Critique of Process Flow Diagram

John B.

Registered Visitor
Hello all,

I am looking for some constructive criticism on the first two pages of a Process Flow Diagram. This is a new format that our customer is requesting.

Our previous Process Flow Diagrams contained only the process step, description and symbol.

Additional info that might/might not be helpful
1) The part in question might be considered by some to be similiar to a
manual transmission gear.
2) "Wickman" is a six-spindle screw machine.

I can see how this new format will more easily flow into the PFMEA and CP.

Looking forward to your comments/suggestions.

Thanks,
John
 

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V

Valeri

John,

My :2cents:. It looks like they are trying to merge the flow/fmea/control plan and not getting much bang for the buck. I'm at a loss as to why this wheel is being reinvented. Have they changed their fmea or control plan? If they are only using this form, they are missing an enormous amount of information.
 

Miner

Forum Moderator
Leader
Admin
The main advantage of this process flow format is that it identifies all of the incoming sources of variation, product characteristics and process parameters at each operation. This helps speed up the PFMEA process because you identify potential failure modes for each. This is more efficient and effective than the usual brainstorming approach that many take in the PFMEA.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
I like how they treated each tool as a suboperation. It would have been nice to see the inspection section. One thing that is difficult on this style, but handier on the box and arrow type is rework operations. Ok, ok, let's get real, you will have rework - and you know it. Deburr, whatever. Identifying as a part of the process will help you if you have to PPAP, in that if you need to do it you do not need a customer approval each time you do it. Fess it up, tell them how you would rework it, put it in there as a contingency. The style presented is very linear, so it is tougher to deal with decision points. :2cents:
 
V

Valeri

The main advantage of this process flow format is that it identifies all of the incoming sources of variation, product characteristics and process parameters at each operation. This helps speed up the PFMEA process because you identify potential failure modes for each. This is more efficient and effective than the usual brainstorming approach that many take in the PFMEA.

This may help "speed" the FMEA process but are all the risks actually identified, are all process owners involved with this new flow or just a select few? Without a robust FMEA system, you can get yourself into bunches of trouble including liability issues.

John - The customer will get whatever they want. Having said that, however, I have a couple of questions, just out of curiosity, about this "new" process flow; is this an automotive customer and are you still required to produce a FMEA and control plan?

Coury - I did get discussion going:biglaugh:
 

Patricia Ravanello

Quite Involved in Discussions
Hello all,

I am looking for some constructive criticism on the first two pages of a Process Flow Diagram. This is a new format that our customer is requesting.

Our previous Process Flow Diagrams contained only the process step, description and symbol.

Additional info that might/might not be helpful
1) The part in question might be considered by some to be similiar to a
manual transmission gear.
2) "Wickman" is a six-spindle screw machine.

I can see how this new format will more easily flow into the PFMEA and CP.

Looking forward to your comments/suggestions.

Thanks,
John

I have to agree with Bob and Valerie...and.. to reinforce Bob's comment relating to rework, there is no consideration of management of non-conformances which might arise or be identified during the process...While you do identify "inspection" in Operation 20, resultant failures are not accounted for...(or minimally, a link or mention to another process for managing exceptions). Additionally, there is no description of who has responsibility or authority to disposition...or who to contact to disposition, so I wouldn't find this format suitable for a Work Instruction in its current format.

Re: Operation 10 - Receive Material...under Characteristic, you've described an "inspection" activity, which probably belongs under Operation 20. Further to that, what happens if "material" and "Quantity" are not verified?

As identified before...this is somewhat redundant if you are still required to submit a PFMEA and Control Plan. In general, I think it's moving in a desirable direction from the perspective of the operator...but could use further enhancements if it's intended to replace the "Work Instruction" of a sole operator. (Having said that, I find it somewhat confusing that the Operations described are probably being performed by two or more individuals...so it's not just a single "Operator Instruction".

Perhaps this is an improvement from the customer's perspective...I don't know what you were offering them before.

Patricia
 

John B.

Registered Visitor
Man do I love this site! Thanks to all for the critique.

Miner, the “incoming sources of variation” is exactly what our customer is looking for. This is the new part of the process flow for me.

Miner and bobdoering, you are right, there will be rework. I will be adding this contingency to the process flow. Although I am not sure how to do it with this format.

Valeri, yes this is an automotive customer. This process flow will flow into the PFMEA and ultimately the CP. As far as I know the PFMEA and CP have not changed. I believe what the customer is looking for with this new style of process flow is “incoming sources of variation”.

Patricia, yes a PFMEA and CP will be submitted. The “reaction plan” for management of non-conforming parts is on our CP.
This process flow does will not be used as “work instructions”. Individual “work instructions” will be written for each process step. Our previous Process Flow Diagrams contained only the process step, description and symbol.

I will incorporate rework process into this process flow. But, as bobdoering mentioned it would be a lot easier with the old “box and arrow” style process flow.

Any other suggestions?

Thanks to all,
John
 
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