Last updated: 2026-09-02 · 5 min read

First Article Inspection (FAI) for Injection Molded Parts — What Does the Process Actually Include?

First Article Inspection (FAI) is the dimensional verification of the first production-representative parts from a new mold — measuring every dimension on the drawing with calibrated instruments (CMM, calipers, height gauges, pin gauges), recording the results in a report that maps each measurement to the drawing callout, and comparing the results against the drawing tolerances to determine whether the mold produces parts within specification. The FAI is the gate between mold completion and production — no parts ship to the customer until the FAI report is approved.

Cycle time — The total time for one injection molding cycle: injection + packing + cooling + mold open/close + ejection. Typical range: 15–60 seconds. Cycle time determines production rate and cost per part — reducing cycle by 5 seconds saves 10–15% annual production cost. See also related guide.

Key Facts

  • FAI measures 100% of the dimensions on the drawing — not a sample. Every critical dimension, tolerance, GD&T callout and surface finish requirement is verified on the first 3–5 shots from the production mold.
  • The FAI report format follows AS9102 (aerospace), AIAG PPAP (automotive) or the customer’s own template — the report maps each measurement to the drawing balloon number, the nominal value, the tolerance and the actual measured value.
  • FAI is performed on production-intent parts — molded with production resin, production mold, production process parameters and production cavity. Parts from a prototype mold or different machine do not qualify.

    • Cycle time — The total time for one injection molding cycle: injection + packing + cooling + mold open/close + ejection. Typical range: 15–60 seconds. Cycle time determines production rate and cost per part — reducing cycle by 5 seconds saves 10–15% annual production cost. The related guide covers adjacent topics.

    FAI Process Steps

    Step Activity Deliverable
    1. Drawing review Identify all dimensions, GD&T callouts and special characteristics Balloon-numbered drawing with measurement plan
    2. T1 molding Mold 3–5 shots with production resin and documented process parameters Labeled samples with mold number, date, cavity and material lot
    3. CMM measurement Measure all dimensions on the drawing with calibrated instruments Raw CMM data file and measurement report
    4. Report generation Map each measurement to drawing balloon, nominal, tolerance and actual FAI report (AS9102, PPAP or customer format)
    5. Approval or deviation Compare results against tolerances; approve or document deviations Signed FAI approval or deviation list with corrective actions

    What the FAI Report Must Include

  • Balloon-numbered drawing: every dimension on the drawing is numbered (ballooned) and mapped to a measurement row in the report — no dimension is left unmeasured.
  • Process parameters: the injection pressure, melt temperature, mold temperature, cycle time and cooling time used for the FAI samples are recorded — if the process changes, the FAI must be repeated.
  • Material lot: the resin grade, manufacturer and lot number are documented — material changes require a new FAI to confirm dimensions are not affected by material variation.
  • Instrument calibration: every measuring instrument used in the FAI must have a current calibration report traceable to national standards.

    • What This Means for Your Quotation

    The quotation should include FAI as a line item — specifying the report format (AS9102, PPAP or customer template), the number of samples measured and the delivery timeline. The FAI cost covers CMM time, report generation and sample labeling — typically $300–$1,500 depending on part complexity. When the FAI is omitted from the quotation, the cost appears as a surprise after the mold is built.

    Frequently Asked Questions

    What happens if the FAI fails?

    If dimensions are out of tolerance, the mold maker identifies the cause (shrinkage mismatch, cooling imbalance, gate location) and corrects the mold — then repeats the FAI on new samples. The corrective action and re-FAI timeline should be documented in the deviation report. Multiple FAI failures indicate a fundamental mold design problem, not a process tuning issue.

    Is FAI the same as PPAP?

    No — FAI is one component of PPAP (Production Part Approval Process). PPAP includes the FAI report plus material test reports, process flow diagrams, control plans, capability studies (Cpk) and sample parts. FAI verifies dimensions; PPAP verifies the entire production system. Not all programs require PPAP, but all programs should require FAI.

    When should FAI be repeated?

    FAI must be repeated when the mold is modified (gate relocation, core replacement), when the material changes (different grade or supplier), when the process parameters change significantly, or when the mold is moved to a different machine or facility. Annual re-FAI is common for production molds to verify that mold wear has not shifted dimensions out of tolerance.

    Key Takeaways

    1. FAI measures 100% of drawing dimensions on production-intent parts — it is the gate between mold completion and production shipment, with no parts shipping until the FAI is approved.
    2. The FAI report maps every measurement to the drawing balloon number, includes process parameters and material lot, and requires calibrated instruments with traceable calibration records.
    3. The quotation should include FAI as a line item ($300–$1,500) — specifying the report format and delivery timeline — so the cost is documented before the mold is built.

    Send aCatMould the part drawing, and the quotation includes FAI as a line item — with the report format, sample count and delivery timeline specified — so the first article inspection verifies the mold produces parts within drawing tolerances before production begins.

    Sources
    SAE AS9102 — Aerospace First Article Inspection standard
    AIAG — Production Part Approval Process (PPAP) manual
    MoldMaking Technology — first article inspection best practices

    Sources: Plastics Technology · Plastics Technology Online · Society of Plastics Engineers (SPE) · ThomasNet