AS9100 rev D 8.5.1 c 2 - Defining the Machine in-process frequency per ANSI/ASQ

[Christopher Doherty]

"the basis of recognized statistical principles", gentlemen as a quality manager of a machine shop we state and use ANZI/ASQC Z1.4 level II AQL 4 as a vehicle for accepting received or shipping final parts. The auditor has NCR'd me for not defining the Machine inprocess frequency per ANZI/ASQC. My inprocess inspection reports say 1 out of every 5, in most cases, which ironically exceeds our standard AQL, in others where i know i have heavy tool wear or previous issues i have used 1 out of 3 or even 100%. To clarify, this is in between machining operation not a criteria for final acceptance. Does the auditor have a case?

 

[dsanabria]

"the basis of recognized statistical principles", gentlemen as a quality manager of a machine shop we state and use ANZI/ASQC Z1.4 level II AQL 4 as a vehicle for accepting received or shipping final parts. The auditor has NCR'd me for not defining the Machine inprocess frequency per ANZI/ASQC. My inprocess inspection reports say 1 out of every 5, in most cases, which ironically exceeds our standard AQL, in others where i know i have heavy tool wear or previous issues i have used 1 out of 3 or even 100%. To clarify, this is in between machining operation not a criteria for final acceptance. Does the auditor have a case?

How is the NCR from the auditor worded - you might have a case for appealing because the auditor has become an expert is SPC - out of scope.

Furthermore, what is your customer requiring as far as SPC?

 

[Christopher Doherty]

The customer requirement does not extend to our internal between machining operations as i'm unaware of any that do, I meet or exceed all customer requirements for shipping. The NCR references the AS9100 spec and states "The process of defining the sampling to be used in Machining operations for key characteristics verification is not accurately defined." My procedure for sampling was defined for receiving and Final inspection. How can i justify the fact that I decided what to do and how frequently? Should i just change my internal procedure to state" the Quality Manger and engineering will determine the frequency for Machining inprocess inspect frequency? will this satisfy "based on recognized statistical principles"? I don't think so but i'm sure not going to follow a spec that doesn't relate to machining 101.

 

[dsanabria]

The customer requirement does not extend to our internal between machining operations as i'm unaware of any that do, I meet or exceed all customer requirements for shipping. The NCR references the AS9100 spec and states "The process of defining the sampling to be used in Machining operations for key characteristics verification is not accurately defined." My procedure for sampling was defined for receiving and Final inspection. How can i justify the fact that I decided what to do and how frequently? Should i just change my internal procedure to state" the Quality Manger and engineering will determine the frequency for Machining inprocess inspect frequency? will this satisfy "based on recognized statistical principles"? I don't think so but i'm sure not going to follow a spec that doesn't relate to machining 101.

OK lets try this again...

Does the customer requires that you need a sampling plan? yes or no

 

[Mike S.]

"the basis of recognized statistical principles", ... we state and use ANZI/ASQC Z1.4 level II AQL 4... The auditor has NCR'd me for not defining the Machine inprocess frequency per ANZI/ASQC.

First, not having the auditor's exact wording for the NCR makes it difficult for us to assess, as does the limited context you provide.

However, IMO, the clause you mention states you monitor and measure at "appropriate stages". You, not the auditor, determine those appropriate stages.

Further, if you use sampling inspection for product acceptance, select your sampling plan "...on the basis of recognized statistical principles...matching the sampling plan to the criticality of the product and to the process capability."

Can you explain how and why you chose your sampling plan? Did your customer set the sampling rate/plan? Did you look at OC curves and process capabilities and consider the criticality of the parts and what would/could happen if a bad part made it through your sampling? You would want a different inspection plan if you were doing final inspection on artificial heart valves than if you were making water valves for sale to consumers at Home Depot.

 

[Sidney Vianna]

Does the auditor have a case?

I know of, at least, one very large aerospace OEM which does not allow suppliers to use sampling inspection, unless formally authorized by them after their own assessment. Their actual requirement reads:

Seller's Inspection Requirements: Seller shall perform 100% inspection for in-process and final inspection, or Seller shall conform to requirements of document D1-8007 "Requirements for Supplier Statistical Plans" as may be amended from time to time. With the exception noted herein Seller‘s statistical sampling procedure/plan
conformance to D1-8007 will constitute Boeing Quality approval.

Note: Any characteristics identified in the design documentation as "Safety" or "Critical" (or "Safety Critical," et al.) characteristics shall not be accepted using statistical product acceptance methods unless prior written authorization is granted by the specific Boeing design authority, or the method for acceptance is specifically defined in the design documentation. A "Safety" or "Critical" (or "Safety Critical," et al.) characteristic is defined as a characteristic designated by the design authority, where the responsibility for its definition is outside the scope of recommended practice ARP9013.

Buyer reserves the right to disallow a supplier's statistical methods for product acceptance for specific sites/ programs, parts or characteristics, and to conduct surveillance at Seller's facility to assess conformance to the requirements of document D1-8007, available at Boeing Authentication within the "Supplier Quality" webpage.

Sampling inspection must have the risk based thinking treatment. Characteristics, criticality, process maturity, complexity, etc..all should be asssessed prior to determining if sampling is allowable and, if so, what AQL and Acc/Rej criteria.

 

[Roberticus]

Is D1-8007 an implicit requirement to PO note Q33/D6-84279? I'm still a newbie to aerospace, still waiting on my BSCP access, have met with my Supplier Quality Rep last week and things went well, but don't want to start peppering him with (likely) dumb questions... really need to get that access and get my head around the CSRs for our customers...

Thanks in advance!

 

[Mike S.]

Boeing does not flow D1-8007 on all PO's. We have some Boeing jobs where it is specified, and some where it is not.

 

[Christopher Doherty]

Of course, as ive stated already for "we meet or exceed all customer requirements"