| glowplug | I've made some more progress in the motor control department. | 02:11 |
|---|---|---|
| glowplug | The design that I am going to use is controlling steppers directly with the parallel port and LinuxCNC. Encoder data feeds directly into the parallel port. And two L298N for the powerstages. | 02:13 |
| glowplug | Total closed loop stepper motor control hardware cost. $10. | 02:15 |
| glowplug | Hello. =) | 02:43 |
| B0101 | sigh, if there only was a piece a software to simulate sub atomic particle collisions... | 03:36 |
| glowplug | I'm sure they have that at CERN. | 03:47 |
| glowplug | We should ask for them to GPL it. 8) | 03:47 |
| B0101 | It would be good they did so, and could be useful in testing transmutation reactions | 03:53 |
| glowplug | So why does your name show up as B0101 half the time? Hah | 03:59 |
| B0101 | huh? my nickname is always B0101! | 04:00 |
| glowplug | Oh. Fair enough. | 04:36 |
| glowplug | Haha | 04:36 |
| azonenberg | That feeling when you open up the Edmund Optics catalog and drool over all of the stuff you can't afford... | 21:08 |
| Sync_ | heh | 21:11 |
| Sync_ | I used to work in the quantum optics lab | 21:11 |
| Sync_ | we used to order stuff from EO, coherent or thorlabs daily | 21:12 |
| glowplug | Speaking of optics I'm updating the litho section of the wiki. Work in progress! | 21:22 |
| azonenberg | lol | 21:51 |
| Sync_ | we also had the lab snacks stacked on a wall | 21:53 |
| glowplug | I think I found a suitable webcam for the microscope. | 21:55 |
| glowplug | Would 1000x magnification be too much? | 22:17 |
| Sync_ | o.0 | 22:17 |
| glowplug | Not for inspecting parts. Just for the direct-write. | 22:19 |
| glowplug | Nevermind. The digital scope they used in that PDF is way underpowered for 1 micron detail. | 22:21 |
| glowplug | I can't believe they paid $150 for that thing. O_O | 22:22 |
| azonenberg | lol | 22:23 |
| glowplug | I'm new to the microscope stuff. =) | 22:25 |
| glowplug | A WF10 eyepiece and 100x achromatic objective is reasonable for the direct-write? | 22:27 |
| Sync_ | is it really just one page or is the firefox pdf viwer acting up on it? | 22:28 |
| glowplug | It really is just one page. Those bastards. | 22:28 |
| glowplug | Crap I think this channel is logged! | 22:28 |
| glowplug | I mean... amazing individuals! | 22:28 |
| Sync_ | hmm | 22:29 |
| glowplug | I realize that you are going to shut down this idea. | 22:29 |
| glowplug | But here goes anyways. | 22:29 |
| glowplug | I was researching micrometers and apparently within their range most micrometers have some amount of error. Even if their zero mark is calibrated. | 22:30 |
| glowplug | They are basically .5mm pitch leadscrews with a dial and some writing. | 22:30 |
| glowplug | If we assume there is going to be error anyways (and that error is probably constant throughout the usage of that leadscrew). | 22:31 |
| glowplug | We can assemble an x,y stage for $5. Measure its absolute position with a interferometer throughout its movement range. Use that data for controlling the stage with nearperfect accuracy. | 22:32 |
| glowplug | The result will probably be more accurate than a set of micrometers for $200. | 22:33 |
| glowplug | The same could be accomplished in realtime also. But I think it would be more reliable to categorize the stage beforehand in software then the PID loop can be less aggressive. | 22:35 |
| Sync_ | sdf | 22:35 |
| Sync_ | gah | 22:35 |
| Sync_ | I cannot find the paper anymore | 22:35 |
| glowplug | Which one? | 22:35 |
| Sync_ | the one paper thing | 22:36 |
| glowplug | I put it here. | 22:36 |
| glowplug | http://homecmos.drawersteak.com/wiki/Direct_write_laser_exposure_system | 22:36 |
| Sync_ | what the hell | 22:38 |
| Sync_ | it really is just a page | 22:38 |
| Sync_ | wtf | 22:38 |
| glowplug | Yeah it really is... | 22:38 |
| glowplug | Their microscope is a Celestron 44340 | 22:38 |
| glowplug | I finally figured that out | 22:38 |
| glowplug | It is max 400x. =( | 22:40 |
| Sync_ | 400x is fine | 22:41 |
| glowplug | 1000x will only cost $80 including hd webcam with nice optics (significantly better than the Celestron unit but still not amazing). | 22:41 |
| Sync_ | hmm, actually, it'd be pretty easy to make the spindles oneself, 8x0.5 is a standard die size | 22:42 |
| glowplug | Spindles? | 22:42 |
| glowplug | Oh! The micrometers? | 22:42 |
| Sync_ | yes | 22:42 |
| glowplug | http://www.mcmaster.com/#standard-threaded-rods/=lzaa1c | 22:42 |
| glowplug | You can get a meter of the stuff for $8. | 22:42 |
| glowplug | Pack of 50 hex nuts for $2.50 | 22:43 |
| glowplug | You could probably build an x,y stage for $5 using acrylic realistically. | 22:43 |
| glowplug | Thats my current plan at least. | 22:44 |
| Sync_ | the error in a regular threaded rod is awful | 22:44 |
| glowplug | Thats what I was reffering to earlier. | 22:44 |
| Sync_ | I don't really see fine ones there | 22:44 |
| glowplug | Did you get those messages? | 22:44 |
| glowplug | On mcmaster they have .5mm pitch stainless steel. Same as micrometers. | 22:45 |
| Sync_ | oh haha they have fine pitch stainless | 22:46 |
| Sync_ | I did not expect the fine ones there | 22:46 |
| glowplug | The only way to eliminate the error in any threaded rod, mcmaster or micrometer either one is to characterize the rod in software with absolute data throughout its range measured with an interferometer. | 22:46 |
| Sync_ | yeah lol it is m3 | 22:46 |
| glowplug | That should work fine. =) | 22:47 |
| glowplug | My strategy will be to laser cut the acrylic to shape with m3 sized rectangular holes for the nuts. Then I can lower them in and epoxy into place. | 22:49 |
| Sync_ | nice. just looked into my tap and die drawer and found a complete M8 set | 22:49 |
| Sync_ | so I also have M8x0.5 | 22:49 |
| glowplug | Very cool. =) | 22:50 |
| glowplug | I'm ok with the m3 given the cost ($8 per meter). | 22:50 |
| glowplug | I haven't figured out the linear slides yet. Given the slow speeds kapton tape could be used. | 22:51 |
| Sync_ | well it is only a chinese set but I'll make a micrometer tomorrow | 22:53 |
| glowplug | Sounds good. =) | 22:53 |
| glowplug | I'm thinking a design like this. | 22:56 |
| glowplug | http://www.velmex.com/images/motordriven/xslide/2-x-4-inch-450px.jpg | 22:56 |
| glowplug | Two smooth rods as guides should be the easiest way to do it. | 22:57 |
| Sync_ | yes, a challenging thing is how to make the thrust bearing assembly | 22:57 |
| Sync_ | because it has to be preloaded | 22:57 |
| Sync_ | two rods is easy but you need pay close attention to the fit of the bushings | 22:58 |
| Sync_ | and it will be a pain to get everything aligned perfectly | 22:58 |
| glowplug | http://web.mit.edu/imoyer/www/portfolio/parametric/index.html | 22:59 |
| glowplug | That design is fantastic. | 22:59 |
| glowplug | He has every detail in a PDF. | 23:00 |
| glowplug | Just has to be miniaturized and I'll be using acrylic just because its a ton easier to work with. | 23:01 |
| Sync_ | yes just don't expect micron precision | 23:04 |
| glowplug | Why not? | 23:04 |
| Sync_ | because it is unrealistic | 23:04 |
| glowplug | Which component is the bottleneck? | 23:05 |
| glowplug | This design is a clone of the pdf design with .5mm pitch leadscrews instead of .5mm leadscrews inside of a retail micrometer (chinese). | 23:06 |
| glowplug | Wouldn't the closed loop control and interferometer feedback make it more accurate? | 23:06 |
| Sync_ | yes | 23:07 |
| Sync_ | there still is the problem, that the x and y need to aligned very very perfectly | 23:07 |
| Sync_ | which is not that easy to do | 23:07 |
| Sync_ | and also the play in the bushings needs to be very low which is not going to happen | 23:08 |
| Sync_ | oh haha wow | 23:13 |
| Sync_ | more or less it comes down to the problem that 1µm is not a lot :D | 23:17 |
| --- Fri Mar 22 2013 | 00:00 | |
Generated by irclog2html.py 2.9.2 by Marius Gedminas - find it at mg.pov.lt!
