Preventing Pad Lifts

[Michael A. Terrell]

Depending on what type of component you are removing the heat, time
and tools are all important. The general rulle its least amount or
heat in the least amount of time with no downward pressure and lots of
patience, thats what I preach to my students. As with all processes
the tools need to do the work and not be used improperly, which in
soldering means avoid at all cost pressure, soldering should not be
pressure activated. Pressure is what gets us in trouble when using
poor maintained equipment or improper techniques.

For most lead bearing solders, which is most likely what you are
dealing with, you should always start with a temp around 600 f and
modifiy from there. If its lead free you will need to up that
slightly, but not dramatically.

If you just do a lot of repair on the cheaper boards, I would suggest
looking into the circuit repairkits/techniques, some of the kits will
be better than the original when used correctly and again good well
maintianed tips and tools are key.

Anyway thats my 2cents email if you have questions or specifics of the
application you would like help with.

Ruffin Blackard
IPC Instructor
http://www.circuittechnology.com

I DID NOT WRITE ANY OF THE QUOTED TEXT AT THE TOP OF THE PREVIOUS
MESSAGE. I have worked in electronics for over 40 years, and did my own
surface mount rework under a stereo microscope. Your recommended
temperature was too low for the work I was doing, because I did a whole
row of pins in one pass, with the corner of the tip. I used .015"
Multicore rework solder, but the reduced contact area required over 700
degrees to allow proper wetting and flow on the leads. This was for
items that are in orbit, BTW.

I am very familiar with the IPC, your publications were all over the
QC inspection tables at my last job. They couldn't tell which pins I
had hand soldered, compared to the joints done by the new Heller reflow
oven, until I showed them the proper angle to look at them to see that
the new joints had more shine than the reflowed joints. (less time for
oxides to form) The running joke was that if they couldn't find my work,
they HAD to stamp it off.



I was teaching proper rework soldering technics in the mid '70s at a
defense plant that built military radios. The assembly people who
soldered had all been certified to NASA standards. It was a union
plant, so I rather enjoyed the angry stares from the union steward while
a final test QA inspector taught new rework methods. As usual, they
were using too little heat to do the job at hand. There were no large
irons allowed on the production floor, and they were using fixed
temperature Weller soldering stations so it took two irons to get any
reflow. A third one would have been handy, but they were not allowed to
move anything between work stations.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Smitty Two]

I DID NOT WRITE ANY OF THE QUOTED TEXT AT THE TOP OF THE PREVIOUS
MESSAGE.

Neither did I, and my name's up there, too! Hey! Be careful about
quoting, you guys.

 

[carneyke]

Smitty Two wrote:







I DID NOT WRITE ANY OF THE QUOTED TEXT AT THE TOP OF THE PREVIOUS
MESSAGE. I have worked in electronics for over 40 years, and did my own
surface mount rework under a stereo microscope. Your recommended
temperature was too low for the work I was doing, because I did a whole
row of pins in one pass, with the corner of the tip. I used .015"
Multicore rework solder, but the reduced contact area required over 700
degrees to allow proper wetting and flow on the leads. This was for
items that are in orbit, BTW.

I am very familiar with the IPC, your publications were all over the
QC inspection tables at my last job. They couldn't tell which pins I
had hand soldered, compared to the joints done by the new Heller reflow
oven, until I showed them the proper angle to look at them to see that
the new joints had more shine than the reflowed joints. (less time for
oxides to form) The running joke was that if they couldn't find my work,
they HAD to stamp it off.

I was teaching proper rework soldering technics in the mid '70s at a
defense plant that built military radios. The assembly people who
soldered had all been certified to NASA standards. It was a union
plant, so I rather enjoyed the angry stares from the union steward while
a final test QA inspector taught new rework methods. As usual, they
were using too little heat to do the job at hand. There were no large
irons allowed on the production floor, and they were using fixed
temperature Weller soldering stations so it took two irons to get any
reflow. A third one would have been handy, but they were not allowed to
move anything between work stations.

--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida- Hide quoted text -

- Show quoted text -

I have to agree with Mike. I found 700 degrees F to work best in my 35
years soldering. Most of my work has been through hole and very little
surface mount.