Quality Control Inspection Guidelines

Quality Control Procedures

Maintaining product quality through systematic inspection and testing.

Inspection Frequency

First Article Inspection:

• First piece of new run
• After setup or changeover
• After extended downtime
• 100% dimensional check
• Documented on first article form

In-Process Inspection:

• Hourly or per production plan
• Sample size per control plan
• Critical characteristics checked
• Results recorded on control chart

Final Inspection:

• Before packaging
• Visual and dimensional checks
• Functional testing if required
• Accept/reject decision
• Documentation per procedure

Measurement Tools

Common Tools:

• Calipers (digital/dial)
• Micrometers
• Height gauges
• Pin gauges
• Thread gauges
• Radius gauges
• Optical comparators
• CMM (Coordinate Measuring Machine)

Tool Calibration:

• Check calibration sticker
• Verify due date
• Do not use expired tools
• Report damaged tools
• Handle with care

Inspection Process

1. Prepare:
   • Review control plan
   • Gather required tools
   • Verify calibration
   • Obtain inspection forms
2. Sample:
   • Use random sampling
   • Follow sample plan
   • Mark inspected parts
3. Inspect:
   • Check all characteristics
   • Use correct technique
   • Record actual measurements
   • Note any defects
4. Evaluate:
   • Compare to specifications
   • Determine conformance
   • Calculate Cpk if required
5. Document:
   • Record results
   • Sign and date
   • Enter into QC database
6. Decide:
   • Accept lot
   • Reject lot
   • Hold for evaluation
   • Notify supervisor of rejections

Defect Classification

Critical Defect:

• Safety hazard
• Non-functional product
• Immediate rejection
• 100% inspection required
• Root cause analysis mandatory

Major Defect:

• Reduces usability
• Customer likely to notice
• May affect function
• Lot rejection possible

Minor Defect:

• Cosmetic issue
• Doesn't affect function
• May be acceptable per criteria
• Document and trend

Control Charts

Statistical process control:

• Plot measurements over time
• Watch for trends
• Check for out-of-control conditions
• Calculate control limits
• Take action when out of control

Out of Control Conditions:

• Point beyond control limits
• 7 consecutive points on one side
• Trends up or down
• Sudden shifts in average
• Stop production and investigate

Non-Conforming Material

When parts fail inspection:

1. Tag parts as "HOLD" or "REJECT"
2. Move to designated quarantine area
3. Complete non-conformance report
4. Notify supervisor immediately
5. Document quantity and issues
6. Await disposition decision

Disposition Options:

• Rework: Can be corrected
• Use As Is: Customer approval required
• Scrap: Cannot be salvaged
• Return to Supplier: For incoming material

Customer Complaints

When quality issues are reported:

1. Quality engineer investigates
2. Pull samples from suspect lot
3. Re-inspect to specification
4. Review production records
5. Identify root cause
6. Implement corrective action
7. Verify effectiveness
8. Document in CAPA system

Internal Audits

Regular quality audits:

• Verify procedures followed
• Review documentation
• Check calibration compliance
• Evaluate training records
• Identify improvement opportunities
• Corrective actions tracked

Measurement Uncertainty

Understanding tolerances:

• Tool accuracy affects measurements
• Use appropriate tool for tolerance
• Rule of thumb: 10:1 ratio
• Example: ±0.001" tolerance needs 0.0001" resolution
• Consult quality engineer if uncertain

Record Retention

Quality records kept for:

• Inspection results: 7 years minimum
• First articles: Life of program
• Non-conformances: 10 years
• Calibration records: Life of tool + 1 year
• Customer complaints: Indefinitely

Continuous Improvement

Quality initiatives:

• Suggestion program
• 5S workplace organization
• Kaizen events
• Six Sigma projects
• Lean manufacturing
• Employee involvement encouraged