https://www.youtube.com/watch?v=dz7ltWBDm7U
Notice how in the second part of the video, once the solder has melted, the body of the BGA moves so it is correctly centred over the PCB pads. This is happening by itself, without an external influence pushing the chip into position.
Small BGAs can be hell to hand solder.
Surface tension acts on all the solder balls, pulling the package into place along both the X and Y axes. So once the first few balls are in place, the whole thing “snaps” into alignment. Misaligning only some pads while others are perfectly aligned isn’t possible unless something’s seriously wrong, like a warped board or damaged package.
It’s an all-or-nothing situation—either everything aligns, or nothing does.
It's possible when your pcb-making process is on the odge of what designer wanted. Some pads on some boards may be not perfectly aligned in such cases. Or the board was heated not enough or in too short time and not all balls melted properly. Or it cracked under stresses because designer put too much vias in one place near the chip.
> It’s an all-or-nothing situation—either everything aligns, or nothing does.
In theory, practice and theory agrees. In practice, it sometimes does not.
In the extreme misalignment example they also did not use flux so I guess they were purposefully showing what NOT soldered looks like. They did show how the solder flows in the "too much solder paste" example.
A few years ago I had quite a lot of fun with one of those cheap $30 wireless USB microscopes with up to 1000x magnification that connects to some app. My family and I always came up with new ideas about what we should look at next. Incredible fun. Unfortunately it broke down rather quickly. But it opened up the world much more than traditional backlight microscopes I am used to. They are basically “just” specialized cameras with bright flash lights.
I wonder if prices have come down a bit and if there are good options out there for such a portable microscope that doesn’t break so quickly. Better quality and magnification in the $200 range?
Such amazing scope is built in into 70k professional SMD rework station I use sometimes for complex repairs. Replacing RAM and processor chips is easy, but slow. Honestly I don’t think, that the scope in video is extraordinary expensive. Definitively cheaper than my old Olympus gear.
- simple boards you can probably solder with a cheapo (~50-100$) soldering system, or a solder-paste+hot air machine setup
- components you can get for very cheap from LCSC, aliexpress or at okay prices but good reliability from digikey, mouser etc.
You'll also need stuff like multimeter, ocsilloscope, logic analyzers, etc for debugging your boards but you'll know when you need them, and there are cheap-enough options available up to the point when you start doing advanced stuff and you know what you need.
Here's a SparkFun blog post: https://www.sparkfun.com/news/3319
I'm not sure. Back in the day we avoided SMD like the plague and it had a reputation of being unapproachable. THT parts were highly sought after and I would even say that a good deal of the success of AVR was because they offered THT versions of their µs long after most others had stopped. Some of us even engaged in the uphill battle of lead-free soldering only to be disillusioned.
We thought hand soldering will die with THT but it didn't.
I see a young generation that has mostly overcome these hurdles. With their young steady hands, sharp eyes, high-lead solder, small temperature controlled irons and other modern equipment they just go about. I envy them.
For what it's worth, I took the time to learn leadless soldering specifically so that I could teach my kids. I like to introduce them to safe hobbies (that why they all went skydiving before their 10th birthday, too).
This allows burning away and tinning enameled wire with the soldering tip.
Though there are only two lead-free solders that qualify. I use the Felder Ultra-Clear EL Sn100Ni+. The other one is the Amasan BF32-3.
As for “high lead solder” - you won’t buy it in Europe. We had to learn using lead free for rework and you know what - it’s not much different, assuming you have high quality equipment.
That's bollocks. You can buy leaded solder in Europe just fine. You only need to worry about lead-free if you want to sell a commercial product.
Also stuff like reflow solder is/can still be done by hand! Its a common thing to do if you need to touch up or modify a PCB and dont want to reflow the whole thing/damage any components
It's also a necessary skill in a lot of technical hobbies. Modular synthesis by means of DIY modules, the whole mechanical keyboard thing, electric guitar maintenance...
Let me tell you that I'm holding up the flag. Very poorly and with shaky hands, but I'm trying to hold it up... :-D
They don’t have an API which is a big miss from my perspective. Every inspection requires a human operator to drive the thing.
Now that being said, I would have never been able to record such a high quality video! The depth of field in particular is really amazing :)
https://amscope.com/collections/stereo-microscopes-zoom-powe...
https://eakinsmicscopestore.aliexpress.com/store/3200040/pag...
With 10x eyepieces and a 0.5x auxiliary objective, these scopes provide a very useful range of 3.5x-22.5x magnification and a comfortable working distance. At the minimum 3.5x magnification, the standard widefield 10x eyepieces give a field of view of about 50mm.
They are available in various bundles with a wide variety of stands and accessories; the essential accessories are a ring light and a 0.5x Barlow lens. I would recommend the biggest, heaviest boom stand you can reasonably fit on your desk, because any instability in the stand will be greatly magnified in your vision.
The key to using these microscopes successfully is to adjust the parfocal, which will allow you to adjust the zoom without having to refocus.
https://www.youtube.com/watch?v=R00KyVGRMpc
The preferred industrial option is the Vision Engineering Mantis, which uses very clever projection technology to provide a stereoscopic image without eyepieces. The ergonomics are dramatically better than a conventional stereo microscope, but you'll be lucky to find a used model on eBay for less than $1000. A big investment for a hobbyist, but worth every penny if you've got back or neck problems.
https://www.visioneng.com/products/eyepiece-less-stereo-micr...
One thing to consider is the light. I was never happy with the light on this scope, and instead use a different flexible desk lamp. Most of the ones mounted to the scope have pretty short stems, and can't be positioned to shine from the front, or very low to the side.
[1] https://amscope.com/products/c-sm-4ntp-64s?variant=414205946...
* The hot plate I used was the "Presto 07211 Liddle Griddle", which worked well. https://www.amazon.com/gp/aw/d/B00006IUWL
Though I’ve had many a SOICs magically realign on the hot plate — they were pretty forgiving — it’s not worth it to run without proper temperature profiling, even if it’s from a hacked toaster oven :)
Reddit says around $70k: https://www.reddit.com/r/microscopy/comments/nqo4qy/keyence_...
What are the tradeoffs on particle size?
See:
https://fctsolder.com/solder-paste-type-3-vs-type-4-vs-type-...