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geekhack Projects => Making Stuff Together! => Topic started by: vatin on Wed, 28 August 2013, 10:00:58
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I tried soldering some smds on one of the pcbs. Do you think this has some hope in it?
It is harder than it looks. It is difficult to get the lead where I want. I'm struggling because the lead keeps sticking to the iron. I am considering whether to abort and get something pre assembled. Or may be pre assembled ergogp down the line.
*Edit1
With much effort, I have completed my ergodox ;D
http://geekhack.org/index.php?topic=42772.msg1407236#msg1407236
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Unless you've burned the pads off the pcb, there is hope yet!
Disclaimer: I have not soldered SMDs before, but I do have experience soldering.
I would try it this way:
Ignore the SMD at first. Use your iron and solder to load a small bit of solder to the two pads on the pcb. You don't need much. Most of the solder will stick to the iron, this is fine, but a small amount should stay on the pad.
Next up, forget the solder, and get your SMD and whatever you're using to manipulate it (pliers, helping hands, etc). Hold the SMD over the pads so that (in this case) the two legs of the device are touching the solder covered pads.
Press your iron to the legs of the SMD. This should melt the small amount of solder on the pads to the legs.
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the ergodox pcbs can take quite a bit of punishment, so no, it's probably not ruined yet. but you do need to do some clean up work, and learn how to solder smds properly.
What kind of gear do you have at the moment?
Edit: If you have a soldapult or a similar pump/wick, you probably should get rid of that excess solder in the holes for SW1:4 and 1:3, although they shouldn't affect the functionality of the board if you do leave it in.
For tacking smds, this link is a pretty good guide.
http://store.curiousinventor.com/guides/Surface_Mount_Soldering/Resistor/
basically, ignore the smds first. solder flows to wherever the heat goes, so you melt a tiny bit onto one of the pads, just enough to cover the small square. Then you place one end of the smd (do keep in mind that there's a directionality to the smd) onto the pad with the solder, apply the soldering tip to that end. The smd should slip in place easily enough once the solder melts. A pair of tweezers might help make the job easier. After that is done, it is much easier to apply solder to the other end.
Gets easier once you get into a rhythm - I'll tack one pad for every single switch position in a row before I even start placing the smds. Rinse and repeat.
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Solder doesn't stick to "dirty" pads. You need to have flux.
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Ideally, pick up some solder with rosin core and you won't really need separate flux. What solder do you use? Your soldering iron tip might need cleaning/retinning/replacment.
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Ideally, pick up some solder with rosin core and you won't really need separate flux. What solder do you use? Your soldering iron tip might need cleaning/retinning/replacment.
That depends on technique too however. I prefer separate flux since I prefer to use a small blob of solder on the iron without adding more since SMD is so tiny. You just flux the pads, stick the devices to the flux and then hit it with hot solder. This also lets you use your off-hand for holding the device down with tweezers and not needing a 3rd hand to play with the solder wire.
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That depends on technique too however. I prefer separate flux since I prefer to use a small blob of solder on the iron without adding more since SMD is so tiny. You just flux the pads, stick the devices to the flux and then hit it with hot solder. This also lets you use your off-hand for holding the device down with tweezers and not needing a 3rd hand to play with the solder wire.
^^^^^
This!
separate flux, and life is easier!
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It isn't as bad as it looks.
I would suggest this:
1. Add flux to the pads
2. For each SMD add solder to one pad, no SMD required here
3. Hold the SMD with a pair of tweezers and then just heat the solder you added in step 2.
4 Carefully solder the other end of the SMD.
Remember to periodically clean your soldering iron.
Watch WhiteFireDragon's videos for assitance.
What soldering iron are you using?
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to be honest i would say that you give it to somebody else to assemble (mainly to protect your investment)
or if you want to spend a little more on equipment and have the courage to go on, you can do that too.
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It isn't as bad as it looks.
I would suggest this:
1. Add flux to the pads
2. For each SMD add solder to one pad, no SMD required here
3. Hold the SMD with a pair of tweezers and then just heat the solder you added in step 2.
4 Carefully solder the other end of the SMD.
Remember to periodically clean your soldering iron.
Watch WhiteFireDragon's videos for assitance.
What soldering iron are you using?
Best advice, right there.
I solder surface mount resistors for work and that's exactly what I do.
1. Tiny bit of solder on one pad
2. Hold the component on pad, solder join and hold for 1-2 seconds
3. Solder other side carefully while holding component down with tweezers to prevent movement.
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It isn't as bad as it looks.
I would suggest this:
1. Add flux to the pads
2. For each SMD add solder to one pad, no SMD required here
3. Hold the SMD with a pair of tweezers and then just heat the solder you added in step 2.
4 Carefully solder the other end of the SMD.
Remember to periodically clean your soldering iron.
Watch WhiteFireDragon's videos for assitance.
What soldering iron are you using?
Best advice, right there.
I solder surface mount resistors for work and that's exactly what I do.
1. Tiny bit of solder on one pad
2. Hold the component on pad, solder join and hold for 1-2 seconds
3. Solder other side carefully while holding component down with tweezers to prevent movement.
Thanks man. My uncle taught me this technique, they own a factory assembling cheap electronics.
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AHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHHhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh.................................
It's a sin dude!
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I use what I have which happen to be the cheapest soldering iron.
I've changed my plan. I desoldier those SMD and decided to go with through hole diode instead. So far so good. I've finished one hand already.
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Before anything, make sure your iron is hot enough. I can't stress the importance of a good soldering iron for SMD work. Solder sticking to the iron makes me thing that the tip isn't hot enough. I used a Hakko FX888D set to 700 degrees and it works beautifully.
As far as soldering the SMDs themselves, here's how I did both my ErgoDoxes:
1. Make sure you use decent rosin-core (important!) solder. In my experience the lead-free stuff is a pain in the butt for electronics like this. I just picked up a roll of this (http://www.radioshack.com/product/index.jsp?productId=2062717&filterName=Brand&filterValue=RadioShack) from my local Radio Shack.
2. I start off by applying a tiny tab to one of the pads, just enough to bead.
3. Then, I use tweezers to place the SMD with one of the contacts resting on the bead.
4. Apply the iron to the contact, and when hot enough it should just "sink" into the bead of solder already placed.
5. Apply a tiny bit to the other lead.
Usually I'll do the same step to a bunch in a row, for instance I'll do #2 for an entire row, then #3 to the whole row, then finally #4. On my last 'dox it was able to do an entire PCB in like 15-20 min. Both my ergodoxes worked perfectly the first time using this technique.
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Before anything, make sure your iron is hot enough. I can't stress the importance of a good soldering iron for SMD work. Solder sticking to the iron makes me thing that the tip isn't hot enough. I used a Hakko FX888D set to 700 degrees and it works beautifully.
Hmmm, personally I do prefer hot air instead of hot iron.
Less chance to make mistakes and it's easier after you get the way ...
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Yeah but buying a hot air rig for one board is a bit overkill. Of course if you're going to be doing a lot of SM work then go for it
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Yeah but buying a hot air rig for one board is a bit overkill. Of course if you're going to be doing a lot of SM work then go for it
Agreed. Hence my choice for through hole diode.
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0603 resistor
I like to use this technique myself. I generally tin one of the pads first, with only enough solder to make the component stick. Then apply flux, solder the other pad, and then move back to the first one again. If the solder only sticks to the iron, the solder contact areas are either dirty, or they don't heat up enough.
Going even smaller
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On a related matter, since I've gone with the through hole route, would you recommend facing the diode up or facing the diode down? And should those legs that protude from the opposite side of the diode be trimmed flush to the PCB or could I leave a tiny stub, say 1 cm and just fold them flush with the PCB?
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On a related matter, since I've gone with the through hole route, would you recommend facing the diode up or facing the diode down? And should those legs that protude from the opposite side of the diode be trimmed flush to the PCB or could I leave a tiny stub, say 1 cm and just fold them flush with the PCB?
I have mine on the underneath, I doubt for the through hole you can have them on the top side, I doubt there is enough space.
I left a stub of 1mm, as anything more and the acrylic layers wouldn't lay flat on each other
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Another question. Is the bottom diode needed? Come to think of it, there is no switch there. Should I remove it? Or it's ok leaving there as dummy.
Wfd demo video did soldier an smd at such location.
While in one of the massdrop instruction picture showed a diode missing at such location, so I assume that's a dummy location? As in it does nothing whether you put there or not?
(http://img.tapatalk.com/d/13/09/07/te5y3yda.jpg)
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It doesn't matter that there is an extra diode there, it won't make any difference.
Nit-picking, but you should use enough solder to make it flow out into a cone shape around the component lead on both sides of the PCB, according to guide-lines. The gold contact surfaces should be covered.
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also make sure the diodes are in the right orientation.
It makes a difference for diodes! not for resistors though.
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I don't see why he keeps adding the solder to the tip in advance. I find it a lot easier to get the correct amount by holding the solder against the joint and then pushing the iron through. Some would probably say it is just as bad for the fluxing. But it gets you the correct amount of solder anyway. Drag soldering is another story, but I almost never do that.
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also make sure the diodes are in the right orientation.
It makes a difference for diodes! not for resistors though.
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this, it is looks like from these pictures the direction of the diodes isnt being followed
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also make sure the diodes are in the right orientation.
It makes a difference for diodes! not for resistors though.
I'm surprise this is not mentioned even once in the assembly instruction!!! I soldered them in every which way I can pick them up!! After all these effort I've ruined my investment afterall.
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also make sure the diodes are in the right orientation.
It makes a difference for diodes! not for resistors though.
I'm surprise this is not mentioned even once in the assembly instruction!!! I soldered them in every which way I can pick them up!! After all these effort I've ruined my investment afterall.
uhm......
Step 2.
Solder the diodes onto the backside of the PCB for both the left hand side and right hand side PCB. Note the cathode of the diode (denoted with a line) connects to the square pad on the PCB.
Source: https://www.massdrop.com/ext/ergodox/assembly.php
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Thank you I missed that bit. i'll try de/resoldier them today.
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Second though, I'll recycle switches and keycaps and use them on the pre-assembled ergogp and sell off the unsoldier teensy and ergodox case.
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With much effort, I have completed my ergodox ;D
http://geekhack.org/index.php?topic=42772.msg1407236#msg1407236