AS9100D clause 8.5.1 f) ＆ 8.5.1 g) - Special Processes

[Howard]

1. clause 8.5.1 f) the validation, and periodic revalidation, of the ability to achieve planned results of the processes for production and service provision, where the resulting output cannot be verified by subsequent monitoring or measurement.
Q1: Due to Turning, Holemaking, Grinding, Broaching, Milling, and Edge Treatment are listed in the CONVENTIONAL MACHINING AS A SPECIAL PROCESS (CMSP) of PRI, do those processes classify as the “special process” defined by the AS clause 8.5.1 f)?

2. clause 8.5.1 g) the accountability for all products during production (e.g., parts quantities, split orders, nonconforming product).
Q2: Does the requirement of the clause mean that "every part" in the manufacturing process must be controlled (such as quantity, quality status)?
Q3: I don't know much about the meaning of "split orders". Are there any examples in the actual situation?

Can anyone help? Thank you.

 

[thermal duc]

On your first question, "Special Process" commonly refers to a procedure that cant easily be tested, or that requires destructive testing. Good examples are heat treating metals or composite manufacturing, in both cases procedures and specifications can be followed to the letter but you cant really prove the harness developed or the break strength of the composite part with out damaging them. With such processes an alternative to normal inspection needs to be in place to ensure conformity. That process can vary depending on the criticality of the part with things like equipment calibration records being a bare minimum, testing on a coupon processed with a part or lot of parts, or even destroying a part out of a lot of parts. In general conventional machining is not a special process, you can measure critical dimensions, surface roughness, edge radii, etc. after the operation is complete to confirm it is correct before the next step of production occurs. In some cases that check is not possible (I can't actually think of when this would apply but I suppose in a manufacturing environment a multi step automated process might create an internal feature that cant be directly measured?) As I understand it only in those rare instances does CMSP apply, so odds are good that those processes are not special process for you.

On the second question, you need to be able to account for every part from beginning to end. lets say you have an order for 500 parts, the parts take 10 steps to make and you know that each step has a failure rate (that cant be reworked) of 1%. To prevent delays in production you get raw material for 560 (500/.99^10=553 plus 7 to be safe) parts. As soon as step one happens those are parts in progress, including the parts that fail their inspections, you need to have documentation that shows 560 parts at step one 6 failed and were destroyed beyond use, 554 parts at step two 4 failed and were destroyed, etc. the reason for this is to prevent the release of counterfeit and nonconforming parts. There are plenty of stories (not just in aviation) of parts failing inspection that are thrown away without being destroyed or documented being collected finished to make them visually passable (but still very much counterfeit and nonconforming) and being sold.

The split orders question is just a continuation of the above. If a customer orders the above 500 parts, but they want 200 in 2 months, and the other 300 2 months later. Assuming that all the things noted in the second paragraph are true, then your records should show a total order of 500 parts with 200 in the initial delivery and 300 in the second delivery. Essentially you should know where all the parts are at any given time until the customer has taken possession of them.

 

[Howard]

On your first question, "Special Process" commonly refers to a procedure that cant easily be tested, or that requires destructive testing. Good examples are heat treating metals or composite manufacturing, in both cases procedures and specifications can be followed to the letter but you cant really prove the harness developed or the break strength of the composite part with out damaging them. With such processes an alternative to normal inspection needs to be in place to ensure conformity. That process can vary depending on the criticality of the part with things like equipment calibration records being a bare minimum, testing on a coupon processed with a part or lot of parts, or even destroying a part out of a lot of parts. In general conventional machining is not a special process, you can measure critical dimensions, surface roughness, edge radii, etc. after the operation is complete to confirm it is correct before the next step of production occurs. In some cases that check is not possible (I can't actually think of when this would apply but I suppose in a manufacturing environment a multi step automated process might create an internal feature that cant be directly measured?) As I understand it only in those rare instances does CMSP apply, so odds are good that those processes are not special process for you.

On the second question, you need to be able to account for every part from beginning to end. lets say you have an order for 500 parts, the parts take 10 steps to make and you know that each step has a failure rate (that cant be reworked) of 1%. To prevent delays in production you get raw material for 560 (500/.99^10=553 plus 7 to be safe) parts. As soon as step one happens those are parts in progress, including the parts that fail their inspections, you need to have documentation that shows 560 parts at step one 6 failed and were destroyed beyond use, 554 parts at step two 4 failed and were destroyed, etc. the reason for this is to prevent the release of counterfeit and nonconforming parts. There are plenty of stories (not just in aviation) of parts failing inspection that are thrown away without being destroyed or documented being collected finished to make them visually passable (but still very much counterfeit and nonconforming) and being sold.

The split orders question is just a continuation of the above. If a customer orders the above 500 parts, but they want 200 in 2 months, and the other 300 2 months later. Assuming that all the things noted in the second paragraph are true, then your records should show a total order of 500 parts with 200 in the initial delivery and 300 in the second delivery. Essentially you should know where all the parts are at any given time until the customer has taken possession of them.

Thank you very much for your detailed reply, which gave me a more practical understanding of the provisions