I suppose a concern here is small batch size, and VPR does bring a certain amount of piece of
mind with respect to uniform heating which I suppose you are equating to small delta T. This is
a two way street, The amount of heat you are going to stuff into your assemblies will also be
quite large, be interesting to know if any one has any numbers for internal temperatures on
devices VPR in FC71 equivalents.....
Personally I think that if you have a 10 zone convection machine this should be well able to
reflow Sn/Ag soldered aeemblies. If you haven't already, before you blow a few $0000 on VPR why
not invest a few $00 on a data profiler and see what your max thermal excursions really are?
Mike
----- Original Message -----
From: Stephen R. Gregory <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, March 21, 2000 7:39 PM
Subject: [TN] Vapor Phase reflow chemicals and equipment..
Hi ya'll!
I got some general questions about vapor phase reflow. I went back and looked
at all the responses to Jason Gregory's (no relation...that I know of anyway)
question about vapor phase reflow.
We may get some business that will require it. It's for oil well downhole
boards that will be soldered with a SN96/AG04 solderpaste. I've got a 10-zone
Conceptronics oven that I can create a profile that will reflow the paste,
but I don't think it will do it in a manner that won't cook the parts. With
vapor phase, you can get the board down in the vapor, reflow the solder, and
get it back out before the parts fry...
The liquidous for the SN96/AG 04 is somewhere between 221º - 229º C., so the
regular Fluorinert (FC-70) won't work as it's boiling point is 215º C. I
checked on the FC-71 and it's boiling point is 253º C....so that looks like
the one I should use.
Problem is, don't know where to get it. I've called 3-M and left a message,
but haven't got a call back yet...
This all is just in the planning stages now...we haven't got the business
yet. But I'm being asked what it will take for us to have vapor phase
capabilitiy. I've been web searching and mostly what I've found on the NET is
used equipment, Centech, HTI, Baron Blakeslee....who makes new vapor phase
equipment now? Also, what kind of ball-park figures will we need to spend for
a decent vapor phase unit?
If anybody knows, what kind of money (per gallon) are we talking about for
FC-71? There will also be a secondary chemical that we'll need to use to
contain the FC-71 won't there? Or has the equipment technology advanced
enough so a secondary chemical isn't needed? I rememember using freon the
last time I worked with a vapor phase unit.
As usual, thanks a lot!
-Steve Gregory-
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