Mold component FAI inspection of precision inserts and sliders before final mold assembly
Pre-Assembly Component Verification
Mold Build · Component Control

Mold Component FAI Checklist Before Assembly

A mold component FAI checklist verifies whether custom inserts, sliders, lifters, guide components, and other critical tooling parts conform to the approved drawing before they are released into final mold assembly.

The inspection should connect the component ID and drawing revision to material and heat-treatment evidence, ballooned critical dimensions, datum and GD&T results, surface or EDM condition, mating-fit checks, and a documented release disposition. For the broader sequence of project-stage inspections, see our injection molding checklist framework.

This page covers mold-component inspection before assembly. It does not replace molded-part FAI, PPAP, mold-trial validation, or final tool acceptance. Where component FAI becomes part of the wider qualification record, refer to the Injection Mold Validation Guide.

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  • Custom Inserts
  • Sliders & Lifters
  • Material & Hardness
  • Critical Dimensions & GD&T
  • Mating Fit & Traceability
Mold component checked against the approved drawing and revision before FAI measurement
Confirm the controlled drawing, revision and component identity before recording any FAI result.
FAI Control Point 01

Confirm the Approved Drawing, Revision & Component Identity Before Measurement

Before any FAI result is accepted, confirm that the physical mold component matches the correct tool, component ID, drawing number and approved revision. Measurement data cannot support release if the inspected part is not tied to the same controlled engineering definition used for manufacturing.

The inspection record should identify the mold or project number, component name or part number, drawing number, current revision and inspection date. These fields establish the configuration baseline before dimensional, geometric or functional evidence is added later in the FAI process.

If an engineering change affects a datum, tolerance, material, hardness requirement or functional interface, review the inspection scope against the newly approved revision. Repeat the affected characteristics and any related checks influenced by the change; perform a full re-FAI only when the change scope, project quality plan or customer requirement justifies it.

Uncontrolled prints, superseded PDFs, temporary shop-floor markups and unidentified components should not be used as the release baseline. Resolve the configuration status first, then continue the component FAI against the approved revision.

Minimum Configuration Record Before Measurement

Revision-Controlled Baseline
  • Tool / Project Mold ID or Project No.
  • Component Component ID / Part No.
  • Drawing Drawing No. + Approved Revision
  • Inspection Date + Inspector
Outside-process prerequisite: if the component has returned from heat treatment, plating, texturing, grinding, EDM recovery or another subcontract operation, complete the Outside Processing Acceptance Form for Mold Components before the component enters full FAI measurement.
FAI Control Point 02

Verify Material & Heat-Treatment Evidence Before Dimensional Release

A mold component should not be released on dimensional results alone. The FAI record must first establish that the inspected part was made from the specified material and, where required, received the correct heat treatment or surface-hardening condition.

Start with the requirement shown on the released drawing or project specification. Record the material grade or material specification against the same component ID and revision controlled in the FAI record. When material certification, batch identification or supplier documentation is required, the reference should remain traceable to that individual component or production lot.

For heat-treated components, the record should identify the required condition and the actual verification result. The inspection method should match the material, treatment and drawing requirement rather than defaulting every component to a single hardness scale. Rockwell, Vickers or another suitable method may be used according to the applicable specification and inspection plan.

Hardness evidence is especially relevant when the component function depends on wear resistance, shut-off durability, sliding contact or dimensional stability after treatment. However, the FAI should record the requirement and measured evidence—not create a new hardness target that is absent from the approved engineering definition.

Where heat treatment is subcontracted or separately documented, link the FAI record to the corresponding mold component heat-treatment inspection record instead of duplicating the entire treatment history inside the component FAI sheet.

Material Grade / Specification
Treatment Required Condition
Verification Actual Result + Method
Traceability Certificate / Batch / Record ID
Mold component inspection using ballooned drawing references before final assembly
Balloon numbers connect each controlled drawing characteristic to its recorded inspection result and measurement evidence.
FAI Control Point 03

Balloon Critical Dimensions and Record Actual Results

Once the component identity, drawing revision, material and treatment status are confirmed, convert the released drawing into a traceable inspection record. Each controlled characteristic should be linked to a unique balloon number so the reviewer can move directly from the drawing requirement to the recorded result.

The FAI sheet should record the balloon number, nominal value, tolerance or drawing requirement, actual measured result, measurement method and conformity status. This creates a direct evidence chain between the approved engineering definition and the component being released for assembly.

Ballooning does not mean that every visible dimension on a drawing must automatically receive the same inspection depth. The inspection scope should reflect the released drawing, project quality plan, component function and identified critical characteristics. Features controlling fit, alignment, shut-off, motion or molded-part geometry normally require clearer evidence than non-critical reference dimensions.

Where a characteristic is inspected by an alternative method, gauge or functional check, the record should identify that method rather than forcing every result into a CMM-style dimensional format.

01 Balloon ID Unique reference tied to the released drawing.
02 Requirement Nominal dimension, GD&T or drawing-defined condition.
03 Tolerance Applicable limit or acceptance range from the drawing.
04 Actual Result Recorded measured value or verified inspection result.
05 Method & Status Inspection method plus pass, fail or deviation reference.

Example: Ballooned Mold Component FAI Record

The values below illustrate the record structure only. Actual dimensions, tolerances and inspection methods must come from the approved project drawing and inspection plan.

Balloon Characteristic Nominal Tolerance Actual Method Status
#01 Insert datum face Drawing Requirement Per Drawing Recorded Result CMM / Suitable Method PASS
#07 Slider mating feature Drawing Requirement Per Drawing Recorded Result Gauge / Functional Check PASS
#12 Shut-off geometry Drawing Requirement Per Drawing Recorded Result Optical / Suitable Method PASS
FAI Control Point 04

Verify Datum Schemes & GD&T Relationships Before Assembly

A critical mold component can meet several individual dimensions and still fail during assembly if its controlled features are located or oriented incorrectly relative to the drawing-defined datum reference framework.

The FAI record should therefore preserve the same datum logic used by the released engineering drawing. Primary, secondary and tertiary references establish how the component is constrained for inspection; position, perpendicularity, parallelism, flatness or other applicable geometric controls should then be evaluated from that defined reference system.

Measurement method must be selected according to the feature geometry, tolerance, accessibility and drawing requirement. A CMM may be appropriate for complex positional relationships, while optical measurement, gauges, surface equipment or other qualified methods may provide better evidence for different characteristics. The method should support the requirement rather than being selected simply because a particular machine is available.

Record the result against the corresponding balloon or inspection characteristic established in the previous section. This keeps GD&T evidence traceable without turning the component FAI into a separate metrology procedure.

Reference Confirm Datum A / B / C
Requirement Identify GD&T Control
Verification Select Suitable Method
Evidence Record Result + Status

Example GD&T Evidence Structure

The table below shows how geometric requirements can be organized in a mold component FAI. It does not prescribe one universal inspection method; the approved drawing and inspection plan remain the governing references.

Characteristic Reference Engineering Intent Evidence Method FAI Record
Position Per drawing datum framework Controls feature location relative to mating or functional geometry. CMM / Suitable Method Actual result + conformity status
Perpendicularity Defined datum surface or axis Controls orientation of a face, bore or working feature. CMM / Gauge / Suitable Method Recorded result linked to characteristic ID
Parallelism Drawing-defined reference Controls relationship between functional or sliding surfaces. CMM / Surface Method Actual result + measurement reference
Flatness No datum unless drawing specifies otherwise Controls form of a seating, sealing or support surface. Suitable Surface Method Actual result + inspection status
Inspection of tooling shut-off edge and EDM surface condition before mold assembly
Inspect tooling-surface, EDM and shut-off condition against the component drawing without assuming one universal magnification, roughness or acceptance limit.
FAI Control Point 05

Inspect Tooling Surface, EDM & Shut-Off Condition Before Assembly

Dimensional conformity does not confirm that every functional tooling surface is ready for assembly. Mold inserts and moving components may also require evidence that EDM-produced surfaces, critical edges, seating areas and shut-off interfaces remain consistent with the released component drawing and manufacturing intent.

Where a tooling-surface condition or EDM finish is specified, verify the applicable requirement using a suitable inspection method rather than assigning a generic surface-roughness target. For EDM-produced features, review the required condition and check for unintended overburn, local pitting, surface damage or other anomalies that could affect component function.

Shut-off and sealing-related areas deserve separate attention because localized edge damage, burrs, mismatch or poor seating can alter the intended contact relationship even when adjacent dimensions remain within tolerance. Inspection may use visual, optical, surface or functional evidence according to the component geometry and project inspection plan.

When the component was produced through a controlled EDM process, electrode design, spark-gap logic and machining-release requirements belong in the EDM electrode design and release standard. The component FAI should retain only the resulting condition evidence needed to support pre-assembly readiness.

01 · TOOLING SURFACE Drawing-Defined Surface Condition Confirm the specified tooling-surface or working-face condition where the component drawing requires it.
02 · EDM EDM Surface Condition Check EDM-produced areas for the required condition and unintended overburn, pitting or local damage.
03 · EDGE Critical Edge Integrity Review burrs, chips and local edge damage on features that influence shut-off contact or tooling geometry.
04 · CONTACT Shut-Off / Seating Condition Confirm relevant contact areas support the intended mating, sealing or seating relationship before final assembly.

Tooling-Surface & Shut-Off Evidence to Record

Inspection depth should follow the released component drawing, functional requirement and project inspection plan. The examples below describe evidence categories—not universal acceptance limits.

Inspection Area What to Verify Possible Method Evidence to Record Typical Concern
Tooling Surface Drawing-defined working-surface or tooling-surface condition. Suitable Surface Method Result, method and characteristic reference. Tooling surface inconsistent with the engineering requirement.
EDM Surface Required EDM condition and absence of unintended local damage. Visual / Optical / Suitable Method Condition status plus supporting evidence where required. Overburn, pitting or local surface damage affecting function.
Critical Edge Burrs, chips, damage and geometry-sensitive edge condition. Visual / Optical Condition record or image evidence as appropriate. Local mismatch, poor shut-off contact or edge-related tooling defect.
Shut-Off / Contact Area Seating condition and applicable contact interface. Visual / Functional Check Condition, component reference and deviation ID if applicable. Poor contact, unintended gap or assembly-stage interference.
Paired functional fit verification of mold components before final assembly
Pair-fit evidence should identify the actual mating components and verify their assembled relationship—not just their individual dimensions.
FAI Control Point 06

Verify Mating Pairs & Functional Fit Before Assembly Release

Two mold components can pass individual dimensional inspection and still fail as a functional pair. Before final assembly, fit-critical parts should therefore be reviewed in their intended mating relationship where the drawing, component function or inspection plan requires paired verification.

Start by recording the identity of both mating components. For sliders, lifters, guide components, inserts, wear interfaces and other paired features, the FAI evidence should make clear which part was evaluated against which corresponding component. This is especially important in multi-cavity tools, mirrored geometry and revision-controlled replacement parts.

Functional review may include seating, specified clearance, contact condition, movement, alignment or interference checks. The applicable acceptance requirement should come from the released engineering definition or inspection plan; the FAI sheet should not create a universal clearance value for every slider, guide set or insert.

A functional check also provides evidence for conditions that are not always obvious from isolated measurement data, such as abnormal rocking, localized interference, rough travel or mismatch between paired surfaces. These observations should be recorded objectively and linked to the relevant component IDs.

01 Identify the Pair Record both component IDs and applicable revisions.
02 Confirm Seating Verify intended contact, location and assembled relationship.
03 Check Clearance Record specified clearance where the engineering definition requires it.
04 Verify Movement Check applicable travel or motion for abnormal binding or interference.
05 Record Evidence Document result, method, pair reference and deviation where applicable.

Example Mating-Pair Verification Matrix

Functional evidence depends on the component design and engineering requirement. The matrix below illustrates what may be recorded without prescribing universal clearances or movement limits.

Pair / Interface What to Verify Possible Method Evidence to Record Concern if Missed
Slider / Guide Interface Seating, specified clearance and movement condition. Paired Fit / Functional Check Pair IDs, result and applicable clearance evidence. Binding, localized interference or unstable movement.
Lifter / Guide Feature Fit, movement path and applicable contact condition. Functional Movement Check Component pair reference and inspection status. Rough travel, interference or inconsistent return.
Insert / Pocket Seating, locating condition and unwanted rocking. Seating / Fit Check Insert ID, mating location and verified condition. Local mismatch, poor seating or assembly instability.
Guide Pillar / Bush Matched identity, fit and smooth relative movement where applicable. Pair Verification Matched set reference and functional status. Misalignment, accelerated wear or abnormal guiding condition.
Minimum Functional Evidence

A pair-fit record should show exactly what was paired, what was checked and what condition was observed.

  • Component A ID + revision
  • Component B ID + revision
  • Applicable fit / clearance requirement
  • Verification method
  • Actual result or observed condition
  • Pass / fail / deviation reference
FAI Control Point 07

Control Nonconformance Before the Component Enters Final Assembly

A mold component that fails an inspection requirement should not move forward through an informal shop-floor decision. The FAI record should place the affected characteristic into a controlled nonconformance and engineering disposition process before assembly release is reconsidered.

Start by identifying exactly what did not conform: the drawing characteristic, functional condition, material evidence, mating result or other inspection requirement. Link the issue to the component ID, drawing revision, balloon or characteristic reference, and the measurement or observation that triggered the hold.

The appropriate disposition depends on the nature of the issue and the project's quality process. A component may require rework and re-inspection, formal engineering deviation, replacement or another documented decision. A nonconforming result should not automatically be interpreted as either acceptable or scrap without the applicable review.

After corrective action or an approved change, re-verification should focus on the affected characteristics and any related features that could have been influenced by the work performed. Full FAI repetition is appropriate only when the change scope, risk or customer requirement justifies it.

Status 01 Hold / NCR Isolate the component while the nonconformance, supporting evidence and impact are reviewed.
Status 02 Rework & Re-Inspect Correct the defined issue under controlled instruction, then re-verify affected characteristics.
Status 03 Engineering Deviation Use only when the applicable engineering or customer approval process formally accepts the deviation.
Status 04 Remake / Scrap Apply when repair or deviation is not approved or cannot restore the required engineering condition.

Minimum Nonconformance Record

The component FAI does not need to reproduce an entire MRB system, but it should preserve enough information to show what failed, how the issue was dispositioned and what evidence supports the final re-verification.

Record Field What It Should Capture Why It Matters Typical Reference
Characteristic Balloon, GD&T, material, surface, fit or other failed requirement. Identifies the exact inspection issue instead of a generic NG statement. Balloon / Characteristic ID
Actual Condition Measured result, observed condition or missing evidence. Provides objective evidence for engineering review. Measurement / Photo / Inspection Record
Disposition Hold, rework, deviation, remake or other approved action. Prevents undocumented shop-floor acceptance. NCR / MRB / Deviation ID
Re-Verification Inspection result after the approved corrective action. Confirms that affected requirements have been re-checked. Updated FAI Result / Re-Inspection Record
Re-Inspection Principle

Re-check what changed—and what the change may have affected.

  • Rework dimensions affected directly by machining or polishing.
  • Review related datums or mating features if the corrective work could influence them.
  • Repeat material or hardness verification when the corrective process changes material condition.
  • Update NCR, deviation or rework references in the FAI record.
  • Escalate to broader or full re-FAI when change scope or project requirements justify it.
FAI Control Point 08

Release the Component to Assembly Only After the Evidence Is Closed

Pre-assembly release is the final decision within the mold-component FAI process. A component should move into final tool assembly only after the required inspection evidence is complete, unresolved nonconformances are controlled, and the release decision is traceable to an identifiable inspector and approver.

The release record should reference the same component ID and drawing revision used throughout the inspection. Required balloon results, GD&T evidence, material or treatment records, relevant surface-condition checks and applicable mating-fit verification should be available without rebuilding the inspection history from separate uncontrolled notes.

Release authority should follow the project's quality plan and organizational responsibility. The FAI form does not need to impose one universal four-person approval chain; it should identify who performed the inspection and who had authority to approve the component for assembly under the applicable project requirements.

Once the component is formally released, the next control stage is no longer component FAI. The mold enters the assembly workflow, where fit, motion, sealing, ejection return and dry-cycle readiness are evaluated at the assembled-tool level.

Status 01 Released for Assembly Required evidence is complete and applicable nonconformances have been closed or formally dispositioned.
Status 02 Hold — Evidence Incomplete Inspection, traceability, material evidence or approval remains incomplete and must be resolved before release.
Status 03 Blocked — Open Nonconformance An unresolved NCR, failed re-inspection or unapproved deviation prevents controlled assembly release.

Minimum Pre-Assembly Release Record

The exact approval workflow may vary by customer and project, but the release record should preserve the minimum traceability needed to show what was approved, by whom and on what evidence.

Release Field What to Record Purpose
Component Identity Tool / project, component ID, drawing number and revision. Confirms exactly which physical component was released.
FAI Status Required characteristics complete with pass / fail / deviation references. Shows whether the inspection record is complete.
NCR / Deviation Status Closed NCR, approved deviation or other disposition reference. Prevents release while unresolved exceptions remain open.
Inspector Name or controlled identifier plus inspection date. Provides execution traceability.
Approved By Authorized approver defined by the project quality plan. Records formal pre-assembly release authority.
Release Date / Status Release date and final status for assembly handoff. Establishes a controlled transition into the next workflow stage.
Approval Principle

Sign-off roles should follow the project—not a universal website workflow.

Depending on customer requirements and internal controls, approval may involve an inspector, mold engineer, quality representative, project owner or customer-authorized reviewer. The important control is that the responsible authority is defined, identifiable and tied to the documented release decision.

Next engineering stage: assembled-tool verification After individual components are released, verify their combined fit, movement, seals and mechanical readiness at the mold-assembly level.

Injection Mold Assembly Checklist
Mold component FAI form with ballooned inspection results, traceability and pre-assembly release fields
A usable component FAI form should connect drawing identity, inspection results, exceptions and final pre-assembly release in one controlled record.
Downloadable FAI Record

Use a Mold Component FAI Form That Preserves the Full Evidence Chain

A usable mold component FAI form should bring the evidence from this checklist into one revision-controlled pre-assembly record rather than scattering drawing data, measurements, fit checks and release decisions across unrelated documents.

At minimum, the form should identify the tool and component, record the approved drawing revision and material status, connect ballooned characteristics to actual inspection results, identify the measurement method used, and preserve any NCR or deviation references before final release.

Functional evidence should also remain traceable where the component depends on a mating relationship. The final record should show who performed the inspection, who approved the assembly release and when that decision was made.

This document is for mold-component inspection before assembly. Molded-part FAI, PPAP, mold-trial validation and final tool acceptance remain separate downstream records.

Group 01 Identity & Revision
  • Tool / Project ID
  • Component ID / Part Number
  • Drawing Number
  • Drawing Revision
  • Inspection Date
Group 02 Material & Process
  • Material Grade / Specification
  • Heat-Treatment Requirement
  • Actual Hardness / Treatment Result
  • Certificate / Batch / Record ID
  • Applicable Process Reference
Group 03 Inspection Results
  • Balloon / Characteristic ID
  • Nominal / Requirement
  • Tolerance
  • Actual Result
  • Measurement Method
  • Gauge / Equipment ID
Group 04 Fit, Disposition & Release
  • Mating-Pair Reference
  • Pass / Fail Status
  • NCR / Deviation ID
  • Inspector
  • Approved By
  • Release Date / Status

For examples of how insert fit, wear condition, micro-feature geometry, and replacement qualification can be connected to release records, see our mold insert inspection case evidence .

Minimum controlled record

  • Tool ID
  • Component ID
  • Drawing Revision
  • Material
  • Heat Treatment
  • Balloon No.
  • Nominal
  • Tolerance
  • Actual
  • Measurement Method
  • Gauge ID
  • Pass / Fail
  • NCR / Deviation
  • Mating Pair
  • Inspector
  • Approved By
  • Date
Downloadable Template

Mold Component FAI PDF Form

Use the template as a starting structure for component identification, ballooned inspection evidence, fit verification, disposition and pre-assembly sign-off.

Download FAI PDF Form
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