Jack,
The end use of this product is for aircraft cabin pressurization. Yes, I happen
to be very carefull what is called out when my safety when flying is
concerened. Someone needs to get this information to all the BSEE designers.
Gary Bremer
Senior Manufacturing Engineer
Quoting "Jack C. Olson" <[log in to unmask]>:
> Those are some great comments, very valuable
> (You should give a presentation at the conference! <grin> )
>
> but I have to make one point on the opposite side of the coin.
>
> DON'T SPECIFY MORE THAN YOU NEED TO.
>
> In fact, the way the question is presented is not answerable,
> in my opinion, without knowing more about the product.
>
> What if the board is for a toy in a kids value-meal from your
> favorite burger joint? I know people who would litter the fab
> dwg with all kinds of notes, when the fact of the matter is that
> no one is gonna complain of the gizmo doesn't work a week
> later, and it probably doesn't even have to be flame retardent.
> So why specify anything at all? Let the vendor use whatever
> material they have in stock if it doesn't make a difference.
>
> Driving up the cost with inspection criteria that doesn't add
> value is absurd.
>
> ok, flame me.
>
> Jack
>
>
>
>
>
>
> "Dack.Kelly"
> <[log in to unmask]
> OM>
> Sent by: To
> DesignerCouncil To
> <DesignerCouncil@ [log in to unmask]
> ipc.org> cc
>
>
> 01/12/2005 10:42
> AM
>
> Subject
> Please respond to Re: [DC]
> "(Designers
> Council Forum)"
> <DesignerCouncil@
> IPC.ORG>; Please
> respond to
> "Dack.Kelly"
> <[log in to unmask]
> OM>
>
>
>
>
>
> Caterpillar: Confidential Green Retain Until: 02/11/2005
> Retention Category: G90 -
> General
> Matters/Administration
>
>
> Greetings Gary,
>
> With regards to quality problems, if everyone in the design and mfg and
> Q.C.
> chain has done their job right, you shouldn't have to expect any.
> Hopefully, this is the case.
>
> If the fabrication drawing is calling for .062 FR4 copper clad and nothing
> more, here are some issues to consider depending PERFORMANCE CONSTRAINTS of
> the design:
>
> (1) .062 CC commonly infers an off-the-shelf "stock" material which will
> be
> processed into a two-sided design. If this is the case, go to (2) If not,
> go to (A)
>
> (2) "Copper Clad" might be a little vague if this design has any current
> carrying constraints. If this design has no current carrying capacity
> req's
> over 1amp, check to make sure that min trace width is >/= to ~.010 [.25]
> Check to make sure that the copper clad is at least 1/2oz. It will be
> plated
> up another ~1oz during processing. Go to (3)
>
> (3) Coordinate a manufacturability review with your contract assembly
> vendor. They will be an invaluable source of information. They will
> require the raw data from the design - the design database. They will get
> back to you with a detailed set of issues, if any. If there are issues,
> cycle them back thru the EE. Make sure that the issues are addressed in
> the
> source design database. Often, CM's offer to just fix the problem. If this
> happens, it is sure to crop up again in another iteration of the design as
> it is re-output from the source.
>
> (A) If this is a multi-layer design, ".062thk FR4 Copper Clad" is way too
> vague. If this design is impedance controlled, it will need to spec the
> impedance along w/ a layer stackup. You need to get with EE and contract
> mfr and get requirements spec'd on the fabrication drawing.
>
> Just some thoughts I had time for this morning.. Hope this helps.
>
> -- Kelly
>
> Kelly Dack
> PCB Dsnr
> Reno, NV
>
> -----Original Message-----
> From: DesignerCouncil [mailto:[log in to unmask]] On Behalf Of Gary
> Bremer
> Sent: Wednesday, January 12, 2005 7:18 AM
> To: [log in to unmask]
> Subject: [DC]
>
> Hello Designer Council members
>
> At the company I am working for is calling out matterial .062 thick FR4
> green copperclad laminate for their bare board.
>
> My question for the form:
>
> When this design was done in the Northeast by the electrical engineer and
> outsourced to a board assembly house as a turnkey component. What type of
> quality problems can I expect to deal with durning final assembly and final
> test? What long term (customer returns) problems may result from this? Do
> the board fabracation houses on the east coast march to a different drummer
> than the rest of the country? The electrical engineer does not want to
> change the drawing to specify what laminate matterial he truly intends to
> use. The last company I worked for also had this same type of problem.
> The
> electrical engineer designs/releases and I have to fix his mistakes.
>
> Gary Bremer
> Senior Manufacturing Engineer
> Company located in California
>
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