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From [log in to unmask] Sat Apr 27 15: |
33:41 1996 |
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There are a number of published papers on the subject -- suggest you do a
literature search. No-clean assembly may require tighter process controls
and possibly changing to an OSP compatible no-clean flux. I would also
recommend working with your PCB shop/OSP supplier to address specific
issues. I found our OSP supplier very helpful for providing support
on assembly-related technical "roadblocks".
Dave Boggs
Merix Corporation
phone: (503) 359-9300
fax: (503) 359-1181
[log in to unmask] Wrote:
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| I would greatly appreciate any input regarding changing from
| HASL to OSP. We assemble heavy copper boards and are
| experiencing difficulties as we move to 0805 chip packages.
| We
| are comtemplating changing to OSP to alleviate some of the
| pain. I would appreciate any info regarding process changes
| we
| may have to make (pad design, pre-heat, flux application
| method, etc). A typical application is 4 layer board with 2
| oz. internals and 2 oz. externals plated to 3 oz. Three
| thermal cycles (top side reflow, bottom side epoxy cure, and
| wave solder). SOIC and SOT-23 on top, 0805 on bottom, plus
| through hole components. No-clean paste and wave solder
| flux,
| wave flux applied by foaming on most machines but spray
| fluxer
| also available. Assemblies have high thermal mass (large
| magnetics and heatsinks). Thanks for your help.
|
| Pat Bailey
| Zytec Corporation
| phone 507 637-2966 x355
| fax 507 644-3720
| e-mail [log in to unmask]
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