Hey, I think I may be too young for this then, can you elaborate on the
C-cuts?
Thank you!
Regards
Thomas Ahrens, Boostedt
e-mail [log in to unmask]
----- Original Message -----
From: "Bob willis" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, July 22, 2004 5:03 PM
Subject: Re: [LF] LeadFree and Land Patterns (Wave solder)
> C cuts in pads is an old trick used for years on single sided boards, a
> variation of this works with test points on double sided boards.
>
>
> Bob Willis
> 2 Fourth Ave, Chelmsford,
> Essex, CM1 4HA, England
> Tel: 01245 351502
> Fax: 01245 496123
> Mobile: 07860 775858
> Email: [log in to unmask]
> Web: www.leadfreesoldering.com
> Web: www.bobwillis.co.uk
>
>
> -----Original Message-----
> From: Leadfree [mailto:[log in to unmask]] On Behalf Of
> [log in to unmask]
> Sent: 22 July 2004 15:44
> To: [log in to unmask]
> Subject: Re: [LF] LeadFree and Land Patterns (Wave solder)
>
> Dear Bill,
>
> Within Philips we have seen the necessity to change the solder pads for
> wave soldering in some cases ad have made design rules.
> Some general rules that we apply are stated below:
> -Enlarged solder spacing QFP end solder thief pads
> - Enlarged solder spacing multi row connectors
> - Place multi pin components parallel to the solder transport direction
> - Additional solder thief application
> - No track/solder land connection, which reduces solder spacing
>
> We reported about this at the IPC/JEDEC Pb-free conference in San Jose
> in
> March this year together with our experiences of introducing Pb-free. If
> you would like I can send a copy of this paper to you.
> We have also worked with C-cut pads for similar problems and this seems
> to
> work.
>
> With kind regards,
>
> Pascal
>
> ------------------------------------------------------------------
> Dr. ir. P. Oberndorff
> Philips CFT, SAQp 233
> Process Technology/ Electronic Packaging & Thin Film
> P.O. Box 218
> 5600 MD Eindhoven
> Tel: +31 (0)40 27 32223
> fax: +31 (0)40 27 36815
> e-mail: [log in to unmask]
>
>
>
>
> To:
> [log in to unmask]
> cc: (bcc: Pascal
> Oberndorff/EHV/CFT/PHILIPS)
> Subject: Re: [LF]
> LeadFree and Land Patterns (Wave solder)
>
> "William E. Hunt" Classification:
> <[log in to unmask]
> M>
>
> Sent by:
> Leadfree
> <[log in to unmask]>
>
> 2004-07-21 10:21 PM
> Please respond to
> "(Leadfree Electronics
> Assembly Forum)"; Please
> respond to
> william.e.hunt
>
>
>
>
>
>
> Has anyone seen changes for LF wave solder pad geometries? Our contract
> mfg has requested pad changes for a component that is hand soldered
> after
> the board passes through wave solder. The pad was collecting too much
> solder and filling the hole. Then the hole would need to be cleaned out
> and the part hand soldered to the board. The change was to a C-cut pad.
> The idea of a C-cut pad is to prevent solder from filling the hole
> during
> wave soldering so the component can be easily inserted and hand soldered
> post wave. Instead of having just one opening in the pad the CM proposed
> openings on both sides (leading and trailing edges) of the pad. This is
> a
> high volume, simple type III assembly using a XPC laminate. We are
> still
> investigating the need for this change and continue to test but I'm
> interested in other experiences with LF wave soldering.
>
> What are your experiences with LF wave solder?
>
>
>
> Bill Hunt
> Eastman Kodak
> Office: 585-726-4892
> Fax: 585-726-3278
>
>
>
>
> Pratap Singh <[log in to unmask]>
> Sent by: Leadfree <[log in to unmask]>
> 07/21/2004 03:13 PM
> Please respond to "(Leadfree Electronics Assembly Forum)"; Please
> respond
> to Pratap Singh
>
>
> To: [log in to unmask]
> cc:
> Subject: Re: [LF] LeadFree and Land Patterns
>
>
> Roger,
> No need to fret. Land pattern should not be affected by converting to LF
> solder. Depending upon the solder used, reflow profile settings will
> change since LF solders flow at higher temperature.. Visual inspection
> and void inspection should also remain same.
>
> _____________________
> pratap singh
> Tel./Fax: (512) 255-6820
> email: [log in to unmask]
> www.rampinc.com
>
> ------------------------------------------------------------------------
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