First Article Inspection Injection Molding First Article Inspection is your proof that the tool makes what it’s supposed to make.
I’ve seen FAI submissions rejected because of missing dimensions. I’ve seen projects delayed because the documentation wasn’t complete. Here’s how to get FAI right the first time.
Understanding FAI
What Is FAI? FAI verifies that the first production parts meet all drawing requirements before full production begins.
When FAI Is Required
| Trigger | Typical Requirement |
|---|---|
| New tool | Always required |
| Tool modification | If CT Qs affected |
| New supplier | Usually required |
| Process change | If quality affected |
| Annual requalification | Per customer |
FAI Scope
| Scope | Definition |
|---|---|
| Full FAI | All characteristics (100+ dimensions) |
| Partial FAI | Changed has only |
| Plus-1 | First production part |
FAI Requirements by Standard
PPAP Requirements (AIAG)
| Level | Documentation | Typical Use |
|---|---|---|
| 1 | Part submission warrant only | Rare |
| 2 | Warrant + results for one part | Common |
| 3 | Warrant + results for all samples | Most common |
| 4 | Warrant + all data | Customer specific |
| 5 | Warrant + all data + reviewed | Critical parts |
Key PPAP Elements
| Element | Description | Required? |
|---|---|---|
| PSW | Part Submission Warrant | Yes |
| IMDS | Material declaration | Yes |
| Appearance approval | AAI report | If applicable |
| Dimensional results | Full layout inspection | Yes |
| Material certs | Test results | Yes |
| Mold/tooling record | Tool history | Yes |
| Process flow | PFMEA reference | Yes |
| PFMEA | Process failure modes | Yes |
| Control plan | Quality control plan | Yes |
| MSA | Measurement system analysis | Yes |
| Process capability | Cpk study | Yes |
Dimensional Inspection Requirements
Measurement Plan
| Step | Action | Output |
|---|---|---|
| 1 | Review drawing | Identify all dimensions |
| 2 | Classify dimensions | Critical, major, minor |
| 3 | Select measurement methods | CMM, gages, etc. |
| 4 | Define locations | GD&T interpretation |
| 5 | Create inspection plan | Document procedures |
Dimension Classification
| Class | Symbol | Measurement | Acceptance |
|---|---|---|---|
| Critical | ★ | 100% measurement | Per tolerance |
| Major | • | Sampling or 100% | Per tolerance |
| Minor | • | Sampling | Per tolerance |
Critical Characteristics
| Identification Method | Verification | Frequency |
|---|---|---|
| Fit dimensions | CMM or functional gage | 100% |
| Regulatory dimensions | CMM | 100% |
| Safety dimensions | CMM | 100% |
| Critical tolerances | CMM | 100% |
Non-Critical Dimensions
| Verification Method | Frequency | Notes |
|---|---|---|
| CMM | Sample (3-5 parts) | Random selection |
| Go/No-go | Sample | Attribute check |
| Visual | Sample | Document |
Measurement System Requirements
MSA (Measurement System Analysis)
| Analysis | Purpose | Acceptance |
|---|---|---|
| Gage R&R | Repeatability, reproducibility | <10% acceptable |
| Bias | Accuracy | <5% of tolerance |
| Linearity | Accuracy across range | <10% of tolerance |
| Stability | Over time | Statistical control |
Gage R&R Acceptance Criteria
| Gage R&R | Interpretation | Action |
|---|---|---|
| <10% | Acceptable | Use as-is |
| 10-30% | Marginal | May be acceptable |
| >30% | Unacceptable | Improve system |
Measurement Equipment
| Method | Use | Uncertainty |
|---|---|---|
| CMM | Precision dimensions | <0.0001“ |
| Optical comparator | Profiles, contours | <0.0002“ |
| Height gage | 2D dimensions | <0.0001“ |
| Functional gages | Fit verification | Based on tolerance |
| Hand tools | General | Per tolerance |
FAI Documentation
Part Submission Warrant (PSW)
| Field | Information |
|---|---|
| Supplier name | ____________ |
| Customer | ____________ |
| Part number | ____________ |
| Part name | ____________ |
| Supplier code | ____________ |
| Production plant | ____________ |
| Tool number | ____________ |
| Tool status | [ ] Production [ ] Modified |
| Supplier code | ____________ |
| Change level | ____________ |
| Issue date | ____________ |
Dimensional Results
| Dimension | Spec | Actual | Pass/Fail | Method |
|---|---|---|---|---|
| 1.001 | ±0.005 | 1.003 | Pass | CMM |
| 2.500 | ±0.010 | 2.498 | Pass | CMM |
| 3.050 | ±0.020 | 3.045 | Pass | Gage |
Material Certification
| Test | Method | Spec | Result | Pass/Fail |
|---|---|---|---|---|
| Melt flow | ASTM D1238 | 20-30 g/10min | 24.5 | Pass |
| Tensile | ASTM D638 | >6000 psi | 6850 | Pass |
| Izod impact | ASTM D256 | >3 ft-lb/in | 4.2 | Pass |
Process Capability Requirements
Capability Study Requirements
| Factor | Standard | Notes |
|---|---|---|
| Sample size | ≥30 consecutive parts | Production conditions |
| Data collection | 1 shift minimum | Normal production |
| Analysis | X-bar/R or I-MR | Based on data type |
| Reporting | Cpk, Ppk, Pp | All indices |
Capability Acceptance
| Characteristic | Cpk Requirement |
|---|---|
| Critical (★) | ≥1.67 |
| Major | ≥1.33 |
| Minor | ≥1.00 |
When Cpk Is Low
| Action | Threshold | Purpose |
|---|---|---|
| Document | Cpk < 1.33 | Traceability |
| Investigation | Cpk < 1.00 | Root cause |
| Containment | Cpk < 0.67 | Prevent shipment |
| Re-submission | After improvement | Verify fix |
Visual and Appearance Standards
Appearance Approval
| Element | Requirement |
|---|---|
| Surface finish | Per spec |
| Color | Master standard |
| Gate vestige | Per standard |
| Parting line | Per standard |
| Packaging | Per requirement |
AAI (Appearance Inspection)
| Item | Standard | Evaluation |
|---|---|---|
| Color | Master sample | Match |
| Gloss | Master sample | ±5 units |
| Surface | Specification | No defects |
| Gate | Standard | Acceptable |
Submission Requirements Checklist
Pre-Submission
- Tool completed and trials run
- Process validated
- Parts production-ready
- All dimensions identified
- Measurement system ready
- Documentation started
Documentation
- PSW completed and signed
- Dimensional results (full layout)
- Material certifications
- MSA reports
- Process flow diagram
- PFMEA
- Control plan
- Capability studies
- IMDS submission
- AAI report (if applicable)
- Tool drawings (as applicable)
Part Submission
- Sample parts (quantity per customer)
- Representative production parts
- All cavities represented
- Proper labeling
- Packaging per requirement
- Shipping documents
Common FAI Failures
Documentation Issues
| Failure | Prevention |
|---|---|
| Missing dimensions | Complete drawing review |
| Outdated documents | Version control |
| Incomplete records | Checklist completion |
| Unclear specifications | Clarify before starting |
Measurement Issues
| Failure | Prevention |
|---|---|
| Wrong measurement method | Define in inspection plan |
| Inadequate MSA | Complete before FAI |
| Poor sampling | Statistical sampling plan |
| Wrong equipment | Calibrated, appropriate tools |
Process Issues
| Failure | Prevention |
|---|---|
| Non-representative parts | Production conditions |
| Process not capable | Cpk before FAI |
| Tool not production-ready | Proper debugging |
| Operator not trained | Training records |
FAI Report Structure
Standard FAI Report
SECTION 1: GENERAL INFORMATION
- Part number, name, revision
- Supplier name, location
- Tool number, status
- Date of FAI
- Customer requirements SECTION 2: PART SUBMISSION WARRANT
- Signed PSW form
- Approval signatures SECTION 3: DIMENSIONAL RESULTS
- Inspection plan
- Full layout results
- Acceptance status
- Non-conforming items SECTION 4: MATERIAL CERTIFICATION
- Resin certification
- Test results
- Compliance verification SECTION 5: PROCESS DOCUMENTATION
- Process flow
- PFMEA
- Control plan SECTION 6: MEASUREMENT SYSTEM
- MSA reports
- Equipment calibration SECTION 7: PROCESS CAPABILITY
- Study data
- Cpk/Ppk results
- Analysis SECTION 8: VISUAL/APPEARANCE
- AAI report
- Master samples
- Standards SECTION 9: TOOLING
- Tool drawings
- Maintenance records SECTION 10: APPROVALS
- Quality approval
- Engineering approval
- Customer approvalThe Bottom Line FAI is your quality promise—the documentation that says “we made it right, we measured it right, and it meets requirements.”
Complete the documentation. Use the right measurement systems. Verify the capability. Don’t submit incomplete FAI. Don’t use uncalibrated equipment. Don’t skip the process validation. That’s how you get FAI approved the first time.