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Are Special Characteristics mandatory?

Casana

Blueberry Nut
#1
Regarding element 4.2.3.2, do we HAVE to identify Special Characteristics at all? As I read the standard, I don’t see the word “SHALL” in that paragraph or the Note that follows it, but a colleague insists that we HAVE to identify these.
Our customer is not one of the Big 3, and did not specify any special characteristics. What they’ve specified in their contract would not make sense for us to track and measure, all they care for is to receive matching pairs of our product; they have no interest in what we would consider “key” processing characteristics.

Also, if we DO have to identify these special characteristics, aside from putting a little mark on the Control Plan, would we need to do anything else? It seems like a silly practice, to be honest… what would that little mark do, anyway? We still need to test and pass all specs regardless.

Thanks for any and all input!
 

Stuart Andrews

Involved - Posts
#2
Originally posted by Casana:
Regarding element 4.2.3.2, do we HAVE to identify Special Characteristics at all? As I read the standard, I don’t see the word “SHALL” in that paragraph or the Note that follows it, but a colleague insists that we HAVE to identify these.

--> 4.2.3.2 QS-9000 Third Edition does state "shall"

Our customer is not one of the Big 3, and did not specify any special characteristics.

--> Have you already identified the Special Characteristics for the Big 3? If so, why adopt two systems if you've already got the information? If you haven't, why haven't you done the FMEAs, which will give you your information.

What they’ve specified in their contract would not make sense for us to track and measure, all they care for is to receive matching pairs of our product; they have no interest in what we would consider “key” processing characteristics.

Also, if we DO have to identify these special characteristics, aside from putting a little mark on the Control Plan, would we need to do anything else?

--> Yes! Your Flow Charts, Engineering Specification, Product Drawings, Process Instructions etc all require the symbol marked against the part of the document that the Control Plan has referenced.

It seems like a silly practice, to be honest… what would that little mark do, anyway? We still need to test and pass all specs regardless.

Thanks for any and all input!
If your customer is completely non-automotive, and they don't want Control Plans etc then don't do it! QS-9000 is an automotive standard - but as I said why adopt two systems, unless it's more efficient. Make sure your procedures reflect the option for either system if you do!

[This message has been edited by Stuart Andrews (edited 01 June 2001).]
 
J

J.R. Strickland

#3
If your customer has NOT designated any SC's, you do NOT need to identify any. The "shall" in 4.2.3.2 refers to when the customer design records indicate an SC by their symbol. In fact, we have been told by customers (GM and Ford) that they want no SC designation on their drawings because it implies added cost or that this characteristic may have excessive variation and therefore need special controls.
 
Q
#4
Hi, I also get confuse for implementing QS-9000. Today, in my manufacturing, we have some discussion about SC implement in control plan. For example, we do have our SC for Hardness characteristic. This characteristic is controlled by Heat Treating Process. We don’t understand
1. Heat Treatment Process have to be defined as “Special Process”?
2. If yes, what about trained personnel at this process, require or not?
3. Do we have to identify SC symbol mark in every step of operation in H/T control plan?
4. What about some Job Instruction and Monitoring check sheet related to H/T? Do we have to put SC mark on those document?

We would like to response to SC as simple as possible, but at least comply to requirement and customer need.
Thank you
QSMSO
 

Stuart Andrews

Involved - Posts
#5
Firstly, I would like someone to clarify this point for me - If a customer hasn't identified Special Characteristics then "we" (the supplier/sub-contractor) should identify them. To do this must we first complete the FMEAs?

If the above is correct then QSM read on!

1.When you complete the FMEAs these will tell you if Heat Treatment is an SC.
2.Every process should be controlled by trained personnel.
3.I would identify the SC only at the point where the process is measured or the characteristic that needs special control is mentioned in the control plan. You don't have to mention the SC at every step - because not every step will have an SC.
4.Yes, if you have identified SCs then the symbol should be cross-referenced on the significant documentation.

Hope this helps!
 

Marc

Captain Nice
Staff member
Admin
#6
The first source of 'critical' or 'special' characteristics is the print. There may be characteristics determined during design to be critical from experience or such. If followed correctly, the design FMEA will also address these.

While it is not particularly unusual, typically items on the Design FMEA are not relevant to the process FMEA - typically they don't carry over.

Remember that items on the design FMEA typically address the product in service. Examples: What if the air bag fails to deploy? What if the air bag deploys off-center?

On the opther hand, a process FMEA typically addresses issues of processing the product. Examples: If dimension A is > 0.005mm the part will not fit and if < 0.004 joint will rattle (giving you a tolerance) {an example of a possible flow-down from a D FMEA}. Or part A123-456 not properly installed in sub-assembly. I remember one where you had to cut metal - a shaft. It had a 'high' OD spec at one point in the process which was determined to be critical because if it was exceeded this dimension it would either not fit into or would jam the next machine which further cutting metal on the rod (moving towards finishing). Jamming the next machine was a possible 20+ hour down time. So - it became, at that step in the process, a critical characteristic even though that characteristic was changed in the next operation.

While you are looking at the function of the product, you are also looking at the assemply process and the effects on steps further down in the processing as well.

So - the bottom line is critical characteristics may pop up anywhere from a brainstorming FMEA meeting to a reaction to a processing 'disaster' experienced.

last of all I have seen many cases where the customer specified no critical characteristics even when they were design responsible. There were none on the print nor in the contract or elsewhere. My experience in QS registrations is the auditors do expect to see at least 1 critical characteristic identified by you - the supplier. And if you told an auditor that the customer had none and you didn't have any either - well, you had one heck of a lot of talking and explaining to do even if what you supply is relatively simple.

If it's not an automotive product and your customer doesn't require any, no big deal. But if it's automotive they usually want to see that you have at least 1. And an FMEA may have 1 line item or it may have many line items. Total numbers is less important than assurance that you have looked at your product through the eyes of the FMEA.

A last comment - or rather a question - if you have defined no 'critical' characteristics, do you have any inspections and/or tests? If so, are none of them critical?
 

Marc

Captain Nice
Staff member
Admin
#7
-> 1. Heat Treatment Process have to be defined as "Special
-> Process"?

Heat treat is a special process I believe. I know Ford has its own heat treat spec.

-> 2. If yes, what about trained personnel at this
-> process, require or not?

Yup - trained personnel.

-> 3. Do we have to identify SC symbol mark
-> in every step of operation in H/T control plan?

I would think so in some way. The control plan has a column for that, doesn't it?

-> 4. What about some Job Instruction and Monitoring
-> check sheet related to H/T? Do we have to put SC mark on
-> those document?

I don't know that there is a requirement for this - I'm not sure, honestly, but I don't think so.
 
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