REWORK SOLUTIONS
THE CHIP QUIK SMD REMOVAL KIT
Included
in each Chip Quik SMD 1 kit is a special low temperature removal
alloy that has excellent wetting ability and melts at 136deg.F
(58deg.C), a special paste flux in a syringe used for solder &
desolder, alcohol pads for clean up, and complete instructions. The
kit will remove 8-10 SMD's depending on the amount of leads.The SMD
1 is the basic starter kit. The complete line of Chip Quik products
are illustrated on the Chip Quik Web site and on the card that comes
in the SMD 1 package.
PLEASE PASS THIS INFORMATION ON TO ALL OF YOUR TECHNICAL
ASSOCIATES
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TYPICAL REWORK SITUATION
In a typical rework situation, an engineer designing a
prototype board may have to change an SMD, install a test
socket or adapter, replace a chip component, lift some SMD
pins for test access, run tests with different SMD components,
run a QC analysis after removing a failed component, etc. A
technician may have to change a defective SMD, install an
upgrade modification, repair a poor solder connection, remove
components from a board, make a field repair on location,
troubleshoot an inoperative board, etc. A contract
manufacturer may have to change a component due to a
production error, touch up solder joints after inspection,
repair a board after going through the ATE (automatic test
equipment), etc. These examples fall into the category of low
volume rework. Fast, safe, easy, and affordable rework is
needed. To send the board out to a rework specialist or to
hire a trained technician would not be practical and/or
economically feasible.
As you can see, becoming proficient at SMD solder/ desolder
rework is to your advantage. You will save time and money.
Also, you become less dependent on others. Best of all, fewer
boards will be scrapped.
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HOW DO I SAFELY REMOVE THAT SMD?
 The removal procedure is included in the
Chip Quik instructions in four simple steps. For learning
purposes, I will explain the procedure in full detail. First,
apply paste flux generously to all the pins of the SMD to be
removed. Flux is important because it removes oxidation and
enhances wetting. Secondly, use a solder iron set at 500 to
600Deg. F with a flat chisel tip. The size of the tip will
depend on the size of the chip leads. With the solder iron,
melt Chip Quik low temperature alloy (136Deg.F) along each
side of SMD. Thirdly, continue running the iron along pins
until a bead of alloy is formed all around the chip. Maintain
the alloy in a molten state long enough to combine with the
interconnect solder (melts at 361deg.F) between the pin and
the pads. Once the Chip Quik mixes with the interconnect
solder, we now have a molten mass of a new alloy with a low
melting temperature below 200deg.F. At this new low melting
temperature the pins stay in a molten state long enough to
easily remove the Chip. In most cases the chip will easily
slide off the pads when it is fully molten. Finally, when the
SMD is held down with an adhesive, applying pressure with a
dental pick will pop off the chip. As long as all the pins are
released, you will not lift any pads. This procedure will
eliminate all potential damage to the PCB.
*This is the basic Chip Quik SMD Removal Method. It is
simple, safe, and affordable.
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CLEAN PADS THOROUGHLY FOR NEW SMD
 It is of the utmost importance
to thoroughly clean all of the pads prior to installing the
new SMD. In order for the new chip to seat correctly on the
pads, we need coplanarity. This means that the adjacent pads
are of equal height. Additionally, this will help the resolder
procedure.
All remaining alloy should be removed from the pads in
order not to allow any foreign material to remain. This will
insure the integrity of the new solder joint.
To clean pads, run a soldering iron with a wide tip along
all pads while polishing them with a swab dipped in Chip Quik
paste flux. This procedure will do an excellent job. I do not
recommend solder braid in this application because of the high
temperature risk of lifting pads. Clean up all the remaining
residue with Isopropyl Alcohol. You are now ready to solder on
the new SMD.
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FUTURE CHIP QUIK NEWSLETTER SUBJECTS
*HOW TO SOLDER THE CHIP BACK ON (in detail including which
method is best for you, how to choose the right equipment, and
which tools are the best.)
*CHOOSING THE CORRECT SOLDER IRON AND TIP (which includes,
what determines a good solder iron , how the right iron can
prevent PCB damage, and heat transfer theory.)
*OTHER UNIQUE REWORK METHODS (which includes hot air
pencil, preheat, convection, and conduction, etc,)
*SOLDER, FLUX, CLEANING CHEMICALS (solder paste, paste
flux, flux removers, etc.)
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THE NEXT CHIP QUIK NEWSLETTER WILL EXPLAIN IN FULL
DETAIL HOW TO SOLDER ON THE THE NEW SMD.
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