What Is FAI? First Article Inspection for Silicone Components

FAI stands for First Article Inspection. It is a documented inspection of production-representative parts made from a new or changed manufacturing setup. The purpose is to show whether the submitted parts meet the approved drawing, material specification, functional requirement, and customer quality expectations before routine production is released.

Small manufacturing differences can change how a silicone part works. Flash on a sealing edge may create a leak, while a change in wall thickness can alter the force needed to move a valve. FAI checks these functional details against the specification before the samples are accepted.

FAI connects each inspected sample to the drawing revision and the conditions used to manufacture it. The report records how the characteristics were measured and whether the results were accepted. That traceable record distinguishes FAI from an informal first-piece check.

Quick Answer

First article inspection answers one practical question:

Do the first production-representative samples meet the approved requirements?

A typical package uses a ballooned drawing to connect each requirement with its measured result. Material verification and any required visual or functional checks accompany those results. Sample identification and the approval outcome are recorded in the First Article Inspection Report, often called a FAIR.

The scope can be full or partial. A full FAI usually covers all drawing characteristics and required notes. A partial FAI focuses on selected features, such as changed dimensions, critical-to-quality characteristics, or customer-defined inspection points.

FAI confirms the submitted first articles. It does not prove long-term process capability by itself, and it does not replace PPAP, IQ/OQ/PQ process validation, routine inspection, or customer change approval.

What Buyers Want to Know

Most people searching for FAI are not looking for a theory lesson. They usually want to know what they should ask from a supplier and what the report should prove.

For custom silicone rubber parts, the buyer normally wants to confirm:

• the sample was made from the correct drawing revision
• the material grade, hardness, color, and cure condition match the requirement
• critical dimensions were measured with suitable equipment
• soft features were not distorted during measurement
• flash, trimming, surface finish, and cosmetic limits were checked
• cavity or tool traceability is clear when a multi-cavity mold is used
• the sample represents the intended production process
• any nonconformity, deviation, or concession is visible in the report

This is why a good FAI report should contain actual results, not only a statement that the part is acceptable.

When FAI Is Required

FAI is usually performed before normal production begins, but it can also be required after a change.

Common triggers include:

• new part number
• new drawing revision
• new mold, cavity insert, extrusion die, fixture, or checking aid
• transfer from prototype tooling to production tooling
• change in silicone material grade, hardness, colorant, primer, adhesive, or coating
• change in molding, extrusion, post-cure, trimming, washing, packaging, or inspection method
• transfer to a different machine, line, facility, or supplier
• restart after a long production stop, if required by the customer
• reinspection after a failed or conditionally approved first article

For low-risk industrial parts, the customer may accept a simple report. For aerospace, automotive, medical, or high-reliability silicone parts, the report may need stronger traceability, more complete data, and clearer approval records.

What a FAIR Should Include

A FAIR should make it easy for the customer to compare the physical sample with the released requirement.

For silicone components, useful FAI records often include:

• Part identity: part number, part name, drawing revision, material specification, and customer order reference.
• Inspection scope: full FAI or partial FAI, sample quantity, cavity coverage, and characteristics inspected.
• Ballooned drawing: numbered drawing dimensions and notes that match the inspection report.
• Dimensional results: nominal value, tolerance, actual measurement, pass/fail status, and measurement method.
• Material records: silicone grade, hardness, color, lot number, certificate review, shelf life, and post-cure requirement.
• Tool and cavity traceability: mold number, cavity number, insert revision, extrusion die, or fixture reference when applicable.
• Visual criteria: flash, short shot, bubbles, flow marks, dirt, discoloration, tearing, deformation, parting line, and trimming quality.
• Functional checks: leak test, pull test, compression force, opening pressure, flow performance, snap fit, bonding strength, or keypad force-travel behavior when required.
• Packaging and labeling: bagging method, label content, lot number, cleanliness requirement, and protection during shipment.
• Disposition: approval, rejection, conditional approval, deviation request, corrective action, or reinspection requirement.

Example FAI report format covering material confirmation, dimensional inspection, visual inspection, structural checks, function checks, packaging review, and final disposition.

If cleanliness is part of the requirement, the FAI sample should represent the intended handling and packaging route. A loose trial part from a bench does not prove that clean packaging, labeling, and traceability are controlled.

Full FAI vs Partial FAI

Full FAI is usually used for a new part, new tool, new supplier, or major production change. It covers the complete drawing and relevant specifications.

Partial FAI is used when only part of the requirement has changed or when the customer asks to inspect selected characteristics. For example, a partial FAI may focus on a revised sealing lip, a repaired cavity, a changed material hardness, a new post-cure cycle, or a new inspection fixture.

Partial FAI should still be controlled. The report should make clear which characteristics were inspected, why the scope was limited, and whether any previous approval remains valid.

Silicone Projects Inspection Points

Soft silicone can deform under a gauge, so the inspection method must control the measuring force. A method suitable for a rigid metal part may give misleading results on an elastic component.

Important points include:

• define whether dimensions are measured before or after post-cure
• allow molded parts to cool and stabilize before final measurement
• use controlled contact force for soft walls, lips, tubes, and thin features
• check cavity-to-cavity variation in multi-cavity tools
• inspect flash at sealing edges, valve lips, tube ends, and assembly interfaces
• confirm trimming does not damage thin transitions or functional surfaces
• review color, translucency, surface finish, and contamination under agreed lighting
• keep retained samples or master samples when the customer requires them

Inspection should follow the part’s function. For a gasket, check the surfaces and dimensions that control compression, including flash along the sealing edge. For a valve, assess how the slit opens and recovers. A keypad needs checks that relate its web geometry and contact position to the intended travel and return force.

Where FAI Matters Most

FAI fits the General category because the method is useful across many industries. The reason for using it changes by market.

Aerospace typically expects a formal record that accounts for each drawing characteristic at the correct revision. Material and special-process records must be traceable to the samples, with approval documented before release.

Automotive customers may use FAI within a broader production approval process. Where PPAP is required, first article results sit alongside evidence that the production and measurement processes are controlled.

Medical uses FAI as a supplier-quality and production-release checkpoint. It can support first production review, but it does not replace process validation, risk management, cleanliness control, traceability, or the device manufacturer’s quality system.

Consumer electronics and industrial programs may use a lighter FAI format, but it becomes more important when the silicone component controls waterproofing, tactile feel, cosmetic appearance, assembly fit, or high-volume reliability.

Conclusion

FAI is a practical approval checkpoint for production-representative silicone samples. It helps confirm that the part, material, measurement method, and supporting records match the released requirement before routine production moves forward.

The value of FAI is not the form itself. The value is the confidence it gives the customer that the inspected silicone parts are traceable, measurable, and ready for the next stage of production control.