I THINK I'M ON THE RIGHT PAGE.
I FORGOT, IS IT O.K. TO USE CAPS? I NEED SOME HELP WITH AN AQL QUESTION.

I am the Quality Management Systems Rep. and The Internal Auditor for for an aerospace machine shop, yes it's a cool job:cool:.

I write all the policies and the procedures. This is a new company for me as I was laid off my last job, in Feb and got a job 2 days later. Thank God!! I was the AS9100 Auditor, a Lathe machinist and Tool Crib Manager, aerospace and oilfield.

So, this company I'm with now wants to get their certification and we are well on our way. But I have bumped into an area that I am not familiar with, and it has become my "pet peeve":bonk:also making me very crazy!!

I need to write a procedure on our AQL Statistical Acceptance Level. I have been researching this for about 3 days now and kept coming up on your website. So I thought I would ask someone for help.:confused:

I am finding that I don't really need to know our AQL, only how I arrived at our statistics. In aerospace parts we can have zero non-conformance, but we do run into problems and usually rework the parts or they are scrapped before anything leaves here. What I mean is we don't ship bad parts and our customers do not "accept" a certain level of defects. Our parts have to be precision machined 100% of the time.

We 100% inspect our parts and only want to have to "write down" a certain percentage, for our "in process inspection documentation" records and THAT the is the AQL number I am looking for and the methods I used to arrive at it.

Does anybody understand? Is there a chart online somewhere, that I can get this info...I would really appreciate some input.

Thanx...QMSlady:agree:

I THINK I'M ON THE RIGHT PAGE.
I FORGOT, IS IT O.K. TO USE CAPS? I NEED SOME HELP WITH AN AQL QUESTION.

Slightly (OK a lot) off subject, but reading that made me think of the old joke:
"Why do you always answer my questions with a question"?
"DO I"?

Years ago I could understand the value of AQLs but nowadays not so much. AQLs infer that are certain number of defects are allowable. A "Monday car" used to be a joke to all except the unfortunate buyer!
I'd hate to be passenger in a "Monday aeroplane" :mg:
With machined parts it is almost entirely about knowing what the machine is capable of manufacturing and that the operator pays attention to what is being produced.
It probably won't be "accepted" by the powers that be, but personally I'd never put in writing that I found it acceptable to manufacure even an infinitesmal quantity of faults.
Let the suppliers documented deliveries speak for themselves. Common sense would deem always to have at least two supliers for all (and definately for the critical) parts. Compare at regular intervals what the quality of the deliveries is and focus the suppliers attention to what is classified as critical. If it isn't critical and there are problems perhaps a new tolerance or acceptance criteria is the way forward.

I'll probably write more after I read the comments that come in ;)

Hi gordon,

thanx for the jokes. Just so everybody knows...we are the sub-supplier, the last in the chain...like i said before we measaure all dims 100% inspection is criteria from some customers, we always check criticals, especially on parts with known problem specs. I need to know how to calculate an aql, show the criteria used to arrive at an aql of say 1.0? For inspecting all of our parts and get on with other things, i have a lot of procedures to write as well a quality manual and the training of the employees on the new standards they are being asked to perform...
Qmslady :)

I FORGOT, IS IT O.K. TO USE CAPS? I NEED SOME HELP WITH AN AQL QUESTION.You can use all caps if you want us to think you're shouting at us... :mad:
We 100% inspect our parts and only want to have to "write down" a certain percentage, for our "in process inspection documentation" records and THAT the is the AQL number I am looking for and the methods I used to arrive at it.

You're not really using an AQL, since you're already doing 100% inspection. So the question is, how many readings are you going to record?

The first question I have is: What do your customers want/need/require? If they want all values recorded, and are willing to pay for it, record them all.

If they don't specify or don't care, you get to decide. What is your batch size? If it's not too large, you might consider recording the range of readings for each batch.

An AQL is so much calculated as it is determined. You ould pick any AQL level you wanted depending on what level of quality you want to live up to.

The AQL will determine you sample quantity to inspect from a lot. If you are performing 100% inspection, then you are not sampling and therefore don't need to have any AQL level. Just write your procedure that you do not use any sampling inspection (if that's the case).

If not (more likely) then you need to select the AQL that gives you the most assurance with the inspection resources you have available. Or (as is often the case in aerospace) your customer forces a certain minimum AQL level through their contract or specs.

You can (and will) use different AQL's for different characteristics depending on their individual signifigance, tolerance, customer designation, process capability, etc.

Good luck, and read your customer's requirements carefully on this subject and how to apply them in different manufacturing and lot situations.

Hi gordon,

thanx for the jokes. Just so everybody knows...we are the sub-supplier, the last in the chain...like i said before we measaure all dims 100% inspection is criteria from some customers, we always check criticals, especially on parts with known problem specs. I need to know how to calculate an aql, show the criteria used to arrive at an aql of say 1.0? For inspecting all of our parts and get on with other things, i have a lot of procedures to write as well a quality manual and the training of the employees on the new standards they are being asked to perform...
Qmslady :)

Hi M'lady :D
I don't get it. Usually (always?) it's the customer that specifies the AQL level - not the supplier.
If you really inspect 100% then how often do you delivery faulty parts?
I think you are paying the price due to the fact that your customer has had a bad experience at some time. Either that or the ones interested in AQLs must have been around when man (and woman) started to walk upright on two legs.
To me, if the dimensions can be measured, supply the customer with documentation that you're within tolerance. SPC. If your spread is 70% or less of +/-3 sigma then you have the process well under control.
An AQL of 1.o???? One percent is acceptable????? You've never delivered to Europe or Japan :cool::lmao:
In MIL STD 105D or whatever you use, the sampling size depends on quantity.

Another (poor) joke:
If you did 100% control on a box of matches you could always tell the customer they were all OK and every single one ignited. :bonk:

I THINK I'M ON THE RIGHT PAGE.
I FORGOT, IS IT O.K. TO USE CAPS? I NEED SOME HELP WITH AN AQL QUESTION.

I am the Quality Management Systems Rep. and The Internal Auditor for for an aerospace machine shop, yes it's a cool job:cool:.

I write all the policies and the procedures. This is a new company for me as I was laid off my last job, in Feb and got a job 2 days later. Thank God!! I was the AS9100 Auditor, a Lathe machinist and Tool Crib Manager, aerospace and oilfield.

So, this company I'm with now wants to get their certification and we are well on our way. But I have bumped into an area that I am not familiar with, and it has become my "pet peeve":bonk:also making me very crazy!!

I need to write a procedure on our AQL Statistical Acceptance Level. I have been researching this for about 3 days now and kept coming up on your website. So I thought I would ask someone for help.:confused:

I am finding that I don't really need to know our AQL, only how I arrived at our statistics. In aerospace parts we can have zero non-conformance, but we do run into problems and usually rework the parts or they are scrapped before anything leaves here. What I mean is we don't ship bad parts and our customers do not "accept" a certain level of defects. Our parts have to be precision machined 100% of the time.

We 100% inspect our parts and only want to have to "write down" a certain percentage, for our "in process inspection documentation" records and THAT the is the AQL number I am looking for and the methods I used to arrive at it.

Does anybody understand? Is there a chart online somewhere, that I can get this info...I would really appreciate some input.

Thanx...QMSlady:agree:

Are you trying to establish a sampling plan?

M'lady,
All of the replies/suggestions you have been getting are serious and express the same doubt as myself, although I do tend to be less serious than most. If I were you, I'd pick one of the "contributors" (cheapest within the USA) and give the person a phonecall. That's probably the quickest way to solve your apparent dilemma. You can then write and let the rest of us know how things progressed.

An AQL is so much calculated as it is determined. You ould pick any AQL level you wanted depending on what level of quality you want to live up to.

The AQL will determine you sample quantity to inspect from a lot. If you are performing 100% inspection, then you are not sampling and therefore don't need to have any AQL level. Just write your procedure that you do not use any sampling inspection (if that's the case).

If not (more likely) then you need to select the AQL that gives you the most assurance with the inspection resources you have available. Or (as is often the case in aerospace) your customer forces a certain minimum AQL level through their contract or specs.

You can (and will) use different AQL's for different characteristics depending on their individual signifigance, tolerance, customer designation, process capability, etc.

Good luck, and read your customer's requirements carefully on this subject and how to apply them in different manufacturing and lot situations.
o.k.
I think I get what your saying, say what we do, and do what we say? We inspect 100% and write down 10%. Our customers have NO "set requirements" as yet, but we just picked up a new job. Our batches run from 1 piece to 100 pieces. Mostly around 25 to 50 pieces, so 100% is not too time consuming, and is checked while the next part is running.

So you are right in saying that we do not do "sampling inspection". But how can I justify the percentage that we write down? To say that we are writing down 10% of 100% inspected parts over the quanity of, say, 20 pieces and every part of 15 pieces or less? What's the AQL for that measurement?

Most of our customers do not specify their inspection criteria in "terms", only the tolerances given in the specs, which we abide by, usually running nominal. There are some parts that have pretty tight tolerances, critical dims and we have been writing down every other part to show consistancy in conformity, unless the lot is small, we write 1st piece, (FAI), every piece "in process" and Final.

If it's just a matter of writing down "how" we do it, that I can handle, but if we have to "justify" how we came to this conclusion, of writing down only 10%, I need an AQL number and how we arrived at that number, being careful not to "pin" us down to any one way.
Appreciate this, you have been very helpful...qmslady

Unless you can justify which parts you choose to write down, you can't justify writing down only 10% or 15% when inspecting 100%.

I have found a tutorial on acceptance sampling (http://www.samplingplans.com/modern3.htm). I am not affiliated with Servicco. I hope this helps.

Thanx Jennifer,

I copied this to my computer so I can go over it. We do, however, write which number the part is on our Operator In Process Inspection sheet and on the part itself. So we can justify which part is being written down and specify that "all" are 100% inspected.
QMSLADY :)

I think you really should explore SPC and capability measurements.

CAPABILITY MEASUREMENTS like Cpk and Ppk are typical measures of how well you are actually doing. You calculate these by looking at your measured results, finding the mean and standard deviation, and then doing some calcualtions comparing the mean and stadard deviation to the specs. (And as Bob would rightfully point out, for precision machining you might want to do the calculations slightly differently than you would for other processes.)

A typical rule of thumb is to measure at least 30 pieces. More is better, but 30 gives pretty good results. Because capability calculations are based on variable data (ie numbers that can take on many results over the range of interest), a relatively small number of measurements (like 30) will give clear and effective results. These sorts of capability measurements are well known and well accepted in many industries.

This should be done in conjunction with control charts to see that the proceses is behaving consistently.



AQL SAMPLING PLANS, on the other hand, are based on a value you choose. Basically you are say "if the parts meet the chosen AQL (or are better), then the lot will usually be accepted, and if the lots are noticeably worse than the chosen AQL, then the lot will usually be rejected." In your case, an AQL sampling plan at the end (or when they receive the parts) could be effective as insurance on top of your other measurements. For example, if a shipment got mislabeled, a sample of a few parts would quickly spot the error.

Because AQL plans use attribute data (eg pass/fail), they require large samples if you want a high degree of certainty. You might check this thread for info http://elsmar.com/Forums/showthread.php?t=33830. For exampl, if you wanted to be 95% certain that at least 99% of the parts are good, you would have to sample 299 parts! Since you don't make this many parts, then this is not effective. But 30 parts for an estimate of Cpk could give you a similar certainty.


Let me recap my opinions on the matter:


SPC (control charts) shows that you are being consistent
Capability (Cpk) shows how well you actually have done relative to specs.
Sampling (AQL) provides a rough check of how well you have done


Tim F

Thanks Tim,
I will take this into consideration with all the other good advice I am getting...gotta go to work on it now... :)
QMSLADY

M'lady,
All of the replies/suggestions you have been getting are serious and express the same doubt as myself, although I do tend to be less serious than most. If I were you, I'd pick one of the "contributors" (cheapest within the USA) and give the person a phonecall. That's probably the quickest way to solve your apparent dilemma. You can then write and let the rest of us know how things progressed.

Give who a phone call? :confused:

Hey Gordan,

That's how we say "HI" in Oklahoma. This is probably Jim's post, but I can't find Gordan's post.

Jennifer gave me a good website to go to, I am starting to understand this a little more. It talks in "plain english" that I can grasp. Still researching the web and coming up with some plans and charts, got "free" 30 day trial on some Sampling Program Software that is helping too. Will let ya'll know what happens and what I decide on.

Thanx...QMSLADY:bigwave::topic:FOR NOW

Give who a phone call? :confused:

Depends on who (if anone) she chooses :)
I'm not in the USA so I'm out ;) - apart from the fact too, that I'm against AQLs.
I can't get my head around that "defects are acceptable".

can't get my head around that "defects are acceptable".

I guess this depends on the situation. Consider a box of 100 paper clips. If I have the choice between


spending $1 and perhaps having one or two bad paper clips
spending $5 for a box certified to have exactly 100 good paper clips

I can tell you I would take #1 just about every time. The "cost" to sort & throw out the 1 or 2 bad clips as I use the paper clips is much less than the cost for "zero defects". Now if the certified box was only $1.02, I might spend the couple extra pennies.

It's always a balance -- the cost of the part, the cost of inspection, the cost when there is a failure ...

For the original post of this thread, it sounds like 100% inspection and 0% failure is the economic decision.



Tim F

Depends on who (if anone) she chooses :)
I'm not in the USA so I'm out ;) - apart from the fact too, that I'm against AQLs.
I can't get my head around that "defects are acceptable".

It would be better to think of it as acceptable risk level. The term originated a long time ago in US MIL standards when mass inspection was common. Nonetheless, as Tim Folkerts points out, there are times when the economics of the situation does make some defects "acceptable."

OK let's try an alternative approach. (Although Tim's suggestion about SPC has merit for the future)

To summarize, correct me if I've gotten something wrong:
You are doing a 100% inspection, which isn't too difficult given your relatively small batch sizes...
You only write down soem of the data around 10%
you were thinking that you needed some statistical validation for writing down only some of your data.
at this point you know that AQL applies to determining sample size

this is not a typical situation for aerospace and would probably result in many questions.

SO: why don't you simply write down all of the results?

alternatively you can write down only the min and max value

there is no statistical requiremetn behind either of these...make it simple on yourself

I guess this depends on the situation. Consider a box of 100 paper clips. If I have the choice between


spending $1 and perhaps having one or two bad paper clips
spending $5 for a box certified to have exactly 100 good paper clips
I can tell you I would take #1 just about every time. The "cost" to sort & throw out the 1 or 2 bad clips as I use the paper clips is much less than the cost for "zero defects". Now if the certified box was only $1.02, I might spend the couple extra pennies.

It's always a balance -- the cost of the part, the cost of inspection, the cost when there is a failure ...

Tim F

I mentioned earlier what I described as critical and non critical dimensions for determining what to concentrate time and effort on. I doubt very much if the products we're discussing are comparable to paper clips.
The "clips" example seems to me a bit far fetched unless we're dealing with people that have been forbidden to use common sense.

I'll give an example along the same lines.

A Russian general and an American general, sitting by a swimming pool, were discussing who had the bravest soldiers.
A Russian soldier walked past, was stopped by the Russian general and ordered to climb to the top of the 30 foot diving board and jump in with a heavy rucksack. He did so and drowned.
The American general stopped an American G.I. and gave him the same order.
The G.I. looked at the general and said, "Are you mad" sir"?
The American general turned and smiled to the Russsian general and said, "Now that is bravery".

I support Bev's suggestion, based on batch sizes and the inevitable question: "What prompts you to write down the inspection results of part 2, 10 and 12 versus, for example 3, 7 and 13? A suspicious mind would ask is there was "cherry picking" going on, even if it's unintended.

My point is, sampling is supposed to be random. That means you draw the sample, inspect it and process the results of that sample.

O.K. Folks,
I'm back:bigwave:...I have attached the Procedure I wrote this morning after all my searching, down loading, hair pulling, :read: and :frust:.

I have forwarded it to a 3rd party Auditor friend who teaches auditing at Tulsa Tech, for critique. I'm sure it needs help and I was unsure about some of things, like "random" which is more like structred and "no sampling plan", which isn't true now that i think about it. But it is still in the making...thanks to all of you who helped, sent me links, and email addresses(one worked out really well Gordan):agree1:.
Soooo...if anyone reads this and has some suggestions, I'm open and objective and not easily offended by criticism. I play well and like to share:rolleyes:...Thanks,
QMSLADY

read the procedure and I don't understand why you will only record some of the measured values. Now a standard accepted practice is to record the min and the max - not random.

How will you control the random selection of 10% of the values? I also think that an auditor will find this strange, particularly with your low batch sizes.

Also the zero acceptance refence makes no sense when you are 100% inspecting. Zero acceptance refers to the need to perform 100% remediation of a lot that has 1 or more defects in it's inspection sample. Since you are already inspecting 100% of the parts, a simple statement that any rejected part falls under your procedures for handling nonconformance would be sufficient.

100% inspection is not sampling. The sampling plan's purpose is to understand risks and set out a plan to randomly pull some number out of the lot, inspect those pieces, and record results for each inspected piece.

As an auditor I would not accept the idea of inspecting 100% and writing down 10%. That is not sampling, and it would be very hard to convince me that the parts written down were randomly selected. :nope:

An AQL is so much calculated as it is determined. You ould pick any AQL level you wanted depending on what level of quality you want to live up to.

The AQL will determine you sample quantity to inspect from a lot. If you are performing 100% inspection, then you are not sampling and therefore don't need to have any AQL level. Just write your procedure that you do not use any sampling inspection (if that's the case).

If not (more likely) then you need to select the AQL that gives you the most assurance with the inspection resources you have available. Or (as is often the case in aerospace) your customer forces a certain minimum AQL level through their contract or specs.

You can (and will) use different AQL's for different characteristics depending on their individual signifigance, tolerance, customer designation, process capability, etc.

Good luck, and read your customer's requirements carefully on this subject and how to apply them in different manufacturing and lot situations.
I attached a copy of the Procedure i wrote this morning at the end of this forum...if you want to see how I did.

Thanx...QMSLADY

M'lady,
All of the replies/suggestions you have been getting are serious and express the same doubt as myself, although I do tend to be less serious than most. If I were you, I'd pick one of the "contributors" (cheapest within the USA) and give the person a phonecall. That's probably the quickest way to solve your apparent dilemma. You can then write and let the rest of us know how things progressed.
I attached a copy of the Procedure i wrote this morning at the end of this forum...if you want to see how I did.

Thanx...QMSLADY

I thought I posted in this tread earlier today, but I don't see it...Well...I attached the procedure I wrote this morning...anybody have any critiques? I emailed a copy to a friend who teaches "Aditing" at Tulsa Tech. U...waiting to hear what she says :notme:...I know it's not perfect, maybe a little rough around the edges, but I think we might be able to use this.
Thanks everyone for all your help and advice and emails...they really helped...:thanx:
QMSLADY

There are several items that caught my attention:

Your procedure says that all parts will be 100% inspected, but it fails to mention how the person doing the inspection knows what characteristics will be measured. Will they also inspect 100% of all print dimensions and notes?

Your procedure says "measurements taken by the operator shall be recorded randomly up to 10% of the lot or customer requirements (which ever is less)." This means that if your customer specifies that more than 10% of the measurements will be recorded, you'll ignore their requirement and just do 10% anyway. I don't think that's what you really want it to say.

Since you're not doing sampling, why do you have the C=0 sampling table and reference MIL-STD-1916?

Also, your procedure References AS9100-2008. It should be either 2004 or 2009. There is no 2008 version.

I hope this helps...

read the procedure and I don't understand why you will only record some of the measured values. Now a standard accepted practice is to record the min and the max - not random.

How will you control the random selection of 10% of the values? I also think that an auditor will find this strange, particularly with your low batch sizes.

Also the zero acceptance refence makes no sense when you are 100% inspecting. Zero acceptance refers to the need to perform 100% remediation of a lot that has 1 or more defects in it's inspection sample. Since you are already inspecting 100% of the parts, a simple statement that any rejected part falls under your procedures for handling nonconformance would be sufficient.
Bev,

I see what you mean...as I said, this is a rough draft...but all week end the wording has been bugging me...I think you narrowed it down for me...:) thanx qmslady

Bev,

I see what you mean...as I said, this is a rough draft...but all week end the wording has been bugging me...I think you narrowed it down for me...:) thanx qmslady

OK to the "rough draft" as there are quite a few spelling and grammatical mistakes. I'm also left wondering who it is actually written for? One of the things that impressed me most on visits to the USA was how simply instructions and procedures were often written - especially due to the population mix you have. I don't feel this is the case here - unless everyone employed by your company has no problem with the English language. KISS comes to mind :D

I was also under the impression that your batches were in relatively small number so why the inclusion of "vast qualtities" in the sampling plan? As you apparently don't accept defects :applause: then why have a sampling plan anyway? It can't take long to find out what dimensions and characteristics to be on the look-out for. SPS when possible on the machines would pay off quickly. The SPC can also be used to monitor the machinists. A person that never makes a mistake doesn't do anything - but there are always one or two that think they have to make mistakes frequently to show the world how much they do do :lmao:

There are several items that caught my attention:

Your procedure says that all parts will be 100% inspected, but it fails to mention how the person doing the inspection knows what characteristics will be measured. Will they also inspect 100% of all print dimensions and notes?

(Yes we always inspect the prints, but do I need to mention that? Isn't it a given?)

Your procedure says "measurements taken by the operator shall be recorded randomly up to 10% of the lot or customer requirements (which ever is less)." This means that if your customer specifies that more than 10% of the measurements will be recorded, you'll ignore their requirement and just do 10% anyway. I don't think that's what you really want it to say.

(This is the part that bugged me all weekend. All dims will be checked, the "random" is the actual part, i.e. Part #5 is marked on the part, and all the dims will be taken and recorded. But I still don't think "random" is the word I'm looking for. And at first I had (whichever is more) but I wasn't sure if that was right, now I know.)

Since you're not doing sampling, why do you have the C=0 sampling table and reference MIL-STD-1916?

(Like I said before, I need to justify "why" we only "write down" a percentage instead of 100%, the auditor says we need a "sampling plan" to do this. So I am taking out the part that says we don't have one.) No one is perfect and sometimes, one gets by us to the customer and is sent back for rework or is scrapped.)

Also, your procedure References AS9100-2008. It should be either 2004 or 2009. There is no 2008 version.

(I didn't find anything (rev.) saying which year and assumed it was "2008" because that's when the revision was made. But since it came out in "2009" I didn't know for sure. Isn't this year a reference to the ISO standard rev.? Or is it for the AS9100 rev.? They have both been revised.)

I hope this helps...

I wasn't sure how to answer each question, so I put my answers in parenthesis..
Thanx for your help...waiting for your reply...:read:QMSLADY

Like I said before, I need to justify "why" we only "write down" a percentage instead of 100%, the auditor says we need a "sampling plan" to do this. So I am taking out the part that says we don't have one.) No one is perfect and sometimes, one gets by us to the customer and is sent back for rework or is scrapped.


Did the auditor really mean "sampling plan" as litteraly as you've taken it?
It could be what ws said/implied was
"What do you do when you don't do 100% inspection"?

If I were you I'd also be curious as to why "one gets by you" occasionally. Is it the same dimension/chararteristic (type) and/or by the same operator?

I think the troubling part that remains unanswered is the random recording. We understand that you are inmeasuring all dimensions on all parts. Good without SPC and proven capability most arespace Customers require 100% final inspection.

However, you still need to justify why you are only recording some of the measurements. You also need to specify how you will "randomly" determine which parts will be recorded. Are you going to use a random number generator each time?

I wasn't sure how to answer each question, so I put my answers in parenthesis..
Thanx for your help...waiting for your reply...:read:QMSLADY

I have been taking in all the advice and see how my "words" can be confusing...

The 3rd party auditor said and I quote, "You can't just say that you are writing down 10% of the parts that you inspected, even tho you inspected all of them. You must justify how you arrived at that percentage as a "statisically valid" number. To do that you need an SPC, if you like, I could come and show your inspectors how to do this." For a fee of course:D.

You may ask why am I saying 10%? Because it is what we "do" to show "in process" inspections and uniform conformity. If one is out of print, we stop until the non-conformity is fixed.

As for the "one getting by us", that was at another company I worked for. Also AS9100 and the customer requirement stated 10% inspection. Although I checked all dims, and every part, it was the nature of the material to change with temperture.:yes: It was teflon. The company did not require a controlled environment and the lots were 750 to 1000 parts(small). While I ran them nominal, they could change drastically if it was very hot or very cold (in the building) while I was running them, so sometimes it happened that there some out of print, but not very often. Made me crazy! :biglaugh:
I attached my revision for more critique...anybody game?:)
QMSLADY

I attached my revision for more critique...anybody game?:)
QMSLADY

I've made some changes (suggestions) so now I'm opening up for critique too :D :bonk:

You still haven't answered your auditor's question about why you will only record 10% of the parts you measure. what is your statistical rationale fro 10% (v.s. all, min/max or a simple conforms notation which are the traditionally accepted approaches) and how will you ensure randomness?

Additionally you say the operator will measure 100% of all dimensions on all parts before during and after each of the machining processes. Really? isn't that over kill? How will this be done and why? I can see measuring every part as it completes a machining operation. That makes sense.
I know there are inprocess measures on dimensions that require multiple cuts but these typically aren't recorded and aren't required to be recorded even for aerospace.

You still haven't answered your auditor's question about why you will only record 10% of the parts you measure. what is your statistical rationale fro 10% (v.s. all, min/max or a simple conforms notation which are the traditionally accepted approaches) and how will you ensure randomness?


And that is why I've eliminated all percentages (except 100%) from my "suggestions" in the file I included in my last response.
M'Lady you seem determined to make life difficult for yourself :D

You still haven't answered your auditor's question about why you will only record 10% of the parts you measure. what is your statistical rationale fro 10% (v.s. all, min/max or a simple conforms notation which are the traditionally accepted approaches) and how will you ensure randomness?

Additionally you say the operator will measure 100% of all dimensions on all parts before during and after each of the machining processes. Really? isn't that over kill? How will this be done and why? I can see measuring every part as it completes a machining operation. That makes sense.
I know there are inprocess measures on dimensions that require multiple cuts but these typically aren't recorded and aren't required to be recorded even for aerospace.
Hi Bev,

I'm not sure what you mean by multiple cuts. And on the "before, during and after" I meant the prints, program, etc. before, the part is inspected after each process or "op" and then again when it is finaled.

She is the one that said we had to have an SPC if we were not going to write down all the dims every time we inspected the part. The AQL chart (suggested by the auditor) she says, is to show our 'statistical rationale'.

Before she brought this up, I didn't even know it existed...as I stated a while back...I am new to this company and starting from scratch...as an Internal Auditor at the last company I was with, I was also a lathe machinist, tool crib manager and purchasing agent for company of about 45. I asked her how we were able to get by with this at the last company, she said "They had a procedure for an AQL of 1.0%". That still doesn't tell me "how" one arrives at a statisically valid conclusion without a chart.

Are you telling me I need to take some samples before I can use the chart? What are you trying to tell me?

I don't need to spend anymore time spinning my wheels this week, I have been working on this since Monday the 11th...and I'm still not sure of what is being asked of me.

Some direction would be good at this point...Thanx...QMSLADY

"All regulations are subject to interpretation"...

And that is why I've eliminated all percentages (except 100%) from my "suggestions" in the file I included in my last response.
M'Lady you seem determined to make life difficult for yourself :D
O.K.
Don't you think I already thought about that? If you don't state it you don't have to do it. But she (Auditor) told me that that would not work. Just like Bev. D was saying, How do I assure them that it's every tenth part of 100? Or that it's random and not selective? It really isn't random and it is selective that we write down, say...every fifth part. Why can't we just say that ? That we are writing down every fifth part to show we are staying in conformity as we process the part? If the Standard is open to interpretation...Then this is how I understand 8.2.4...The exact words of the clause (2009 rev. C) "When the organization uses sampling inspection as a means of product acceptance," we don't use sampling as means of acceptance, we inspect 100% "the sampling plan shall be justified on the basis of recognized statistical principles and appropriate for use." and "Evidence of conformity with the acceptance criteria shall be maintained." My acceptance criteria is my print and my First article passing inspection. If I wanted to use the ZBA CHART to show my selection of recording, not just certain dims, but parts with all the critical dims. I am checking all and writing some, I am 'basing my selection on the statistical principles of a recognized chart' am I not?...
It's late...I'm tired...time to go home...will check in tomorrow...thx qms

But she (Auditor) told me that that would not work.

She "told" you, but did she put anything in writing? Every third, fifth or tenth etc. item would be random - at least in the sense that the person doing the inspection wouldn't be "choosing" what to take.

I stopped long ago believing everything I heard and read. You have a practical background - have more faith in your own judgement. I've never met an auditor yet that was infallible :notme:

Thank You Gordan,

For your help on this procedure and the wording. Sorry to everyone if I sounded a little (ok a lot) grumpy yesterday. I have revised it again and feel much more confident this time.:yes:

Please take a look and tell me what you think. I have changed a lot and am still apprehensive about some of the wording and "redunantcy". I have put the chart back in, but if you read 2.0 and 4.0 you'll see why. It may be that I can do without it still.

But as I entered just below it, the wording is from DoD, not mine. (Could probably leave that out too) I don't know...:rolleyes:

This forum has been very helpful to me. Not just this thread, I have also been reading in other areas as well. And I have made a few friends...I hope :o

Thanks to all of you who helped, (even you Bev) :applause:for making me think.
:bigwave:QMSLADY

I think the troubling part that remains unanswered is the random recording. We understand that you are inmeasuring all dimensions on all parts. Good without SPC and proven capability most arespace Customers require 100% final inspection.

However, you still need to justify why you are only recording some of the measurements. You also need to specify how you will "randomly" determine which parts will be recorded. Are you going to use a random number generator each time?I am also troubled...for two reasons.

1) If 100% inspection is being done because a customer wants it, wouldn't that customer also expect there to be evidence of the 100% inspection? That is, inspect 100% and record 100%, or inspect 10% and record that same 10%.

2) The sampling plan's entire purpose is to inspect less with some defined degree of confidence (that degree of confidence is what gets decided on as AQL) because costs of inspecting 100% are high. Inspecting 100% and writing down 10% is not sampling.

Am I missing something here?

Have you received permission to reprint that table? ASQ sells those sampling plans, and to my knowledge they are copyrighted material.

I am also troubled...for two reasons.

1) If 100% inspection is being done because a customer wants it, wouldn't that customer also expect there to be evidence of the 100% inspection? That is, inspect 100% and record 100%, or inspect 10% and record that same 10%.

2) The sampling plan's entire purpose is to inspect less with some defined degree of confidence (that degree of confidence is what gets decided on as AQL) because costs of inspecting 100% are high. Inspecting 100% and writing down 10% is not sampling.

Am I missing something here?

Have you received permission to reprint that table? ASQ sells those sampling plans, and to my knowledge they are copyrighted material.
Thanks Jen,

Yes...to all the above, I do hear your point, but read further in the threads or just skip to this mornings post by me to Gordan and view the Procedure again...just forget the "word" random...it no longer exists. ")
qmslady

Sorry. I've read the revised procedure and I don't see that the initial confusion has been cleared up regarding recording of only a partial set of results. You seem to be changing words but not the meaning of your sentences. You point to the AQL Plan but provide no guidance on how to determine how many values will be recorded nor how you will determine which of values will be selected. Which "AQL level" (for recording purposes) do they choose? It is also not sufficient statistical justification for recording only a portion of the results to simply point to a statistical sampling plan table.

More importantly, WHY are you determined to record some smaller portion of the values? you seem to be very adamant about it, so if we can get to the heart of that question, perhaps we can provide better guidance as to the real justification for it. What is it about a recording a portion of the results that is more valuable - or less wasteful - to you than recording all of them, or just the min/max values?

additionally the wording "first part, during and after machining" doesn't clear up the instruction. Are you trying to say that each part will be measured after it has completed the machining operation, even if other parts are not yet complete? In other words you are saying "don't wait until they are all done before measuring them"?

I am also troubled...for two reasons.

Have you received permission to reprint that table? ASQ sells those sampling plans, and to my knowledge they are copyrighted material.

I'm not "troubled" (puzzled?) but I must say the two points are very relevant.

I honestly still don't see the need for a sampling plan - at least certainly not the one shown. If it is a "must" (for some obscure reason) then it'd be easier to make a simple one relevant to the number quantity your company produces.

I also read the procedure, and it clearly enough states that parts will be 100% inspected but recorded as per the sampling plan. That is not acceptance sampling. Period. Those tables are not intended for the purpose of minimizing recording, they are intended for the purpose of minimizing inspection where it's allowable.

Just a thought or the beginning of an idea. Why don't you mark all dimensions on the customer drawing with 3 colours?
Red could mean 100% inspection and measurement documentation.
Yellow could be 100% inspection by gauge.
Green could be a sample size - i.e. 1:3 or 1:5 (or whatever) after each dimension.
The colours would/could also signify criticality.
Your customer would then know you'd been over the drawing carefully and given it some thought.
It's just an idea, so any remarks/suggestions would be regarded as a plus rather than critique :bigwave:

I'd definately drop the "official" standard sampling plan.

By the way - it's GORDON with two Os :D
My name is common in English speaking countries, but I'm the only one in Denmark with that name ;)

Suggestion for a revision to your procedure :)

Hi,

I've ben reading yours and Bev's stuff ;

(Bev)"It is also not sufficient statistical justification for recording only a portion of the results to simply point to a statistical sampling plan table."

O.K. (I think)

More importantly, WHY are you determined to record some smaller portion of the values? you seem to be very adamant about it, so if we can get to the heart of that question, perhaps we can provide better guidance as to the real justification for it. What is it about a recording a portion of the results that is more valuable - or less wasteful - to you than recording all of them, or just the min/max values?

"I" am not the one making these rules. There are procedures that B.T. had in place before I came here. If they are spinning "their" wheels by recording useless information, then I need to tell them to stop. But...

According to AS9100-2009, 7.1 (c & d) and Procedure 7.1.2-RM, Risk Management and the "requirements of the organization"???

I went out on the floor and questioned some of the guys about how they determine these things since you all put the question to me. They are writing down "critical dims" for parts with less than .002 tolerance and using the 10 % method. I asked one guy, after picking up a part, "which one is this?" He smiled and shrugged??? I asked "How do I know you aren't writing down the same piece over and over?" He says "I guess I'll have to write it on the part". O.K.

Now...How does he justify the sequence? We came up with dividing the AQL number under 1.0% into the lot size. i.e. 90 parts '/. 13=6.92 or every seven parts. O.K. But now, how do we justify using the AQL 1.0% ??? How do we determine that number?

(Bev)"additionally the wording "first part, during and after machining" doesn't clear up the instruction. Are you trying to say that each part will be measured after it has completed the machining operation, even if other parts are not yet complete? In other words you are saying "don't wait until they are all done before measuring them"? No

I fixed that part to be more specific,

Gotta go...will check in tomorrow...Thx..qms:bigwave:

AQL is roughly the fraction defective that would usually be accepted. If AQL = 1, then most lots with 1% defective would be accepted. The defect rate that will usually be rejected is several times higher. This doesn't really seem to be what you want.

If you want to be (fairly) sure that (most of) the parts are good, then this thread on reliability and sample size gives some good advice. http://elsmar.com/Forums/showthread.php?t=33830 (Note that the sample sizes are nearly nearly independent of sample size. So picking a fixed samlpe size - like "60" - is statistically more valid than picking a fixed % -- like "10%".)

If you can record & analyze the actual numbers, then you might be able to justify smaller sample sizes. For example, 30 good parts all near the center of the specs would be much better than 30 good parts all hugging one spec limit.




It almost sounds like you are saying


"we test all the parts because it is valuable and important that all the parts are good."
"we record some of the results just because it was written into the procedures."

This might be a good place to try some root cause analysis to find out why the procedures are set up this way - like "5 Whys". "Why do we record just some of the data?" ... "Then why ...?"


Tim F

"I" am not the one making these rules. There are procedures that B.T. had in place before I came here. If they are spinning "their" wheels by recording useless information, then I need to tell them to stop. But...

I went out on the floor and questioned some of the guys about how they determine these things since you all put the question to me. They are writing down "critical dims" for parts with less than .002 tolerance and using the 10 % method. I asked one guy, after picking up a part, "which one is this?" He smiled and shrugged??? I asked "How do I know you aren't writing down the same piece over and over?" He says "I guess I'll have to write it on the part". O.K.


I'm getting the notion that B.T. is extremely like the following scenario:

Start with a cage containing five monkeys. Inside the cage, hang a banana on a string and place a set of stairs under it.
Before long, a monkey will go to the stairs and start to climb towards the banana. AS soon as he touches the stairs, spray all of the other monkeys with cold water.
After a while, another monkey makes an attempt with the same result all the other monkeys are sprayed with cold water.
Pretty soon when another monkey tries to climb the stairs, the other monkeys will try to prevent it.
Now, put away the cold water. Remove one monkey from the cage and replace it with a new one. The new monkey sees the banana and wants to climb the stairs. To his surprise and horror, all of the other monkeys attack him. After another attempt and attack, he knows that if he tries to climb the stairs, he will be assaulted.
Next, remove another of the original five monkeys and replace it with a new one. The newcomer goes to the stairs and is attacked. The previous newcomer takes part in the punishment with enthusiasm! Likewise, replace a third original monkey with a new one, then a fourth, then the fifth. Every time the newest monkey takes to the stairs, he is attacked.
Most of the monkeys that are beating him have no idea why they were not permitted to climb the stairs or why they are participating in beating the newest monkey.
After replacing all the original monkeys, none of the remaining monkeys have ever been sprayed with cold water.
Nevertheless, no monkey ever again approaches the stairs to try for the banana. Why not? Because as far as they know that's the way it's always been done around here.

And that, my friends, is how a company policy begins.

Maybe you should get it printed and hand it out when talking to your co-workers :D

Good Morning G. C. ")

That was great!! And that about sums it up around here!! I was wondering when i started here why the last auditors left...there is a lot of resistance to change by the management and employees. They say they want it, need it and must have it to go forward. When I try to implement it I get all kinds of reasons about "that's always how its been done around here" and " I don't see the need to change that because it's how we do it". Obviously, its not working anymore. I can only go as fast and as far as "they" will let me. There is a lot of resistance to this "sampling plan" testing. I have a QMS meeting this morning and of course this will be the main topic, as I will not let this go until it gets resolved. It will also be the topic next week if its not resolved and I get another meeting! (Bumping my head against the wall).
I'll check in later...Thanx...qms

Hi GORDON...:D

I left everything the way you had changed it and tried to answer your question with this...

5.1 MONITORING, MEASUREMENT AND ANALYSIS
The appropriate department employee or authority shall inspect the part produced or the product supplied to verify conformity. Parts produced shall be inspected for conformity to customer print requirements for First part, during manufacturing and as a final inspection. Any critical dimensions, (.002 tolerances or less) as specified by QA, shall be monitored and measured by the operator during each operation. The customer's critical requirements, the inspection results, and numbering sequence for each part inspected shall be recorded on Operator Inspection Sheet Form 7.5.1.3-10 and the sequence number written on the correlating part with a black Sharpie marker.

I had already changed it to this yesterday:

5.1 MONITORING, MEASUREMENT AND ANALYSIS
The appropriate department employee or authority shall inspect the part produced or the product supplied to verify conformity. Parts produced shall be inspected for conformity to customer print requirements for First Article, during processing, and Final Inspection. Critical dimensions with tolerances at .002 or less shall be monitored and measured by the operator for every part. Print minimum and maximum requirements, tolerances, inspection results, and numbering sequence determined by QA according to customer requirements, shall be recorded on Form 7.5.1.3-10 and the sequence number marked on the correlating part with a black Sharpie marker.

Either way, they both sound about the same to me. But I still have the problem of validating "determined by QA or as specified by QA"...right?:confused: Where did QA get their info? "They" tell me the customer has not specified any requirement other than the print. So, how much authority does QA have making this rule?

AS9102 states (regarding FAI) "In the absence of any contractual requirement, compliance is not mandatory. However, the supplier (that's us) must have a process and should utilize AS9102 for guidance." If it works for the 1st Article, why not the rest of the parts? The Scope of this standard states, "The purpose of this standard is provide a consistant documentation requirement for aerospace components."

Am I mis-interpreting this? AS9100, 4.2.4-"Records shall be established and maintained to provide evidence of conformity..." 8.2.4 Evidence of conformity with the acceptance criteria shall be maintained."
Our "acceptance criteria" is the customer's print requirements and therefore their release of the product. Our records provide the evidence of conformity according to the customer's print requirements. We do not use "sampling inspection" as a means of acceptance.

Almost time for my meeting...gotta go...qms

That was great!! And that about sums it up around here!!

I thought you'd be needing a "pick-me-up" so that's why I sent the "policy" story :D
I was being serious about you copying and printing it. Maybe not handing it around, but at least have it on your desk ;) Even in the tight-xxxxx organization ifthere isn't any humour it's time to look for a new job.

If management is asked to make a decision it's usually easier to say "No" than "Yes" or hum and haw and avoid answering directly. Therefor don't ask and do what you feel should be done. Then management, if they don't agree, have to come out into the open if they want things to remain at status quo.

Don't forget - we're probably quite a few by now that will want to know what happens. :yes:

A very bad translation of saying by a Danish poet (Piet Hein) is:
"If you always do what you've always done,
You'll always get what you know must come".

Gordon's right about going ahead and doing. As a "young puppy engineer" I was told, "It's always better to beg for forgiveness than to ask for permission."

Gordon's right about going ahead and doing.

Good grief Walt - thanks :agree:
Can I print, frame and hang that up on my wall? :lmao:

Well...that's another meeting skipped, second week in a row...so much for "management commitment"...:frust:

Guess I'll just have to take Walt up on his statement and get things moving myself...:whip:

There is one person "above" me who will have a cow, a horse, and a litter of kittens, that I didn't ask before proceeding. A lot of what needs to be done around here is with the machinists and making them aware of the changes and what their part is, in the scheme of "QMS".

My husband and I like to use the saying; What's the definition of insanity? "To keep doing the same thing over and over again and expecting a different result"...:yes:

P.S. Did anyone have any comments about my last post?
:thanks: QMSLADY

AQL is roughly the fraction defective that would usually be accepted. If AQL = 1, then most lots with 1% defective would be accepted. The defect rate that will usually be rejected is several times higher. This doesn't really seem to be what you want.

If you want to be (fairly) sure that (most of) the parts are good, then this thread on reliability and sample size gives some good advice. http://elsmar.com/Forums/showthread.php?t=33830 (Note that the sample sizes are nearly nearly independent of sample size. So picking a fixed samlpe size - like "60" - is statistically more valid than picking a fixed % -- like "10%".)

If you can record & analyze the actual numbers, then you might be able to justify smaller sample sizes. For example, 30 good parts all near the center of the specs would be much better than 30 good parts all hugging one spec limit.




It almost sounds like you are saying


"we test all the parts because it is valuable and important that all the parts are good."
"we record some of the results just because it was written into the procedures."

This might be a good place to try some root cause analysis to find out why the procedures are set up this way - like "5 Whys". "Why do we record just some of the data?" ... "Then why ...?"


Tim F
Thanks Tim,
I will do that and I did look at your links...I printed out the one from Reliasoft. I have a software program(trial) that has the ability to do this. I just didn't know what to put where or how many to put in for a sample or for acceptance. I have managed to understand some of it. It will print out the OC, ASN, AOQL, etc. and has the ability to "match the plan". It has many choices that I'm not sure of choosing. Like "single, double, & multiple" with "switching-limited, switching full, Reduced, tightened, normal...and so on. When I choose to edit the program there are more choices. It will let me put my own AQL and Sample size instead of choosing it for me.

I get confused when I read the charts afterwards, I don't know if it's telling me how many will fail or pass. Like under the AQL .95% it will say something like .0023456???? How do I know what number should be there? I keep playing with it and reading all the info I can to better understand what to put in the right places and choose the right catagories. Like Defective units or defects per unit or both. It has choices for ANSI Z1.4 and 1.9, which, I'm told, that is the specs we should be using. But I can't get anything on them without paying for it. Around here that's like asking for ice water in the desert. I'm looking this print out over and it is helping me to choose better, especially with your other comments earlier...so...Thanks again...QMSLADY ")

Let's take step back. If you aren't doing sample inspection you don't need to know how to use an AQL for this situation. PERIOD.

Your original question was how to justify - statistically - only recording 10% of the measurements when you always perfrom 100% inspection. This has NOTHING to do with sampling. Your company has simply always done this. I'm sorry, but you cannot justify an irrational non-statistical choice by attempting to wrap it in a sampling table. The fact is - as you have stated - that your company just wants to record 10% and be done with it. Fine. Just tell your auditor that. any attempt to make it sound like you have statistical rationalization will only trip you up.

Simply write into the procedure that you inspect 100% of the parts. The machinist will record the first part and every 10th part after that. Keep it simple. If your auditor has a problem with that, then you will have your leverage to change. The auditor shouldn't have a problem with it although he may find it a bit different than what he is used to....

If you keep trying to somehow justify it with sampling tables or whatever, you will only get the auditor's **** detector pinging and you will have a very bad day...


If you choose to continue to learn about AQLs and sampling (not a bad thing) you might want to take it to a new thread...However, if your company is having trouble with the whole 10% recording thing, I doubt very much that it will be an easy go to get to sample inspection. Most Aerospace companies require that you have real SPC and can prove capability prior to allowing sampling in lieu of 100% inspection.

There is one person "above" me who will have a cow, a horse, and a litter of kittens, that I didn't ask before proceeding.

Great. He can then quit his job and be a farmer. ;)

It looks like we are getting somewhere.

AS9102 states (regarding FAI) "In the absence of any contractual requirement, compliance is not mandatory. However, the supplier (that's us) must have a process and should utilize AS9102 for guidance." If it works for the 1st Article, why not the rest of the parts? The Scope of this standard states, "The purpose of this standard is provide a consistant documentation requirement for aerospace components."The customers tell us what they want. If they do not, we can design our inspection plans as we see fit for the need, cost, and the risk of not inspecting enough. The word should and the clause In the absence of any contractual requirement, compliance is not mandatory give you freedom to do that. Am I mis-interpreting this? AS9100, 4.2.4-"Records shall be established and maintained to provide evidence of conformity..." 8.2.4 Evidence of conformity with the acceptance criteria shall be maintained."If you are inspecting 100% because you choose to, then recording 10% is okay. But if you are required to do an inspection to verify conformance to specifications - at whatever point, and however many - 8.2.4 wants evidence of that conformity. Not evidence that every 10th part conformed. Inspect one piece, record one piece. Inspect 1,000 pieces, record 1,000 pieces. This is evidence of conformance; you are doing 100% inspection for some valid purpose; it stands to reason you will make a record of performing that inspection - and did not send out a flawed part - 100% of the time.

Iin such a case, I would never use "sampling" to describe any of this, because it simply isn't sampling.

I hope I made sense here.

I have found in aerospace that often you are not required to record 100% of hte values from a 100% inspection to document conformity. *I* have used the min/max approach with a column for number of inspected parts, number of accepted parts. *Most* auditors and companies I have dealt with accept this. (Of course, I've had lot sizes in the hundreds, so it was pretty onerous)

You mean like this one I attached?

I only wrote the procedure because the "Training Auditor" said I needed an SPC to justify these actions. Why couldn't she have simply said what you and Jennifer just did? :mad:

"If we don't sample, we don't need a plan"...simple enough...I'll go over it again...Thank you

:ca:I have found in aerospace that often you are not required to record 100% of hte values from a 100% inspection to document conformity. *I* have used the min/max approach with a column for number of inspected parts, number of accepted parts. *Most* auditors and companies I have dealt with accept this. (Of course, I've had lot sizes in the hundreds, so it was pretty onerous)I take the risk of getting it wrong when I talk of aerospace requirements because it's been 10 years since I worked in an aerospace QMS. I take the cautious route when advising to record what's inspected because, well, it's aerospace. If we're not required to do that, it should be clarified in some way I would think. I would hope... I do hope not to lead anyone astray.

When working with steam plant systems on board ship and salt water boundary systems on submarines, we had components that were 100% tested. They were individually marked with the date, location and lot number of the test, not only to "prove" they conformed to requirements, but in event of failure via the investigation the other parts in that lot could be found and dealt with as needed. Of course this turned a valve into a very expensive valve when ot could have been the identical counterpart of a $18.95 valve. But the evidence of conformance brought the value as the quality program demanded it. So it goes with inspection planning. Determine the needs, then meet the needs, and you'd better make sure you can show you do. :ca:

You mean like this one I attached?

I only wrote the procedure because the "Training Auditor" said I needed an SPC to justify these actions. Why couldn't she have simply said what you and Jennifer just did? :mad:

"If we don't sample, we don't need a plan"...simple enough...I'll go over it again...Thank youWhat kind of auditor said exactly what please?

Was this auditor from a certification body, an internal auditor or what? Please share the requirement and description of the problem as it appears in the write up.

O.K.

It didn't take as long as I thought it would...so here goes again...hopefully we are done here...and I can visit under more desireable circumstances:rolleyes:

Going home....thanks everyone...Ginger (formerly qmslady):bigwave:

What kind of auditor said exactly what please?

Was this auditor from a certification body, an internal auditor or what? Please share the requirement and description of the problem as it appears in the write up (Jennifer)




Good Morning Jennifer,

I just read through the threads and don't see the one where, I thought, I explained...

I am the QMS Rep, and the Lead Internal Auditor here, as well as, the Tool Crib Manager among other things.

They hired me to get them ready for certification. I went thru this process at my last company as a Secondary Auditor after going thru the class at Tulsa Tech University. I audited the QMS there and some of the Lead Auditor's work as well.

They had an Auditor/Teacher from TTU come and give classes to prepare the employees for auditing too. She helped to write the procedures and does "pre-auditing" before certification to see what needs to be changed or fixed.

We became friends and she helped me alot with my auditing. We passed the audit and were certified last Nov. 2008 with 9 minors. Five we fixable immediately and they gave us 30 days to fix the other 4. They were all documentation and records errors. She helped us clear these up before the 30 days and then we passed.

She is on the Auditors Board at the college, as well as, a teacher there. I may not have been clear with her as to what I was trying to accomplish. We were discussing the new revision and in process inspection documentation.

I told her how we did it and she said that we needed a "statistically valid" reason for how we did this. When I asked her how we did it at the last company, she only said they "had a written procedure for and AQL of 1.0".

She also said I needed to learn about ANSI Z1.4 and Z1.9 and that for a price she come and teach me and the inspectors, then she went on vaction...:mg: and left me with that.

That is how this whole thing got started. If she had simply said, "If you don't do sampling as a criteria for acceptance then you don't need an SPC." I may not have even written a procedure at all.

But nothing happens by mistake, for me anyway, and I have gained knowledge I would not have otherwise had, since coming to this site. I need to move forward, continual improvement and all that, as the management rep. And, as Auditor, start auditing this company to show them how many things need to change.

Thanx for everything...did you look the last edited procedure over? Anyone?

Ginger:bigwave:

The risk we run into with consultants is that their advice may be more than we truly need - they may be advising something that they think is a good idea, even if it's not really required. This auditing teacher may or may not have done that. The overall impression I am left with is that there was inadequate communication going on.

In the case of a certification audit, the process owner should be able to clearly describe or show the requirements and how they are being met. In the case of an inspectionplan design, such requirements would start with the customer. The customer either dictates the requirements, or accepts how you have described them in your QA manual/process documents...without issue. Boom, that's it.

I am relieved to see all reference to sampling taken out of the process document. The procedure seems fine so long as it meets your customer, business and industry needs. When this consultant said you needed a statistically valid basis for writing down only occasional inspection results, it's fair to ask why she thinks it's necessary. When probing like that it is important to know what you are asking: Is the question about inspection design, or the record keeping requirement?

It might help to just base the question on the standard's clause. You can hold the standard in your hand, and stand your ground with this woman or a registration auditor and ask, "Gee where does it say XYZ is required?"

No doubt this woman would happily explain ANSI Z1.4 and Z1.9 to you for a fee, but although it is a subject you would be wise to understand you don't need her paid services to teach it.

Learning how to push back and drill down for more information can take time, and success will vary depending on the type of people each of the parties are. I look forward to hearing about your adventures as you go forward, and disentangle yourself from the briar patch that can come with consultants and QMS management.

Thanx Jennifer,

I am keeping this thread open for awhile...just in case...and I will look for a thread on auditing techiques and help. I do have a few questions already
:thanx: moving on...Ginger

You're welcome Ginger.

When you have a question on a specific subject you can search for threads using the function in the toolbar - see "Search" in yellow font.

I am an internal auditor (but not for aerospace) as are plenty of others here, so ask away.

After going through the suggestions given so far I hope m'lady has found the right answers. If doubt exists I would like to add a few points. But before that I need some clarifications. You have mentioned (correct me if I am wrong)

a) (In the 1st post) "we check 100% all dimensions"
b) (In the 2nd post) "we check all dimensions 100 % for SOME customers"
c) Also (in the 2nd post) " we always check criticals, especially on parts with known problem specs."
d) (in the 1st post) "... only want to write down a certain percentage for our in-process inspection documentation"

From the above do I understand that
1) You check all dimensions on 100 % of the lot for all parts for some customers, OR

2) You check only critical dimensions on 100 % of the lot for all parts for some customers OR
3) You check all dimensions on 100 % of the lot of only the critical parts for some customers.
My next question:
4) Do you find rejections/deviations in your in-house 100 % measurements?
If yes have you analysed, determined the cause, taken corrective action and found the same effective? If there are rejections/deviations the process capability of your machines may not be adequate. (Gordon has already implied that)
5) If you have no deviations/rejections during 100 % check, does the customer report rejections/deviations?

Why am I asking these questions? Because you say that you 'need to write a procedure on our AQL...'. Since you are machining components for aerospace applications the requirements may be critical.The key to the requirement is to study the process capability of your machines (if you havn't already done that) and decide on CPk figure e.g. 1.67 that would give defectives in terms of PPM rather than AQL in terms of %age.

As for the recording of readings you can adopt any figure as long as no customer has stipulated any particular AQL.

In my experiences with Z1.4 sampling both when mandated by customers or internally determined, it just felt a bit artitrary, as if someone threw a dart backwards over their shoulder, hit the policy dartboard, and turned around and said, "OK, AQL 0.65 it is!"

Like Jupitor, I prefer closely monitoring the process (preferably in real time) using a tool like Cpk or Ppk with corrective actions trigggered below a certain value on the index that is well above 1.0. This way, instead for looking for non-conformances after the the product is finished, you anticipate them before they occur.

My only caveat is that this approach works much better with large quantity production runs that provide large statistical populations than for short-term low quantity runs.

After going through the suggestions given so far I hope m'lady has found the right answers.

I'm not going to quote everything Jupitor wrote :)
I was about to write that I couldn't have written it better! Truth be told, I couldn't have written it a tenth as good :applause:

I appear to get misunderstood at times (I no longer regard English as my "native tongue" having lived in Denmark most of my life), so I'd better stress that it is a compliment from me to Jupitor.