What Is First Article Inspection in Injection Molding and How Do You Use It?

Wat is First Article Inspection bij Spuitgieten?

¹ (FAI) is een gestructureerd, gedocumenteerd verificatieproces dat bevestigt dat de eerste onderdelen uit een nieuwe spuitgietmatrijs – of een significant gewijzigde matrijs – voldoen aan elke afmeting, tolerantie, materiaal- en functionele vereiste op de technische tekening. FAI is geen algemene kwaliteitscontrole; het is een systematische, kenmerk-voor-kenmerk meting van 100% van alle tekeningkenmerken op een minimale steekproef van 3–5 eerste-serieonderdelen. Bij ZetarMold behandelen we FAI als de laatste poort tussen matrijskwalificatie en serieproductie.

Het proces is ontstaan in de luchtvaartproductie onder ², maar tegenwoordig is het standaard in de auto-industrie (⁴ Niveau 3), medische hulpmiddelen (ISO 13485) en precisie-elektronica-industrieën. Van elke fabrikant die kunststofcomponenten levert aan gereguleerde toeleveringsketens wordt verwacht dat deze een gedocumenteerd First Article Inspection Report (FAIR) opstelt. Zonder dit hebben klanten geen objectief bewijs dat uw matrijs daadwerkelijk maakt wat de tekening specificeert.

Waarom is FAI belangrijk voor spuitgietonderdelen?

Spuitgieten introduceert verschillende bronnen van dimensionale variatie die alleen verschijnen wanneer staal daadwerkelijk kunststof verwerkt: holtedrukverdeling, koeluniformiteit, bevriezingstijd van de poort en materiaalkrimp. Nominale krimpwaarden gepubliceerd in materiaalgegevensbladen zijn gemiddelden, geen garanties. Een onderdeel ontworpen voor ABS met 0,5% nominale krimp kan daadwerkelijk 0,45–0,65% krimpen, afhankelijk van wanddikte, smelttemperatuur en pakdruk. FAI detecteert deze afwijkingen voordat ze een productieprobleem worden.

In onze fabriek hebben we gevallen gezien waarbij een matrijs de T1 (eerste proef) visuele inspectie glansrijk doorstond, maar de FAI-dimensionale meting aantoonde dat een kritieke klikarm 0,15 mm te klein was – binnen de staaltolerantie van de matrijs, maar buiten de montagepasvereiste. Het ontdekken hiervan bij de FAI kostte twee dagen matrijsaanpassing. Het ontdekken na 50.000 onderdelen zou catastrofaal zijn geweest.

Wat omvat een First Article Inspection Report?

Een volledig First Article Inspection Report (FAIR) documenteert elke eigenschap die op de onderdeeltekening is aangegeven. De structuur volgt AS9102 Sectie 4, zelfs voor niet-luchtvaarttoepassingen, omdat dit het meest rigoureuze industriële raamwerk is dat beschikbaar is. Het rapport moet worden ondertekend door een gekwalificeerde kwaliteitsingenieur en worden gearchiveerd voor de levensduur van het onderdeelprogramma.

Standaard FAI-rapportsecties en Belangrijke Inhoud

FAIR Sectie	Wat wordt gedocumenteerd	Typisch Acceptatiecriterium
Onderdeelnummer & revisie	Tekeningnummer, revisieniveau, ingangsdatum	100% overeenkomst met door klant verstrekte tekening
Materiaalcertificering	Hars lotnummer, leveranciers CoC, materiaaltestgegevens	Voldoet aan UL, ASTM of klantmateriaalspecificatie
Dimensionele Ballonering	Elke afmeting op de tekening krijgt een ballonnummer toegewezen	Alle kenmerken geïnspecteerd; 0 openstaande afwijkingen
Kritieke Kenmerkmeting	CMM of schuifmaatgegevens voor alle kritieke afmetingen	Cpk ≥ 1,33 voor kritieke kenmerken
Visuele / Cosmetische Inspectie	Oppervlakteafwerking, kleur, laslijnen, zinkmarkeringen	Voldoet aan AQL 0,65 Level II steekproefplan
Functionele Test	Klikverbinding, schroefdraadpassing, montagepascontrole	100% geslaagd op alle eerste-artikelmonsters
Procesparameterregistratie	Injectiesnelheid, smelttemperatuur, koeltijd, druk tijdens het napersen	Parameters gearchiveerd voor toekomstige referentie
Goedkeuring door klant	FAIR goedgekeurd door kwaliteitsvertegenwoordiger van de klant	Schriftelijke goedkeuring voor productievrijgave

The dimensional ballooning section is the most labor-intensive part of a FAIR. Every tolerance callout on the drawing—linear dimensions, radii, hole diameters, ⁵ symbols—receives a unique balloon number. Each balloon is then measured on each sample part, and the actual value is recorded alongside the nominal and tolerance. Our quality team at ZetarMold typically records 60–150 balloon entries per part for a medium-complexity component.

Hoe wordt een Eerste Artikel Inspectie stap voor stap uitgevoerd?

FAI follows a defined sequence that ensures all verification activities are completed before any data is recorded. Shortcuts—such as measuring parts before they have fully cooled to ambient temperature, or measuring only one of the three sample parts—invalidate the inspection and typically result in customer rejection of the FAIR.

Step 1 is part conditioning. Injection-molded parts must be conditioned at 23°C ±2°C for a minimum of 4 hours (per ASTM D618) before measurement. Parts measured immediately after molding will read differently due to residual heat and stress relaxation. Step 2 is drawing review: the quality engineer balloons every dimension and assigns a unique ID. Step 3 is CMM programming or fixture setup for measurement. Step 4 is measurement of all three to five sample parts, with actual values recorded. Step 5 is material and process record archiving.

Step 6 is Cpk analysis for critical features. For any dimension with a critical-to-function tolerance, we calculate the process capability index (Cpk). The accepted minimum is Cpk ≥ 1.33, which corresponds to a process running at least 4 sigma from its nearest tolerance limit. Features below this threshold require mold rework before FAI can be approved. Step 7 is customer submission and sign-off. The complete FAIR package is transmitted to the customer; written approval is required before production begins.

Welke afmetingen zijn het meest kritiek om te meten bij spuitgietonderdelen?

Spuitgietproces variables directly affect four categories of dimensions that are most likely to deviate from nominal. Understanding which features are at highest risk helps quality engineers prioritize CMM time and flag potential issues during DFM review.

Wall thickness is the single most critical dimension because it controls both structural performance and cooling uniformity. Target tolerance for uniform wall sections is typically ±0.1 mm for non-critical features and ±0.05 mm for critical-to-fit interfaces. Gate location and dimensions affect fill pattern, weld line position, and surface cosmetics. Boss diameter and depth control thread engagement and press-fit retention. Snap-fit arm length and tip geometry determine assembly force and retention strength—even a 0.1 mm deviation in snap-fit tip height can increase insertion force by 30–50%.

Flatness and warpage are especially problematic for large, thin-walled parts. A 200 mm × 150 mm panel with 2 mm nominal wall thickness can warp by 0.5–2.0 mm if cooling is non-uniform or if packing pressure is not optimized. FAI flatness measurements are taken on a granite surface plate using dial indicators at a defined grid of points—typically every 25 mm. Analyse van de vormstroom simulation can predict warpage before steel is cut, but FAI is the ground truth.

Welke gereedschappen worden gebruikt om onderdelen te meten tijdens FAI?

De ³ (CMM) is the gold standard for FAI dimensional verification. A CMM probes the part surface at programmed points and reports actual coordinates versus nominal CAD data. Modern CMMs achieve measurement uncertainty of ±0.002 mm under controlled conditions. For production FAI, the CMM program is written from the 3D CAD model and then validated against the ballooned drawing to confirm every feature is captured.

Not all features require CMM. Thread gauges (go/no-go) verify thread engagement more quickly than CMM for standard thread forms. Vision systems measure 2D profile features—hole diameters, edge radii, slot widths—with sub-micron accuracy at high throughput. Digital calipers and micrometers are acceptable for non-critical features (tolerance ≥ ±0.1 mm) when calibrated to NIST-traceable standards. Optical comparators project part silhouettes for rapid profile checking on complex 2D contours.

In our factory, we operate a Zeiss Contura CMM with a 0.001 mm resolution probe for all critical-feature FAI measurements. For spuitgieten van kleine aantallen programs where a full CMM program may not be cost-justified, we use a combination of calibrated hand tools and a structured light 3D scanner to capture full-surface deviation maps against the CAD nominal.

Hoe lang duurt een Eerste Artikel Inspectie?

FAI duration depends on part complexity (number of drawing features), available measurement equipment, and customer reporting requirements. A simple two-cavity mold with 25–40 drawing balloons typically takes 1–2 days from part conditioning to completed FAIR submission. A complex 8-cavity medical device component with 120+ balloons, GD&T callouts, and material traceability requirements may take 5–7 working days.

The biggest time drivers are CMM program development (4–16 hours for a new program) and customer-required reports with statistical analysis (Cpk calculations for 20–30 critical features). Customers who provide CAD models and a pre-ballooned drawing dramatically reduce FAI turnaround time. Those who only supply a 2D PDF drawing require our team to model the nominal geometry before CMM programming can begin.

At ZetarMold, we build FAI time into every project schedule at the mold qualification stage. Customers who treat FAI as an afterthought—requesting it only after they expected parts to ship—create delays. Our standard lead time commitment: T1 trial parts within 4 weeks of mold approval; FAI report within 5 business days of T1 parts being conditioned; production release within 3 business days of customer FAIR approval.

Wat Gebeurt Er Als een Onderdeel de First Article Inspection Niet Haalt?

FAI failure means that one or more measured features fall outside their drawing tolerance on the first-article sample parts. The response depends on the nature and magnitude of the deviation. Minor deviations (within 20% of the tolerance band outside nominal) may be addressed through process adjustment—changing pack pressure, cooling time, or melt temperature—without touching the mold steel. These are documented as process NCRs and re-measured on a fresh set of conditioned parts.

Dimensional deviations that exceed process adjustment capability require mold steel modification. Steel removal (cutting more material) is straightforward; steel addition (welding or insert replacement) is more expensive and time-consuming. In either case, a partial re-FAI is performed: only the affected features and any dimensions that could have been influenced by the modification need to be re-measured. A full re-FAI is required if the modification involved significant steel removal affecting multiple cavity regions.

Some customers allow a Deviation Approval (also called a concession or waiver) for features that are marginally out of tolerance but demonstrably do not affect function or assembly. This requires engineering sign-off from the customer and a defined review timeline. Deviations are never permanent; the mold must be corrected before the next tool change or at the next scheduled maintenance window. In our factory, we track all open deviations in our ERP system and flag them for action at each mold service interval.

Veelgestelde Vragen over First Article Inspection bij Spuitgieten

Is FAI vereist voor elke nieuwe spuitgietmatrijs, of alleen voor gereguleerde industrieën?

FAI is mandatory for aerospace (AS9102), automotive (PPAP), and medical device (ISO 13485 / FDA 21 CFR Part 820) supply chains. However, any manufacturer running injection molds for precision assemblies should perform FAI regardless of industry, because the cost of discovering dimensional non-conformance at production scale vastly exceeds the cost of a structured first-article inspection. At ZetarMold, we recommend FAI for any production program with tolerances tighter than ±0.15 mm or any assembly with critical-to-function fit interfaces, irrespective of the customer’s industry sector.

Hoeveel onderdelen worden doorgaans geïnspecteerd tijdens FAI?

The standard minimum is 3–5 parts from the actual production mold, running under production-intent process parameters. For multi-cavity molds, parts should be taken from every cavity—not just one representative part. If you have a 4-cavity mold, a proper FAI measures parts from all four cavities and records cavity-specific data. Cavity-to-cavity variation is a common failure mode in injection molding; FAI is the only way to confirm that all cavities are within tolerance simultaneously. Some customers specify larger sample sizes (10–30 parts) for statistical process capability calculations.

Wat is het verschil tussen FAI en PPAP?

FAI (First Article Inspection) is a measurement and verification activity—it confirms that a specific part from a specific mold meets its drawing. PPAP (Production Part Approval Process) is a broader submission package required by automotive customers that includes FAI data as one of its 18 required elements, alongside design records, process flow diagrams, control plans, MSA studies, and capacity analysis. PPAP Level 3 (the most common) requires all 18 elements to be submitted to and approved by the customer. FAI is necessary but not sufficient for PPAP; PPAP wraps FAI inside a larger quality management framework.

Kan FAI worden uitgevoerd door de molder, of moet het door een onafhankelijk laboratorium worden gedaan?

In most commercial and industrial applications, the molder’s own quality team performs the FAI using calibrated, NIST-traceable measurement equipment. The customer reviews and approves the FAIR. For aerospace and defense applications, some customers require that FAI be witnessed by their own quality representative or a third-party inspection agency. Medical device applications under FDA oversight may require measurement system analysis (MSA / Gage R&R studies) to demonstrate that the molder’s measurement process itself is capable before FAI data is considered valid.

What should I do if I receive a FAIR with some features marked ‘actual dimension not reported’?

Any feature listed on the drawing that appears in the ballooned inspection plan must be measured and reported. ‘Not reported’ entries indicate an incomplete FAI and are not acceptable for formal approval. Common reasons for missing measurements include: features that are difficult to access with standard tooling (requiring fixtures or specialized probes), features inadvertently omitted during drawing ballooning, or features that require destructive testing (cross-section cuts for internal wall thickness). For each case, the molder must either provide measurement data, request a customer deviation, or use alternative measurement methods. Accept no FAIR with blank or ‘N/A’ entries unless formally approved.

Hoe beïnvloedt materiaalkrimp de FAI-resultaten bij spuitgieten?

Material shrinkage is the primary reason why injection-molded part dimensions differ from the mold cavity dimensions, and it is a major source of FAI failures. Most engineering thermoplastics shrink 0.3–2.0% as they cool from melt temperature to ambient. The mold cavity is intentionally cut oversize by the expected shrinkage factor, but actual shrinkage varies with wall thickness, melt temperature, packing pressure, cooling rate, and material lot. FAI catches cases where actual shrinkage deviates from the design assumption. When FAI shows a systematic dimensional offset across all measured features, the root cause is almost always a shrinkage factor error, which is corrected by steel adjustment.

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1. First Article Inspection: First Article Inspection (FAI) is a formal validation process that verifies the first production part or assembly from a new or modified manufacturing process meets all engineering design requirements before mass production begins. ↩

2. AS9102: AS9102 refers to the aerospace industry standard that defines requirements for First Article Inspection reports, specifying documentation, dimensional verification, and material certification procedures. ↩

3. Coordinate Measuring Machine: A Coordinate Measuring Machine (CMM) is a precision metrology device that measures the physical geometrical characteristics of a part by probing its surface with a contact or non-contact sensor, typically achieving accuracy within ±0.001 mm. ↩

4. PPAP: PPAP (Production Part Approval Process) is an automotive industry standard that requires suppliers to demonstrate, through documented evidence including FAI data, that their manufacturing process can consistently produce parts meeting all customer specifications. ↩

5. GD&T: GD&T (Geometric Dimensioning and Tolerancing) is an engineering notation system used on technical drawings to define the allowable variation in form, size, orientation, and location of part features, providing a universal language for precision manufacturing. ↩