Hm
So
An AFM / STM isn't that hard to build, right?
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Dang why does everything have such a high CTE
50 nm per K in Z.... maybe that can be compensated with the right materials to even out... kinda.
Maybe I just build everything out of fused silica and invar
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Ohhh I can build it in a way that the CTEs cancel each other out perfectly(ish)
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This looks... ok?
Provided I can cut the glass, that V-Groove is going to be fun. I have an idea or two.
Tests to be done!
The Piezo (why does fusion render brass blue??) does X/Y/Z for the actual raster, the micrometer provides rough (maybe too rough?) Z travel and the kinematic coupling between both plates in combination with the right material choices should cancel out most of my thermal expansion to keep it all stable.
Piezo - Glass rod - Needle are one replacable assembly.
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The basic kinematic coupling is already soooo satisfying to play with!
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Hmmmnice.
It works as expected, and the kinematics reduce the mvement by a factor of ~3, so every Division moves the center by ~3 um.
Should be just about ok, meaning that the piezo can do the rest of the Z travel.
Issue is that I now need to constrain the ball on the micrometer, which means that I either have to grind a cup in the micrometer shaft or buy a different micrometer with a rounded tip to take the ball out entirely.
...maybe I should build a dremel tool mount for the lathe.
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This feels like it shouldn't work as well as it does
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This will be very interesting under the SEM
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Well that's disappointing, the tungsten has cracked on most of them, and the tip radii are on the order of a few 100 nm
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Just missing a few milling steps on the other side (two V-Grooves for the balls) and then I can try and case harden this thing!
Worst part was getting the blanks round, the lasercut edge was hard enough to ruin a few inserts :(
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Workholding adventures!
I've had a whoopsie or two, but it's functional, doesn't have to be pretty 😉
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And now we're onto the carburizing step!
Takes tiiiime
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Woohoo!
It came out really well, isn't really distorted (nothing to be felt, didn't measure), and the surface finish didn't suffer.
But the real test is to do another heat treatment to harden it, that will reveal if it actually worked!
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Aww yis, the other parts are coming together as well!
I'm really looking forward to machining the glass, I've never done anything like that.
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👀
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🥵
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Hardened and sandblasted!
I really like that finish. Next up is adding a grounding stud.
Not sure what kind of finishing I want then, maybe just a bit of spray paint...
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Lol.
Lmao
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Hmm.
Now I'm not sure where to buy glass that I can actually trust being borosilicate...
But I still want to try something new (to me) here, so I'm thinking about machining the base plate out of slate instead, it's reasonably cheap and still has lower CTE than Soda Lime. Plus it's (supposedly) actually easy to machine!
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But I'll say, even with just a 3D printed base plate the result is already quite satisfactory!
That's a few mm of total travel, easily controllable down to a micrometer, maybe even less. Definitely enough to allow a piezo to servo out the rest.
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B r i c k !
Luckily this "roughly 10x10 cm² Sample" is a few mm bigger in each direction, so I have the stock to clean it up all around!
I'm not sure if I like the look of a round top on a square base, but I also don't really want to turn it round... well, I guess square it is.
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This machines sooo well!
I love it, a real joy to work eith, and finally a cheap "machinable ceramic" aaaaah
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Just a few more parts missing until I can no longer hide from doing electronics.
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More mineral machining!
This time it's a granite plate, as a base for the vibration isolation.
Four holes to epoxy in some threaded rods, and that worked just fine with a diamond hole saw. The rest are simple screws and springs, I entirely lucked out with dimensioning random springs from the hardware store!
Next up are some magnets on the granite, to add some dampening to this Spring-Mass-System, because at the moment it takes over 10 minutes to ring down.
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...and what a ringdown it is!
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Why reinvent the wheel when you can use SEM probe holders on the STM, too.
The thing is held with an o-ring and the fit is oh so satisfying
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This really dampens my vibe
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10 min ringdown to just a few seconds, woohoo!
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@gigabecquerel 600 secs? 🤯😱
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@gigabecquerel 10/10, sehr befriedigend! ^^
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@gigabecquerel don't forget to thank eddy
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@gsuberland ...what a guy!
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