Sender: |
|
X-To: |
|
Date: |
Thu, 23 Feb 2012 07:14:11 -0600 |
Reply-To: |
|
Message-ID: |
|
Content-Transfer-Encoding: |
quoted-printable |
Subject: |
|
From: |
|
X-cc: |
|
In-Reply-To: |
<148E352831AB44C18C89A8A82DC66DA8@stephenPC> |
Content-Type: |
text/plain; charset="ISO-8859-1" |
MIME-Version: |
1.0 |
Parts/Attachments: |
|
|
Hi Steve - based on your pictures, I think Bev has the correct assessment
- I don't think those are air bubbles but you have flux separation in the
syringes. Flux separation is an indication of incorrect syringe filling
parameters or damaged solderpaste. I recommend you contact your
solderpaste supplier and request replacement of the entire lot.
Dave Hillman
Rockwell Collins
[log in to unmask]
Steve Gregory <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
02/22/2012 06:51 PM
Please respond to
TechNet E-Mail Forum <[log in to unmask]>; Please respond to
Steve Gregory <[log in to unmask]>
To
<[log in to unmask]>
cc
Subject
[TN] Air Bubbles in Syringes of Solder Paste...
Hi All,
I have a question about syringes of dispensable solder paste. We purchase
10cc syringes of Type-4 dispensable solder paste for work that we do. It?s
used much of the time to dispense paste for the stacked capacitors that we
do, much of the time it?s for 0402 caps, so the dispensing has to be very
precise.
Recently our operators have complained about the paste, they said they?re
having a hard time being consistent with the dots they?re trying to
dispense. One of the operators showed me the syringe that she was using,
and I was surprised at the air bubbles I saw inside the syringe. The
photos below are pictures I took under a microscope through the side of
the syringe:
http://stevezeva.homestead.com/AirBubbles.jpg
http://stevezeva.homestead.com/AirBubblesClose.jpg
I can see why she was having trouble. As I said, we buy these syringes
pre-filled, they come to us packaged in a cool pack, and we store them
immediately in the refrigerator until they are ready to be used. They are
taken out and allowed to come up to room temperature before they are ever
attached to a dispenser. We use EFD dispensers BTW.
I looked at the syringes that were un-touched and stored in the
refrigerator, and they had the same sort of bubbles. So our dispensers are
not introducing them, and it seemed like the bubbles were only associated
with one lot of of syringes. There was another lot in the refrigerator
that did not have the bubbles.
So my question is (not being a solder paste vendor), how are these
syringes filled ? Do they centrifuge them to eliminate the bubbles ? I
know I did that in the past when I filled syringes with chip bonder for
our Fuji dispenser, in fact, the centrifuge was sold to us by Fuji. But
I?m not sure about solder paste. How do you go about making sure there are
no bubbles in syringes of solder paste ? Is there anything we can do with
the paste that we have to eliminate the bubbles or should we just send the
paste back ?
Steve
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask]
______________________________________________________________________
|
|
|