#emc | Logs for 2009-02-24

[00:02:28] <jmkasunich> any PCB millers out there? cradek, jepler, skunkworks?
[00:02:48] <jmkasunich> looking for recommended spindle speed
[00:03:07] <Dallur1> Just uploaded a video of some plasma cutting with EMC if anyone is interested: http://video.google.com/videoplay?docid=-252012548542272059
[00:04:06] <JymmmEMC> jmkasunich: 50 kazillion RPM =)
[00:04:28] <jmkasunich> yeah, I was afraid of that
[00:04:51] <jmkasunich> Dallur1 that is a large table
[00:05:13] <dmess> whats you cutting tool??
[00:05:21] <JymmmEMC> jmkasunich: But, since it's copper... wouldn't you use similr speeds like aluminum to prevent buildup?
[00:05:25] <jmkasunich> itty bitty carbides
[00:05:29] <jmkasunich> drills and mills
[00:05:33] <dmess> and your cutting fiberboard i presume
[00:05:47] <dmess> capacity??
[00:06:02] <jmkasunich> jas
[00:06:04] <Dallur1> jmkasunich: 2.5m x 6.5m
[00:06:18] <JymmmEMC> meters?! yoew
[00:06:31] <Dallur1> I made it for cutting 2x6m platers for my boat
[00:06:37] <Dallur1> err plates for my boat
[00:06:53] <BigJohnT> Dallur1 hows the boat progressing?
[00:07:00] <JymmmEMC> oh you talking the machine, I thought you meant the pcb =)
[00:07:17] <JymmmEMC> I was thinking... That's a DMAN BIG ASS PCB
[00:07:23] <Dallur1> BigJohnT: Well, probably going to turn it next weekend
[00:07:35] <BigJohnT> Sweet!
[00:07:46] <jmkasunich> http://www.precisebits.com/applications/pcbtools.htm
[00:07:59] <jmkasunich> those cutters ^^^^^
[00:09:08] <dmess> FYI do not change cutter while in the machine... it will drop out of your hand and become SWARF
[00:09:19] <jmkasunich> 20K to 100K RPM - that is a big range
[00:09:28] <dmess> well ok only 30% of the time
[00:09:44] <dmess> torque??
[00:09:49] <jmkasunich> I have a 400W 18000 RPM motor, and am trying to design a belt drive from motor to spindle
[00:10:04] <jmkasunich> 400W at 18KRPM is 1.87 lb-in
[00:10:12] <dmess> i'd use it direct
[00:10:24] <jmkasunich> that is rather slow for those cutters
[00:10:27] <BigJohnT> I watched a guy build a 40' shrimp boat in his back yard... he got 90% complete before they caught him...
[00:10:28] <jmkasunich> I was thinking 2:1
[00:10:39] <JymmmEMC> Dallur1: what you have a junk yard?
[00:10:46] <JymmmEMC> Dallur1: what you have, a junk yard?
[00:10:59] <jmkasunich> BigJohnT: what do you mean :"caught him"?
[00:10:59] <BigJohnT> he got the 3rd shift crane operator to set the steel over the fence into his truck...
[00:11:34] <jmkasunich> it's illegal to build boats now? (or was he doing it with someone else's steel?)
[00:11:36] <BigJohnT> he was stealing the steel from the shipyard where I worked
[00:11:40] <jmkasunich> ah
[00:12:16] <Dallur1> JymmmEMC: nope, it's the place I rent to build the boat, the guy buys all this crap and it just rusts outside
[00:12:16] <BigJohnT> magnet crane would set it over the fence into his truck
[00:12:30] <JymmmEMC> Dallur1: Ah, ok.
[00:12:51] <JymmmEMC> BigJohnT: Did they repo the boat?
[00:14:00] <dmess> dont worry the chines will end up with the steel sooner than later
[00:14:08] <JymmmEMC> Oh, for you guys in the boonies that are still on dialup... If you have cell service you can get a data card from (like) AT&T for $60/mo
[00:14:11] <BigJohnT> it disappeared for sure
[00:14:55] <BigJohnT> and my dial up is $19 a month
[00:14:57] <JymmmEMC> ...and they have routers now that you can use to share the 3G bandwidth on your LAN
[00:15:59] <BigJohnT> Dallur1 are you the chap on the left or the right in the video?
[00:16:24] <Dallur1> BigJohnT: im the chubby one with the black hair
[00:16:33] <Dallur1> BigJohnT: most of the time I'm the one operating the table
[00:16:56] <BigJohnT> but you both have helmets on :)
[00:17:38] <JymmmEMC> CTHD AVI+Sub's.... hawt damn!
[00:18:03] <Dallur1> BigJohnT: http://dallur.com/index.php?id=44&tx_lzgallery_pi1[showUid]=7
[00:18:11] <Dallur1> BigJohnT: that's me
[00:21:27] <BigJohnT> Dallur1 this is me http://i47.photobucket.com/albums/f163/johnplctech/hunting/P1010063.jpg
[00:21:46] <BigJohnT> I'm the one with the orange cap
[00:21:58] <JymmmEMC> BigJohnT: Joos one ugly sucker with a hole in your belly!
[00:22:19] <BigJohnT> bad hair day for sure
[00:22:20] <JymmmEMC> Damn, didn't type fast enough =)
[00:22:28] <JymmmEMC> yeah, no doubt
[00:22:36] <JymmmEMC> 3030?
[00:22:42] <BigJohnT> 50 cal
[00:23:03] <JymmmEMC> you trying to kill it, or butcher it all at the same time?
[00:23:11] <BigJohnT> single shot... one shot one kill
[00:23:34] <BigJohnT> shoot them in the neck so you don't have to wander about looking for them
[00:23:36] <JymmmEMC> Ah, I've only gone deer hunting once.
[00:23:54] <JymmmEMC> Found bear cubs, and we got the hell outta there =)
[00:24:19] <BigJohnT> where there is cubs there is momma and she ain't happy your there
[00:24:46] <JymmmEMC> Exactly. And by the looks of where the cubs were, we were probably between them and Momma.
[00:24:47] <BigJohnT> I have to be careful I don't shoot a cow where I hunt
[00:25:21] <JymmmEMC> private land?
[00:25:28] <BigJohnT> yep
[00:25:52] <BigJohnT> Dallur1 I like this one http://dallur.com/index.php?id=44&tx_lzgallery_pi1[showUid]=7&tx_lzgallery_pi1[old]=5x5x1&tx_lzgallery_pi1[pic]=6&tx_lzgallery_pi1[colrows]=1x1
[00:25:59] <JymmmEMC> Nice that they let you. I suspect many wouldn't even let hunters on their land with all the fscksup out there
[00:26:16] <BigJohnT> yes that is true
[00:26:26] <Dallur1> BigJohnT: I got bet I could not fit that on my head, it fit, it stuck I won, yet lost
[00:26:35] <BigJohnT> LOL
[00:26:51] <JymmmEMC> lol
[00:27:25] <BigJohnT> well time to head up out of the beer cave
[00:27:31] <BigJohnT> talk to you guys later
[00:27:40] <JymmmEMC> Hasta John
[00:28:10] <JymmmEMC> * JymmmEMC watches CTHD and rips more DVD's =)
[00:28:50] <Dallur1> later
[01:20:45] <tomp> haha! pic16f84's bought from microchip online dublin, ireland, shipped from chacherngsao, thailand, arrived in taiching, taiwan in 4 calendar days ! pretty good stuff this internet.
[01:25:13] <cradek> nooooo are they still making those cursed things?
[01:25:30] <jmkasunich> pics?
[01:25:35] <cradek> ha
[01:25:52] <cradek> the 16f84 specifically - I think that's the one hobbyists started using 10 years ago and didn't have the sense to stop using :-)
[01:26:11] <jmkasunich> cradek: PCB milling - what speed do you use? "as fast as it will go" ?
[01:26:46] <cradek> yes
[01:27:01] <cradek> and .001 inch per rev (two flutes)
[01:27:30] <jmkasunich> I've once again got the bug to build a PCB mill
[01:27:41] <jmkasunich> each time that happens I get closer to actually doing it
[01:27:42] <cradek> iirc, the manufacturer says spin the isolation tools at least 20krpm
[01:28:10] <cradek> they definitely cut cleaner at 20k than 10k
[01:28:16] <jmkasunich> the website is rather vague - they say "20K to 100K" when referring to an entire product line, nothing more specific
[01:29:10] <jmkasunich> I have an 18K motor, and I'd really rather not do direct drive (obstructing the back end of the spindle is a pain - drawbar, etc wants to be there)
[01:29:19] <jmkasunich> so I'm investigating belt technologies
[01:29:47] <jmkasunich> MXL timing belts are adequate for the power I have, but the chart tops out at 20K, and the tables at 12K rpm
[01:29:54] <cradek> doubling (or more) the speed would be nice
[01:29:58] <jmkasunich> yeah
[01:30:17] <cradek> what's a reasonable feed rate on that thing?
[01:30:29] <cradek> you're accel limited I'm sure
[01:30:38] <jmkasunich> think = the shoptask?
[01:30:41] <jmkasunich> thing
[01:30:41] <cradek> yeah
[01:30:47] <jmkasunich> I'm not planning shoptask
[01:30:51] <cradek> oh!
[01:30:54] <jmkasunich> too much lash, too much slop
[01:31:08] <jmkasunich> I'm thinking dedicated machine, about 8x12
[01:31:13] <cradek> if you can get 40ipm 40krpm it'd be slick
[01:31:23] <jmkasunich> IPM shouldn't be a problem
[01:31:36] <jmkasunich> oh, actually one place where IPM will be limited - Z
[01:31:44] <cradek> without rounding corners too much...
[01:31:46] <jmkasunich> how fast do you feed when drilling?
[01:31:58] <cradek> lemme look
[01:32:30] <jmkasunich> for axis drives on X and Y I'm thinking the ametek motors, with 2500 PPR 10K count encoders
[01:33:31] <cradek> http://unpythonic.net/cgi-bin/viewcvs.cgi/eagle/ulp/singlesided.gpar?rev=1.4
[01:33:34] <jmkasunich> with direct drive 5tpi screws I'd have 50K counts per inch, and 240 ipm max speed
[01:33:38] <cradek> looks like I drill at 8
[01:33:57] <jmkasunich> cool
[01:33:58] <jmkasunich> I
[01:34:13] <jmkasunich> I'm thinking smaller motor for Z, since it will most likely be on the Y carriage
[01:34:26] <jmkasunich> Z travel will only be 1-1/2 to 2" so rapids aren't important
[01:34:42] <cradek> right
[01:34:59] <cradek> you'll only move .050 anyway
[01:35:08] <cradek> accel is the issue
[01:35:20] <jmkasunich> I have several possibilities for Z that will let me do 20 ipm with >20K count/inch resolution
[01:35:38] <cradek> hm, maybe almost .100 for drilling
[01:35:57] <jmkasunich> you buy tools with depth rings>?
[01:36:14] <cradek> no, I probe them for length
[01:36:23] <cradek> well, last I made pcbs - it's been a while
[01:36:24] <jmkasunich> seems like the biggest Z travel is for toolchanging
[01:36:32] <cradek> yes
[01:36:52] <cradek> maybe you could have a way to move the spindle out from above the table somehow?
[01:37:00] <cradek> you don't have to go up, necessarily
[01:37:04] <jmkasunich> right
[01:37:19] <jmkasunich> although an inch or so of travel would improve versatility
[01:37:20] <cradek> you don't need much TLO either
[01:37:23] <jmkasunich> engraving, etc
[01:37:30] <cradek> yes you might use up a lot of an inch for TLO flexibility
[01:37:44] <jmkasunich> or work that is thicker than 0.062
[01:38:37] <jmkasunich> I'm thinking of a quill for Z - piece of 1-1/4 or 1-1/2" round steel sliding in bushings
[01:38:56] <jmkasunich> Y carriage will be a THK SR-45 car
[01:39:32] <jmkasunich> I have a 14" length of track for that car, it is about 4" long, so 10" travel
[01:39:41] <jmkasunich> I have a ballscrew about that long as well
[01:40:09] <jmkasunich> the main stumbling block (as always) is motor-to-spindle drive, toolholding, and Z screw location
[01:41:49] <jmkasunich> the two main choices for high speed belt drive are fine pitch timing belts, and small flat belts
[01:42:10] <jmkasunich> Gates has tech data for timing belts, but the stop at 20K RPM
[01:42:23] <jmkasunich> tech data for flat belts is defying my google skills
[01:43:02] <cradek> seems like rpm of a belt means little
[01:43:41] <fenn> limiting factor for belts is surface speed (quoted in feet per minute usually)
[01:43:47] <cradek> I can imagine a speed vs radius of bend tradeoff
[01:43:58] <jmkasunich> fenn: gates quotes 6500 fpm surface speed
[01:44:14] <jmkasunich> with small pulleys that would allow over 20K, probably 30K
[01:44:35] <jmkasunich> but there will be other effects - flex = losses = heat, above a certain speed that may be the limit
[01:44:58] <jmkasunich> also, centrifugal force at high speeds tends to stretch the belt away from the pulley
[01:45:44] <jmkasunich> I found a machine design article that says flat belts can hit 10K fpm surface speeds
[01:50:20] <jmkasunich> if I aim for 8K sfm, and 18K motor RPM, that gives a motor pulley of 1.7" diameter
[01:50:34] <jmkasunich> motor torque is 1.9 in-lb
[01:51:06] <jmkasunich> so I need 2.2 lb difference in tension between loose and tight sides of the belt
[02:10:29] <jmkasunich> heh, you learn the strangest things on the internet
[02:10:52] <jmkasunich> they make urethane belts (mostly for conveyer use) that contain copper fibers
[02:11:34] <jmkasunich> reason? because when used on a food packaging line, a broken belt that falls into the product will be detected by the metal detectors and that product rejected - plain belts would be missed and might be shipped with the food
[04:37:33] <maddash> uh guys?
[04:37:36] <maddash> I need some help
[04:37:49] <maddash> I'm re-compiling 2.6.22 with rtai-3.6-cv
[04:38:11] <maddash> i've already gotten to the stage where i compile rtai
[04:38:35] <maddash> sudo make gives an erro: '/usr/include/limits.h:125:25: error: limits.h: No such file...'
[04:38:38] <maddash> wtf?
[04:42:00] <maddash> anyone? please?
[04:45:41] <tomp> maddash: we work with a specific version in a specific environment, we just have no experiencde outside of that, and many (like me) just repeat a series of incantations and cross our fingers. go outside that, and you're better off asking on an rtai channel.
[04:47:10] <tomp> if this <is< std for emc, then you dont have the basics installed, so review the instructions on wiki, which worked for me last nite
[04:47:12] <dgarr> you may need more dev packages, try $ sudo apt-get build-dep emc2
[04:48:45] <dgarr> maddash: also see: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Installing_EMC2
[04:48:56] <maddash> wtf, i'm following the lenny install instructions
[04:48:59] <maddash> http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Debian_Lenny_Compile_RTAI
[04:51:15] <tomp> uh, dapper and hardy are explained here , i dont know about lenny http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?Installing_EMC2 starting at 2.1.2
[04:52:34] <tomp> wow, thers a lot there about lenny, sorry, no experience on lenny
[04:53:30] <maddash> wtf wtf wtf it's a problem with libc6-dev
[04:54:22] <tomp> yeh that lib is picky and has loads of deps withit, in that brick stacking game, its near the bottom!
[04:55:04] <maddash> no
[04:55:42] <maddash> there's a line, "# include_next <limits.h>"
[04:56:03] <maddash> if I comment it oiut, the error goes away, but ten there's a 'LONG_MAX' undefined error
[04:58:12] <tomp> i cant even check where it is on mine now, using xp for cad and vista cant see linux partitions, sorry. you DO need that header file, and it comes in one of those preliminary apt-gets
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