BRIGHTSTAR
PROTOTYPE CNC CO., LTD
+86 137 5010 5351
EN
May. 25, 2026
Have you ever encountered this situation? After batch production of CNC machined parts is completed, you discover during assembly that a critical dimension is incorrect, rendering the entire batch unusable. Or, the parts you receive do not match the sample you previously approved, yet the supplier says "we followed the drawing."
These problems are not uncommon in CNC machining, and their root cause is often the same: First Article Inspection was not performed, or it was performed incompletely or improperly.
First Article Inspection, commonly abbreviated as FAI, is one of the most critical links in the CNC machining quality control system. It is not optional "paperwork" but rather the "first line of defense" to ensure batch production goes smoothly without errors.
So what exactly is FAI? What is its process? Why is it mandatory in CNC machining? What does an FAI report contain? This article will comprehensively explain every aspect of First Article Inspection, helping you understand and value this quality control tool.
First Article Inspection refers to the comprehensive inspection of the first part or first few parts machined before batch production begins. Its purpose is to verify whether the production process can stably produce parts that meet drawing requirements.
Simply put, FAI answers this question: Under the current process, equipment, tools, programs, fixtures, and other conditions, does the part we made actually meet the design requirements?
If the first article passes, production can proceed with confidence. If the first article fails, the problem needs to be identified, the process adjusted, and a new first article machined until it passes. This avoids producing a large batch of non-conforming parts and causing massive waste.
The concept of FAI originated in the aerospace industry. In the supply chains of aircraft manufacturers like Boeing and Airbus, any new or modified part must have an FAI report submitted before batch production can begin. Later, this practice was widely adopted by many industries including automotive, medical, and electronics, becoming a basic requirement of quality management.
In CNC machining, FAI typically applies in the following situations:
When a new part is produced for the first time, FAI must be performed.
When the drawing or process changes, FAI must be performed again.
When the production location, equipment, material, etc., undergo significant changes, FAI must be performed again.
When production resumes after a long period of inactivity, FAI must be performed again.
FAI is not performed arbitrarily. It has clear standards and specifications.
The most commonly used FAI standard is AS9102. This is the international standard for First Article Inspection in the aerospace industry, but it is also widely adopted by many industries including automotive, medical, and electronics. AS9102 specifies the FAI process, form formats, report content, and acceptance criteria.
The AS9102 standard divides FAI into three parts:
Part One is a summary of part information, including part number, revision number, material information, process information, customer information, etc.
Part Two is a product characteristic verification checklist, listing every dimension, tolerance, and characteristic requirement on the drawing, with recorded actual measurements and pass/fail results.
Part Three is a verification of materials and special processes, recording the material source, batch number, certificate information, as well as the parameters and certification information for special processes such as heat treatment and surface finishing.
In addition to AS9102, some customers may have their own FAI requirements. For example, the automotive industry may require certain elements of PPAP, and the medical industry may require validation documents related to ISO 13485. When accepting an order, it is important to confirm which standard will be used with the customer.
A complete FAI process typically includes the following steps.
Before machining begins, thorough preparation work needs to be done.
Programmers generate CNC programs, determining toolpaths and cutting parameters. Process engineers design fixtures and workholding solutions. Quality inspectors prepare inspection tools and equipment, including CMMs, calipers, micrometers, height gauges, thread gauges, surface roughness testers, etc.
At the same time, drawings, technical specifications, inspection standards, and recording forms need to be prepared. All dimensions and tolerances to be inspected should be marked on the drawing. Using a drawing with bubble numbers is best, where each dimension has a number for easy recording and tracking.
Follow the established program and process to machine the first part. During machining, the operator should pay close attention to the cutting condition and record key parameters. If any abnormality occurs, the machine should be stopped and checked promptly.
After the first article is machined, do not rush to the next step. Clean the part thoroughly, removing burrs and cutting fluid residue.
This is the core of FAI. The inspector needs to perform 100% dimensional inspection on the first article. That is, every dimension, every tolerance, and every technical requirement on the drawing must be inspected and recorded.
Inspection content includes:
All linear dimensions, such as length, width, height, diameter, etc.
All geometric tolerances, such as flatness, roundness, perpendicularity, parallelism, concentricity, true position, etc.
All surface characteristics, such as surface finish, hardness, coating thickness, etc.
All thread and hole features, such as thread specification, thread depth, hole diameter, etc.
All material and process requirements, such as material grade, heat treatment hardness, surface finishing type, etc.
During inspection, appropriate measuring tools and inspection equipment must be used. General dimensions can be measured with calipers, micrometers, and other standard instruments. High-precision dimensions require a CMM. Threads require go/no-go gauges. Surface finish requires a roughness tester.
Record the inspection results item by item in the FAI report, including nominal value, tolerance range, actual measurement, and pass/fail judgment. If any dimension is out of tolerance, it should be specially noted, and an explanation should be provided on whether it can be accepted through concession, rework, or scrap.
When making judgments, strictly compare against the requirements of the drawing and technical specifications. Even a 0.01 millimeter deviation cannot be lightly ignored, as it may affect assembly or function.
After completing the FAI report, submit it to the customer or internal quality department for approval. If all dimensions pass, the customer approves moving to batch production. If non-conformances are found, the customer may require a new first article to be machined, or may grant a concession for certain non-critical dimensions.
Batch production can only begin after FAI approval is obtained.
Many customers ask: My part is simple, only a few dimensions. Why is FAI still necessary? Can it be skipped? The answer is no. The value of FAI is reflected in the following aspects.
CNC machining is a complex process involving many variables such as programming, tool selection, cutting parameters, fixture design, coolant, etc. Even if the drawing looks simple, unexpected problems may occur during actual machining.
FAI can verify whether the entire process can stably produce conforming parts before batch production begins. If the first article passes, the process is proven feasible. If the first article fails, the process can be adjusted promptly to avoid expanding losses.
This is the most direct value of FAI. Suppose a part costs 10 dollars each, with a batch quantity of 1000 parts, total value 10,000 dollars. If batch production proceeds directly and quality problems cause complete scrap, the loss is 10,000 dollars. If a first article is made first, costing 100 dollars, and batch production proceeds only after it passes, even if the first article fails, the loss is only 100 dollars.
The investment in FAI is very small relative to the total value of batch production, but it can avoid huge losses.
The FAI report is an important document for quality traceability. If quality problems arise in the future, the FAI report can be used to trace back to the production status, inspection data, and judgment results at that time. This is very helpful for analyzing the cause of problems and defining responsibility.
In aerospace, medical, automotive, and other industries, the FAI report is a required document for customer audits. Without an FAI report, customers will not accept batch delivery.
The approved first article can serve as a benchmark for subsequent batch production. If quality problems occur in later batches, they can be compared with the first article to quickly identify where the difference lies. The first article can also serve as a sample for customers to confirm appearance and feel.
A complete FAI report typically contains the following content.
Part name and part number, revision number, drawing number, customer name and order number, production date and batch number, supplier name and contact information.
Material grade and specification, material supplier and batch number, material certificate number, heat treatment process and parameters.
Dimension number (corresponding to bubble numbers on the drawing), nominal value and tolerance range, actual measurement and deviation, inspection equipment number, pass/fail judgment, and inspector signature.
Tolerance type (flatness, roundness, perpendicularity, etc.), nominal value and tolerance range, actual measurement and deviation, inspection equipment number, pass/fail judgment.
Surface finish Ra value, hardness value, coating thickness, inspection equipment, and pass/fail judgment.
Anodizing type and parameters, passivation process and parameters, coating type and thickness, heat treatment temperature and time.
Non-Conformance Handling Record
Non-conforming dimension number and description, deviation magnitude, root cause analysis, disposition method (concession, rework, scrap), customer approval record.
Overall judgment result, approval to proceed with batch production or not, quality responsible person signature and date, customer approval signature and date.
Misconception 1: Only complex parts need FAI
Any new or modified part, regardless of complexity, should have FAI. Simple parts can also have non-conformances due to material issues, tool issues, or program issues. The cost of FAI is low, but the risk it can avoid is high.
Misconception 2: FAI only inspects critical dimensions
The AS9102 standard requires 100% inspection of all dimensions on the drawing. Inspecting only critical dimensions may miss non-critical but assembly-affecting dimensions. If the customer has no special requirements, it is recommended to strictly follow the standard.
Misconception 3: FAI is a one-time event
FAI only verifies the production status at that time. If subsequent production processes change, such as tool replacement, parameter adjustment, material batch change, etc., FAI or partial inspection needs to be performed again. FAI passing does not mean passing forever.
Misconception 4: The FAI report is just paperwork
The FAI report is a tool for quality management, not a document to satisfy customers with minimal effort. Carefully completing and analyzing the FAI report can identify weak links in the process and continuously improve machining quality. Treating it as formalism loses the true value of FAI.
If you are the buyer, after receiving an FAI report from a supplier, you can review it from the following aspects.
Check whether the report is complete. Are all required fields filled? Does the dimension list cover all dimensions on the drawing? Are inspection equipment records included? Are non-conformances properly documented?
Verify critical dimensions. Pay special attention to mating dimensions, mounting hole positions, bearing bore diameters, and other dimensions that directly affect assembly and function. Confirm whether the actual measurements of these dimensions are within tolerance.
Verify materials and processes. Confirm whether the material grade meets requirements and whether material certificates are complete. Confirm whether special processes such as heat treatment and surface finishing comply with specifications.
Confirm non-conformance disposition. If there are non-conformances, confirm whether the customer has approved a concession or whether the supplier has reworked them to passing.
Save the report. File and save the FAI report as a benchmark for subsequent batch acceptance and as a basis for traceability.
At Brightstar, FAI is an indispensable part of our quality system. We strictly follow the AS9102 standard for First Article Inspection, ensuring that every new part is fully verified before batch production begins.
Our FAI process includes:
After receiving an order, we first perform drawing review, confirming all dimension and tolerance requirements and identifying potential machining difficulties in advance.
After machining the first article, our quality team uses CMMs, optical measuring instruments, roughness testers, and other equipment to inspect every dimension on the drawing.
After inspection is complete, we generate a complete FAI report, including dimensional inspection records, material certificates, special process records, etc.
We submit the FAI report to the customer for approval. Only after approval is obtained do we begin batch production.
We archive the FAI report and the first article sample as a benchmark for subsequent batch production.
Through this strict FAI process, Brightstar ensures that every batch of parts starts with a qualified first article, minimizing the risk of batch quality incidents.
Q: How long does FAI take?
It depends on the complexity of the part. For a simple part, FAI may take 1 to 2 hours. For a complex part with dozens or even hundreds of dimensions to inspect, it may take half a day to a full day.
Q: Who bears the cost of FAI?
Typically included in the order quote. For simple parts, the FAI cost is low, and suppliers usually do not charge separately. For complex parts, FAI requires significant manpower and equipment time, and a separate fee may be itemized.
Q: Can partial inspection be done?
If the customer agrees, only critical dimensions may be inspected. However, the AS9102 standard requires 100% inspection. It is recommended to confirm the acceptance standard with the customer.
Q: What happens if the first article fails?
If the first article fails, the cause needs to be analyzed, the process adjusted, a new first article machined, and FAI performed again until it passes. A failed first article cannot be used as the basis for batch production.
Q: Do you provide FAI reports?
Yes. Brightstar provides a complete FAI report for every new part, including inspection records for all dimensions and material certificates.
First Article Inspection is an indispensable part of the CNC machining quality control system. It is not optional paperwork but rather the first line of defense to ensure batch production goes smoothly without errors.
The core value of FAI is: verifying process correctness, avoiding batch scrap, providing traceable evidence, and serving as a benchmark for subsequent production.
For buyers, paying attention to the review of FAI reports can effectively reduce quality risks. For machinists, strictly performing FAI reflects a responsible quality attitude.
Brightstar always puts quality first. We strictly follow the AS9102 standard for First Article Inspection, ensuring that every part starts with a qualified first article. Whether your part is simple or complex, whether the quantity is 1 or 10,000, we will provide you with a complete FAI report and quality assurance.
Ready to Perform First Article Inspection for Your CNC Parts?
Whether you need a single prototype or batch production, Brightstar can provide you with complete FAI reports and quality assurance. Contact us right now!
Email Amy: amy@brightstarprototype.com
Call or WhatsApp: +86 13750105351
Send us your CAD files and drawings for an FAI process explanation and quote.
Brightstar – Precision CNC Machining. First Article Inspection, Quality First.
