FAI per AS9102 affecting Fit, Form, Function

J Allen

Involved In Discussions
AS9102 states that a partial First Article Inspection (Delta) for affected characteristics is required when: any of the following occurs:
2. A change in manufacturing source(s), Process(es), Inspection method(s), location of manufacturing, tooling, or materials that can potentially affect fit, form, or function (FFF)of the part.

The key wording is the part about affecting FFF.

If there is a change to the CNC program that changes the tolerance of an in-process operation but does not affect the final blue print dimensions, is a delta FAI still required base on the above statement?

There has been no change to design, sequence of operations, machining process, or final dimensions.
 

dsanabria

Quite Involved in Discussions
AS9102 states that a partial First Article Inspection (Delta) for affected characteristics is required when: any of the following occurs:
2. A change in manufacturing source(s), Process(es), Inspection method(s), location of manufacturing, tooling, or materials that can potentially affect fit, form, or function (FFF)of the part.

The key wording is the part about affecting FFF.

If there is a change to the CNC program that changes the tolerance of an in-process operation but does not affect the final blue print dimensions, is a delta FAI still required base on the above statement?

There has been no change to design, sequence of operations, machining process, or final dimensions.

Not sure if I follow your thinking but it appears that you are thinking of placing the in process inspection on the FAIR - Why? - not required.

The FAIR is done to validate the process...
 

J Allen

Involved In Discussions
No, not at the in-process operation. The question is: do I need to perform a delta FAI on that characteristic at final inspection because there was a CNC program change that can potentially affect FFF? How do you determine if the change really affects FFF when you are not changing any design characteristics?
 

howste

Thaumaturge
Trusted Information Resource
How do you determine if the change really affects FFF when you are not changing any design characteristics?

That's the question and the answer. If you don't know if it might affect FFF, that's when you do an FAI to verify that it didn't have a negative effect.
 

dsanabria

Quite Involved in Discussions
No, not at the in-process operation. The question is: do I need to perform a delta FAI on that characteristic at final inspection because there was a CNC program change that can potentially affect FFF? How do you determine if the change really affects FFF when you are not changing any design characteristics?

From AS9102B

Quote:
"4.6 Partial or Re-accomplishment of First Article Inspection

a. The FAI requirement, once invoked, shall continue to apply even after initial compliance.

b. The FAI requirements may be satisfied by a partial FAI that addresses only the changes from a baseline part number provided all other characteristics were conforming on the previous FAI and are produced by the original production processes.

c. When a partial FAI is performed, the organization shall, as a minimum, complete the affected fields in the FAI forms.

d. When the organization performs a partial FAI, the organization shall record the “Baseline Part Number”, including the revision level and reason for the partial FAI on Form 1 (see field 14).

e. FAI requirements may be satisfied by a previously approved FAI performed on identical characteristics of similar parts produced by identical means. When FAI requirements (partial or full) are satisfied in this manner, identify the “Baseline Part Number” on Form 1 (see field 14).


f. The organization shall perform a full FAI or a partial FAI for affected characteristics, when any of the following occurs:

A change in the design characteristics affecting fit, form, or function of the part.

2. A change in manufacturing source(s), process(es), inspection method(s), location of manufacture, tooling, or materials that can potentially affect fit, form, or function.

3. A change in numerical control program or translation to another media that can potentially affect fit, form, or function.

4. A natural or man-made event, which may adversely affect the manufacturing process.

5. An implementation of corrective action required to complete a previous FAI, as described in 4.4.

6. A lapse in production for two years shall require an update for any characteristics that may be impacted by the inactivity. This lapse is from the completion of last production operation to the actual restart of production."

So to answer your question - if a repaired was done to the part because it did not meet BP or customer requirements - yes a Delta is required.

When and where you do it is irrelevant as long as it is done. You could do it on the machine, constraint condition, in-process or at final - but it must be done and other affected areas.
 

Bev D

Heretical Statistician
Leader
Super Moderator
We really can't assess the potential failures without understanding the material, the cutting process and material and the subsequent operations as well as the measurement system(s) and associated error. I can envision (and have experienced) scenarios where you could increase the probability of a failure (in part properties or dimensions). The safe route is to simply do the FAI. We and you do not know the answer and the FAI has the (contractual) chance of answering the question.

FAIs are required for more than just changes to design characteristics. The standard specifically calls out changes to CNC programs...

I've been a supplier and I understand that change notification, FAIs and V&V prior to Customer approval is time consuming and not always intuitively obvious as to why. And as a Customer I completely understand this absolute requirement. My suppliers cannot possibly know all there is to know about how their parts interact in my system in the users hands. I've been burned so many times by "it was just a little change". The cost, risk to my business and my customers is simply intolerable.

Do the FAI...
 

Eredhel

Quality Manager
If there is a change to the CNC program that changes the tolerance of an in-process operation but does not affect the final blue print dimensions...

Sometimes we will require tighter tolerances at the machine than what is on the actual blueprint. Do you mean a situation like that?
 
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