Soldering Techniques For Tiny Chips to Tiny Boards

I have soldered some pretty small pots on some small boards, along with the clips, I had several 2 x 4's stacked, to rest my wrists on. There was no way I could keep steady enough without make shift wrist rests.

Good luck. I won't even try to solder surface mount devices (SMDs).

You some trained ant solderers.....

I have a copper wire scorpion that will eat that guy up and spit him out!

www.nve.com/Downloads/AAT001.pdf

Fairly easy; no alignment jig needed, but, I'm not sure that a USB microscope will do the job.

I thought my soldering days were over, and I thought it was my hands which could no longer cope, but, someone bought a proper 3D microscope for the lab (Mantis I think), and suddenly all my hand trembling disappeared.

Surprisingly I normally only use it on 4 times magnification, I think it's the fact that it restores/enhances your 3D vision that makes the difference.

I don't know how easy it would be to borrow the use of one though.

I am thinking my USB one is really good at inverting the image so that up is down, right is left, and so on. Kinda like US Congress right now.

Yup you beat me to it! GA from me.

Look into reflow soldering and low-temp eutectic solders. If you take care to properly shield the package you can reflow with a heat gun.

Laser soldering might be good for this.

Except I don't have the freaking laser. I live in Low buck TX, after all.

I don't have any experience with it, but one would think that the power requirement might be (nearly) in the range of an adapted laser pointer.

A hot-air solder-reflow pencil in conjunction with solder paste is much safer than working with a laser powerful enough to melt solder, and for microscope work there are no safety goggles to get in the way.

Most of the specific and latent heat numbers for metals are fairly modest. Melting 0.1mm droplets of solder doesn't take enormous power.

This technique is called Laser Depaneling.
https://www.solder.net/services/pcb-laser-depanelization/

GA, Sir Robin. Funny you should mention using a toaster oven. I was chatting online with someone else who rigged-up up microcontroller to a toaster oven for that very purpose. The controller regulates the heating element temp using PWM, measures the board temp, manages the timing, etc. Works quite well she said.

The microcontroller sounds like over-kill. Some people do things because THEY CAN. (I'm guilty too. I assembled an outdoor duck pen with biscuits and finely mitered joints. ) My co-worker just did a little experimenting with the 'toast' settings and found #6 worked just fine every time.

I think we gave our toaster oven to a homeless guy (I have no idea how he was supposed to find an outlet in his tent to plug it in), so I might hit the pawn shops.

On the other hand, I have a testing oven made for heating phonon cells I made, and it was able to easily reach 145 C. I did not use the largest lamp I had on hand for that run. I have a badass lamp I can install in it, and temperature monitoring is with a cooking probe.

Voila - one homemade reflow oven.

What BSR outlined is precisely what the guy at NVE said they do when testing. Tin everything, and reheat each.

Thanks for the timely tip.

That sounds easy and perfectly within my ability.

Work such as yours is accomplished with a tiny heat gun [hot air wand]. Other areas are masked off with mylar tape [heat tolerant] and the hot air is applied only to the part. When the solder melts the part settles into position by the surface tension of the liquid solder. There is a dance to be done between blowing the part, or others, off of the board before the magic happens. To help that case, preheating of the board always helps. Typically there is another heat-gun below the board in a bracket assembly holding the board using very low heated air volume. The board is warmed up so that the application of the hot air wand can be very brief limiting stress on the parts to be soldered and adjacent parts.

The reflow process could be done with a soldering iron applied to the part. I would never do this for anything I intended to deliver to a customer, I consider it a post apocalyptic need it to survive tactic only. You want to heat the part as evenly as possible. Might seem funny but put flux on top of the part if you try this.

So, how do you wash the flux off later? Alcohol? Distilled water?

I will check and see what my electronics supply house has to offer, in terms of hot air pencil, paste solder, flux, etc. I think I might try several of the various suggestions, and get pack with the panel and report what is really easy for a one-off solder job like this. I am not selling the finished product. That might come a few years down the road, but certainly not right now.

Without trying to sound rude:-

At least it is not canned pee - "Piss Off!"

What I learned about (electronic) soldering.

Farm it out. Life is too short to solder.

Find a local outfit that has some folks into serious micro-soldering. In this case, it was someone close to the commercial side of your sensors - a bunch of neuro stimulator/sensor probes for juicing up the nervous systems of frogs, flies and worms. They had 15-20 folks, all women, putting this stuff together under microscopes, several of whom were set up at their homes.

I took the QA/QC person, also woman, to lunch. She knew the one for moonlighting, connected me and I was off and running for several years, mostly with repairs to NDT stuff that I work with made on distant shores, and that put me on the phone for hours in the middle of the night while multi-metering and oscilloscoping with marginal speakers of English in tech support. Along the way I also started getting help from a couple of geeks at the local community college, but they were more into conversation and ''cool'' electronics.

I absolutely hate soldering...of anything. I do a lot better with welding and brazing.

No, No, NO! Buy a small tube of low temperature soldering paste such as this product made by Chip Quick. Once you use it you will never use regular wire solder again. It is composed of micro balls of solder in a flux paste and, when you heat it (even with a large solder tip), the solder balls melt and condense onto the nearest cold metal surfaces. The less the better, else you will create solder bridges (which can be removed by wick or a sweeping action away from the part with your soldering tip).

Also, keep your temperature lower on SMD components or you will melt the internal connections between the pins and the substrate or chip.

Thank you and God Bless You, I copied the link from that page and emailed it to myself for later ordering and use (this week, hopefully), that is the answer I must have been waiting for.

You are most welcome. I was delighted when I saw how well it worked. I may never use regular solder again.

NotUrOrdinaryJoe, thank you for this information. Will definitely try it if I can source a supplier in South Africa. Do you actually keep the product refrigirated?

I only keep it refrigerated when I'm not going to be using it. The problem is that it cuts the storage life in half if left out on the shelf. By that, I mean that it drys out making it very difficult to dispense.

_{Thank you for the information.}

I own one of these and it cost me about £30. Takes practice but I have done some very improbable soldering. No solder paste needed, just thin solder wire and tin the pads with a conventional iron. Get a flux pen and use what seems like too much flux ...it will stop solder joining where you dont want it to. Also use tweezers and plenty of light. If you have not done this before practice for an hour or four on an old surface mount board..taking components off and splodge of flux... put them back. ---Ensure ventilation----. Its fun.

THEE 450W 110V Durable LCD Display Easy Hot Air Heat Gun Soldering Station with 9 Nozzles US Plug