The Role of Metrology in FAI and Dimensional PPAP Reporting

First Article Inspection (FAI) and dimensional PPAP (Production Part Approval Process) reporting are two critical checkpoints in manufacturing. Both are used to validate parts. At the core of both is one foundational capability: metrology.

Why Metrology is Foundational in FAI and PPAP

When a new part hits the production floor, the first question is simple: Does this part match the print? Metrology provides the tools and techniques needed to answer that with precision.

Through accurate and traceable measurements, metrology enables manufacturers to confirm that every feature matches the specified dimensions and tolerances on the print. These features can include holes, walls, surfaces, or edges, to name a few. This verification comes during:

• First Article Inspection (FAI): Used during new part introduction or engineering changes to validate design intent. It is a proactive approach to mitigate discrepancies before mass production.
  
  
• Dimensional PPAP: A formal submission showing the customer that the manufacturing process can produce parts that meet specifications consistently. Typically, it is an ongoing process used during a production run or if there is a change in supplier. Part of the 18 requirements of the PPAP process is dimensional results.

You can’t submit a dimensional PPAP or complete an FAI report without reliable dimensional data. That’s where dimensional inspection services like those offered at Nel PreTech come in handy.

FAI vs. Dimensional PPAP: A Quick Breakdown

While often discussed together, FAI and dimensional PPAP serve distinct but related purposes:

• FAI is the first dimensional inspection of a new part and is a one-time event unless changes are made.
  
  
• Dimensional PPAP is part of the broader PPAP submission required by industries like automotive, aerospace, and electronics. The full PPAP report includes a complete dimensional report, process flow diagrams, material certifications, functional test data, and much more.

Both require metrology-grade accuracy in the form of traceable measurement systems.

Modern Metrology Tools for Dimensional Validation

Today’s advanced metrology lab relies on more than just calipers. Depending on complexity and material, FAI and PPAP dimensional inspection may include these other technologies:

• Coordinate Measuring Machines (CMM): Originally, the preferred method for high-accuracy inspection of machined or precision components. However, drawbacks may include time-consuming setups and programs.
  
  
• Structured Light Scanners: Both white and blue light scanners are used for fast, non-contact surface inspection.
  
  
• Industrial CT Scanning: Ideal for internal and external dimensional inspection. Particularly useful when part geometry is too complex or fragile for traditional methods.
  
  

Each of these tools feeds into final inspection reports, forming the data backbone of FAI and dimensional PPAP documentation.

Traceability, Standards, and Accreditation

In regulated industries, the dimensional data provided must be traceable to national or international standards. Without traceability, the numbers on the report mean little.

That’s why many manufacturers and suppliers turn to ISO/IEC 17025-accredited labs like Nel PreTech Corporation. Accreditation ensures that measurement systems are calibrated, procedures are validated, and personnel are qualified to deliver trustworthy results.

What Can Go Wrong Without Reliable Metrology?

When dimensional accuracy is overlooked, problems multiply:

• Nonconforming parts and rework
  
  
• Rejected shipments
  
  
• Loss of customer trust
  
  
• Delayed product launches
  
  
• Costly production line interruptions or recalls
  
  

FAI and PPAP should not be considered pass or fail tests. They're about validating a process, and that should start with accurate measurements.

How Metrology Supports a Smoother Production Launch

With a metrology-first approach to inspection:

• OEMs get the data they need to approve new parts
  
  
• Tier 1 and Tier 2 suppliers prove process repeatability
  
  
• Engineers have confidence that parts meet fit, form, and function
  
  
• Quality teams reduce risk from undetected deviations
  
  

Whether you’re working with injection-molded components, castings, or 3D-printed prototypes, comprehensive metrology allows you to launch with confidence.

Ready for FAI or Dimensional PPAP Support?

Nel PreTech Corporation offers advanced dimensional inspection with CMM, structured light, and industrial CT scanning, all under one ISO/IEC 17025-accredited roof.

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