[HN Gopher] A kinematically coupled, nanometer-resolution piezo ...
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A kinematically coupled, nanometer-resolution piezo focus stage
Author : todsacerdoti
Score : 57 points
Date : 2024-03-31 06:24 UTC (16 hours ago)
(HTM) web link (www.bunniestudios.com)
(TXT) w3m dump (www.bunniestudios.com)
| mhb wrote:
| Related items of interest:
|
| Dan Gelbart on Flexures:
| https://www.youtube.com/watch?v=PaypcVFPs48
|
| Design of a kinematic mount:
| https://practicalprecision.com/kinematic-mount-design/
| javiramos wrote:
| Dan Gelbart, a great. Adding MIT Alex Slocum's kinematic and
| flexure design resources:
| http://pergatory.mit.edu/resources/fundamentals.html
| varjag wrote:
| Also this video of a JWST-inspired positioning flexure:
| https://www.youtube.com/watch?v=5MxH1sfJLBQ
| atoav wrote:
| I had to immidiately think of the JWST as well, the idea
| being to use basically a compliant mechanism as a lever that
| turns a big weak movement into a tiny stronger one.
| anymouse123456 wrote:
| There was also this paper [0] making the rounds in 2022.
| Ultrahigh precision equipment for hobby level prices makes me
| super excited to be alive right now.
|
| [0]
| https://www.sciencedirect.com/science/article/pii/S246806722...
| aconz2 wrote:
| I've been enjoying these posts about the IRIS project. I would
| love to see some quantitative measurements of its performance. If
| it works for the autofocus purpose, that is great. But I'm
| skeptical of calling this kinematically coupled or nanometer
| resolution with vhb taped non spherical balls and no preload. I
| wouldn't expect that to repeat very well. Also, I'm having a hard
| time thinking about whether you can actually use the maxwell as a
| trim/tram table like this, is this known? The piezo's are going
| to be moving in 3 slightly different axes and surely with some
| parasitic motion so the ball's position won't stay in radial
| symmetery. And they have to slide in the groove so there will be
| stiction. I think a linear stage at 1um would suffice because the
| correlation between images should be higher
| iancmceachern wrote:
| Totally, it would be interesting to put an interferometer on
| this thing
| barfbagginus wrote:
| I like that it's not a product for regulatory reasons. Now I
| wonder about the boundaries on "productionizing" open hardware
| without selling it.
|
| Let's suppose the creator makes it dead simple to make. Solves
| problems that would tie up any replication effort for months.
| Replication now takes a week of effort for a pair of hobbyists
| with a 3d printer, a CNC machine, and a soldering iron. Setup for
| mass production setup now takes a month for a well appointed
| electronics factory.
|
| The creator has eliminated all production problems, while
| skipping all the steps required to earn a revenue.
|
| Does this increase the risk of a cease and desist? After all,
| G-men might be worried that a foreign power will replicate the
| tech without paying an American corporation!
| Aurornis wrote:
| > Does this increase the risk of a cease and desist? After all,
| G-men might be worried that a foreign power will replicate the
| tech without paying an American corporation!
|
| Many of the regulations he talks about aren't related to the
| United States or corporations at all. We like to poke fun at
| America, but in my experience it has been much easier to launch
| physical products in America than many other countries. The
| blog gives one example of requiring "UKCA" stamped somewhere to
| deal with some post Brexit thing. Then there's the matter of
| customs and import issues, which are a nightmare to navigate in
| many of the various countries you might ship to other than the
| US.
|
| > The creator has eliminated all production problems, while
| skipping all the steps required to earn a revenue.
|
| Even with full instructions, production problems would actually
| be the majority of the work. It's still quite difficult to set
| up manufacturing for something like this. Furthermore, it's
| nearly impossible for someone to perfect a manufacturing
| process and document it without having done the manufacturing
| and learned from experience.
|
| Finally, the product described isn't actually that novel.
| Anyone sufficiently motivated and capitalized to set up a
| manufacturing line would also have the resources to have
| developed something like this.
|
| The comments in the blog read more like a commentary on the
| difficulties of low volume product logistics, not a suggestion
| that "G-men" are trying to crush someone's hobby project so
| that an American corporation can have more profit.
| barfbagginus wrote:
| I'm an industrial designer and manufacturing engineer who
| founded a reverse engineering firm. We use some nice
| techniques to virtually eliminate defects in our client
| production streams, even though we have basically no tacit
| knowledge of their production back ends. What we do
| understand is our design geometry and its quality metrics.
|
| In our case, simply controlling the quality of our geometry
| is enough to stamp out defects and rework, which is why our
| clients use us as a turnkey solution for eliminating design
| risks.
|
| Those kinds of quality controls and universal productions
| sims don't get developed for simple open source designs.
|
| So yes I understand that productionizing a design
| traditionally depends mainly on accruing tacit knowledge.
|
| At the same time I understand also how important quality
| controls in the design phase are for eliminating rework in
| the production phase. And we are increasingly able to plan
| designs that will enter into production flawlessly.
|
| The scenario I'm asking you to envision, therefore, is not
| this project, but some hypothetical other scenario where the
| creator really supports larger scale efforts with novel
| quality controls that have traditionally been too expensive
| for open source.
|
| I'm also interested in a political scenario where we're
| designing a purely software weapon, a new drone munition, or
| other dangerous tech. Let's even suppose we're doing this
| because we hope it will disrupt for corporations and
| governments.
|
| The question then remains: when due this kind of work cross
| into dangerous territory, and incur outside risks. Where are
| the limits? How much can we expect to "get away with"?
|
| Obviously the answer is "it depends' and "talk to a lawyer".
| But I'm curious about insights and stories folks might have
| here.
| TaylorAlexander wrote:
| I'm doing this process for my open source farming robot [1],
| though not to dodge any patents I simply want people all over
| the world to have access to this technology for as cheaply as
| possible, and someone in Bangalore or Nairobi will be able to
| get them more cheaply from a local fabricator than from some
| California company shipping overseas.
|
| https://community.twistedfields.com/t/join-the-solar-farming...
| barfbagginus wrote:
| This is awesome, and I'm going to look into your project!
|
| I think you're doing it for the right reason. I hope we can
| get many more of the world's engineers thinking that way in
| the next decade. And I feel like humanity's future might ride
| on it!
| TaylorAlexander wrote:
| Thank you! Yeah I think that "proprietary thinking" is
| really shooting ourselves in the foot as far as cumulative
| development of humanity. Community development of 3D
| printers after the patents expired showed me that
| proprietary single-organization patent encumbered
| engineering development is only one way to get critical
| engineering done, and it has many downsides. A major
| advantage of community oriented engineering, where you
| share your designs without restriction, is that people all
| over the world find ways to contribute to your design. You
| end up with a better result in the end, and in the process
| you're lifting potentially billions of people out of
| poverty. To me it seems like it's just the right thing to
| do aside from the fact that it provides real material
| benefit to the people that may have originally produced the
| ideas. But these concepts are not taught in schools, and
| there is a minor problem with financial allocation that
| needs to be solved with for example donations. I think it's
| an extremely important mode of engineering for humanity to
| explore!
| rkagerer wrote:
| _I grew up in a world with fewer trade barriers, and without a
| DMCA. I remember when we were free to think, travel, and trade,
| and I liked it. I feel kind of sorry for the youth today, growing
| up in a world shaped by narratives of safety, fear, and
| ultimately, control. Also, climate change._
| zh3 wrote:
| To give an idea how accurately these things can be used, the
| quantum computer group at the local university use piezo
| actuators to move their ions around with sub-100nm resolution (to
| create fast interconnects between quantum chips, for reasons of
| modularity). Got lucky enough to have a demo/playtime (which
| involved pushing rubidium ions around a few nanometres at a time)
| before they went commercial [0] with it. As Feynman said, "plenty
| of room at the bottom".
|
| [0] https://thequantuminsider.com/2022/11/02/universal-
| quantum-s...
| crispyambulance wrote:
| I had always thought that kinematic mounts consisted of the three
| balls on one side and then on the other side, each ball would
| rest on a flat, a v-groove, and a cone, respectively.
|
| This design seems to have each ball in its own v-groove. Doesn't
| that require extraordinary machining precision with each of the
| three grooves?
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