Search the Elsmar Cove!
**Search ALL of Elsmar.com** with DuckDuckGo Especially for content not in the forum
Such as files in the Cove "Members" Directory
Social Distancing - It's not just YOUR life - It's ALL of OUR lives!
Me <——————— 6 Feet ———————-> You

4th Edition PPAP manual - Bulk Materials - Can you guess what this means?

Jim Wynne

Staff member
Admin
#1
I was just idly glancing through the 4th Edition of the AIAG PPAP manual when I ran headlong into the attached brick wall (a scan of a photocopy, and a bit skewed on the page). While the entirety of the page seems to indicate that its author had no idea what he was trying to say, or did know and failed miserably in the execution, I would like to concentrate here on the initial abuse of English at the top of the page, which says, with regard to determination of special characterisics for bulk materials,
If product characteristics/attributes can have normal variation resulting in movement outside their design-intended robust range which results in significant impact, they are designated special and must be controlled by special controls.
Can you provide a brief interpretation of what you think the sentence means?
 

Attachments

Last edited:
D

Duke Okes

#2
Re: 4th Edition PPAP manual--Bulk Materials--Can you guess what this means?

I was just idly glancing through the 4th Edition of the AIAG PPAP manual when I ran headlong into the attached brick wall (a scan of a photocopy, and a bit skewed on the page). While the entirety of the page seems to indicate that its author had no idea what he was trying to say, or did know and failed miserably in the execution, I would like to concentrate here on the intial abuse of English at the top of the page, which says, with regard to determination of special characterisics for bulk materials,Can you provide a brief interpretation of what you think the sentence means?
Actually no different than the definition of special characteristic for anything in automotive. If a specific tolerance/specification/characteristics can have a significant impact on the final product/customer, then that characteristic is considered a "special characteristics" (an automotive industry term) and must be controlled more carefully than other characteristics that are deemed less risk. Usually this means the use of SPC, either on the characteristic itself (the Y variable) or on process variables (X variables) that create/impact this characteristic.
 

Jim Wynne

Staff member
Admin
#3
Re: 4th Edition PPAP manual--Bulk Materials--Can you guess what this means?

Actually no different than the definition of special characteristic for anything in automotive.
Well, it is different, otherwise it would be the same as the manual's definition of special characteristics in the glossary (page 68):
SPECIAL CHARACTERISTICS are product characteristics or manufacturing process parameters which can affect safety or compliance with regulations, fit, function, performance or subsequent processing of product. Refer to customer-specific requirements.
(Emphasis in the original.)

That definition has problems of its own, but never mind. The sentence I'm questioning has specific language about "...normal variation resulting in movement outside...design-intended robust range which results in significant impact..." and control which is to be achieved through "special controls" which your answer doesn't address.

May we have our next contestant?
 
C

Cordon - 2007

#4
Re: 4th Edition PPAP manual--Bulk Materials--Can you guess what this means?

All I see is "normal variation=special controls"...:biglaugh:
 
D

Duke Okes

#5
Re: 4th Edition PPAP manual--Bulk Materials--Can you guess what this means?

Jim Wynne; said:
May we have our next contestant?
Sorry to hear you view it as a contest. I've always thought forums were about dialogue and learning.
 
Last edited by a moderator:
D

Duke Okes

#7
Re: 4th Edition PPAP manual--Bulk Materials--Can you guess what this means?

My point was that it really is no different. I believe they are just trying to point out to process industries (as opposed to discrete manufacturers) that the same principles for identifying special characteristics also apply to them. Sort of like someone on Elsmar the other day who said they were design responsible (under TS), but didn't think that DFMEA applied (I believe because they are producing a bulk material).

There are similarly many repetitive/useless statements in ISO 9001. A classic example is sections 4.1.b and 4.2.2.c ... How could they document the relationship if they hadn't determined it
 

Jim Wynne

Staff member
Admin
#8
Re: 4th Edition PPAP manual--Bulk Materials--Can you guess what this means?

My point was that it really is no different. I believe they are just trying to point out to process industries (as opposed to discrete manufacturers) that the same principles for identifying special characteristics also apply to them. Sort of like someone on Elsmar the other day who said they were design responsible (under TS), but didn't think that DFMEA applied (I believe because they are producing a bulk material).

There are similarly many repetitive/useless statements in ISO 9001. A classic example is sections 4.1.b and 4.2.2.c ... How could they document the relationship if they hadn't determined it
I understand your point. But I pointed out to you the fact that it the sentence in question is demonstrably different from the glossary definition of "Special Characteristic." So if you're saying that you think they mean the same thing, I'd like to hear your justification for the assumption. And I'm not being snarky or argumentative; I value your opinion and I 'm trying to prove a point, which is that the AIAG documentation is the work of Satan:mg: who wants to make us crazy.
 
D

Duke Okes

#9
Here's the rationale based on my view:

Most of the companies that supply automotive industry are supplying piece-parts. In this case the specific functional or dimensional requirements are something that could be measured on the automobile, and affect the function of the auto. This is the typical application of TS and the glossary.

There are companies that supply materials used to make some of the component parts, such as bulk materials used to make rubber gaskets. In this case the specifications for the bulk product are not something that can be measured in the final product/automobile. AIAG has then developed an Appendix in PPAP manual that is specifically written for that type of product, and they have defined critical/special characteristic in terms that make more sense for this situation.

While discrete manufacturing can somewhat easily measure/control the Y variables, and reject any parts not meeting the requirements. In bulk industries the Y variable represents a large batch of product, and it is control of the X variables that create Y that they need to focus more on.

Now as to your second point about AIAG ... the former Big 3 OEMs have proven that they believe they are smart enough in order to tell their suppliers how to do business, but not smart enough in order to be able to maintain their market share in a competitive environment. Anyone who thinks that creating more manuals, standards, procedures, etc. will help make business better is dreaming. Granted there are certain places where procedures (e.g., operating a nuclear plant) or standards (electrical wall outlets) are valuable, they often get in the way of many companies who could do a much better job without them. Sorry ... I'm on a rant.
 
C

Craig H.

#10
Although we do not directly supply automotive, and only posses a 9001 certificate, I think I might be able to make a guess at the rationale here.

The statement about discrete parts versus bulk parts is profound. Instead of looking at rocks in a stream, we are looking at water running over the rocks. Sometimes the water has a leaf in it, sometimes not. We don't like leaves. But, they are naturally occurring (normal) variation. With sampling we may or may not catch a sample with a leaf in it, but we can control the process to try to prevent leaves from getting in, and equipment to remove them if they do.

A lot of people have problems (present company excluded, of course) with the concept of monitoring and controlling a bulk system, and they can present some, um, interesting problems. It may be, as you suggest, Jim, that the author was a little confused as to what, exactly, they were trying to accomplish.

Hope I made at least some sense...
 
Top Bottom