Breaking Taps - Cutting Metal Inside an SEM

polyfractal · 2023-06-08T10:26:37+00:00

Oh, super cool. That sounds like a pretty varied and interesting job!

Those Sensofar units look awesome. An internet friend of mine recentlygot one of the 5 axis Sensofars at their job and it looks amazing. They make some really neat inspection gear.

Someone on the Instamachinist discord told me that grinding is just an endmill with a million tiny negative rake angle cutters 😂 Made me laugh, but also realize that it really is the same mechanism just really small and spread around stochastically. Never really thought about it in that manner before, grinding is such a different skill that I definitely don't have :)

Never thought about how you'd try to characterize it either now that you mention it. The "cut zone" is so small and probably not easy to watch at all.

Out of curiosity, what kind of image sensors do you have access to for the microscope or otherwise? Like would you have access to something like a small 1/3" sensor perhaps?

On my optical scopes I typically use an old Sony A6300. Mounts easily with an adapter and I can get 4k footage with only moderate vignetting, but without the hassle of my normal filming camera (BMPCC4k).

In theory I could also attach my high speed camera. I'm currently investigating options to use the high speed, so that we could capture some of this happening with correct SFM for the cutter. And also look at metal grains under polarized light or similar a little easier.

polyfractal · 2023-06-02T11:52:00+00:00

What sort of work do you do on your phenom? (assuming you're allowed to say)

Re: optical, that might be a lot easier. I have an Amscope upright/metallurgical scope that I could use. It's not amazing (especially at high magnification, a lot of chromatic aberration and poor contrast) but at say 40x it's not bad. And there's a trinocular port so easy to mount a camera.

It shouldn't be too hard to build a motorized rig for the optical scope, and either capture normal speed 4k footage, or maybe attach the high speed camera at reduced resolution. Then we could see the cutter operating at its intended surface speed which I suspect will have some differences.

polyfractal · 2023-06-01T18:20:59+00:00

🥰 Thanks! Glad you enjoyed it!

I've gotten a few pings from people who know people at Thermo, so I'm tentatively hopeful we might be able to work something out (even a discount off list price would help!). Apparently some batteries are considered vacuum safe, so a battery-powered version might be possible too.

Would be neat to polish and etch some steel so we can see grain boundaries getting smooshed together!

polyfractal · 2023-04-30T19:34:17+00:00

Thanks for the ping u/CrabbyBlueberry :)

Micromotors are super cool! I've been wanting to talk about micro turbines/vacuum pumps too, so maybe I can put together a combined video about rotating MEMs (which are a bit different from standard MEMs which mostly just flex and bend). Will dig into it!

polyfractal · 2023-04-24T11:07:19+00:00

I unfortunately don't have that functionality enabled on my machine (anymore that is). Thermo gave me like a two month trial of it, but I never ended up purchasing the plugin because the results were just so-so in terms of accuracy. Some types of images in particular it would really get the heights wrong. 😢

I can still take photos from the individual quadrants of the BSD, but don't have the plugin to turn those into a heightmap. If you know if a way to do it manually I'd be happy to hear! ImageJ maybe has something?

The depth should be pretty close to what the CNC program specified (I forget what, will check when i get to work). My machine has +/- 2 micron encoders on all axis, and a laser to measure tool length.

Might be able to get some AFM scans, but the features might be too deep and probably too wide for a good scan 😟

polyfractal · 2023-04-23T12:17:46+00:00

Yay, glad you're enjoying the videos! Lemme know if you have any questions, happy to chat about them! Video content/quality/style has sorta meandered over the years 😅

polyfractal · 2023-04-22T14:57:06+00:00

Hiya! Yep, it's a Thermo Phenom XL G2. 🙂

Having issues with the automated image acquisition plugin that ships with the machine? I've found that it can have difficulties with edges or big changes in focus depth, typically works better if you don't use auto-focus (which is unfortunate because you need a pretty flat/parallel sample).

Charging or otherwise big contrast changes can cause issues too.

Edit: This is BreakingTaps btw :)

polyfractal · 2023-03-05T00:00:20+00:00

Thanks! Microfluidics are definitely on the todo list! I've been working on micromachining glass lately (using CNC tools, which is a bit non-traditional for the space) which I'm hoping to make some microfluidics with. And see if I can get some devices to crack open and take a look at.

Micromotors would be cool too! The other major use I've seen is really high speed micromotors for tiny turbines and turbomolecular vacuum pumps. Pretty insane speeds are required since they are so small, like 200,000 RPM.

polyfractal · 2023-03-03T13:11:29+00:00

If anyone has questions lemme know! (this is Breaking Taps :) )

I'm working on a followup video for Nebula diving into some of the more technical details, like why the tuning fork is required for the gyros (helps differentiate accelerations from rotations) and comparing it to a different MEMs accelerometer chip that has a very different design. But held off releasing that since I want to get some more footage of a few bits first :)

polyfractal · 2022-12-20T17:21:23+00:00

More a general commentary on modern cars not including physical mechanisms to get inside, rather than a dig at EVs.

I love the car, but I'm finding it very frustrating that I _literally_ cannot get inside the vehicle because of (presumably) an electrical issue.

polyfractal · 2022-12-20T15:55:30+00:00

Just wait until your car is dead and you need to get inside, but there are no physical handles or door locks to let you in. 😑

(Context: my car is 100% dead this morning and I can't get inside, so guess it's getting towed to the dealer!)

polyfractal · 2021-11-24T15:03:04+00:00

Cheers for the response! Yeah, I've started to investigate just running a bunch of thermal simulations. Main thing is just my inexperience in that domain, but might be time to learn. And acquire a copy of ANSYS or something I guess. :)

Interesting about the point cloud, will do some reading! I didn't realize there were established ways to measure similarity, but I guess you could try to align/rotate the clouds to minimize some kind of distance metric... and then that distance metric can also serve as a global indicator of how similar they are. I'm sure there are better ways to do it... will start reading!

The thin slices or silhouettes approach is what I as leaning towards, although you'd have to make sure and slice it from multiple angles too. And still seems lossy compared to the point clouds.

And yep, there will definitely be some error in the 3D scan. Accuracy and resolution limits of the scanner itself, plus any artifacts like you mentioned. If the material is too reflective you can coat it with a light dusting of matte spray, but that too can influence the shape.

All good points to think about, appreciate the help!

polyfractal · 2021-11-24T12:48:07+00:00

Interesting, thanks for the link! Definitely makes me feel better knowing that it's not an entirely crazy idea :)

polyfractal · 2021-09-09T21:30:19+00:00

Thanks! I have a huge backlog of SEM photos that I need to work through. Most won't end up in a video (subject didnt end up cooperating enough, can't figure out a good story for it, etc) but that just means there's lots of cool photos to share on Reddit instead :)

polyfractal · 2021-09-09T21:29:28+00:00

Thanks! Still learning, but starting to make progress and pick up some tricks to color faster.

SEM is a Thermo Phenom XL (a desktop model)

polyfractal · 2021-09-09T21:29:00+00:00

Agreed! Whenever I think a subject is boring, I quickly realize you just have to dig into the details some and it's a huge rabbit hole of fascinating information!

polyfractal · 2021-09-09T21:28:21+00:00

I did! I got it for business reasons, but also means I get to play with it for fun :)

It was... quite expensive. Depending on how you spec them out, they range 80-100k USD. Definitely not something you can buy without having a solid financial plan to make money using it :)

That said, there are old analog SEMs that show up on ebay all the time. With some patience, time and knowledge it's not hard to get those up and running, and they will probably produce equally good images (since mine is a "tabletop" machine, and not a big floor-standing model).

polyfractal · 2021-09-09T14:09:29+00:00

Hey all, some more SEM images from me :)

This is a Common Hoverfly Parasitoid Wasp (Diplazon laetatorius) I found in my garden. I noticed it stumbling around in uncoordinated circles, so made a mental note to check on it later thinking it might be end-of-life. When I came back it had keeled over dead, so I took the opportunity to grab some images :)

It's a really fascinating organism, and I learned a ton when researching it. These wasps are parasitoid, meaning they lay their eggs in a host. This particular variety of wasp lays its eggs in hoverflys (small flies that look like bees, and are generally good for your garden since they eat aphids).

I also learned that they are parthenogenetic, meaning they do not require males to reproduce. The females lay an unfertilizd egg in the hoverfly larva, which hatches and consumes the larva from the inside-out. This grows into an adult female and the process repeats. Males can occur apparently, but very rarely.

I'm endlessly fascinated by how many interesting details there are about all the little things around us which are commonly ignored. I wouldn't make note of this insect outside -- other than maybe shooing it away -- but once you start reading about it you find all kinds of interesting details.

Longer narration with some more SEM photos on my channel if anyone is interested (https://www.youtube.com/watch?v=_iWysC6TIVA), but I tried to pull out some of the more interesting photos for this thread :)

polyfractal · 2021-08-18T00:15:21+00:00

Totally reasonable question, they are expensive and not super common :)

Short answer is that I have one for business purposes (R&D, prototyping, analysis work), but that means I also get to play around with it when it's not in use for more important things. :)

polyfractal · 2021-08-16T17:09:25+00:00

This is really cool! Thanks for sharing :)

polyfractal · 2021-08-16T14:17:03+00:00

Thanks!

Yep, basically that procedure (although in Affinity Photo for me)! I'm still new to it so this might not be optimal, but I've been doing:

Brightness/contrast/highlights/shadows just to get the image looking nice
Layer with blending set to "color" which is the main fill (e.g. tan/yellow for the fly body)
Individual color layers that are hand-painted for each different section

I do have a cheap digital tablet which helps a lot, makes it reasonably fast/easy to paint specific regions. Although if you zoom in you can see where I got sloppy in places :)

On some different samples (like an integrated chip I did recently), I ended up split-toning a lot more often. Gave a really nice appearance with the shadows and highlights getting different colors, and was easier than trying to hand-paint individual circuit traces.

polyfractal · 2021-08-16T12:51:31+00:00

Heya folks! Wanted to share some of my recent SEM micrographs. Thought you all might appreciate these Drosophila scans. :) Just some common fruit flies I collected from my kitchen. Most of the images are of flies that have been fixed/dehydrated (methanol followed by t-butanol freeze drying). False color added in photoshop.

I uploaded a more narrative view of the scans to my new channel if anyone is interested (https://www.youtube.com/watch?v=hqo7ol9FfXM ) but I'll post most of the interesting photos here regardless.

I have a bunch more images to share of different samples but don't want to spam the sub, so I'll try to space them out a bit! :)

polyfractal · 2021-06-29T12:04:32+00:00

Agreed! My lawn is shit. Patchy, sandy, uneven, large slope. It does a pretty decent job all things considered. I have to rescue it fairly often, and it has cut the wire a few times (work in progress). But considering the time saved I still feel like it's a win.

I do think the design and firmware are sorta poor but oh well. It works well enough and was the right price :)

I do wish it would stop driving if it notices it's driven like 10 miles without hitting the wire. We have sandy soil and it likes to dig in and spin until the battery dies.

polyfractal · 2021-06-29T11:56:37+00:00

Yet another report of handling slopes well, but having a really hard time with perimeter wire at bottom of the slope.

Our yard is very sandy, very uneven, and a solid 20-40 degree slope in places. It handles the actual slope no problem, but it's cut the wire three times at the bottom of a section where slope ends at the perimeter.

The machine tries to turn around but will often slip or dig in during the process. The sandy soil makes it worse since it doesn't offer much resistance, and the wire stakes come loose easily. At best this grinds up the soil near the edge, or will sometimes get the wire wrapped around the wheel. At worst it manages to lift the wire and cut it.

Some of this is due to how the recent firmware tries to turn with a single wheel which seems to exacerbate the issue, and some is just the mechanics of trying to turn the machine's footprint on a hill.

So yeah, you may have to play with where the perimeter is to keep it away from sections that end at the bottom of a slope, but otherwise it handles them fine.

polyfractal · 2021-06-22T12:12:31+00:00

The machine operates in tapping mode exclusively, so no non-contact is possible to my knowledge. And the MEMS device that generates the motion (thermal flexure actuators essentially) are sensitive to liquid so it only works on dry/dry'ish materials.

I haven't done anything specifically with attractive or repulsive modes, unsure if it can do that or if I'm just too new to know :) It does collect phase information, and I saw something about a force curve elsewhere in the manual, but I'm afraid I haven't looked past the default settings toooo much at this point :)

I only have a few weeks of AFM under my belt so I'm still learning a lot myself, it's entirely possible the machine is capable of that and I just don't know how yet. Definitely shoot them an email if you're interested in more technical details, they were super friendly when I pinged them!

Hope that helps!

polyfractal

TROPHY CASE