yes i know,
that is what we did and what i meant when i said ' we did that in the gerbers as well'


but the fab shop was quibbling over the meaning of the term 'tenting'

(they probably got burned once)

'tenting' seems to imply that the hole is guaranteed blocked and gas tight, which at certain dimensions i guess can only be done with dry film

when they use the common LPI mask and the protel gerbered 'tented' vias they described the result as 'covered' vias

Dennis Saputelli

_______________________________________________________________________
Integrated Controls, Inc.           Tel: 415-647-0480  EXT 107
2851 21st Street                    Fax: 415-647-3003
San Francisco, CA 94110             www.integratedcontrolsinc.com


Brooks,Bill wrote:
Dennis,

There is an option in Protel Software that lets you choose the 'tent'
feature for vias... then the Gerbers produced will reflect exactly what you
want done. You designate the tenting on the pads themselves, collectively or
individually, I believe this is a better solution to having them figure out
what I want done...

Best regards,


Bill Brooks - KG6VVP PCB Design Engineer , C.I.D.+, C.I.I. Tel: (760)597-1500 Ext 3772 Fax: (760)597-1510 e-mail:[EMAIL PROTECTED] http://www.dtwc.com http://pcbwizards.com


-----Original Message-----
From: Dennis Saputelli [mailto:[EMAIL PROTECTED] Sent: Monday, January 10, 2005 1:46 PM
To: Protel EDA Discussion List
Subject: Re: [PEDA] Tenting Phenomenon (Is it riskless)



i recently sent a board to a new shop for us

the notes said 'tent smallest vias'

we did that in the gerbers as well

they called and said they can't tent the vias unless they use dry film, but they usually use LPI

i said, 'but we do this all the time!'

they said 'well we can *cover* the vias with LPI but we can't *tent* them'

so i guess there is a possibly significant issue of terminology about this

Dennis Saputelli


_______________________________________________________________________ Integrated Controls, Inc. Tel: 415-647-0480 EXT 107 2851 21st Street Fax: 415-647-3003 San Francisco, CA 94110 www.integratedcontrolsinc.com


Brad Velander wrote:

Adeel,
        I believe the issue you have mentioned about soldermask thickness

variation was in regards to the old thick-film soldermask. Previously thick-film solderemask was not used for SMT assemblies because it's thickness could keep components lifted off their pads. With most thin-film or liquid soldermasks this is not an issue because they are not typically thick enough to cause this problem.

The other comments mentioned so far match with my experience/opinion

as well.

Sincerely,
Brad Velander
Senior PCB Designer
Northern Airborne Technology
1925 Kirschner Rd.,
Kelowna, BC, V1Y 4N7.
tel (250) 763-2329 ext. 225
fax (250) 762-3374




-----Original Message-----
From: Adeel Malik [mailto:[EMAIL PROTECTED] Sent: Monday, January 10, 2005 5:06 AM
To: [email protected]
Subject: [PEDA] Tenting Phenomenon (Is it riskless)


Hi All,
            I intend to tent vias under components to prevent them

from shorting the component body. But I have been told that "Solder mask


thickness can vary enough to cause issues. Also tenting could mean that
debris in a via hole remains unremoved, and unremovable.".
Can someone comment on this whether tenting is safe or not.
If not, can I use silk screen layer to cover the exposed vias ?>

Regards,
Adeel Malik






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