surface mount device soldering

Surface Mount Device SolderingMaterials by Linz Craig

Surface Mount Device Soldering

Soldering Iron

The main soldering toolUsed to melt solder

SolderMetal glue used to join together metal partsContains fluxMade of Tin and Copper, sometimes Lead

Tweezers, Clippers, & Pliers

Tools used to handle components and PCBs

Sponge

Used to clean off soldering iron tip Can be made of various materialsShould be used every time before soldering a joint

Flux

Makes solder melt easierAlways use extra flux for rework

Solder Wick

Use to remove solderCareful, it gets really hot!

PCB

Printed Circuit BoardComprised mainly of fiberglass and copper foil

Pads and Leads

Component and board parts that you will solder together

Pads

These are the metal surfaces on the PCB that conduct electricity to the components

Leads

These are the pieces of metal coming out of the components

Safety Goggles

Wear them, you only have 2 eyes and solder is very, very hot! (Like this guy.)

What is oxidization?

Oxidization is what happens when oxygen breaks down matterIt impedes heat and electricity transferAs a result you must clean your iron tip constantly really!

What is polarity?Some parts have to be attached in a very particular way due to polarityThese parts will not work if you put them in incorrectly, pay attentionPolarized parts are highlighted in yellow in your kit cardExample of polarized LEDs

Cleaning your soldering iron

Cleaning your soldering iron is one of the most important aspects of soldering. With SMD we suggest doing it after every jointIf you cant get the oxidization off using a sponge try tip tinner

Perfect solder joint, step 1 of 4

Hold the iron touching one of the pads for a count of oneMake sure to touch the side of the iron tip to the pad, not the actual tip of the iron

Perfect solder joint, step 2 of 4

Feed a tiny bit of solder onto the pad while continuing to hold the iron to the padFeed enough solder onto the pad to cover the pad, but no more

Perfect solder joint, step 3 of 4

Continue to hold the soldering iron on the pad and pick up your component using the tweezers with your other handMake sure the tweezers are making contact only with the sides of the component that do not have leads, otherwise you may get your tweezers in the solder

Perfect solder joint, step 3 of 4

Continue to hold the soldering iron on the pad so the solder stays liquidSlide the component into the solder from the side while keeping the bottom of the component flat on the PCBMake sure you slide the component far enough into the pad so that the pad on the other side of the component is at least half exposed

Perfect solder joint, step 3 of 4

Continue to hold the component on the pad with your tweezers and remove the soldering iron, wait for the solder to solidify and then remove your tweezers

Oops.

If you dont slide the component in from the side you may wind up with a component that does not touch pads on both sidesIf this happens just reflow the solder on the first join and replace the component

Heres How to Use Solder Wick

Apply flux to the solder you want to removePlace the solder wick on top of the solder you want to removeSandwich the solder wick between the solder and your iron until the heat sucks the solder into the wick

Heres How to Use Solder WickThe solder will flow into your wick and the wick will turn silver with solderThis may take a while, be patient and apply constant contact with the ironTry rolling the soldering iron along the wick if youre really having troubleYou might also want to try cleaning your iron if it isnt working

ICs are Tricky!

Tack down a corner lead of your IC onto the corner padDo this just like your other componentsDont worry if you accidentally solder two leads (you can clean it up with wick later)

ICs are Tricky!

The most important thing is to make sure that the IC is flat and all the leads line up with the pads

ICs are Tricky!

To keep the IC in place next solder the lead on the bottom right corner (or the corner diagonal from your first solder joint)

ICs are Tricky!To keep the IC in place, next solder the lead on the bottom right corner (or the corner diagonal from your first solder joint)

After that put solder on the rest of the leads and pads

Dont worry if you wind up with a lot of jumpers, you can clean them up later

Cleaning Up an ICSome people will create jumpers on the IC leads on purpose and clean them up with wick later

You can also apply flux to the jumper and if there is not too much solder, push the iron tip between the IC leads. This will melt the jumper that is connecting the two leads

Cleaning Up an ICYou can also use the solders tendency to be drawn towards heat to push or pull the solder along the IC leads to a corner lead and then use wick to remove the excess solder

To do this you will need to touch at least two leads at once with your soldering iron, constantly clean your iron and use a lot of flux

More InfoThere is a whole bunch of info on SMD soldering, stenciling and rework here:

http://www.sparkfun.com/tutorials/category/2

http://www.youtube.com/watch?v=wE4BoCNXRXA(Just Google SMD Solder SparkFun Tony)

Questions?

www.sparkfun.com6175 Longbow Drive, Suite 200Boulder, Colorado 80301

*

*

*

*

*

*

*

*

*

*

*Polarity, multiple leads

*Polarity, conductive portions,

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*

*