Need pre-heat from the other side (or switch to an alloy which doesn't
erode). Depends on overall thermal mass the jetted solder has to heat up.

Wayne

-----Original Message-----
From: Peter Wong [mailto:[log in to unmask]] 
Sent: Tuesday, July 08, 2014 5:35 PM
To: TechNet E-Mail Forum; Wayne Thayer
Subject: RE: Dissolving pins

Thanks everyone,

It's been so long for me that I forgot about SAC305 eroding metals.  I will
get our tech to pull up the program to get more details about dwell times
and nozzle speeds.

I believe our temperature is set that high to assist with solder fill.  What
solder pot temperatures are others running for SAC305?

Peter

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Tuesday, July 08, 2014 1:51 PM
To: [log in to unmask]
Subject: Re: [TN] Dissolving pins

Hi Peter-

SAC305 is well known for eroding metals. 325C sounds pretty darned hot to
me! Why so high?

I have run a solder fountain rework station filled with SAC305, and it was
very difficult to stop it from eroding the ends of the via barrels. That was
only at 230C!

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Peter Wong
Sent: Tuesday, July 08, 2014 4:32 PM
To: [log in to unmask]
Subject: [TN] Dissolving pins

Hi Everyone,

We ran some assemblies where after selective soldering with SAC305, the
phosphor bronze leads on a Harwin connector look to have been dissolved.
The solder pot temperature is set at 325 deg C and we dwelled on each pin
for no more than 3 seconds.  We are using an OA flux.  Harwin tells me that
the melting point of the pins is 954 deg C.

We are having the solder in our selective solder pot analyzed to see if
there is anything out of spec that could be causing this.

Has anyone else experienced something similar or does anyone have an idea as
to what could be causing this?

A photo is available at the following link.
http://ipc-technet.groupsite.com/galleries/show/27385

Thanks
Peter


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