Multiple Machines & Fixtures - PPAP run on all 6 machines using all Tombstones?

[Garry]

We have a part that gets CNC machined on a tombstone with 6 banks and each bank has 5 cavities (= 30 parts per tombstone/Fixture). We do have 4 Tombstones/Fixtures. We are planning to use those 4 Tombstones on 6 CNC machines. The machines are basically all the same (brand and model). Eventhough they are all the same, my point is that I think they are not (Age, Wear etc.). To my question: Does the Trial-run for PPAP have to be done on all 6 machines using all Tombstones or is it ok to run it on 2 or 3 machines only.

 

[Howard Atkins]

excuse my ignorance but what is a tombstone, I assume it is not the usuall definition.
Please give more info so I can relate.
Thanks

 

[Garry]

Howard

This is a block of Aluminium (6 faces in this case) that holds one bank per face. The "Tombstone" is basically a fixture for 6 x 5 = 30 parts that sits on a pallet.

 

[Sam]

"Does the Trial-run for PPAP have to be done on all 6 machines using all Tombstones or is it ok to run it on 2 or 3 machines only."

If you are going to use all six machines and tombstones in production, then yes, you have to nclude all in the trial run.

refer to para. 1.2.1, 1.2.2.7 & 1.2.2.13 of the PPAP manual.

Now once this is done ; what do you do to meet the requirements of 4.9.2 of the QS?

 

[Garry]

Contingency Plan

Sam, you basically confirmed what I thought. It just gets even more complex with the use of multiple sets of formtools.

Here is another one:

How about contingency plan. If we identify in our contingency plan that in a case of serious breakdown we swop to a different machine that originally wasn't part of the PPAP? Does this require a PPAP before proceeding?

 

[Howard Atkins]

The real problem as I see it is

). Eventhough they are all the same, my point is that I think they are not (Age, Wear etc.).

If they were the same you would have no problems.

 

[Randy Stewart]

When we went through our PPAP for stampings we covered this issue. If we use a similar press (tonage, hyldraulic, etc.) then we would not have to submit a PPAP package, just inform the customer. However, if we changed the type of press or manufacturing location we would need to resubmit.

 

[A. Stuart Dyer]

The PPAP should be submitted with documentation on each die in each machine and the results submitted. Once the warrant approval is approved you are free to move the die from machine to machine.

If you have 4 machines and four dies, you test each in each, get it all up front to make the rest of your life easier.

On one PPAP we submitted a warrant that said the parts would be produced on XXX machines 1 through 4 depending upon production requirements. Interchangeability is the lifeblood of industry and they do respect it because it does lower final costs.

Imagine this scenario:

We have a PPAP for die #1 that is only approved to run on machine #2. The customer doubles the order and we say to them, sorry, it is only approved for machine #1???? In the real life, what will they say, "I don't give a flying finger where you produce it" just give me the parts.

In real life we can choose to follow protocal to the tee and refuse their order, or we can add the product to the second machine and make the customer happy.

This is why I would say do the work up front so you don't have to fight the fires further down the line. Sure it might take some extra effort on the front end, but you don't have to fight the fires on the rear end.

Aal...

 

[Dawn]

Do we need to re-ppap or dont we?

Page 11 of the pap blue book states we must re-ppap (no. 3); when we reconstruct or modify a machine to increase the performance.

Page 14 (no.3); states we dont need to reppap when there are changes in equipment if we maintain the same process flow. Examples are new equipment, replacement.

A bit contradicitive wouldnt you say?