First Article Inspection: Ensuring Quality from Day One#
Your design is complete. Prototypes validated. Manufacturing fixtures built. The supplier just delivered the first production units. You're eager to start shipping. But before you authorize full production, there's one critical gate: First Article Inspection.
This is where you discover if theory matches reality. If your tolerances are achievable. If the manufacturing process is stable. If the supplier truly understands your requirements. Skip this step or rush through it, and you risk expensive consequences.
I recently investigated a production disaster where a company received 5,000 machined aluminum housings—their entire annual volume—before anyone performed a thorough first article inspection. The problem? A critical mounting hole pattern was off by 3mm. Every single unit. The parts were unusable. Total loss: $180,000 in scrapped parts, plus $45,000 to expedite replacement parts, plus 8 weeks of delayed product launch.
The tragedy? A proper first article inspection on the initial 3 pieces would have caught the error before the supplier machined 4,997 more bad parts. Cost to catch it early: $800 in inspection time. Cost of not catching it: $225,000 plus market opportunity loss.
This isn't unusual. First article inspection is the most valuable quality gate in manufacturing—and the most commonly skipped or poorly executed.
After 17 years developing products across aerospace, automotive, heavy equipment, and packaging, I've performed hundreds of first article inspections. This article shares the process, documentation requirements, common failures, and decision frameworks that separate effective FAI from expensive oversights.
Let me expand on that housing disaster because it illustrates every principle of proper first article inspection.
Part: Aluminum housing for industrial equipment
Manufacturing process: CNC machining from 6061-T6 billet
Critical features:
- Mounting hole pattern (4 holes, 0.250" diameter, ±0.010" positional tolerance)
- Internal bore (2.500" ±0.005" diameter)
- Face perpendicularity (0.005" per inch)
Supplier: New supplier, first production order
Volume: 5,000 units (annual requirement)
Unit cost: $36 per part
Total order value: $180,000
Proper FAI process:
- Supplier machines 3 first articles
- Supplier performs internal dimensional inspection
- Supplier submits parts and inspection report
- Customer receives parts and documentation
- Customer performs receiving inspection (full dimensional check)
- Customer approves or rejects based on results
- If approved, supplier proceeds with full production
Timeline: 2 weeks for FAI before production release
Cost: $800 (inspection labor, documentation review)
Actual sequence:
- Supplier machined 3 "samples"
- Supplier performed visual inspection only (no dimensional check)
- Customer received samples, checked fit with mating parts
- Samples appeared to fit (actually slightly loose, not noticed)
- Customer: "Looks good, proceed with production"
- Supplier immediately machined all 5,000 units
- Supplier shipped all 5,000 units
Timeline: 4 weeks from order to full delivery
Problem discovered: When customer tried to install units in first production assemblies
What was wrong:
- Mounting hole pattern shifted 3mm from specified location
- Holes located from wrong datum in CNC program
- Pattern was internally consistent (holes relative to each other correct)
- Pattern positioned wrong relative to part features
Why it wasn't caught:
- No dimensional inspection of first articles
- Fit check was ambiguous (oversized clearance masked error)
- Production run completed before any units installed in assemblies
Why all 5,000 were bad:
- CNC program error affected all parts
- Supplier machined entire batch without staged approval
- No in-process inspection caught the datum error
Immediate costs:
- Scrapped parts: 5,000 × $36 = $180,000
- Expedited replacement: $45,000 (premium pricing + air freight)
- Engineering investigation: $8,000 (root cause analysis, corrective action)
- Total direct cost: $233,000
Indirect costs:
- Production delay: 8 weeks (missed sales window)
- Opportunity cost: $120,000 (estimated lost sales)
- Customer dissatisfaction: 4 customers delayed (relationship damage)
- Management time: 40+ hours dealing with crisis
Total impact: $353,000+ for lack of $800 FAI process
A proper FAI would have:
- Caught the datum error in first 3 parts
- Cost $800 and 2 weeks
- Resulted in corrected CNC program
- Prevented $353,000+ in losses
Key insight: The value of FAI isn't the inspection itself—it's preventing production of bad parts. One hour of inspection time prevents potentially thousands of hours of crisis management.
Before diving into process, let's define what FAI is and why it exists.
First Article Inspection (FAI) is a comprehensive verification process performed on the first production unit(s) from a new or modified manufacturing process to ensure:
- The manufacturing process is capable of producing parts meeting specifications
- All drawing requirements are understood and implemented correctly
- Measurement systems and inspection processes are adequate
- Documentation is complete and traceable
"First article" means:
- First unit(s) from a new production setup
- First unit(s) from a new supplier
- First unit(s) after a significant design or process change
- Typically 1-3 units (not just one)
"Inspection" includes:
- Full dimensional verification
- Material certification verification
- Process verification (heat treat, coating, etc.)
- Functional testing if applicable
- Documentation review
Validates assumptions:
- Drawing interpretation (did supplier understand requirements?)
- Process capability (can they actually achieve the tolerances?)
- Material selection (correct alloy and condition?)
- Inspection methods (are they measuring correctly?)
Prevents waste:
- Catches errors before mass production
- Identifies process instabilities early
- Finds documentation gaps before they cause issues
Establishes baseline:
- Documents what "good" looks like
- Provides reference for future production
- Creates traceability for quality system
Manages risk:
- New suppliers (unknown capabilities)
- Complex parts (many opportunities for error)
- Critical applications (high cost of failure)
- First-time processes (learning curve)
Mandatory situations:
- First production from new supplier
- After design change affecting form, fit, or function
- After manufacturing process change
- After production interruption >2 years (process degradation)
- Aerospace/defense contracts (AS9102 standard)
- Automotive contracts (PPAP requirements)
- Medical device regulations
- Customer contractual requirements
Recommended situations:
- New manufacturing equipment or tooling
- Change in manufacturing location
- Significant time since last production run (>6 months)
- Previous quality issues with this supplier
- Critical or safety-related parts
- High-volume production (cost of error is high)
May not be needed:
- Replenishment of proven parts from proven supplier
- Simple commercial parts (fasteners, standard components)
- Very low volume (1-10 pieces total)
- Non-critical applications
First Article Inspection: Validates manufacturing setup and first production units
PPAP (Production Part Approval Process): Automotive-specific process including FAI plus much more documentation
IQ/OQ/PQ: Qualification protocol for equipment and processes (pharmaceutical/medical)
Design Validation: Proves design meets requirements (covered in Blog 5)
Incoming Inspection: Routine receiving inspection of production parts (ongoing, not just first)
A systematic FAI process ensures nothing is overlooked. Here's the complete workflow.
Step 1: Define FAI requirements in purchase order
Include in PO or contract:
- FAI is required before production release
- Number of first articles (typically 3)
- Documentation required (inspection report, material certs, etc.)
- Acceptance criteria and approval authority
- Timeline (when FAI must be completed)
Example PO language:
"Supplier shall manufacture three (3) first article samples and perform First Article Inspection per AS9102 standard (or customer specification). All dimensional characteristics shall be inspected and documented. First articles and FAI report shall be submitted for customer approval before proceeding with production. Production is not authorized until customer issues written FAI approval."
Step 2: Identify critical characteristics
Review drawing and identify:
- Safety-critical features
- Features affecting form, fit, function
- Tight tolerances (where process capability is uncertain)
- New or difficult processes
- Features with history of problems
Mark on drawing or create separate list for supplier.
Step 3: Prepare inspection plan
Document:
- What will be measured
- How it will be measured (equipment, method)
- Acceptance criteria for each characteristic
- Who will perform inspection (supplier, customer, third-party)
- Required documentation
Step 4: Communicate with supplier
Pre-production meeting or communication covering:
- Drawing requirements and critical features
- Any ambiguities or special requirements
- FAI process and timeline
- Documentation expectations
- Process capability concerns
Step 5: Supplier manufactures first articles
Supplier:
- Sets up production process (fixtures, programs, tooling)
- Manufactures first article quantity (typically 3 units)
- Uses production materials and processes (not special one-offs)
- Documents process parameters
Step 6: Supplier performs internal inspection
Supplier inspects first articles:
- Full dimensional inspection per drawing
- Material verification (certification review)
- Process verification (heat treat, coating thickness, etc.)
- Functional testing if required
- Document all results
Step 7: Supplier prepares FAI documentation
Supplier creates:
- Dimensional inspection report (all characteristics)
- Material certifications
- Process certifications (heat treat, plating, etc.)
- Non-conformance report (if any out-of-spec features)
- Corrective action plan (for any discrepancies)
Step 8: Supplier submits first articles and documentation
Supplier ships to customer:
- Physical first article samples
- Complete FAI documentation package
- Request for approval to proceed
Step 9: Customer receives and logs first articles
Customer:
- Receives shipment and documentation
- Logs receipt in quality system
- Assigns inspector and due date
- Secures first articles (prevent use before approval)
Step 10: Customer reviews documentation
Quality engineer reviews:
- Completeness of documentation
- Supplier inspection results
- Material certifications match drawing
- Process certifications match requirements
- Any non-conformances documented with corrective action
Step 11: Customer performs receiving inspection
Customer inspects first articles:
- Verify critical dimensions (at minimum)
- Often re-measure all characteristics (independent verification)
- Compare to supplier's reported values
- Perform functional tests if applicable
- Document findings
Inspection level options:
- Full re-inspection: Measure everything supplier measured (highest confidence)
- Critical features only: Verify most important dimensions (faster, adequate for proven suppliers)
- Sampling: Measure subset of features (lowest confidence, only for low-risk)
Step 12: Customer compares results
Analysis:
- Do customer measurements match supplier measurements?
- Are all characteristics within specification?
- Are any measurements marginal (close to limits)?
- Do non-conformances have adequate corrective action?
Acceptance criteria:
- All measurements within specification: Strong candidate for approval
- Measurements 90%+ of tolerance: Acceptable but monitor
- Measurements 95%+ of tolerance: Marginal, require corrective action or closer monitoring
- Measurements out of spec: Reject, require corrective action and new first articles
Step 13: Customer performs functional verification
If applicable:
- Assemble first article into end product
- Test fit with mating parts
- Perform functional tests
- Verify installation process
Example: Mounting bracket
- Bolts to mounting surface (verify hole pattern)
- Mounts hydraulic cylinder (verify bore fit)
- Load test to rated capacity (verify strength)
- Document results
Step 14: Approve, reject, or conditional approval
Full approval:
- All characteristics within spec
- Documentation complete
- Process demonstrated capable
- Action: Issue written approval, authorize production
Conditional approval:
- Minor non-conformances with acceptable corrective action
- Marginal dimensions with monitoring plan
- Action: Approve with conditions, require production sampling plan
Rejection:
- Out-of-spec characteristics without acceptable corrective action
- Process appears incapable
- Documentation incomplete or inadequate
- Action: Reject FAI, require corrective action and new first articles
Step 15: Document approval decision
Issue formal communication:
- Approval status (approve/conditional/reject)
- Specific findings and concerns
- Any conditions or monitoring requirements
- Authorization to proceed (or not)
- Maintain in quality records
Step 16: Monitor initial production
Even after FAI approval:
- Inspect first production batch closely (10-25 units)
- Verify no process drift
- Confirm stable production
- Graduate to routine sampling after confidence established
Proper documentation provides traceability and protects both parties. Here's what's needed.
1. Dimensional inspection report
Contents:
- Part number, revision, quantity inspected
- All drawing dimensions and tolerances
- Actual measured values for each characteristic
- Measurement method/equipment used
- Inspector name and date
- Pass/fail indication for each characteristic
Format options:
- AS9102 Form 3 (aerospace standard)
- Custom inspection report template
- Spreadsheet with drawing callouts
Example excerpt:
| Characteristic | Nominal | Tolerance | Actual | Accept? | Method |
|---|
| Overall Length | 4.500" | ±0.010" | 4.504" | Pass | Caliper |
| Hole Diameter | 0.250" | ±0.005" | 0.248" | Pass | Pin gauge |
| Hole Position | 2.000" | ±0.010" | 2.008" | Pass | CMM |
2. Material certifications
Required documents:
- Mill test report (material chemical composition)
- Heat treat certification (if heat treated)
- Material traceability (heat/lot numbers)
Verify:
- Material specification matches drawing (e.g., 6061-T6 aluminum)
- Heat/lot numbers on parts match certifications
- Material properties meet requirements
3. Process certifications
For special processes:
- Heat treat: Certification of time/temperature cycle
- Plating: Thickness and adhesion test results
- Coating: Type, thickness, curing process
- Welding: Welder qualification, procedure
- NDT: Inspection results (X-ray, penetrant, etc.)
4. Non-conformance reports (if applicable)
If any characteristics out of specification:
- Description of non-conformance
- Root cause analysis
- Corrective action taken
- Verification of corrective action effectiveness
- Disposition (scrap, rework, use-as-is with waiver)
5. Supplier quality documentation
Supporting documents:
- Control plan (how production will be monitored)
- Inspection frequency during production
- Gage R&R studies (measurement system capable?)
- Process capability studies (Cp, Cpk if required)
For aerospace and defense applications, AS9102 defines specific requirements:
Three-part form package:
Form 1: Part number accountability
- Lists all part numbers in assembly
- Configuration management
Form 2: Product accountability
- Assembly-level verification
- Serialization tracking
Form 3: Detailed inspection results
- Characteristic-by-characteristic results
- Actual measurements and tolerances
- Pass/fail status
Additional AS9102 requirements:
- Ballooned drawings (each characteristic numbered)
- Measurement traceability to NIST
- Documented measurement uncertainty
- Inspector qualifications documented
AS9102 approval levels:
- Level 1: Supplier internal approval
- Level 2: Customer approval
- Level 3: Government or regulatory approval
How long to keep FAI records:
- Minimum: Life of production contract
- Aerospace: 7-10 years minimum (often longer)
- Automotive: Per customer requirements (typically 5+ years)
- Medical devices: Product lifetime + statute of limitations
- General industry: 3-5 years recommended
What to retain:
- Complete FAI package (all forms and certs)
- Approval correspondence
- Sample parts (if practical)
- Photos of first articles
- Any corrective action records
Retrieval requirements:
- Must be able to find records quickly (organized filing)
- Index by part number and date
- Digital archiving recommended (scan paper records)
Aerospace and defense require rigorous FAI per AS9102. Here's what makes it different.
Purpose: Standardize FAI process across aerospace supply chain
Scope: Applies to:
- New part or assembly production
- After design change
- After manufacturing process change
- After change in inspection method
- After production break >2 years
- Non-conforming parts requiring re-verification
Requirements:
- Specific form formats (Forms 1, 2, 3)
- 100% inspection of all characteristics
- Documented measurement uncertainty
- Controlled measurement equipment
- Inspector qualification requirements
Ballooned drawings:
- Every dimension and tolerance numbered (ballooned)
- Numbers correspond to Form 3 inspection results
- Provides unambiguous identification
Measurement traceability:
- Measurement equipment calibrated to NIST-traceable standards
- Calibration certificates on file
- Equipment within calibration period during inspection
Measurement uncertainty:
- Document accuracy of measurement method
- Uncertainty must be significantly less than tolerance (typically 10:1 ratio)
- Example: Measuring 0.010" tolerance, need equipment accurate to ±0.001" or better
Partial FAI provisions:
- If only some characteristics changed, can do "partial FAI"
- Only changed characteristics require full re-inspection
- Unchanged characteristics: Verify but don't necessarily re-measure
- Document which characteristics included in partial FAI
Delta FAI:
- For minor changes (e.g., material cert from different mill)
- Focus on changed elements only
- Still requires formal documentation
Form 1: Part Number Accountability
Captures:
- Part number and revision level
- Change description (why FAI is being performed)
- Assembly structure (parent/child relationships)
- Drawing revisions for all components
- Configuration control information
Form 2: Product Accountability
Documents:
- Lot/batch identification
- Serial numbers if applicable
- Material traceability (heat/lot numbers)
- Processes applied (heat treat, plating, etc.)
- Quantity manufactured/inspected
Form 3: Characteristic Accountability
Line-by-line inspection results:
- Balloon number from drawing
- Characteristic description
- Specification/tolerance
- Actual measured result
- Measurement method
- Inspection equipment ID
- Accept/reject status
- Inspector initials
Example Form 3 entries:
| Balloon # | Characteristic | Specification | Actual | Method | Equipment | Accept | Inspector |
|---|
| 1 | Overall Length | 4.500" ±0.010" | 4.506" | Caliper | CAL-042 | Yes | JRS |
| 2 | Hole Dia | Ø0.250" +0.005/-0.000 | Ø0.253" | Pin Gauge | PG-250 | Yes | JRS |
| 3 | Hole Position | 2.000" ±0.010" | 2.003" | CMM | CMM-01 | Yes | MKT |
Incomplete balloon numbering:
- Missing characteristics from Form 3
- Balloon numbers don't match drawing
- Solution: Systematic review, cross-check
Measurement uncertainty not documented:
- Form 3 requires measurement method and equipment
- Must demonstrate equipment capable
- Solution: Include equipment calibration accuracy
Inspector qualification not verified:
- Must demonstrate inspector competency
- Training records required
- Solution: Maintain inspector qualification matrix
Partial FAI incorrectly applied:
- Changed characteristics not identified
- Claiming partial when full FAI required
- Solution: Engineering review of changes, conservative approach
Calibration issues:
- Equipment out of calibration during inspection
- Calibration certificates not included
- Solution: Check calibration before starting, include certs in package
First articles fail for predictable reasons. Knowing common failures helps you prevent them.
Problem: Measured dimensions outside drawing tolerances
Common causes:
Wrong datum structure:
- CNC program references wrong features
- Example: Holes positioned from edge instead of centerline
- Solution: Review program, verify datum setup
Tolerance stack-up miscalculation:
- Designer didn't account for cumulative tolerances
- Supplier can't achieve dimension due to stack-up
- Solution: Tolerance analysis, drawing correction if needed
Process incapability:
- Process can't consistently achieve tolerance
- Example: Tolerance ±0.002", process capable of ±0.005"
- Solution: Process improvement or tolerance relaxation
Measurement error:
- Supplier measured incorrectly
- Wrong measurement method for characteristic
- Solution: Review measurement procedure, use appropriate method
Insufficient process control:
- Process parameters not controlled adequately
- Example: Temperature variation affecting dimensions
- Solution: Establish process control, monitor critical parameters
Example failure: Shaft diameter out of spec
- Drawing: Ø1.000" ±0.002"
- Supplier measured: Ø1.0045"
- Out of spec by 0.0025"
Investigation:
- Reviewed CNC program: Programmed correctly
- Checked cutting tool: Tool worn beyond spec
- Measured 5 more parts: Similar results (1.004-1.005")
Root cause: Tool wear, inadequate tool monitoring
Corrective action: Replace tool, establish tool life limits, monitor tool wear
Re-FAI: New first articles with fresh tool: Ø0.999-1.001" (within spec)
Problem: Material doesn't match drawing specification
Common causes:
Wrong alloy ordered:
- Supplier ordered incorrect material
- Example: 6063 instead of 6061 aluminum
- Solution: Review material certifications against drawing
Wrong heat treatment:
- Specified T6, received annealed
- Wrong properties (strength, hardness)
- Solution: Material hardness test, heat treat cert review
Material certification doesn't match parts:
- Cert shows correct alloy but heat/lot numbers don't match parts
- Traceability broken
- Solution: Verify marking on parts matches cert, reject if not traceable
Substitute material used without approval:
- Supplier substituted "equivalent" material
- Example: 304 stainless instead of 316 (different corrosion resistance)
- Solution: Reject, require specified material
Example failure: Aluminum alloy wrong
- Drawing: 6061-T6 aluminum
- Mill cert: 6063-T6 aluminum (architectural alloy, lower strength)
Investigation:
- Reviewed purchase order: Correctly specified 6061
- Supplier: "They're both aluminum, should be fine"
- Checked mechanical properties: 6063 has 50% lower strength than 6061
Root cause: Supplier material substitution without engineering approval
Corrective action: Scrap parts, order correct material, add material verification to supplier's inspection process
Re-FAI: New parts with correct 6061-T6 material
Problem: Surface finish, plating, or coating doesn't meet spec
Common causes:
Wrong finish specified in production:
- Drawing calls for 32 Ra, production using 125 Ra tooling
- Solution: Review and update machining processes
Coating thickness wrong:
- Too thin (inadequate protection)
- Too thick (dimensional issues, appearance)
- Solution: Coating process control, measure thickness
Wrong coating type applied:
- Zinc instead of nickel
- Powder coat instead of liquid paint
- Solution: Review coating specifications, ensure understanding
Inadequate surface preparation:
- Contamination before coating
- Poor adhesion
- Solution: Improve cleaning process, adhesion testing
Example failure: Plating thickness inadequate
- Drawing: Nickel plate, 0.0005-0.0008" thickness
- Measured: 0.0002-0.0003" thickness
- Far below minimum requirement
Investigation:
- Reviewed plater's process: Plating time too short
- Checked plater's setup: Using wrong amperage
- Root cause: Plater misunderstood specification, set up for different part
Corrective action: Plater corrected process parameters, replated test samples, verified thickness
Re-FAI: New samples with correct plating thickness
Problem: Part dimensions are within spec but part doesn't work as intended
Common causes:
Assembly interference not caught on drawing:
- 3D CAD interference check missed something
- Parts interfere during assembly
- Solution: Physical mockup, revised design
Tolerance stack-up at extremes:
- All dimensions within spec individually
- Combined at worst-case = doesn't fit
- Solution: Statistical tolerance analysis, adjust if needed
Missed requirement:
- Drawing didn't capture critical requirement
- Part meets drawing but doesn't meet need
- Solution: Drawing update, engineering change
Installation problem:
- Part correct but can't be installed
- Access issues, clearance problems
- Solution: Installation procedure review, design revision if needed
Example failure: Bracket bolt clearance
- All dimensions within spec
- During assembly: Socket wrench doesn't fit (boss interferes with tool access)
Investigation:
- Checked drawing: Doesn't show boss (not considered critical)
- Physical test: Socket indeed can't access bolt
- Root cause: Designer didn't consider assembly tool clearance
Corrective action: Design change - reduce boss height by 0.25", allows wrench access
Re-FAI: New parts with reduced boss height
Problem: Process defects or poor workmanship
Common causes:
Weld defects:
- Porosity, undercut, incomplete fusion
- Fails visual inspection or NDT
- Solution: Welder training, procedure improvement
Machining defects:
- Burrs, tool marks, chatter marks
- Cosmetic or functional issues
- Solution: Tool selection, feeds/speeds optimization
Casting/forging defects:
- Porosity, inclusions, cracks
- NDT rejection
- Solution: Process control improvement at foundry
Handling damage:
- Scratches, dents, contamination
- Occurred during manufacturing or shipping
- Solution: Improved handling procedures, packaging
Example failure: Welded assembly porosity
- Visual inspection: Excessive porosity in multiple welds
- X-ray: Internal porosity exceeding acceptance criteria
Investigation:
- Reviewed welding procedure: Procedure acceptable
- Observed welder: Technique poor (inconsistent travel speed)
- Checked welder qualification: Cert expired 6 months ago
Root cause: Unqualified welder performing production welding
Corrective action: Welder re-qualified, defective assemblies scrapped, new assemblies welded by qualified welder
Re-FAI: New assemblies with acceptable welds
When first articles fail, understanding why prevents recurrence. Here's how to find root cause.
Method: Ask "why" repeatedly until root cause is found
Example: Hole diameter out of spec
- Why is the hole oversize?
- Why is the drill bit worn?
- It machined 500 holes without replacement
- Why wasn't it replaced sooner?
- No tool life tracking system
- Why is there no tool life tracking?
- Operator experience relied on, no formal system
- Why wasn't a formal system established?
- Process planning didn't include tool management
Root cause: Inadequate process planning for tool life management
Corrective action: Establish tool life limits, implement tracking system
Categories of causes:
- Man: Operator skill, training, errors
- Machine: Equipment capability, calibration, maintenance
- Material: Properties, variations, suppliers
- Method: Processes, procedures, instructions
- Measurement: Inspection methods, equipment, accuracy
- Environment: Temperature, humidity, vibration
Example: Coating thickness too thin
Investigate each category:
- Man: Was operator trained on coating process? Did operator follow procedure?
- Machine: Is coating equipment functioning correctly? Calibrated recently?
- Material: Is coating material fresh? Correct viscosity?
- Method: Is procedure documented? Followed correctly?
- Measurement: Is thickness gauge accurate? Calibrated?
- Environment: Temperature during coating within range?
Finding: Material viscosity wrong (too thin) due to incorrect thinner ratio
Root cause: Procedure didn't specify thinner ratio precisely ("add thinner until right consistency")
Corrective action: Update procedure with specific ratios, train operators
Comparison method: What is affected vs. what is not affected
Example: First 3 units have hole position errors, but supplier's internal check parts were OK
Is:
- First articles (failed)
- New production setup (failed)
- Different operator (failed)
Is Not:
- Supplier check parts (passed)
- Previous production run (passed)
- Original operator setup (passed)
Difference: New operator set up fixture differently
Root cause: Fixture setup instructions inadequate
Corrective action: Improve fixture setup procedure, add setup verification step
Measure multiple samples:
- Don't assume single failure is representative
- Inspect 5-10 additional units if possible
- Look for patterns (all high, all low, or random variation?)
Pattern interpretation:
- All measurements on one side of nominal: Systematic offset (program error, setup error)
- Random scatter around nominal: Process variation (capable but not centered)
- Bimodal distribution: Multiple causes or setup changes
- Trend over time: Tool wear, temperature drift
Example: 10 shafts measured
- Target: Ø1.000"
- Measurements: 1.004, 1.005, 1.004, 1.005, 1.004, 1.005, 1.004, 1.005, 1.004, 1.005
- Pattern: All consistently high by 0.004-0.005"
- Interpretation: Systematic offset, not random variation
- Root cause: CNC program programmed to 1.005" instead of 1.000"
- Corrective action: Correct program, remake parts
FAI is a partnership between customer and supplier. Effective collaboration improves outcomes.
Communicate early:
- Don't wait for FAI failure to engage
- Pre-production meeting to review requirements
- Walk through drawing together
- Identify challenging features
Share design intent:
- Explain why features are critical
- Discuss function and mating parts
- Helps supplier understand priorities
- May reveal opportunities for manufacturing-friendly changes
Discuss inspection methods:
- How will supplier measure critical features?
- Do they have adequate equipment?
- Measurement method agreement prevents disputes
Example pre-FAI meeting:
- Review bolt hole pattern: "These holes mate with existing frame, position is critical"
- Discuss coating: "Thickness matters for corrosion protection in marine environment"
- Identify tight tolerance: "This bore houses bearing, runout critical for function"
- Result: Supplier understands priorities, focuses attention correctly
Supplier communication:
- Update customer on progress
- Flag concerns or potential issues early
- Don't surprise customer with failures at submission
Collaborative problem-solving:
- If issue found, involve customer immediately
- Discuss options: design change, process improvement, tolerance analysis
- Faster resolution than formal non-conformance after fact
Example collaborative problem:
- Supplier machines first articles, finds one dimension consistently at limit
- Measurement: 3.496-3.498" (spec: 3.500" ±0.005", so within tolerance but marginal)
- Supplier calls customer: "We're within spec but close to low limit. Concerned about process stability."
- Discussion: Customer reviews tolerance, agrees it's tighter than needed
- Resolution: Customer relaxes tolerance to ±0.010" (still meets function)
- Result: Production capability improved, faster approval
Share findings constructively:
- Focus on facts, not blame
- "Hole position measured 2.008", specification is 2.000 ±0.005"" not "You made it wrong"
- Discuss root cause together
Corrective action collaboration:
- Supplier proposes corrective action
- Customer reviews and provides input
- Agree on action plan and timeline
- Customer verifies effectiveness
Knowledge sharing:
- What did we learn from this FAI?
- How can we prevent similar issues in future parts?
- Update documentation (drawings, procedures, work instructions)
Example post-FAI collaboration:
- Customer finds coating thickness non-conformance
- Customer to supplier: "Measured 0.0003", need 0.0005" minimum. Can you achieve this thickness?"
- Supplier: "Yes, we ran plating cycle too short. We'll increase time and revalidate."
- Customer: "Please run test samples with extended time and measure before replating first articles."
- Supplier replates test samples: 0.0006-0.0008" thickness achieved
- Customer: "Good results. Proceed with first articles using corrected process."
- Result: Fast resolution, confidence in corrective action
Long-term perspective:
- FAI is beginning of relationship, not one-time event
- Invest in supplier success
- Share knowledge and best practices
Continuous improvement:
- Review FAI lessons learned
- Implement improvements for next part
- Recognize supplier improvements
Trust but verify:
- FAI approved doesn't mean stop checking
- Establish production sampling plan
- Periodic audits maintain quality
Not all FAI failures require immediate rejection and re-work. Knowing when to iterate vs. accept with monitoring saves time and money.
Criteria:
- All characteristics within specification
- No marginal dimensions (well within tolerance)
- Good process capability indicated (Cpk >1.33 if calculated)
- Supplier documentation complete and accurate
- Functional testing passed
Action: Approve FAI, authorize production with routine sampling
Example: Machined bracket
- All dimensions: Mid-tolerance or better
- Material: Correct, certifications complete
- Surface finish: Meets specification
- Fit test: Installs and functions correctly
- Decision: Full approval, proceed to production
Criteria for conditional approval:
- All characteristics within spec but some marginal (90-95% of tolerance)
- Minor non-conformances with acceptable corrective action
- Process appears capable but needs monitoring
- First-time supplier or process (lower confidence)
Monitoring plan includes:
- Increased inspection frequency initially (every unit or every 5th unit)
- Specific characteristics to monitor
- Statistical process control if applicable
- Graduated relaxation as confidence builds
Example: Welded frame assembly
- All dimensions within spec
- One dimension consistently measuring 95% of tolerance (close to limit)
- Weld quality acceptable
- Decision: Conditional approval
- Monitor that one dimension on every unit for first 25 units
- If stable, reduce to every 5th unit
- If trend toward limit, stop and investigate
Accept with monitoring when:
- Risk is acceptable: Non-critical application or low consequence of failure
- Corrective action in place: Issue identified, solution implemented, verification underway
- Time-critical: Production delay costs exceed risk of monitoring approach
- Cost-effective: Rejection and re-FAI costs exceed monitoring costs
Criteria for rejection:
- One or more characteristics out of specification
- Corrective action inadequate or unproven
- Process appears incapable
- Material non-conformance
- Functional testing failed
- Safety-critical features marginal or failed
Iteration process:
- Formal rejection notice to supplier
- Root cause analysis (collaborative)
- Corrective action plan from supplier
- Verification of corrective action (test samples)
- New first articles manufactured with corrections
- Re-submit for FAI
Example: Aluminum housing
- Hole pattern out of position by 0.015" (spec: ±0.010")
- Root cause: CNC program error
- Corrective action: Program corrected, test part verified
- Decision: Reject current first articles, require new first articles with corrected program
- Re-FAI: New first articles within spec, approved
Reject and iterate when:
- Out-of-spec conditions: No compromise on specification without engineering waiver
- Safety critical: Any question about safety = reject
- Customer requirements: Contract requires full compliance
- Process capability concerns: Indicates future production will have high scrap rate
- Material traceability: Cannot verify correct material
Rare situation: Part is out of spec but can still be used
Criteria for use-as-is waiver:
- Engineering analysis confirms function not affected
- Non-conformance well-documented
- Customer approves deviation
- Typically one-time or limited quantity
Process:
- Formal deviation request from supplier
- Engineering evaluation of impact
- Management approval (often multiple levels)
- Customer notification and approval
- Documentation in quality records
Example: Cosmetic defect
- Scratch on non-functional surface
- Doesn't affect function or durability
- Would require re-machining to correct (expensive)
- Location: Will be hidden in assembly
- Decision: Use-as-is waiver for these 3 first articles
- Action: Production units must meet cosmetic requirements (no waiver for production)
Use waiver sparingly:
- Overuse of waivers indicates process problems
- Sets bad precedent with supplier
- Erodes quality culture
| Situation | All within spec | 1-2 marginal | Out of spec | Functional issue |
|---|
| Action | Approve | Monitor | Reject | Reject |
| Production | Proceed | Proceed with plan | Hold | Hold |
| Inspection | Routine sampling | Enhanced sampling | N/A | N/A |
| Timeline | Immediate | Immediate | Delayed | Delayed |
| Risk level | Low | Medium | N/A | High |
Cost of rejection:
- New first articles: Material + manufacturing time
- Investigation time: Engineering, quality, supplier
- Production delay: Lost time, expedite costs if needed
- Typical cost: $2,000-10,000 and 1-2 weeks
Cost of acceptance with monitoring:
- Enhanced inspection: Additional labor per unit
- Potential scrap: If monitored characteristic drifts out
- Typical cost: $5-20 per unit additional inspection
Cost of waiver:
- Engineering evaluation: 4-8 hours
- Documentation: 2-4 hours
- Risk of field issue: Variable (potentially high)
Example decision:
- One dimension marginal but within spec
- Enhanced monitoring cost: $10 per unit × 500 units = $5,000
- Rejection and re-FAI cost: $8,000 + 2 weeks delay
- Risk if monitoring fails: 5% probability × $20,000 = $1,000 expected cost
- Total expected cost of monitoring: $5,000 + $1,000 = $6,000
- Decision: Accept with monitoring (lower total cost and faster)
FAI considerations vary by process. Here's what to focus on for common processes.
Critical inspection points:
- Datum location (part zeroed correctly in fixture?)
- Programmed vs. drawing dimensions (program matches drawing?)
- Tool wear effects (stable through production run?)
- Surface finish (achievable with selected tooling?)
Common issues:
- Datum errors (part referenced wrong surface)
- Decimal errors in program (0.1 vs. 1.0)
- Inch/metric confusion
- Tool deflection (thin walls, deep pockets)
Specific checks:
- Run program on first article, measure immediately
- Run program on 3rd article, measure for consistency
- Verify critical dimensions with independent method (CMM, gauge)
Critical inspection points:
- Weld quality (visual inspection, NDT if required)
- Distortion (welding heat causes warpage)
- Dimensional accuracy post-weld
- Material certifications (filler metal matches specification)
Common issues:
- Excessive distortion (wrong weld sequence)
- Porosity or inclusions (contamination, shielding gas)
- Undercut or overlap (incorrect parameters)
- Wrong filler metal (specification confusion)
Specific checks:
- Visual inspection per AWS D1.1 or equivalent
- NDT (X-ray, UT, PT/MT) per drawing requirements
- Dimensional check after welding (not before)
- Verify weld sequence documented
Critical inspection points:
- Bend angles and radii (achievable with available tooling?)
- Flat pattern accuracy (laser cut dimensions)
- Bend location (positioned correctly)
- Hole positions post-forming (bending affects hole locations)
Common issues:
- Springback (material returns after bending)
- Bend location shift (bend not where expected)
- Hole elongation (stretching during forming)
- Surface damage from tooling
Specific checks:
- Measure flat pattern before forming
- Check bend angles with protractor or gauge
- Verify hole positions after forming (not from flat pattern dimensions)
- Inspect for tool marks, scratches
Critical inspection points:
- Dimensions after machining (not as-cast dimensions)
- Surface finish after machining
- NDT for internal defects (porosity, inclusions, cracks)
- Material certifications (correct alloy, properties)
Common issues:
- Porosity (gas trapped in molten metal)
- Inclusions (foreign material)
- Shrinkage (cooling contraction)
- Surface defects (cold shuts, fins)
Specific checks:
- X-ray or UT for internal quality
- Mechanical testing if first-article (tensile, hardness)
- Visual inspection for surface defects
- Dimensional inspection only after machining (as-cast dimensions vary)
Critical inspection points:
- Coating thickness (meets specification range)
- Adhesion (coating bonds to substrate)
- Coverage (no missed areas)
- Appearance (color, gloss, texture match specification)
Common issues:
- Thickness insufficient (too thin)
- Adhesion poor (flakes off)
- Coverage incomplete (bare spots)
- Wrong coating type (miscommunication)
Specific checks:
- Thickness measurement (multiple locations)
- Adhesion test (tape test, bend test)
- Visual inspection for coverage
- Verify coating specification from supplier
Critical inspection points:
- Fits of mating parts (clearances and interferences correct)
- Fastener torque (properly tightened)
- Alignment of components (within tolerance stack-up)
- Functional performance (operates as intended)
Common issues:
- Interference fits too tight (can't assemble)
- Clearance fits too loose (rattles, poor alignment)
- Fasteners over/under-torqued
- Assembly sequence problems (can't reach fasteners)
Specific checks:
- Full assembly of first articles
- Functional testing
- Dimensional inspection after assembly (final dimensions)
- Document assembly sequence and any issues
First article inspection is key to qualifying new suppliers. Here's how to use FAI for supplier evaluation.
What FAI reveals about supplier:
Technical capability:
- Can they interpret drawings correctly?
- Do they have adequate equipment?
- Are their processes capable?
- Do they understand tolerances and GD&T?
Quality system:
- Is their inspection thorough?
- Are measurement methods appropriate?
- Do they have documented procedures?
- How do they handle non-conformances?
Communication:
- Do they flag issues proactively?
- Are they responsive to questions?
- Do they collaborate on solutions?
- Is documentation clear and complete?
Process control:
- Are manufacturing parameters documented?
- Do they monitor critical characteristics?
- Is there evidence of process control?
Excellent (A grade):
- All characteristics within spec, none marginal
- Documentation complete, accurate, professional
- Proactive communication
- Evidence of process control
- Result: Approved supplier, standard sampling plan
Good (B grade):
- All within spec, some marginal (90-95% tolerance)
- Documentation complete, minor gaps
- Responsive communication
- Basic process control
- Result: Approved with enhanced monitoring initially
Marginal (C grade):
- 1-2 characteristics out of spec, good corrective action
- Documentation adequate but could improve
- Communication reactive not proactive
- Limited process control evidence
- Result: Conditional approval, require improvement plan
Poor (F grade):
- Multiple characteristics out of spec
- Inadequate corrective action
- Documentation incomplete or inaccurate
- Poor communication
- No evidence of process control
- Result: Not approved, consider alternate supplier
Track metrics over time:
- First-pass FAI approval rate
- Number of characteristics out-of-spec per FAI
- Time to complete FAI
- Time to resolve non-conformances
- Production quality (PPM defect rate after FAI approval)
Example scorecard:
| Supplier | FAI Attempts | First-Pass Pass | Avg Chars OOS | Avg Resolution Time | Production PPM |
|---|
| Supplier A | 8 | 87.5% | 0.13 | 4 days | 120 |
| Supplier B | 12 | 66.7% | 1.8 | 12 days | 850 |
| Supplier C | 5 | 100% | 0 | N/A | 45 |
Interpretation: Supplier C excellent, Supplier B concerning
Identify improvement areas:
- Where do FAIs consistently have issues?
- Is it same types of characteristics?
- Process capability or inspection issues?
Provide feedback and training:
- Review FAI results with supplier
- Discuss measurement methods
- Share best practices
- Offer training if needed (GD&T, inspection techniques)
Track improvement over time:
- Are subsequent FAIs better?
- Is supplier learning and improving?
- Adjust sampling based on performance
Example supplier development:
- New supplier: First 3 FAIs had dimensional issues
- Analysis: Supplier CMM operator not properly trained on GD&T
- Action: Customer provided GD&T training to supplier inspector
- Result: Next 5 FAIs all first-pass approval
- Outcome: Supplier capability improved, now preferred supplier
Let me share several real projects showing FAI in action.
Part: Aluminum bracket for aircraft interior, 2,000 units/year
FAI submission:
- Supplier submitted 3 first articles
- Dimensional report: All dimensions within spec
- Material cert: 6061-T6 aluminum per drawing
Customer inspection:
- Dimensions verified: All within spec
- Material cert review: Heat number on parts doesn't match cert
- Physical inspection: Parts marked with different heat number
Investigation:
- Customer questioned discrepancy
- Supplier: "We used equivalent material from different supplier"
- Customer hardness testing: 65 HRB (expect 95 HRB for 6061-T6)
Root cause:
- Supplier substituted 6063-T6 (architectural alloy)
- 6063 has 40% lower strength than 6061
- Safety-critical application, substitution unacceptable
Resolution:
- FAI rejected
- Supplier procured correct 6061-T6 material
- New first articles manufactured
- Material certifications verified (heat numbers matched parts)
- Re-FAI approved
Outcome:
- FAI prevented 2,000 under-strength brackets entering service
- Potential safety incident avoided
- Cost: $4,200 (rejection, new first articles, 2-week delay)
- Cost if not caught: Unknown (potential aircraft safety issue)
Part: Steel equipment frame, 4 components welded, 150 units/year
FAI submission:
- Supplier submitted 3 first articles
- Dimensional report: 2 dimensions out of spec (bow/twist from welding)
- Weld quality: Acceptable
Specific issues:
- Frame width: Spec 600.0 ±3.0mm, measured 603.5-605.0mm (out of spec)
- Twist: Spec < 2mm over length, measured 3.5mm (out of spec)
Supplier corrective action plan:
- Root cause: Weld sequence causes distortion
- Corrective action: Revised weld sequence, fixture modifications
- Test samples: 3 frames welded with new sequence, measured 600.5-601.5mm width, 1.2mm twist
Customer evaluation:
- Test samples within spec
- Corrective action adequate
- Decision: Approve new sequence, new first articles required
Re-FAI:
- 3 new first articles with revised sequence
- Width: 600.2-601.8mm (within spec)
- Twist: 0.8-1.5mm (within spec)
- Approved
Outcome:
- FAI caught distortion issue before production
- Weld sequence optimization improved process
- Prevented 150 frames requiring rework
- Cost to prevent: $6,500 (investigation, test samples, new FAI)
- Cost if not caught: $37,500 (150 frames × $250 rework per frame)
Part: Precision shaft, critical bearing surface, 1,000 units/year
FAI submission:
- 3 first articles submitted
- Critical bearing surface: Ø50.00 ±0.02mm, surface finish 0.4 Ra
- Supplier measured: Ø50.01, Ø49.99, Ø50.02mm (all within spec)
Customer inspection:
- Verified dimensions: Ø50.01, Ø50.00, Ø50.02mm (within spec)
- Surface finish: 0.35-0.42 Ra (acceptable)
- Concern: All measurements very close to limits (95%+ of tolerance)
Analysis:
- Supplier ran 10 additional samples: Ø49.98-50.03mm range
- Cpk calculation: 0.89 (barely capable, target is >1.33)
- Interpretation: Process will generate out-of-spec parts in production
Discussion with supplier:
- Customer: "Process appears marginal. What can be done?"
- Supplier: "We're using older lathe, limited rigidity"
- Customer: "Can you use newer machine?"
- Supplier: "Yes, newer CNC lathe available, tighter capability"
Resolution:
- Supplier re-ran first articles on newer equipment
- New samples: Ø49.995-50.005mm range (centered, tighter spread)
- Cpk: 1.55 (capable)
- Decision: Conditional approval
- Production must use newer machine
- Monitor bearing surface on first 50 units
- After 50 units, reduce to standard sampling
Outcome:
- FAI identified marginal process before production
- Process improvement implemented proactively
- Production: 1,000 units produced, zero out-of-spec bearing surfaces
- Cost: $3,000 (additional analysis, re-FAI)
- Value: Prevented estimated 5-8% scrap rate (50-80 shafts × $85 each = $4,250-6,800)
Part: Aluminum housing with black anodize, Type II, Class 2 per MIL-A-8625
FAI submission:
- 3 first articles submitted
- Anodize thickness: 0.0007-0.0009" (specification: 0.0007" minimum per Class 2)
- Color: Black
- Supplier: "Meets MIL-A-8625 Type II Class 2"
Customer inspection:
- Measured thickness: 0.0008-0.0010" (verified supplier measurements)
- Color: Black as expected
- Issue found: Anodize is unsealed (specification requires sealed)
Investigation:
- Drawing: "Black anodize Type II Class 2 per MIL-A-8625"
- MIL-A-8625: Class 2 requires sealing for corrosion protection
- Supplier: "We didn't see sealing called out specifically"
- Customer: "It's implied by the MIL spec reference"
Root cause:
- Specification interpretation disagreement
- Drawing relied on MIL spec without explicitly stating "sealed"
- Supplier didn't realize sealing was required
Resolution:
- Short-term: Supplier sealed the 3 first articles and re-submitted
- Long-term: Drawing revised to explicitly state "sealed black anodize"
- Lesson: Don't assume specification references are understood, state requirements explicitly
Outcome:
- FAI caught specification interpretation issue
- Drawing improved for clarity
- Parts re-processed (sealing done)
- Cost: $1,200 (sealing, 1 week delay)
- Cost if not caught: Parts would corrode in field (warranty claims, reputation damage)
Use these tools to ensure thorough, consistent FAI execution.
First Article Inspection Report
Part Information:
- Part Number: **_**
- Part Name: **_**
- Revision: **_**
- Quantity Inspected: **_**
- Supplier: **_**
Inspection Date: **_**
Inspector: **_**
Dimensional Inspection Results:
| Item | Characteristic | Specification | Actual | Accept? | Method |
|---|
| 1 | | | | | |
| 2 | | | | | |
| 3 | | | | | |
Material Verification:
- Material Specification: **_**
- Heat/Lot Number on Parts: **_**
- Heat/Lot Number on Cert: **_**
- Match? Y / N
Functional Testing:
- Test Description: **_**
- Result: Pass / Fail
- Notes: **_**
Disposition:
□ Approved - Proceed with production
□ Conditional Approval - Monitor per plan: **_**
□ Rejected - Corrective action required: **_**
Approval Signature: **_** Date: **_**
Your first article inspection is complete and approved. Now you're ready to ramp up to full production. The next blog in this series covers: "Production Ramp-Up: Scaling Without Sacrificing Quality"
We'll discuss:
- Pilot production strategies
- Identifying and eliminating bottlenecks
- Training operators and maintaining consistency
- Quality control systems for volume production
If you need support with first article inspection and production qualification:
FAI planning services: We help you define inspection requirements and critical characteristics
Receiving inspection: We perform independent FAI inspection with calibrated equipment and experienced inspectors
Supplier development: We work with your suppliers to resolve non-conformances and improve processes
Documentation review: We review and verify supplier FAI packages for completeness and accuracy
Production readiness assessment: We evaluate manufacturing processes to predict production quality
Contact us to discuss your FAI needs and ensure your production starts with confidence.
First Article Inspection is your last defense against expensive production mistakes. It's the moment when theoretical design meets manufacturing reality. Done properly, it catches issues when they're cheap to fix. Skipped or rushed, it allows problems to multiply into production disasters.
The lessons from 17 years of FAI experience:
Never skip FAI, no matter the schedule pressure: The time you "save" by skipping FAI is nothing compared to the time lost managing production problems.
Three samples is minimum: One part can be an anomaly. Three parts show if the process is stable.
Measure what matters: Focus inspection time on critical characteristics. Don't get lost in non-critical dimensions.
Trust but verify: Review supplier's measurements, but perform your own inspection. Measurement differences reveal calibration or technique issues.
Understand root causes: When FAI fails, dig deep. Superficial corrective actions don't prevent recurrence.
Document everything: Years later, you'll need to reference this FAI. Make it findable and complete.
Collaborate with suppliers: FAI is a partnership. Work together to resolve issues quickly.
Know when to iterate: Not every issue requires rejection. Balance risk, cost, and schedule realistically.
The $180,000 production disaster in the introduction could have been prevented with $800 of inspection time. That's a 225× return on investment for doing FAI properly. Few things in manufacturing deliver that kind of value.
Don't let your production become a cautionary tale. Invest in thorough first article inspection. The parts you prevent from being made wrong are cheaper than the parts you try to fix after they're made wrong.
Ready to implement robust FAI processes? Let's discuss your specific requirements and ensure your production launches successfully.
