Hi friends, how do you structure your PFMEAs in your company? by process or by product or both?

Firstly, I introduce mine:
I'm in IC assembly and Testing Subcon company, we have over 90 customers and all kinds of products -- PDIP, SOIC, BGA, SIP, Stacked Die..., now our PFMEAs are by process from material receiving to shipping. One problem we met is how to rank the Severity, products application are quite different, some for automotive, some for computer..., and really headache.

Hi friends, how do you structure your PFMEAs in your company? by process or by product or both? Firstly, I introduce mine:
I'm in IC assembly and Testing Subcon company, we have over 90 customers and all kinds of products -- PDIP, SOIC, BGA, SIP, Stacked Die..., now our PFMEAs are by process from material receiving to shipping. One problem we met is how to rank the Severity, products application are quite different, some for automotive, some for computer..., and really headache.

If you've chosen to do a modular/process approach to PFMEA, rather than having a specific FMEA for each product, then rankings must be the highest/most critical application for that process step.

Hi friends, how do you structure your PFMEAs in your company? by process or by product or both?

Firstly, I introduce mine:
I'm in IC assembly and Testing Subcon company, we have over 90 customers and all kinds of products -- PDIP, SOIC, BGA, SIP, Stacked Die..., now our PFMEAs are by process from material receiving to shipping. One problem we met is how to rank the Severity, products application are quite different, some for automotive, some for computer..., and really headache.

Hi Allen,
If you designed the product, it will fall under DFMEA and if the product design and functionality varies, you might want to categorise by product. The process to turn the design into the end product and eventually shipped to customer will naturally fall under the PFMEA and in this case, you might want to categorise by process. Hence, you might end up having both the DFMEA and PFMEA.

Since you are in the IC assembly and testing subcon (OSAT - we are in the same industry), your customer might own the design or dictates the process flow, in this case, your customer might have both the DFMEA and PFMEA, you might want to check it out with them for a copy and from there, you should have no problem with ranking the severity. On the other hand, your product or test engineer would be the best person to advise on the severity as they are equipped with the product knowledge.

thks.
jeffrey.

Hi Duke Oke,

Thanks! If rate them with the worst case, possible of a lot of additional controls for those non-critical products, and those customers never provide so high price ^_^, how do you deal with this?

...If rate them with the worst case, possible of a lot of additional controls for those non-critical products, and those customers never provide so high price ^_^, how do you deal with this?

Depending on whether you use common equipment for all parts using the same process --
Common equipment would use the same/similar machine controls, regardless of the product being made. Your PFMEA (and by extension the control plan) may specify that some controls or inspections apply to certain products and not others for whatever applicable reason. (I like to document those reasons in our documentation).

If the equipment or process is product-specific, it may make more sense to take the generic process PFMEA and customize it for that product.

We use both approaches when developing our (process-based) documentation.

B.G. Wiehle
PFMEA coordinator

Hello Allenlee:

We did our IC assembly and test PFMEA's by process and not by product. We took the Semiconductor Supplement (to TS 16949) guideance in that PFMEA's can be done by product family. We acutally took it a little further than that and did our PFMEA's by process.

The Semiconductor Supplement suggest considering supplements to your PFMEA's for differences by product families.

Also, we chose to do our PFMEA's based on auto requirements since they were the most stringent. We scored severity, occurrence, and detection with the auto industry in mind. We decided it was too hard to have a system where some products had greater controls (auto) and some had lesser controls (commercial.) We applied the most stringent controls across the board. If it is good for the auto industry, hopefully it will be good for all customers And there is a cost savings for having standard controls instead of many, product dependent, unique controls.

Regards,

Dirk

Hello Allenlee:

We did our IC assembly and test PFMEA's by process and not by product. We took the Semiconductor Supplement (to TS 16949) guideance in that PFMEA's can be done by product family. We acutally took it a little further than that and did our PFMEA's by process.

The Semiconductor Supplement suggest considering supplements to your PFMEA's for differences by product families.

Also, we chose to do our PFMEA's based on auto requirements since they were the most stringent. We scored severity, occurrence, and detection with the auto industry in mind. We decided it was too hard to have a system where some products had greater controls (auto) and some had lesser controls (commercial.) We applied the most stringent controls across the board. If it is good for the auto industry, hopefully it will be good for all customers And there is a cost savings for having standard controls instead of many, product dependent, unique controls.

Regards,

Dirk

Thanks Dirk,

I know what you are talking about, then how and where do you document your customer's special requirements -- let's say some controls for one customer only? In FMEA and CP or some other document?

Hello Allanlee:

We don't have an customer special requirements. We design all our our product to our own requirements based on market needs, not individual customer requirements. Our customers choose our products from catalogs.

This allows us to have the FMEA and CP document strucutre by product family.

Not sure how to help you. I guess I would put the single customer's requirements in an additional set of docs (FMEA, CP or where ever is best.)

Regards,

Dirk

Hi friends, how do you structure your PFMEAs in your company? by process or by product or both?

Firstly, I introduce mine:
I'm in IC assembly and Testing Subcon company, we have over 90 customers and all kinds of products -- PDIP, SOIC, BGA, SIP, Stacked Die..., now our PFMEAs are by process from material receiving to shipping. One problem we met is how to rank the Severity, products application are quite different, some for automotive, some for computer..., and really headache.

Hello Allenlee :bigwave: ,

Our company is also in the semiconductor industry (automotive). Our production processes are directed to IC probing and final testing.

Our aproach is to globalise the processes. We make our PFMEAs by main processes:
Probing, Final test, Back end...
Receiving, outgoing, QC inspections are included in these processes.
When necessary we make specific PFMEAs (devices, machine) as an encloser to the global process but the intension is for global rather than specific PFMEAs.

Hello Allenlee :bigwave: ,

Our company is also in the semiconductor industry (automotive). Our production processes are directed to IC probing and final testing.

Our aproach is to globalise the processes. We make our PFMEAs by main processes:
Probing, Final test, Back end...
Receiving, outgoing, QC inspections are included in these processes.
When necessary we make specific PFMEAs (devices, machine) as an encloser to the global process but the intension is for global rather than specific PFMEAs.

brutas, thanks for sharing yours. Now what we are doing is to have 2 sets of PFMEAs, one for automotive IC and another one for commercial. Would somebody here from subcon like to share ?

Now what we are doing is to have 2 sets of PFMEAs, one for automotive IC and another one for commercial.

If you're using the PFMEA process to full advantage, and not just as a paperwork exercise, you shouldn't be able to tell the difference between automotive and non-automotive PFMEA processes. The documentation might be different, but the process should be pretty much the same for both categories.