Brendon,

Thanks for the info.
Its going to  be a pain in the rearend to go through manually (even with
global changing) and change all my smt reflow footprints to reflect the 5%
or so reduction that I need to make to keep our manufacturers happy.

Yes - we use a 6thou stainless stencil for solder paste and a 10thou
stainless stencil for glue. Sometimes for low run boards we use brass
stencils.

Cheers



Wayne Trow
PCB Design Technician
Gallagher Group LTD
Hamilton
NEW ZEALAND
[p] +64 7 838 9800 ext 8737
[f] +64 7 838 9801
[e] [EMAIL PROTECTED]



                                                                                       
                                          
                    "Brendon                                                           
                                          
                    Slade"               To:     "Protel EDA Forum" 
<[EMAIL PROTECTED]>                             
                    <slade_b@exico       cc:                                           
                                          
                    m.co.nz>             Subject:     Re: [PEDA] Paste masks           
                                          
                                                                                       
                                          
                    18/12/01 00:00                                                     
                                          
                    Please respond                                                     
                                          
                    to "Protel EDA                                                     
                                          
                    Forum"                                                             
                                          
                                                                                       
                                          
                                                                                       
                                          




Unfortunately Protel only has a radial reduction rule and of course you can
apply this to specific components as I'm sure you're aware, it is however
not that useful.

I generate a raw Gerber.GTP file (with no reductions applied) and edit
apertures only on components with a pin pitch of <= 0.050" using the rule
of; aperture width = 0.5 pin pitch.  eg for a 0.050" pin pitch component I
reduce the aperture to 0.025".  Another useful rule is sticking to an
aspect
ratio of 1.5:1, eg for a paste stencil of 0.006", don't use apertures less
than 0.009".  I haven't had any problems with paste stencil using these
rules of thumb.

I edit the GTP file in Protel an generate the final GTP from this modified
file.  I'm sure Camtastic would be useful for this also.

Have you also thought about reducing the solder paste volume by reducing
the
stencil thickness?  What are you using?  We generally specify 0.006"
stainless steel.

Probably not the answer you're after but I hope it helps.

Cheers and Merry Christmas,
Brendon.


----- Original Message -----
From: "Wayne Trow" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, December 17, 2001 10:34 AM
Subject: [PEDA] Paste masks


> Hi All
>
> Is there a way to tell protel 99se sp6 to reduce the paste mask by a
> percentage rather than a actual measurement ?
>
> We have recently had problems with our smt placement machines and reflow
> causing beading of the solder because of too much solder paste. I have
been
> asked to reduce the paste apertures by 5% on all smt components.
>
> Any help appreciated
>
> MERRY CHRISTMAS
>
>
>
> Wayne Trow
> PCB Design Technician
> Gallagher Group LTD
> Hamilton
> NEW ZEALAND
> [p] +64 7 838 9800 ext 8737
> [f] +64 7 838 9801
> [e] [EMAIL PROTECTED]
>
>




* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
* To post a message: mailto:[EMAIL PROTECTED]
*
* To leave this list visit:
* http://www.techservinc.com/protelusers/leave.html
*
* Contact the list manager:
* mailto:[EMAIL PROTECTED]
*
* Forum Guidelines Rules:
* http://www.techservinc.com/protelusers/forumrules.html
*
* Browse or Search previous postings:
* http://www.mail-archive.com/proteledaforum@techservinc.com
* * * * * * * * * * * * * * * * * * * * * * * * * * * * * *

Reply via email to