TECHNET Archives

March 2005

TechNet@IPC.ORG

Options: Use Monospaced Font
Show Text Part by Default
Show All Mail Headers

Message: [<< First] [< Prev] [Next >] [Last >>]
Topic: [<< First] [< Prev] [Next >] [Last >>]
Author: [<< First] [< Prev] [Next >] [Last >>]

Print Reply
Subject:
From:
Jason Gregory <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Jason Gregory <[log in to unmask]>
Date:
Thu, 10 Mar 2005 09:14:06 -0600
Content-Type:
text/plain
Parts/Attachments:
text/plain (280 lines)
Hey Mike,

The residues are only on the second pass side. The first pass side looks
great.

Go USC!

Jason Gregory
Manufacturing Engineer
Innova Electronics
(281)653-5593
(281)653-5594 fax
(281)212-0844 cell
[log in to unmask]


-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Thursday, March 10, 2005 8:51 AM
To: TechNet E-Mail Forum; Jason Gregory
Subject: Re: [TN] Cleaning residues off of PCB



Are the residues on both sides of the board or just the first reflowed
side?  I've seen some resides under low standoff components migrating back
out after another thermal cycle.  If you pull a part do you see residues
underneath the part - might tweak the stencil (homeplate) and/or reduce the
solder paste volume to limit flux entrapment.

Mike Sewell



                      Jason Gregory
                      <jgregory@INNOVAE        To:       [log in to unmask]
                      LEC.COM>                 cc:
                      Sent by: TechNet         Subject:  Re: [TN] Cleaning
residues off of PCB
                      <[log in to unmask]>


                      03/10/2005 08:14
                      AM
                      Please respond to
                      TechNet E-Mail
                      Forum; Please
                      respond to Jason
                      Gregory






Ramon,

the boards were mine, not Steve's. Anyway, the process WAS first pass
print,
place, vapor phase reflow, clean with vapor degreaser and terpene. Then
second pass print, place, VP reflow, then clean again with vapor degreaser
and terpene. All of the first passes were through VP reflow. After we ran
our first topside and saw the residue, we switched to convection and got
the
same results. We initially thought our VP fluid became contaminated. The
residue only comes off with something hard, like a probe or tweezers.

Jason Gregory
Manufacturing Engineer
Innova Electronics
(281)653-5593
(281)653-5594 fax
(281)212-0844 cell
[log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Dehoyos, Ramon
Sent: Thursday, March 10, 2005 7:58 AM
To: [log in to unmask]
Subject: Re: [TN] Cleaning residues off of PCB


                Hi Steve:
                                Will you describe step by step the process
that these boards go through. Are these type of boards the  only affected?
Or did the process all of a sudden produced this results? Does the
contamination come off by scrubbing it with an alcohol soaked Q tip?
                Regards,
                Ramon


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Jason Gregory
Sent: Wednesday, March 09, 2005 6:37 PM
To: [log in to unmask]
Subject: Re: [TN] Cleaning residues off of PCB


Photo posted. Thanks Steve!

You can see (barely - sorry bad photo) some halo-ing around the leads. Like
I said, no other detection in open areas or two leaded devices just finer
pitch, multi-leaded devices.

Follow the link
http://www.stevezeva.homestead.com/files/residue_closeup.jpg



Jason Gregory
Manufacturing Engineer
Innova Electronics
(281)653-5593
(281)653-5594 fax
(281)212-0844 cell
[log in to unmask]


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of David D. Hillman
Sent: Wednesday, March 09, 2005 4:05 PM
To: [log in to unmask]
Subject: Re: [TN] Cleaning residues off of PCB


Hi Jason! Can you send a photo to Steve for posting? A visual would help.

Dave Hillman
Rockwell Collins
[log in to unmask]



             Jason Gregory
             <jgregory@innovae
             lec.com>                                                   To
             Sent by: TechNet          [log in to unmask]
             <[log in to unmask]>                                          cc

                                                                   Subject
             03/09/2005 02:55          [TN] Cleaning residues off of PCB
             PM


             Please respond to
              TechNet E-Mail
                   Forum
             <[log in to unmask]>
             ; Please respond
                    to
               Jason Gregory
             <jgregory@innovae
                 lec.com>






Hello all,

We have some boards that I am requiring some advice on cleaning residues.

The PCBs were soldered with SN96 (Sn96.5/Ag3.5). The first pass of the
boards look great. However, the second pass looked very suspicious. We are
seeing residue that looks like dried, puddled flux residue around most of
the leads. The areas mostly affected are multi-leaded components and there
is no evidence of this residue in open (non-populated) areas of the board.
If we take something like a probe or tweezers and move them along the areas
of concern, then it flakes off, but not real easily. I am afraid to do this
in fear of damaging the laminate (these are expensive boards). We have
tried
re-fluxing them with aggressive RMA flux and re-reflowing them, but to no
avail. I have just tried soaking them, for 15 minutes,  in a 50/50 solution
of distilled white vinegar and DI water, but again, to no avail.

Does anyone have any suggestions as to something else to use that's
aggressive, but not damaging to polyimide (or the solder joints)?

TIA,

Jason Gregory
Manufacturing Engineer
Innova Electronics
(281)653-5593
(281)653-5594 fax
(281)212-0844 cell
[log in to unmask]

---------------------------------------------------
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
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
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
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
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
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
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
847-615-7100 ext.2815
-----------------------------------------------------

---------------------------------------------------
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
847-615-7100 ext.2815
-----------------------------------------------------




__________________________________________________________________
This message may contain information that is privileged and confidential to
LaBarge, Inc.  It is for use only by the individual or entity named above.
If you are not the intended recipient, you may not copy, use or deliver
this message to anyone.  In such event, you should destroy the message and
kindly notify the sender by reply e-mail.

---------------------------------------------------
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 847-615-7100 ext.2815
-----------------------------------------------------

ATOM RSS1 RSS2