should be recorded step by step on "Final QC Checklist" and signed by responsible personnel. Final checks performed without written FQC procedure are not considered valid by quality system.

41. Are final test results compared with customer specification?​

Test results obtained in final quality control stage should be compared with customer's approved technical specification (Customer Specification / Technical Datasheet).

This verification includes:

• Measurement values (voltage, current, frequency, temperature, signal quality)
• Functional parameters (communication protocols, response time)
• Power consumption and performance tests

All data should be reported as PASS / FAIL in terms of customer specification compliance. Engineering evaluation (Deviation Report) is mandatory before product is taken to shipment in case of nonconformance detection.

42. Does quality assurance department give pre-shipment approval (QA Release)?​

Product cannot be shipped without passing all quality tests. Quality Assurance (QA) Release approval should be obtained before shipment.

This approval is given by quality assurance department together with following documents:

• FQC Report
• Test records (AOI, ICT, FCT, Burn-in)
• Calibration certificates
• Label control form

QA Release signature should be associated with shipment permission in production system (ERP / MES). This check is the last safety barrier preventing defective product from reaching customer.

43. Are product labels (model, serial no, revision, test result) checked?​

Physical label of each product should be verified before shipment.

Information that should be on label:

• Model name / code
• Serial number (SN)
• Revision number
• Test approval status (PASS / QA Released)

Labels should be produced from material resistant to customer standards (e.g., UL969) and environmental conditions (heat, UV, humidity). Incorrect or incomplete labeling directly affects traceability and warranty validity. Therefore, "Label Verification Form" should be mandatory check step in production line.

44. Are customer feedbacks (field failure / RMA) tracked after shipment?​

All field failures or return (RMA) records occurring after shipment should be regularly tracked.

Feedback sources:

• Service records
• Customer emails / support system
• Online portal or CRM system

Each RMA should be recorded in quality system by associating with lot number and serial number. Data should be analyzed in monthly "Field Performance Report". Feedback tracking rate should be measured as KPI (e.g., 100% closure within 30 days).

45. Are field failures analyzed and converted to design/production improvement?​

Failures detected in customer field should be handled not only with repair but with root cause analysis and process improvement.

Each field failure should be analyzed with:

• Failure code (Failure Mode)
• Failure rate (Field Return Rate)
• Root cause (Design / Process / Usage)
• Corrective action taken (ECO, CAPA, PFMEA update)

Analysis results should be communicated to design and production teams as Feedback Loop and entered into product lifecycle (PLM). This loop forms the basis of Closed-Loop Quality System approach.