First Article Inspection for CNC Machined Die Casting Components

2026-06-17 09:58:03

First article inspection is the checkpoint between sample approval and batch production. It is especially useful for CNC machined die casting components because both casting variation and machining accuracy must be confirmed.

What FAI should prove

FAI should show that the selected casting datum, machining process, thread quality and surface requirements can meet the drawing before mass production starts.

FAI record example

When FAI is most important

Use FAI for new tooling, tight tolerance parts, multiple machined faces, coated components or parts that mate with other assemblies.

Related: dimensional inspection and CNC machined mechanical housing.

FAI is not only a measurement report

First article inspection confirms whether the manufacturing route is capable. It checks whether the casting, machining, finishing and inspection plan can produce the part as intended.

What to include in a useful FAI package

• marked drawing with inspected dimensions
• measurement results for critical features
• thread gauge or functional check results
• surface finish review
• notes about deviations or process adjustments

When to repeat FAI

Repeat FAI after tooling changes, major machining fixture changes, material changes or when a critical dimension has been corrected after sample review.

Engineering Detail: FAI Should Confirm the Process, Not Only the Part

A first article inspection report is useful because it proves the chosen process route can make the part. For CNC machined die casting components, the report should show that casting datum, machining fixture, thread quality and surface finish all work together.

When FAI Findings Should Trigger Action

If a critical dimension is out of tolerance, the solution may not be simply changing the CNC program. The root cause could be casting shrinkage, unstable fixture location, insufficient machining allowance or burrs affecting measurement. Good FAI review looks for the cause, not only the number.