glowplug | Went to mcdonalds. =) | 00:16 |
---|---|---|
glowplug | Agreed this is not easy stuff. It will be very painful and slow. | 00:16 |
glowplug | The only way to know if 1um is possible with this design is to try it. =) | 00:17 |
Sync_ | I'll see tomorrow if it is feasable | 00:17 |
Sync_ | I have no small angular contact bearings but that should be no problem | 00:18 |
glowplug | You have some way of making them? | 00:20 |
Sync_ | I'll just order some | 00:21 |
Sync_ | making bearings is no fun | 00:21 |
Sync_ | and 7200 angular contact bearings are like $4 each | 00:25 |
glowplug | Is that like a rollerscate bearing? | 00:28 |
Sync_ | no | 00:30 |
Sync_ | a rollerskate bearing has no angular contact | 00:30 |
Sync_ | which is important here :D | 00:36 |
glowplug | Back! | 00:37 |
glowplug | I did not know about these. They are just more robust in radial and axial directions. | 00:39 |
glowplug | Do you plan on trying to copy the design I linked earlier (the aluminum one)? | 00:40 |
Sync_ | it's not about being more robust | 00:41 |
Sync_ | you can preload them in O or X configuration to get a precise spindle constraint | 00:41 |
glowplug | So this bearing is going to hold the end of the threaded rod. | 00:42 |
glowplug | I was going to buy a rollerscate bearing. Good thing you said something. Haha | 00:42 |
glowplug | I've never done preloading so I have to figure all of that out. The design says "anti backlash nut" I'm assuming thats where I put my normal m3 hex nut? | 00:44 |
Sync_ | yes | 00:47 |
Sync_ | the problem is with a regular bearing that while it supports your piece radially and axially it does so with play | 00:48 |
glowplug | Alright. I'm not sure that m3 antibacklash nuts exist. | 00:48 |
glowplug | Which is insanely important. So preloading it keeps everything level. | 00:48 |
Sync_ | huh. there seems to be standards which specify m8x0.25 | 00:49 |
Sync_ | well the preload forces the assembly in a certain position | 00:49 |
glowplug | .25mm pitch???? | 00:50 |
Sync_ | yes | 00:52 |
glowplug | I wonder how expensive that is per meter. o.O | 00:52 |
Sync_ | I guess you are not going to get threaded rod in that size | 00:53 |
glowplug | How do you get m8x.25 then? | 00:55 |
Sync_ | by making your own spindle? | 00:56 |
glowplug | I'm good on that. Haha | 01:00 |
glowplug | http://www.techno-isel.com/LMC/Products/AmNuts02.htm | 01:00 |
glowplug | I think that 10031AB is an m3 antibacklash nut but its $43. O.o | 01:00 |
glowplug | This is interesting. | 01:03 |
glowplug | http://www.youtube.com/watch?v=99q_1xiZcrE | 01:03 |
Sync_ | hm | 01:06 |
Sync_ | my dumb lathe only goes to 0.45 pitch | 01:07 |
Sync_ | it doesn't need to be that fancy | 01:07 |
Sync_ | you can just use a split nut with two orings | 01:08 |
Sync_ | or a clampable nut | 01:08 |
glowplug | If thats true then I should have no problem putting that mechanism in. I can just design the cuts for that mechanism into the stage. | 01:08 |
glowplug | I don't have a co2 cutter yet I'm just going to have a local shop cut my acrylic parts for now. | 01:09 |
glowplug | I might go into i3 detroit do it for free. | 01:09 |
Sync_ | oh detroit | 01:10 |
Sync_ | I was there once | 01:10 |
glowplug | You poor soul... | 01:11 |
glowplug | Just kidding its not that bad here. There are worse places on Earth. =) | 01:11 |
Sync_ | well it was in 99 or something | 01:12 |
glowplug | I see. 8) | 01:13 |
glowplug | I'm going to do some more updates to the wiki now then. We have a good amount of info at add. | 01:13 |
glowplug | *to add | 01:13 |
Sync_ | visited some relatives in grand rapids | 01:13 |
glowplug | Ahh I see. Grand Rapids is actually really nice. I was born in Lansing which is right next to it. =) | 01:14 |
Sync_ | bah. conflict of interest | 01:20 |
Sync_ | I'm tired but also hungry | 01:20 |
glowplug | Same here. My solution was McDonalds. | 01:20 |
glowplug | Conflict... Resolved... | 01:21 |
Sync_ | well I either go to bed hungry or eat something and go to bed later | 01:22 |
glowplug | Option #2. 8) | 01:26 |
glowplug | Where did you find the angular contact bearings? | 01:27 |
glowplug | They are $28 on mcmaster. O.o | 01:29 |
Sync_ | my local bearing shop | 01:36 |
glowplug | Ahh | 01:36 |
Sync_ | interestingly bearings die pretty fast in vacuum applications | 01:38 |
glowplug | Ok so the 7200 has a 10mm inner diameter and my threaded rod is 3mm. | 01:39 |
Sync_ | yes that is one of the reasons I want a bigger spindle | 01:40 |
Sync_ | :D | 01:40 |
glowplug | I will succeed.... | 01:40 |
Sync_ | one of the issues with the spinde so thin is that it will bend and flex | 01:41 |
Sync_ | even under the small load | 01:42 |
glowplug | I have a solution for that. | 01:42 |
glowplug | Tons of nuts. =) | 01:42 |
glowplug | Actually wait there shouldn't be any flex. | 01:44 |
glowplug | Not if the threaded rod is only ~100mm long. | 01:44 |
Sync_ | hm probably, still larger is better | 01:50 |
Sync_ | and huh 1/4-32 UNS is expensive | 01:50 |
glowplug | What is that? | 01:52 |
Sync_ | a thread | 01:52 |
glowplug | Oh I see. | 01:52 |
glowplug | Well I found a 3mm to 5mm coupler they are $4 on Ebay. | 01:53 |
Sync_ | hm, I really think you are better off using a larger spindle | 01:54 |
Sync_ | even if it is only less fiddly to work with | 01:54 |
glowplug | Ok I didn't notice this before. | 01:56 |
glowplug | There is .5mm "low-strength steel" rod on mcmaster. | 01:56 |
glowplug | In m5 | 01:56 |
glowplug | These are interesting too. 50mm long .5mm pitch bolts. | 02:11 |
glowplug | Not quite long enough I suppose. | 02:13 |
glowplug | 8) | 02:56 |
glowplug | I guess the new wiki needs a logo. O.o | 02:58 |
Sync_ | I thought about that too | 03:04 |
glowplug | I'll try to toss something together tomorrow. | 03:08 |
glowplug | Still working on the litho wiki. | 03:08 |
glowplug | Do you know how to measure changes in X and Y with a single interferometer? | 03:35 |
Sync_ | beamsplitter glowplug | 03:55 |
glowplug | Yes but how do you position the sensor optics? | 03:56 |
Sync_ | after it | 03:57 |
Sync_ | you just put in two interferometers | 03:58 |
Sync_ | https://www.google.de/url?sa=t&rct=j&q=&esrc=s&source=web&cd=8&ved=0CIABEBYwBw&url=http%3A%2F%2Fwww.aerotech.com%2Fmedia%2F247173%2Fsection%25209_laser%2520interferometer%2520implementation.pdf&ei=j9VLUaPGIsKitAad0IGoCg&usg=AFQjCNGkNQc1et8VWKbLCNLuHigNLhmBWQ&sig2=iYy1wAb-l3hM-w8RdDSXPQ&bvm=bv.44158598,d.Yms | 03:59 |
Sync_ | gaaaah | 03:59 |
Sync_ | die google | 03:59 |
glowplug | Haha! | 03:59 |
Sync_ | http://www.aerotech.com/media/247173/section%209_laser%20interferometer%20implementation.pdf | 03:59 |
Sync_ | there | 03:59 |
glowplug | Alright so the "Remote Detector and Interferometer" boxes. | 04:07 |
Sync_ | yes | 04:07 |
glowplug | They take in one beam, offset it, and read the reflection with some optics? | 04:08 |
Sync_ | yes | 04:11 |
Sync_ | you get a fringe pattern | 04:11 |
Sync_ | and the intensity varies | 04:11 |
Sync_ | which you can read with a photodiode | 04:12 |
glowplug | I know how interferometers work. =) | 04:12 |
glowplug | I figured out what those mysterious boxes are. They are "linear interferometers". | 04:12 |
glowplug | A system like that might be more difficult and expensive (due to need for increased optics quality) than just having two seperate interferometers. | 04:33 |
glowplug | Which this really is two seperate interferometers operating off of a single beam source. | 04:33 |
glowplug | Yeah I'm going to try it the other way. Lasers are cheap optics are expensive. Screw that. Haha | 04:42 |
Sync_ | well you are only going to save one beamsplitter | 05:30 |
B0101 | yikes... chlorine gas is never fun to play with, more so when you have a gas leak in your test chamber | 05:30 |
glowplug | You save all of the internal components that comprise a "linear interferometer" which is tons of mirrors, a beam splitter, and a retroreflector. The system is also very very sensitive. | 05:39 |
glowplug | You have to be careful dawg. O_O | 05:39 |
Sync_ | huh how are you going to make a interferometer with just a laser? | 05:40 |
glowplug | They are called "linear interferometers" but its confusing. | 05:41 |
glowplug | They are really black boxes with tons of integrated components. Two of those are added to the configuration to make it work. | 05:41 |
glowplug | So you have all of the necessary components of a single interferometer. Plus the two black boxes which are extremely complex. Plus massively increased system sensitivity. | 05:42 |
glowplug | It's getting late though going to bed. 8) | 05:49 |
Sync_ | glowplug: the integrated linear ones seem to be just michelsons with retroreflectors | 05:57 |
Sync_ | yeah two prisms and a beamsplitter will do | 06:07 |
nmz787 | there's a video online of a $20 interferometer | 07:15 |
nmz787 | using a CD case, laser pointer, mirrors and a cheap lens | 07:16 |
Sync_ | I just ordered some stuff from EO | 07:17 |
Sync_ | you can make one for under $200, that's not too bad | 07:18 |
nmz787 | if you just need micron-ish resolution, you probably just need something like the $20 one and a photodiode and comparator or schmitt trigger | 07:20 |
Sync_ | prisms are cheap and beamsplitter glass too | 07:21 |
nmz787 | if you want better res then you need to keep the sinosoid pretty noise-free, and get an ADC instead of the comparator/schmitt | 07:22 |
Sync_ | well, if it only has to have micron resolution I'd use glass scales all day long | 07:23 |
nmz787 | that's not consistent as interference though, so I guess it depends on your goal | 07:26 |
nmz787 | how do you read glass scales? | 07:27 |
Sync_ | rs422 output | 07:27 |
nmz787 | oh so it's not roll-your-own system? | 07:29 |
nmz787 | link? | 07:29 |
nmz787 | shars.com says $520 | 07:29 |
nmz787 | http://en.wikipedia.org/wiki/Digital_read_out#Glass_scales | 07:30 |
nmz787 | "(the smallest are just 5 m apart)" | 07:30 |
nmz787 | m==micron | 07:30 |
Sync_ | http://www.heidenhain.de/de_EN/products-and-applications/length-measurement/sealed-linear-encoders/for-numerically-controlled-machine-tools/ | 07:30 |
Sync_ | that's not true | 07:31 |
Sync_ | you can get them with 100nm resolution | 07:31 |
nmz787 | heh, I don't like suppliers that don't list prices | 07:49 |
Sync_ | I don't care, I pay what they want | 07:50 |
Sync_ | but actually it is not that bad nmz787, if you get chinese ones with 500nm resolution they are like 200$ for 70mm length | 09:16 |
Sync_ | and not much more for longer ones | 09:16 |
glowplug | Good morning. 8) | 16:14 |
glowplug | I agree with the glass scales being very accurate but we already have *some* amount of mechanical accuracy built into the system via the leadscrew assembly. The interferometers will be a reliable way to know if something else in our system is broken instead of guessing all day. | 16:15 |
glowplug | nmz I agree they can be built for very cheaply. My current plan (need to update the wiki) is to buy a giant piece of 50/50 glass and CNC hundreds of tiny 10x10mm squares out of it. That gives you $1 beamsplitters with extremely good optical quality. | 16:16 |
glowplug | In terms of replicating the linear box units lets call them. As you increase the amount of sensor positions in the beam network you multiply the system sensitivity by many times. | 16:17 |
glowplug | I still think that two beam sources will give the best price/performance/reliability ratio. | 16:17 |
Sync_ | well if you have alot of 50/50 splitters a second source is a waste | 16:32 |
glowplug | That is technically correct. But aligning the system with a second beam is many many times more difficult. | 16:49 |
glowplug | The alignment instruments need to be many times more precise. And I'm not sure if the quality of the optics I mentioned is high enough for a setup like that. | 16:50 |
glowplug | The optics they are using in the PDF you linked are probably $10,000+ | 16:50 |
Sync_ | I just ordered stuff from EO to try that | 16:50 |
Sync_ | I like the idea of using prisms for the beam return | 16:51 |
Sync_ | that way you can shift the receiver diode a bit | 16:51 |
glowplug | Good luck. Haha | 16:52 |
glowplug | The prisms can be fashioned from multiple standard mirrors correct? | 16:52 |
Sync_ | yes but it'll be annoying to align that | 16:54 |
Sync_ | and they are only $29 | 16:54 |
Sync_ | :D | 16:54 |
glowplug | $29 each! Ouch.. | 16:55 |
glowplug | You can get another HeNe tube for $50. | 16:56 |
glowplug | This is why I abandoned the single beam idea. | 16:56 |
Sync_ | wat, you need the prisms anyway | 16:56 |
glowplug | For two standard michealsons you only need beamsplitters and mirrors. | 16:56 |
glowplug | And two beam sources. | 16:57 |
Sync_ | yes but that is not as compact | 16:57 |
Sync_ | with two prisms and a beamsplitter you can move the receiver to the side of the input beam | 16:58 |
Sync_ | which is cool | 16:58 |
Sync_ | and $29 per piece, come on | 16:58 |
glowplug | That is extremely cool. But I have plenty of desk space and not very much money. HAha | 16:58 |
Sync_ | that's not too bad | 16:58 |
glowplug | I'm shooting for $29 for the entire assembly. 8) | 16:59 |
glowplug | I wonder is it possible to put the entire thing under vacuum. That would make the lasers more accurate and reduce the chance of contamination. | 17:03 |
glowplug | Everything is electronically controlled anyways. | 17:04 |
Sync_ | then you cannot make it out of acrylic | 17:10 |
glowplug | Why not? | 17:15 |
Sync_ | outgassing properties | 17:15 |
glowplug | There are retail acrylic chambers that pull 30" | 17:17 |
Sync_ | yes, but 30" is not really a vacuum | 17:18 |
Sync_ | at least from my vacuum perspective | 17:18 |
glowplug | I knew that was coming. Haha | 17:19 |
glowplug | I agree that is not 0 torr but it would still greatly increase laser accuracy and greatly reduce contamination for a very low cost. | 17:20 |
diginet1 | the best way a DIYer can get a vacuum is a bell jar | 17:20 |
Sync_ | and then do what? suck on it? | 17:20 |
Sync_ | ;) | 17:20 |
diginet1 | acrylic is just about the worst possible thing I can imagine for vacuum stuff | 17:20 |
diginet1 | Sync_: well you need a pump too :P | 17:21 |
diginet1 | but I more meant for the chamber | 17:21 |
glowplug | I wonder why they sell $2000 acrylic vacuum chambers then. | 17:21 |
Sync_ | to outgas resin | 17:21 |
diginet1 | yeah, calling that a "vacuum" is a bit of a stretch | 17:21 |
glowplug | So the acrylic chamber wont hold any amount of vacuum that is useful for increasing beam stability and reducing contamination. | 17:22 |
Sync_ | I mean, yeah it is lower than atmosphere but oh well | 17:22 |
glowplug | That just doesn't seem realistic. | 17:22 |
glowplug | Remember it's a $500 litho device. No need for a $1500 bell jar. | 17:23 |
Sync_ | I'd just put some shields | 17:23 |
glowplug | It basically is a shield with a low vacuum. | 17:26 |
glowplug | I mean... maybe its not worth the extra ~$50. | 17:26 |
glowplug | But something that both improves beam stabilit and reduces contamination for such a low cost is at least worth examining | 17:26 |
glowplug | *stability | 17:27 |
Sync_ | nice | 19:36 |
Sync_ | that came out pretty well | 19:38 |
glowplug | ? | 19:40 |
Sync_ | just made a spindle | 19:44 |
Sync_ | rather amazed how backlash free it is | 19:45 |
Sync_ | only the material pairing isn't the best | 19:46 |
Sync_ | yeah I'll need oil but then it'll work fine | 19:51 |
Sync_ | pitch error is very low | 19:52 |
Sync_ | under 1/100mm in 5cm | 19:52 |
Sync_ | backlash when properly adjusted maybe 200nm | 19:52 |
Sync_ | but that is probably my setup | 19:52 |
Sync_ | because it cannot really have backlash | 19:52 |
Sync_ | the next one will have a brass nut and case hardened spindle | 19:54 |
Sync_ | yeah :) I like it | 19:58 |
glowplug | Holy crap that is great! | 20:20 |
glowplug | What material did you use for the stage? | 20:20 |
Sync_ | I did not build a stage yet, just the spindles | 20:25 |
Sync_ | I'll probably use aluminium | 20:25 |
glowplug | How did you test the spindle accuracy? | 20:26 |
Sync_ | mahr extramess 2001 and gage blocks | 20:26 |
glowplug | Aha! I see! | 20:28 |
glowplug | And your leadscrew is standard .5 pitch stainless? | 20:28 |
Sync_ | no | 20:29 |
Sync_ | aluminium, cut it myself | 20:29 |
glowplug | Your joking? That is seriously fantastic! | 20:30 |
glowplug | I would buy that from you in a heartbeat! How much for 200mm? Haha | 20:31 |
Sync_ | I'll verify that next week but it looks quite acceptable | 20:32 |
glowplug | I was actually going to look at alu I saw it mentioned. I would totally buy some as soon as you think they are ready. You made them from M8 rod? | 20:36 |
Sync_ | no, I took some stock, turned it to 7.90mm and cut a thread | 20:38 |
Sync_ | bb in 15 | 20:38 |
glowplug | So it is 7.9mm in diameter. That is A LOT better than the m3 rod from mcmaster. | 20:40 |
Sync_ | no shit | 23:36 |
Sync_ | that's why I wanted to do it that way | 23:36 |
glowplug | Easy there! Haha | 23:37 |
glowplug | I know it's better thats pretty obvious. I just didn't realize you had a precision lathe and mad skills. =) | 23:38 |
Sync_ | I'm more or less amazed that the pitch error is that good | 23:38 |
Sync_ | gotta verify that after my exams | 23:38 |
glowplug | Me too thats awesome if it works. =) | 23:40 |
Sync_ | but in reality it does not matter | 23:42 |
Sync_ | :D | 23:42 |
glowplug | Why is that? | 23:42 |
glowplug | It matters for me I'm the first customer of Sync_'s Custom Aluminum Threaded Rods Inc. | 23:43 |
Sync_ | because if you use closed loop positioning with the interferometers only backlash will hurt you | 23:45 |
Sync_ | but for that to work you need a very rigidly coupled system | 23:45 |
Sync_ | and no backlash | 23:46 |
Sync_ | but the next ones will be made from c45 steel and brass nuts | 23:47 |
Sync_ | the Al-Al pairing likes to bind | 23:47 |
glowplug | Ahh so you will be using steel. Can your lathe cut steel? | 23:52 |
glowplug | I think we can get rid of backlash pretty easily using the DIY spring method. | 23:52 |
glowplug | And I agree about positioning otherwise. As long as we have good absolute feedback the accuracy of the leadscrews is not super important. | 23:53 |
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