Hi Jana: The short answer is "typically" the smaller the mesh number the
larger the screen opening. A 128 mesh screen will deposit more than a 260
mesh.

However; width of the mesh opening, % open area, and thread thickness all
come into play.

 A 128 mesh screen using an "S"(fine) thread thickness will deliver a
thinner  mask deposit than "T"(standard) thread thickness 128 mesh screen.
The smaller diameter(S)threads have more open area than thicker diameter(T)
threads but because the mesh thickness of the S threads is less the deposit
is thinner

The % open area is the relationship of the thread area to the actual open
area. A 40% open area is the amount open in the mesh.
The width of the mesh opening is the relationship of the number of threads
per inch and the thread thickness.
A 128 T mesh with 40% open will deposit more mask than a 128 T with 25%
open.


Clear as mud, right?


                                                                Regards

Michael Barmuta

Staff Engineer

Fluke Corp.

Everett WA

425-446-6076

-----Original Message-----
From: Jana Carraway [mailto:[log in to unmask]]
Sent: Thursday, March 04, 2004 1:43 PM
To: [log in to unmask]
Subject: [TN] Dumb question


I have a pretty simple, most likely dumb question:  does the numerical
designation for mesh size for solder mask screens increase with an increase
in the "thread" thickness of the mesh (thus resulting in less deposit?) or
increase with increasing opening in the mesh, or something entirely differ?

Thank you for answering and thank you in advance for not laughing...in
email...at my dumb question.

Jana Carraway
Portland, Oregon

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to
[log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to
[log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16
for additional information, or contact Keach Sasamori at [log in to unmask] or
847-509-9700 ext.5315
-----------------------------------------------------

---------------------------------------------------
Technet Mail List provided as a service by IPC using LISTSERV 1.8e
To unsubscribe, send a message to [log in to unmask] with following text in
the BODY (NOT the subject field): SIGNOFF Technet
To temporarily halt or (re-start) delivery of Technet send e-mail to [log in to unmask]: SET Technet NOMAIL or (MAIL)
To receive ONE mailing per day of all the posts: send e-mail to [log in to unmask]: SET Technet Digest
Search the archives of previous posts at: http://listserv.ipc.org/archives
Please visit IPC web site http://www.ipc.org/contentpage.asp?Pageid=4.3.16 for additional information, or contact Keach Sasamori at [log in to unmask] or 847-509-9700 ext.5315
-----------------------------------------------------