We also use a semi-automatic printer and have no problems for printing 0.5 mm
pitches.
I think you should use a laser cut metal stencil and a metal squeegee.


Regards
Vincent Bada
Process Engineer
Alcatel ETCA





Daniel Woon <[log in to unmask]> le 03/10/2000 14:13:23

Veuillez répondre à "TechNet E-Mail Forum." <[log in to unmask]>; Veuillez répondre
      à Daniel Woon <[log in to unmask]>

Pour :    [log in to unmask]
cc :   (ccc : Vincent BADA/ETCA/ALCATEL-SPACE)
Objet :   [TN] QFP 20 mils pitch printing






Hi Technetters,

We are now starting the fine pitch printing (20 mils pitch).  Previously,
the smallest pitch size is 25 mils.  However, we encountered paste printing
problem.

We do not have problem with the paste deposition on the pads which parallel
to the squeegee flow direction.  However, we found insufficient solder
paste on those pads which are perpendicular to the squeegee flow direction.

We are using a semi-auto screen printer with rubber squeegee (durometer
#90).  Stencil thickness is 5 mils.

May I know the remedy action for such process problem?

Many thanks in advance

Best regards,

WW Woon
email: [log in to unmask]



Daniel Woon
Assistant Manager, PCBA Department
Comacraft Sdn Bhd (A Subsidiary of Dynavest Group-Asia)
2033, Jalan Bukit Minyak,
Kawasan Industri Ringan Asas Jaya,
14100 Bukit Mertajam,
Penang, Malaysia.
Tel     : 60-4-5889933
Fax     : 60-4-5889953
H/P     : 60-19-4706083
Email   : [log in to unmask]
Website: http://www.dynavest.com.sg

##############################################################
TechNet Mail List provided as a free service by IPC using LISTSERV 1.8d
##############################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text
in
the body:
To subscribe:   SUBSCRIBE TECHNET <your full name>
To unsubscribe:   SIGNOFF TECHNET
##############################################################
Please visit IPC web site (http://www.ipc.org/html/forum.htm) for additional
information.
If you need assistance - contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
##############################################################