Hey all!
I have had a few customers ask about soldering SMD LEDs (especially the teny tiny 0603 package) and I thought I would write a small tutorial about it so I can refer people to it.
The Tools: The first thing you need when dealing with SMD components is a pair of needle nose tweezers! YES, this is the most important! You cannot place an 0603 package without a very fine pair. Of course you will need good eyesight to accompany them hehe.
The second is a good fine tip soldering iron. I personally have a Dick Smith Q99531 soldering station (replaced by
T2250 I think). However, I am an electronic engineer and do a LOT of SMD soldering. If you don’t do much, just get one of those hand-held ones and make sure it’s got a fine tip such as
this one here.
The third important item to have is some fine solder! NO butty solder will do here, you need small stuff such as
this 0.56mm from DSE. Don't worry about lead free crap if your only doing your own projects because you need a special high temperature iron for that and its harder to work with.
The Plan: OK, so you want to know how to solder these little suckers onto the circuit board? Well, there are a few tricks to use which make life very easy! I find these steps the best:
1. Put a bit of solder on ONE pad. This applies to even larger components such as 144pin packages etc.
2. Hold the component with the tweezers in one hand and the iron in the other align the component in place.
3. Solder that ONE pad with the solder already in place. Make sure the component is in place. If you need to re-align the component do it now.
4. Proceed to solder the other pins of the component.
5. Optionally you can reflow the first pad you soldered with a touch more solder to get a good connection. This is because sometimes once the solder is heated twice it loses its flux and can be brittle, so re-flowing with a bit more solder gets a good connection again.
With these steps, your not trying to hold the LED, iron and solder all at once!
Advanced Soldering: If your dealing with a large package such as a 144-pin microcontroller the pin pitch can be as small as 0.5mm, and so it can be hard to apply solder to the pins without them getting bridged. One option is to use solder wick to remove these bridges, however I find it best to apply a thin film of solder to all the pads first. Then place the component and heat each pin enough to re-flow the solder on the pad underneath. This is enough to give a connection and no bridges are formed.
Other Thoughts: A good setup goes a long way to good soldering. Make sure you have a clear bench at a good height to sit at. You will need good lighting so a desk lamp may be handy. If you will be doing a bit of SMD soldering, make sure you get fine solder wick as well as you might need it.
I am an electronic engineer and I am ALWAYS doing fine SMD soldering. When I am designing a board, I use 0603 resistors and capacitors as standard because I like to make my boards small and usually have much to fit in!. If you have any questions about soldering SMD components, feel free to post below.
