Effect of moon phase on tombstoning

I'll assemble a PCB with a couple of very small components every week and track the effect of moon phase on tombstoning.

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Many factors play a role in the overall outcome of PCB assembly, especially when very small components are involved. Broadly speaking, tombstoning is a problem with very small 2-pin components (0201 caps and such) and we've filtered out the following challenges:
- proper paste application
- component placement
- designing for "good" thermal properties of the PCB with regard to tombstoning
- moon phase
It seems that the effect of moon phase is least understood and researched, so I'm now designing a small PCB that is cheap, not useless (if the assembly process was successful), and - most importantly - contains some 0201 components.

"Something" to be found in these logs:

Full TOC:


0201 footprint used in this project

kicad_mod - 2.47 kB - 05/31/2023 at 07:22


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MagicWolfi wrote 06/14/2022 at 11:31 point

Your project got mentioned in the Macrofab Engineering Podcast #331.  They took it almost serious, made me smile.

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Christoph wrote 06/14/2022 at 11:48 point

lol thanks for the tip, I'll check it out!

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Bharbour wrote 12/31/2021 at 21:07 point

Maybe you need a rubber chicken on your bench? :)

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Christoph wrote 12/31/2021 at 22:18 point

I can add various arcane helpers along the way and see if they have any effect! Thanks for the suggestion

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Dan Maloney wrote 10/19/2020 at 21:04 point

First thing that comes to mind is the SMD Challenge kit on Tindie:

That goes down to 0201, but starts at 1206 so you can get warmed up. Little pricey, but they do have volume discounts.

Good luck, interested to see your results.

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Christoph wrote 10/19/2020 at 21:49 point

Well it doesn't have to be a design that's already done. Designing a custom PCB for this project wouldn't be a problem. I'd then simply order a batch of 25 or so (that would already be enough for half a year)

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Dan Maloney wrote 10/19/2020 at 22:08 point

True, like I said, just what popped into my head. The other thought I had was to pass the boards around to various people who can do the test at various times of the month. Could help get better statistics and possibly control for skill level.

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Christoph wrote 10/20/2020 at 18:08 point

Replying to your top level comment because I can't reply to the other one.

Passing the boards around might be fun, otoh if I just publish the design everyone can add their results to the pile.

I'm now leaning towards a PCB with no actual function that just has some 0201 footprints in two different styles (more and less prone to tombstoning) and with different thermal surroundings. I'd place a mix of caps and resistors, maybe 16 per PCB. That's plenty to get me dizzy for a week until the next is due.

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