soldering

[Ralph Mowery]

Clint you asked about the temperature of soldering the surface mounted
devices. Most of them are recommended to follow a heating curve that lasts
about 2 or 3 minutes. Here is a url to a file that shows the preferred way
to heat and cool them. It is for some capacitors,but other devices follow
the same curve. This is for heating them up in something that resembles a
toster oven. The professional devices have timmers and things like that to
make the heat follow the curve.

http://www.vishay.com/docs/45034/soldrec.pdf

 

[Michael A. Terrell]

Ralph Mowery wrote:

Clint you asked about the temperature of soldering the surface mounted
devices. Most of them are recommended to follow a heating curve that lasts
about 2 or 3 minutes. Here is a url to a file that shows the preferred way
to heat and cool them. It is for some capacitors,but other devices follow
the same curve. This is for heating them up in something that resembles a
toster oven. The professional devices have timmers and things like that to
make the heat follow the curve.

http://www.vishay.com/docs/45034/soldrec.pdf

We had a separate profile for every board we ran though the Heller
Reflow oven at Microdyne. The operator selected the profile by the board
type, and build number on a computer near the oven.

 

[Ian Field]

"Ralph Mowery" <rmowery28146@earthlink.net> wrote in message
news:u-ydnSPyEslnaWTLnZ2dnUU7-QvNnZ2d@earthlink.com...

Clint you asked about the temperature of soldering the surface mounted
devices. Most of them are recommended to follow a heating curve that
lasts about 2 or 3 minutes. Here is a url to a file that shows the
preferred way to heat and cool them. It is for some capacitors,but other
devices follow the same curve. This is for heating them up in something
that resembles a toster oven. The professional devices have timmers and
things like that to make the heat follow the curve.

http://www.vishay.com/docs/45034/soldrec.pdf

A few years back; Elektor magazine published a project to convert a pizza
oven into an SMD oven.

There was pretty detailed tech info on heating curves and the reasons why it
was done that way.

 

[Jon Elson]

Ian Field wrote:

"Ralph Mowery" <rmowery28146@earthlink.net> wrote in message
news:u-ydnSPyEslnaWTLnZ2dnUU7-QvNnZ2d@earthlink.com...
Clint you asked about the temperature of soldering the surface mounted
devices. Most of them are recommended to follow a heating curve that
lasts about 2 or 3 minutes. Here is a url to a file that shows the
preferred way to heat and cool them. It is for some capacitors,but other
devices follow the same curve. This is for heating them up in something
that resembles a toster oven. The professional devices have timmers and
things like that to make the heat follow the curve.

http://www.vishay.com/docs/45034/soldrec.pdf

A few years back; Elektor magazine published a project to convert a pizza
oven into an SMD oven.

There was pretty detailed tech info on heating curves and the reasons why
it was done that way.

I bought a big toaster oven in 2007 to reflow PC boards stuffed with my P&P
machine. I got a ramp and soak temperature controller on eBay and some
micro-size thermocouple wire. I first tried doing the boards with the
thermocouple just hanging in the air, but that ended up toasting the boards
to a crisp! I then thought to poke the thermocouple junction into a through
hole in one of the boards, and that has been working fine for years, now.

So, I can program in a ramp to 180 C, hold for one minute, then ramp to
either 225 C (tin/lead) or 246 C (lead-free) and hold for one minute, then
ramp rapidly to room temp. Sometimes the boards at the corners of the oven
don't completely reflow all the way to the edges, but when I get the profile
right, they come out looking quite professional, and with minimal rework.

If the boards have been sitting around for a while, I usually bake them at
50 C for a while, the up it to 75 C and hold for an hour or so. Otherwise,
absorbed moisture can cause the boards to split internally and break vias.

Jon

 

[Ian Field]

"Jon Elson" <jmelson@wustl.edu> wrote in message
news:v6Wdncklm-K7emPLnZ2dnUU7-YXNnZ2d@giganews.com...

Ian Field wrote:



"Ralph Mowery" <rmowery28146@earthlink.net> wrote in message
news:u-ydnSPyEslnaWTLnZ2dnUU7-QvNnZ2d@earthlink.com...
Clint you asked about the temperature of soldering the surface mounted
devices. Most of them are recommended to follow a heating curve that
lasts about 2 or 3 minutes. Here is a url to a file that shows the
preferred way to heat and cool them. It is for some capacitors,but
other
devices follow the same curve. This is for heating them up in something
that resembles a toster oven. The professional devices have timmers and
things like that to make the heat follow the curve.

http://www.vishay.com/docs/45034/soldrec.pdf

A few years back; Elektor magazine published a project to convert a pizza
oven into an SMD oven.

There was pretty detailed tech info on heating curves and the reasons why
it was done that way.
I bought a big toaster oven in 2007 to reflow PC boards stuffed with my
P&P
machine. I got a ramp and soak temperature controller on eBay and some
micro-size thermocouple wire. I first tried doing the boards with the
thermocouple just hanging in the air, but that ended up toasting the
boards
to a crisp! I then thought to poke the thermocouple junction into a
through
hole in one of the boards, and that has been working fine for years, now.

So, I can program in a ramp to 180 C, hold for one minute, then ramp to
either 225 C (tin/lead) or 246 C (lead-free) and hold for one minute, then
ramp rapidly to room temp. Sometimes the boards at the corners of the
oven
don't completely reflow all the way to the edges,

Probably ramping up too fast.

The epoxy encapsulation has a hygroscopic index - its very small, but
expanding moisture can crack the encapsulations.

There's usually a slow ramp to drive out moisture, a short plateau then
ramping up to the soldering temperature.