Composite Materials Machining - Out of Specification Holes in Parts

[Corsair]

From the quality perspective, I need an approach to communicate to a supplier to adrress and to control the out of spec- dimensions for our composite parts.

Do they need to investigate under a DOE?

Or a process capabilities for their current machining techniques will be a better approach?

They submitted their FAI on concessions for Hole Dim- (u/s), Rad- (u/s) and Hole Position (u/s).

Machining on Composite could be a problem, any experience from past threads on this subject?

 

[Jen Kirley]

Re: Composite Materials Machining - Out of Spec-.

Good day Corsair,

When my employer experiences supplier issues we require an 8D analysis and action plan from them. We don't dictate DOE etc., but we can accept/reject the 8D based on our estimation that their approach and plan are sound.

Does this help?

 

[Corsair]

Good Day to you Jennifer, and Happy Memorial,

Agree the 8D tool should be the rigth approach.I suspect that they may be using the wrong tools to machine composite.

An evaluation from engineering may also help.

 

[Jen Kirley]

Thank you Corsair, your suspicions may be well founded and it's fair to require them to do an analysis that includes that in its examination of the problem. In this way you may manage to help "shepherd" the supplier into the desired end result. You might even open a dialog and remark on the idea of machining using the wrong tools, thus planting the idea in their heads. We just can't really mandate such things - outside the contracting process, that is.

 

[Corsair]

I will recommend this approach to my boss.
I will talk to my buyer too.

 

[Jim Wynne]

From the quality perspective, I need an approach to communicate to a supplier to adrress and to control the out of spec- dimensions for our composite parts.

Do they need to investigate under a DOE?

Or a process capabilities for their current machining techniques will be a better approach?

They submitted their FAI on concessions for Hole Dim- (u/s), Rad- (u/s) and Hole Position (u/s).

Machining on Composite could be a problem, any experience from past threads on this subject?

What do you mean when you say "They submitted their FAI [first article inspection] on concessions..."?

Has this supplier done work for your company before? Do they have experience in machining composite material? Why would they not know what tools to use? Are your specifications realistic? Will the parts work in their current state?

There are a lot of questions that need to be answered before you can approach the supplier for corrections. Now is not the time for an 8D or any other sort of formal corrective action, or at least it appears that way. Talk to the supplier and find out what's going on. Review your specifications and find out what's really needed. You should be engaging the supplier in problem solving, but don't do it before (a) you're sure that the specifications represent what's needed and (b) what you're asking for is reasonably possible.

 

[Corsair]

Re: Composite Mater and decide whials Machining - Out of Specification Holes in Parts

The parts were shipped under concessions because we going to evaluated internally and we will decide whether can be use or not.

The supplier is qualified by Airbus to do work on composite and yes our spec's
are realistic.
Too many top notch composites companies are having the same problems like ATK & Triumph to name a few.

 

[bobdoering]

I find it interesting that they would supply product with undersize holes. There are two things that make me curious: did the material move (the only real issue that would be unique to composite machining) or did they have the wrong drilling process? Why didn't they do a finish drilling process to the final hole size? Were they rushed and did not have time, or did they pick a drill that was the wrong size and could not get the correct size drill? Did they need a finishing drilling operation to make the hole correct? Was this an SPC'ed dimension? If so, what does the chart look like? Usually, holes start big and either get smaller (tool wear) or get bigger (dull drills do ugly things, that is why drilling is not "precision machining" by definition.)

Do they have conflicting (shop versus final inspection, pins versus air gage or CMM), inadequate or inappropriate gaging for the hole size?

Depending on the callout, the small hole may have affected the location - so the focus may be the hole size issue.

Also, I find it interesting that the concession did not at least hint as to what the problem was and what they are going to look at to resolve it. Hole sizes really should not be a stumper.

 

[Corsair]

Do not know the exact details for the machining process,seems odd to me
but they did pass the qualification by Airbus for this kind of work. The supplier may have to do some R&D work on this.

From the QA perspective we going to request a root cause analysis and issue a CA.