Hello....
I can't see any difference between those two methods of referencing....
Height in relation to area gives a paste volume....
If you would use level-etched stencils on a PCB that is topographically
complex, and then I could think that volume would be more correct way of
expressing the reference...
But otherwise, this would be an issue of how to express the printing guide
factors...
I design each stencil individually. Why compromise? Optimize! :)
Try checking the IPC-7525: Stencil Design Guidelines
There are some publications you can check:
* DESIGN OF STENCILS FOR PRINTING SOLDER PASTE ON SURFACE MOUNT PRINTED
BOARDS, AND THICK & THIN FILM CIRCUITS - GUIDELINES AND SOFTWARE - by
David Boswell Tel/Fax autoswitch: 44 (0)1258-830302. e-mail:
[log in to unmask] co.uk
*
http://www.cooksonee.com/DOCS/Publications/Optimum%20Printer%20Parameters.pdf
* C. L. Hutchins, "Fine-pitch Stencil Technology," SMT, July 1996.
* W. E. Coleman, "Stencil Design and Application for SMD, Through-hole,
BGA and Flip Chips," Advancing Microelectronics, January/February 1996.
* R. Clouthier, "Appraising Stencils for Fine-pitch Printing," SMT, March
1995.
* W. E. Coleman, "Stencil Design for Advanced Packages," SMT, June 1996.
* http://www.cemcex.com/present/Weldon_Tecan.pdf
* http://www.smtinline.com/html-en/uic0201.pdf
Regards,
Sasha
*************************************************************************
Sasha Miladinovic - Production Engineering
Amersham Biosciences, PCB Production, Umeå
Tel: +46 (0) 90 150 232
Fax: +46 (0) 90 138 372
E-mail: [log in to unmask]
*************************************************************************
pras chop <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
2003-12-12 04:41
Please respond to "TechNet E-Mail Forum."; Please respond to pras chop
To: [log in to unmask]
cc:
Subject: [TN] solder volume vs paste height
hi,
Currently in our smt line we are using the solder paste height as
reference for solder paste printing. But some of our lines are looking
into solder volume as reference.
we are using mostly 5mils stencils and ensure that paste height is between
5mils and 6mils.
I would like to know which direction is better solder paste height or
solder paste volume ?????? what are the advantages and disadvantages of
each type.???
Is there any site where i can find literature on this???
And lastly, I would like to know how to decide on stencil aperture
openings based on solder volume calculations. We get the pad size of the
pcb and then tell the stencil manufacturer about the stencil openings
required.
sorry guys, lots of queries but your opinions and help is valuable.
rgds
Prashant Chopra
JABIL
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