Good day Jan,
The thickness that you are requesting have not presented any "real"
problems from my experience. I will present some general concerns and I'm
sure that the other TechNetters will add.
1) Obviously, the overall length and width of the board will have an effect
on manufacturing and assembly. What is the circuit/pallet size you are
dealing with.
2) Most assembly operations can employ the use of stiffeners during the
wave/reflow stages. Some companies have employed the use of "leaders and
trailers" to assist in the transporting of thin materials through various
operations. Again, the larger the board, the more difficult it will be to
control the sag. If you are palletizing, leave all the copper that you can
on the board/pallet area (make sure it it covered with Soldermask and built
as Soldermask over Bare copper technology or other process that will not
leave a "molten metal" under the Soldermask.
3) The scoring operation should not have a problem as long as you can keep
your remaining web at .008" or greater. Post score handling will need to be
controlled carefully
4) numerous operations at assembly may require special set up with pins and
framing techniques.
In general, the thicknesses you are requesting are not outrageous, but
there are a lot of factors to consider in regards to size, layer count, etc.
During the design stage, look at anything that will enhance the rigidity of
the product throughout the manufacturing/assembly ops. If you want to Email
me, I can give you my phone number and we can discuss further. Good luck-
JOHN WAITE
-----Original Message-----
From: Jan Vercammen <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Thursday, April 09, 1998 9:49 AM
Subject: [TN] pro and contra on thickness reduction of pcb
>hello,
>
>We would like to implement thinner printed circuit boards (pcb).
>Quoted price reductions are -4% for 1.2mm thickness and -6% for
>1mm pcb with respect to the standard 1.6mm boards.
>
>(Also the pcb weigth gets reduced).
>
>
>This sounds nice, however there were some remarks from our component
>assembly contracters: "thinner boards are less rigid". To be specific:
>
>-1- possible bending (and wobbling) of pcb during solder paste or
> adhesive dispensing
>-2- possible sagging of pcb in reflow and wave solder operations
>-3- problems with scoring of pcb
>
>I consulted Coombs' handbook, but could not find any answers.
>
>
>I do not doubt that others out there have been confronted with these
>same questions. As far as we understand it the only problem is with the
>assembly!
>
>Your comments is highly appreciated.
>
>Regards,
>
>Jan Vercammen
>
>PCB engineering Agfa-Gevaert
>
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