Do these solder joints look good?

Discussion in 'The Projects Forum' started by CraiGDaniel, Oct 19, 2012.

  1. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Getting a bit more into soldering specifically micro IC's and tiny components.


    I have just finished on this IC off a motherboard. It's the first clean soldered IC ive replaced on the board after lots of practise. Does the connection look good?


    [​IMG]
     
  2. BSomer

    Member

    Dec 28, 2011
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    From the top it looks good. What does it look like when looking at the side of the pins?
     
  3. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Hard to get a capture from the side due to size & location but this is the best;


    [​IMG]
     
  4. SgtWookie

    Expert

    Jul 17, 2007
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    Looks like you are trying to use a flash attachment or integrated flash. That works very poorly for electronics, as many common electronic solders are highly reflective. You need indirect, soft lighting.

    The very best lighting is outside on a cloudy/overcast day; there are no harsh shadows, bright reflections, and contrast is normal. You can somewhat simulate that with a flash attachment by bouncing the light off a wall/the ceiling, or using a white fabric or translucent plastic sheet between the flash and the object being photographed.
     
  5. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    You lost me? Flash attachments for what? If you're referring to the photograph it's a microscope with built in camera function. Not the best but it's the only way you can see those pins as they're literally micro.
     
  6. takao21203

    Distinguished Member

    Apr 28, 2012
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    Looks like SOIC. I saw better solder joints.
    How did you solder it?

    And the sharpness isn't very accurate.

    No. 2 and 3 from the right side, don't look good actually.
    But it could be due to lack of sharpness.
     
  7. BSomer

    Member

    Dec 28, 2011
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    Here is a good close up picture of what your solder joints should look like. At least as close as you can get using the equipment you have at hand. I agree with takao in that the sharpness of the photos is not the best and is really difficult to see if the joints are good. For the most part though the solder joints don't look to terrible.
     
  8. takao21203

    Distinguished Member

    Apr 28, 2012
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    Hmm I think the backside should be filled as well in a way it makes kind of a tangent curve. In the linked photo there is a little more solder than that.

    In the OP photo as it looks the solder fillets only cover the area between the bottoms of the pins and the pads.

    It depends on the specification if backfill is mandatory. The quality is really inaccurate to see if the joints even have contact at all. From my experience, there is really the case when there is no electrical contact, even if it looks relatively good. The difference is just barely visible.

    If OP gives information about the method of soldering, this would be additionally helpful.

    For instance sometimes people at first bridge, then suck off the solder. This does not give relieable results. It is required to flux, and to drag over all joints very carefully. There has to be just the right amount of solder.

    All joints should be uniform. The fillets should include some level of backfill.
     
  9. takao21203

    Distinguished Member

    Apr 28, 2012
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    I looked really carefully. It is quite obvious towards the right and the left of each joint (pin/pad), there is an empty area. The pins are smaller than the pads!

    Again I think the fillets should demonstrate some kind of tangent curve, means there should be more solder.

    I have soldered TQFP on PCBs where the pads are very small, much smaller than TQFP adapter PCBs. It is quite a pain, and it is required to flux, and drag solder all over the pins very carefully.

    SOIC is quite easy if you know how to.

    Better photo please!! Try indirect light.
     
  10. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Thanks guys very helpful


    To clear a few things up;


    Soldering method:

    Iron: Aoyue 968
    Tip: 0.8 Chisel Tip

    I am soldering by fluxing the pads, positioning connector then adding a small amount of solder to the tip of the iron, and pressing the iron against the pins one by one. A small amount of solder transfers from the iron to the joints - but as said i dont think enough is getting through! The light is from the LED's on my microscope but i cant get a better pic. The scope is cheap and low quality even with natural light.


    What would be the correct method to solder a connector as pictured here?

    http://www.google.co.uk/imgres?num=...&ndsp=61&ved=1t:429,r:14,s:0,i:111&tx=28&ty=3

    Noticed the scale of the connector and the iron tip. Tiny components.
     
  11. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    From top or from the side? You need to have quite a lot of liquid flux applied, then looking at that image you posted, you wiggle the tip slowly left-right wihtout going above the pin. This should reheat the pin and pad, while either giving it some solder if it is missing or removing the excess/spreading it across the next pins on the way down.

    I use a 2mm chisel tip with no problems, and I have no problems even with 0.5mm pin pitch devices. You just need quite a lot of liquid flux applied first. Standard solid resin flux diluted with isopropyl works as well.
     
    Last edited: Oct 19, 2012
  12. takao21203

    Distinguished Member

    Apr 28, 2012
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    For SOIC I don't use flux or only a little. I use a cheaper yellow type which is semi-liquid.

    It is correct one or two pins must be secured to the PCB before actual soldering. Normally I press down the IC manually, heat up one pin and then move until alignment is correct.

    For 0.5mm pitch I sometimes let a large drop fall down on the pins!

    Once you have the IC secured, just apply 1mm solder with a broad tip, and pull off the excess solder. SOIC does not take more than 20 seconds altogether!

    TSSOP and TQFP are more difficult, I always need flux for them, and I use a desoldering pump. After all bridges have been removed, I add flux again, and flush all pins to make sure the joints are uniform.

    The soldering in the video you linked is incorrect. Soldering individual pins takes far too much time. Even for 0.8mm it is possible to pull off solder with a broad tip, and applying more flux. TQFP44 for instance is 0.8mm, relatively easy.

    Using a point tip, you can't pull off solder actually. They also oxydize more easily.
     
  13. KJ6EAD

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  14. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Thanks guys for all the suggestions. There is no way i can add solder as i work as the area is just to small.

    This video is of the connector i want to solder:

    http://www.youtube.com/watch?v=TaysonsA2sE

    However whenever i try i always get solder bridges. The part is so small it's unreal.

    If i drag i get solder bridged aswell, and i use a LOT of flux.
     
  15. kubeek

    AAC Fanatic!

    Sep 20, 2005
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    use solder wick to get rid of bridges. If you dont have that, than som fine braided wire might do the trick as well.
     
  16. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    I've go wick. It seems when i use it, it also sucks solder off the pads and joint - leaving it a little short. Any tips to avoid this
     
  17. ErnieM

    AAC Fanatic!

    Apr 24, 2011
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    Watching that I wanted to grab his board! It keeps moving on him, and his tweezers are magnetized and need to be replaced!

    I normally don't use flux. I keep telling myself I should but I never have. I have some, and occasional I remember it and use it.

    My solder is 63/37 .015 diameter "44" rosin core, so I really do use flux. I keep my solder tip well coated in plenty of fresh solder, wipe it on a damp sponge, re-coat in solder, and whack it onto the stand to flick off excess solder, then touch my work. I refresh the tip frequently.

    My solder wick also has flux, unfluxed solder wick is near impossible to work with.

    To solder that beast (I would) first wick off any solder on the pads. One corner pad gets tinned... and holding part in tweezers with one hand iron in other hand place part and flow that corner pin. Rotate board 180 and do the opposite corner, then do the last 2 corners.

    Now your part is nailed down and you can reflow any way you choose. I tend to do individual pins as it is fairly fast for me, while flow & drag makes too many bridges to stop and clean up.

    Also flow & drag leave way too much solder. I've had Nasa certified solders critique my work (it sucked) and their main statements were 1) too much flux left (and I don't use flux!) and 2) way too much solder. *Exery* picture I see here has at least 2x too much solder. The full outline of the top of the lead or component should be easily visible. Solder should just be a fillet between lead and land.
     
  18. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Extremely informative thank you.

    I am going to give you method a try now and tack the connector down by reflowing a tinned pad. When soldering the pins individually (my preferred way) do i just tin the tip with solder and touch it to the pad and lead. Does this cause enough solder to flow or what is the way to do it?
     
  19. CraiGDaniel

    Thread Starter New Member

    Oct 1, 2012
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    Ok so tinning a pad to tack down the connector made my life a lot easier great advice!

    I found a technique that works for me in soldering each pin and thats adding a small blob of solder to the tip of the iron and applying it to the top of the leg and letting it flow down and fill into the pads - works really welli i think! Here is a finished result;

    [​IMG]

    I really cannot get a better picture but that looks good to me? Anyone else?
     
  20. KJ6EAD

    Senior Member

    Apr 30, 2011
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