#emc | Logs for 2007-05-26

[00:06:26] <JymmmEMC> SWPadnos: I know, but I'd do 20/20 over wood
[00:08:24] <sebastienbailard> JymmmEMC, that's what I'd use as well, _but_ there are people making small hobby cnc routers out of plywood, and they're acceptable for this application.
[00:09:42] <JymmmEMC> Eh, to each his own I guess =)
[00:10:18] <sebastienbailard> As a separate project, I'd like to build a 5' by 10' router some day. I'm not going to use wood for that.
[00:11:18] <JymmmEMC> DUCT TAPE!!! LOL
[00:11:48] <sebastienbailard> I believe all the cool kids are using plastic cutting board.
[00:14:01] <JymmmEMC> HDPE
[00:30:29] <ds2> Humidity is a significant problem with wood
[00:30:46] <ds2> there been claims that hard wood ply is pretty decent
[00:33:13] <sebastienbailard> It's not a perfect material by any means, but this guy: www.mikebeck.org , is selling USD$400 CNC-ready router kits. For this hobby-type application it's probably appropriate, and getting a USD$1K aluminum CNC-ready router / mills is probably overkill for RepStrap builders.
[00:41:21] <renesis> he doesnt sell the screws?
[00:50:46] <ds2> what else do you need to make the $400 kits complete besides time?
[01:00:35] <sebastienbailard> renesis, damn. You're right. Well spotted.
[01:01:07] <renesis> yeah i was like how does he make it move, and then i saw the empty hole
[01:01:19] <ds2> you can get a ready to run CNC system for under $2K, less a PC
[01:01:34] <renesis> yeah i have a taig 2019cr
[01:01:53] <sebastienbailard> likewise. But I'm trying to find resources for people doing it on the cheap.
[01:02:01] <renesis> i got it with 100oz+ steppers and a 4ch xylotex for like $1800
[01:02:11] <renesis> well, taig is small
[01:02:24] <renesis> the 5.5" Y kinda kills it
[01:02:42] <renesis> awesome machine tho, its its little box
[01:02:43] <ds2> but they make it up in frustration if the kits are not complete
[01:03:00] <renesis> be cool to have a big router you could throw 2x4' or 4x8' sheets into
[01:03:22] <ds2> *nod* but the versitility of the taig is incredible
[01:03:25] <sebastienbailard> renesis, there's lots of options for big routers.
[01:03:53] <renesis> yeah ive used it to mill heatsinks in Al, done circuit boards prob within .010" easy
[01:03:59] <ds2> everything just works out of the box, unlike the horrorfreight specials
[01:04:05] <renesis> i dont even have the space tho
[01:04:19] <ds2> I've done CRS on the taig and it didn't complain
[01:04:22] <sebastienbailard> regarding the taig, I don't know of a well built machine that's somewhat bigger but also inexpensive. Maybe the Jet brand mill/drills.
[01:04:41] <renesis> for the money and size its awesome
[01:04:48] <renesis> i dont even thinks its 100lbs
[01:05:23] <toastydeath> jet isn't so good
[01:05:25] <sebastienbailard> 80 lb, I think. No manual, which is annoying, but the taigtools mailing list does a good job of making up for that.
[01:07:21] <sebastienbailard> Looking at the plywood cnc router kits, I think they usually don't include the steel shafts or leadscrews, because the user can supply them.
[01:07:25] <ds2> not like the kits really have a manual
[01:08:01] <ds2> sebastienbailard: do the kits say what kind of ply to use?
[01:08:30] <sebastienbailard> Wood is of the finest clear Poplar, oversized by 20% in thickness.
[01:08:30] <sebastienbailard> Plywoods are of the finest Baltic Birch, imported from the Ukraine
[01:08:45] <toastydeath> that makes me chuckle
[01:09:01] <toastydeath> but you proabably won't beat the price for a router.
[01:09:09] <ds2> heh... good, cuz I had some rather "interesting" experiences with softwood ply
[01:09:24] <sebastienbailard> It reads a bit like SkyMall, but the people building them seem to be happy.
[01:09:50] <toastydeath> if you're strapped for space, and only want to cut 4x8 sheets
[01:09:55] <toastydeath> you could build a panel-saw type router
[01:14:34] <sebastienbailard> I'm going to build a smaller cnc router from wood using the solsylva.com plans, and later I may build a 5'x10' router using the mechmate.com plans.
[01:19:21] <toastydeath> i love how larger manual machines are cheap
[01:19:43] <toastydeath> people are paying 8000 for a 15x80 grizzly
[01:20:00] <toastydeath> yet a 20"x94" pacemaker goes for 700-1000 bucks in pristine condition
[01:24:28] <JymmmEMC> SWPadnos: Damn.... http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&ih=020&sspagename=STRK%3AMEWA%3AIT&viewitem=&item=300115146431&rd=1&rd=1
[01:26:28] <JymmmEMC> SWPadnos: Now, I'd hate to loose that phone in the back of a taxi
[01:32:54] <ds2> JymmmEMC: no worse then loosing a top of the line Treo
[01:33:06] <JymmmEMC> bs
[01:33:17] <JymmmEMC> Palm treo?
[01:33:52] <JymmmEMC> Not even offered in the US yet
[01:35:36] <ds2> Yes, Palm Treo...they were selling at $700ish
[01:35:46] <JymmmEMC> POS
[01:37:15] <toastydeath> amada seems to make a pretty full-featured bandsaw
[01:37:48] <toastydeath> what i always wonder is what advantage a CNC bandsaw gives you over a plain automatic
[01:38:21] <toastydeath> it's not like you can do contouring
[01:39:17] <jmkasunich> maybe if you are in the kind of business where you need '10 pcs 12" long, 5 pcs 18" long, 20 pcs 6" long' all from the same bar or tube
[01:39:42] <jmkasunich> race car frame building? custom bike or motorcycle frames, that kind of thing
[01:40:08] <jmkasunich> load the bar, set up what you need, and go do something else
[01:40:23] <toastydeath> i can see your point, but i'm not sure the automation justifies the expense in this case
[01:40:34] <toastydeath> 30k to get tubes of different lengths?
[01:40:45] <jmkasunich> 30k?
[01:40:46] <toastydeath> maybe in high production frames
[01:40:48] <toastydeath> yeah
[01:40:52] <toastydeath> 30,000 us dollars
[01:40:55] <toastydeath> or more?
[01:41:03] <jmkasunich> thats insane
[01:41:14] <toastydeath> why?
[01:41:17] <toastydeath> it'
[01:41:26] <toastydeath> s pretty expensive, but they've got a lot of automation to them
[01:42:04] <toastydeath> i think 25k is like the price for a bare-bones automatic
[01:42:07] <jmkasunich> whats to automate? clamp at the cutter, clamp on a carriage to advance the stock, the carriage itself, blade assembly up/down
[01:42:08] <toastydeath> and the cnc models go up from there
[01:42:29] <toastydeath> yeah, perhaps
[01:42:48] <jmkasunich> the machanical parts are the same for CNC or automatic, and the "control" is cheap if you take an EMCish approach
[01:42:48] <toastydeath> they're pretty rigid though
[01:43:06] <jmkasunich> if you take a "pay somebody for close source automation" then you deserve to pay to much ;-)
[01:43:34] <toastydeath> uh, that's clearly not the case as hundreds of thousands of businesses across america are paying 30k per saw
[01:43:58] <toastydeath> i don't know what's so special about the control, but the saw itself is very rugged
[01:44:05] <sebastienbailard> One place where CNC control might be useful is if you're doing a bunch of irregular length cuts all day, and you want to maximize your use of stock, and minimize your amount of offcuts, you have the computer figure it out, rather than having to reset the inputs on an automatic saw each time.
[01:44:36] <jmkasunich> I doubt anybody sells 100K saws at 30K each, thats 3 billion dollars
[01:44:49] <ds2> at 30K, isn't it cheaper to get a dedicate lathe + bar puller?
[01:44:50] <jmkasunich> I bet they sell a few thousand saws a year tops
[01:45:01] <toastydeath> ds2: not for all applications
[01:45:09] <toastydeath> not all saw work goes into a lathe
[01:45:20] <toastydeath> and not all lathes have a big bore spindle
[01:45:32] <jmkasunich> the saw can cut things like square tubing, which would be a pain on a lathe
[01:46:12] <toastydeath> and stock bigger than 2" round
[01:46:47] <ds2> but for just parting off work, you can have a lateh with a huge bore like the stuff they use for threading pipes
[01:47:03] <toastydeath> have you priced big bore lathes lately
[01:47:23] <ds2> pipe threading lathes didn't seem that steep
[01:47:27] <toastydeath> also, cutoff at depth is difficult
[01:47:47] <toastydeath> easy for thin walled tubing
[01:48:02] <jmkasunich> ds2: which do you think would cut more parts before wearing out or breaking, a cuttoff tool in a lathe or a bandsaw blade
[01:48:04] <toastydeath> but hard when you start getting past 2"
[01:48:38] <jmkasunich> if its thin walled the cutoff tool might win because the saw would catch
[01:48:52] <toastydeath> not really
[01:48:52] <ds2> it is just 30K is a lot for a saw
[01:48:52] <jmkasunich> but for 2" bar, or 6" tube with 1" walls, the saw will win
[01:49:15] <ds2> go home time
[01:49:16] <toastydeath> my experience with thin walled tubing is that a bandsaw drops through it like butter
[01:49:25] <toastydeath> with the proper blade on it
[01:49:33] <jmkasunich> guess it depends on how thin, and the blade
[01:49:48] <jmkasunich> if you're talking 0.030 wall, thats not gonna be happy
[01:49:58] <toastydeath> you use the right blade, and it's fine
[01:50:05] <toastydeath> you just use a finer and finer pitch
[01:50:26] <jmkasunich> in fact, a saw type vise would have a hard time grabbing a 2" tube with a very thin wall
[01:50:40] <toastydeath> so would a lathe
[01:50:45] <jmkasunich> collet
[01:51:01] <jmkasunich> ;-)
[01:51:17] <toastydeath> for a 2" tube?
[01:51:22] <jmkasunich> in general I agree with you, there are only a few places where a lathe _might_ have the advantage
[01:51:28] <jmkasunich> and that was my point in the first place
[01:51:32] <toastydeath> high production bar feed applications, sure
[01:51:48] <toastydeath> wins out even more if you add a sub spindle
[01:52:17] <jmkasunich> there are so many more places where the saw wins tho
[01:52:30] <toastydeath> i agree with you. i am poorly attempting to point out that in the cutoff operation, it is difficult to beat a saw by much
[01:52:46] <jmkasunich> 1/2 x 2" flatbar for example ;-)
[01:52:49] <toastydeath> lol
[02:05:36] <toastydeath> http://www.machinetools.com/MT/machines/index.tmpl?page=detail&ListingID=1139517927211358574
[02:05:39] <toastydeath> bazing
[03:20:55] <skunkwork1> #join emc-devel
[03:21:01] <skunkwork1> oops
[03:21:47] <Twingy> I'm 50% done the gerber import in GCAM now
[04:35:54] <eric_u> why does everyone want a closed loop system with steppers and encoders?
[04:37:01] <Ziegler> so you can combat step loss
[04:37:05] <petev> it's the only wat to know you lost a step
[04:37:28] <eric_u> is anyone using such a system under EMC2?
[04:37:29] <JymmmEMC> But encoders cost $100 so forget it
[04:37:39] <eric_u> not on ebay
[04:37:47] <eric_u> and U.S. digital
[04:37:51] <eric_u> and in printers
[04:37:57] <JymmmEMC> That IS the US Digital price
[04:38:09] <JymmmEMC> $112.34
[04:38:32] <JymmmEMC> each
[04:38:41] <eric_u> that's not that bad
[04:38:49] <JymmmEMC> per axis
[04:39:03] <eric_u> buy a brushless servo
[04:39:08] <petev> that seems a bit spendy, I can get brand new 600W AC servo motors with 2500 line encoders for $600
[04:39:10] <JymmmEMC> AND... all it will do is tell you that you skipped, not correct it
[04:39:31] <eric_u> that's the problem, isn't it?
[04:39:40] <JymmmEMC> yep
[04:39:49] <petev> JymmmEMC, are you sure about that?
[04:40:05] <petev> I'm pretty sure you could write a HAL file to run steppers closed loop
[04:40:20] <jmkasunich> petev: what would you have it do when it sees a lost step?
[04:40:34] <petev> issue another until it gets into position
[04:40:43] <jmkasunich> try to catch up? that will only increase speed and/or accel and make it lose more steps
[04:41:00] <petev> that's the same thing a servo system does
[04:41:17] <jmkasunich> servos aren't steppers
[04:41:21] <petev> nothing is going to help an overloaded motor, whether stepper or servo
[04:41:27] <jmkasunich> exactly
[04:42:02] <eric_u> can you set it up to throw following errors?
[04:42:11] <jmkasunich> eric_u: yes, you could do that
[04:42:50] <eric_u> I just answered a question about this on CNCZone, told them they were stupid to want it and go try to make i work on Mach
[04:43:04] <eric_u> ok, so I didn't do that
[04:43:07] <eric_u> http://www.cnczone.com/forums/showthread.php?p=301497#post301497
[04:46:04] <eric_u> I have one of these microscopes:
[04:46:13] <eric_u> http://www.company7.com/questar/microscope.html
[04:46:33] <eric_u> it has high end linear encoders and steppers
[04:46:45] <eric_u> they were running it open-loop, and not even reading the encoders
[08:26:12] <kwaj> i'm configuring hal file, and i tred this: newsig spindle-speed-cmd float, linksp spindle-speed-cmd motion.speindle-speed-out, but i get an error: "pin 'motion.spindle-speed-out' not found". Why is tha...i already loaded main motion controller module?
[08:35:41] <alex_joni> kwaj: what version of emc2?
[08:36:07] <alex_joni> older versions of emc2 had iocontrol.0.spindle-speed-out instead of motion...
[08:37:13] <kwaj> latest
[08:37:16] <kwaj> 2.1.5
[08:37:36] <alex_joni> hang on a moment
[08:38:40] <alex_joni> are you sure you have no typo in there?
[08:38:47] <alex_joni> the rest looks as it should be..
[08:40:20] <kwaj> will check again...
[08:42:15] <kwaj> yes, you were right :)
[08:42:24] <kwaj> sorry about that
[08:45:45] <alex_joni> np
[10:14:20] <kwaj> hello, can someone please help me with this ( http://pastebin.ca/511229 ). I wpuld like to configure pwmgen module, but i get no output on parport pin (i checked with osciloscope).
[10:21:48] <alex_joni> you need to addf the pwmgen function to a thread
[10:22:22] <alex_joni> addf pwmgen.make-pulses base-thread
[10:39:24] <kwaj> i added this base-thread, but i still get no output, any idea what else could be wrong?
[10:42:26] <kwaj> pwm-output variable is always false
[10:44:01] <kwaj> spindle-speed variable is and spindle-enable is TRUE
[10:44:23] <kwaj> spindle-speed variable is 5 and spindle-enable variable is TRUE
[10:47:14] <kwaj> is it importat to add the addf command at the beginning of hal file?
[10:47:15] <alex_joni> maybe man pwmgen is helpfull
[10:47:25] <alex_joni> you need to add it after the loadrt
[10:47:47] <alex_joni> kwaj: there are some sample configs which use pwmgen.. maybe you can look at them
[10:52:14] <kwaj> should i also set all parameters? What will be the default value for parameter if i dont set it (did't found this in man)?
[11:01:28] <kwaj> halcmd show thread command shows FP=0 for stepgen.make-pulses....what is this FP?
[11:01:56] <kwaj> halcmd show thread command shows FP=NO for stepgen.make-pulses....what is this FP?
[11:04:11] <alex_joni> FP is floating point
[11:04:19] <alex_joni> you don't need it for pwmgen
[11:07:50] <alex_joni> gone for today
[12:25:49] <skunkworks> guess I wasn't connected
[12:25:53] <skunkworks> http://www.cnczone.com/forums/showpost.php?p=301554&postcount=24
[12:26:05] <skunkworks> discuss and I will be back later ;)
[12:26:20] <skunkworks> (garage saling)
[12:54:54] <maddash> isn't pin 16 supposed to be input (ie, parport.0.pin-16-in) in hal_parport's mode X? and isn't mode x loaded by `loadrt hal_parport "0x378 x"`? or have I got all my config lines wrong?
[14:03:23] <acemi_> acemi_ is now known as acemi
[14:45:33] <sudo_maddash> if my steppers go out of bounds, axis.0.*-lim-sw-in is triggered, and the current call to sendProgramRun stops executing, but doesn't return. How am I supposed to recover from an out-of-bounds error?
[15:56:22] <sudo_maddash> heh, I just remapped the control keys for keystick and fired it up, then started playing quake 3 arena. keystick kicks ass.
[16:00:30] <sudo_maddash> oh shit, smoke is pouring out of the stepper board
[16:00:44] <jepler> uh oh
[16:00:50] <a-l-p-h-a> uh... why are you telling us, and not doing something about it?
[16:01:06] <a-l-p-h-a> "OH !!! SHIT my house is burning down"
[16:01:09] <sudo_maddash> s/is/was/
[16:01:36] <a-l-p-h-a> hopefully they're not toasted, but I suspect they are.
[16:01:49] <sudo_maddash> catharsis, dude. now I'm stuck with the Y-axis only.
[16:02:34] <sudo_maddash> haha, my little Major stick figure can't dodge projectiles anymore
[16:16:51] <sudo_maddash> s/they/that\ they/
[16:17:32] <jmkasunich> preserved for posterity: http://wiki.linuxcnc.org/cgi-bin/emcinfo.pl?IRCquotes
[16:18:22] <sudo_maddash> jmkasunich: hey!!!
[16:19:18] <sudo_maddash> if you're going to include me, at least stick in the q3a part! and "s/is/was/" means that this was all told in hindsight
[16:21:16] <jmkasunich> its a wiki, fix it yourself ;-)
[16:21:32] <jmkasunich> I just posted the most amusing part
[16:22:22] <sudo_maddash> is there a reason why hal doesn't include a rs-232 driver? maybe the rs-232 port isn't realtime friendly?
[16:22:59] <jmkasunich> what do you mean rs-232? a driver that sends messages?
[16:23:15] <jmkasunich> hal works with simple signals, like floats and bits
[16:25:01] <sudo_maddash> I meant serial port. isn't the official name of the serial port, "RS-232"?
[16:25:18] <jmkasunich> I know you meant serial port
[16:25:43] <jepler> there is a HAL driver for the digital I/O pins on an "8250"-style serial port -- DCD, DSR, etc
[16:25:51] <jmkasunich> "officially", rs-232 specs out the voltage levels on the serial port pins and not much more, but thats a side issue
[16:26:23] <jmkasunich> the point is, when most people talk about the serial port, they mean serially transmitted messages of some sort
[16:27:47] <jmkasunich> the driver jepler mentioned doesn't send serial messages, it just uses a few pins of the port as extra outputs (and maybe an input or two?)
[16:28:32] <jepler> jmkasunich: the "serport" manual page lists all the HAL pins and the pins they correspond to
[16:29:05] <kwaj_> what will happen, if i generate a pwmgen module, and i leave enable pin not connected...will pwmgen be enabled or dissabled?
[16:29:27] <jmkasunich> I figured it did, was too lazy to look.... I'm assuming sudo_maddash isn't talking about that concept though, and I'm trying to get him to tell us what he means
[16:29:39] <jmkasunich> kwaj_: disabled
[16:29:45] <jepler> kwaj_: if not specified otherwise in the documentation, the default value for a pin is FALSE, 0, or 0.0.
[16:29:48] <jmkasunich> the default value of an unconnect pin is zero
[16:29:59] <jepler> kwaj_: you can also use 'halcmd show pin' to check
[16:32:56] <jepler> and "halcmd setp" to define the value without connecting a signal
[16:35:05] <sudo_maddash> jmkasunich: i'm lost. why can't a hypothetical hal serial port driver treat its port like how hal_parport treats the parallel port?
[16:35:24] <jmkasunich> you mean just twiddle the pins? no baud rates or anything?
[16:37:22] <sudo_maddash> no baud rates. "twiddle"?
[16:37:31] <jmkasunich> manipulate
[16:37:58] <jepler> did you read the "serport" manpage?
[16:38:16] <jmkasunich> if all you want to do is use a few pins as bit inputs or outputs, the driver jepler is talking about already does that
[16:38:38] <jmkasunich> however, most people who ask about serial ports actually want to communicate serially with something
[16:39:12] <jmkasunich> dumb terminal, modem, or more interestingly servo drives with serial interfaces
[16:39:24] <sudo_maddash> jepler: reading it right now.
[16:46:40] <jepler> * jepler wanders off
[16:48:22] <lerneaen_hydra> random question: with an encoder/servo system, how many steps on the encoder are you from ideal when machining? +/- 2-3?
[16:48:46] <jmkasunich> that depends on how well tuned it is
[16:49:29] <jmkasunich> during rapids (especially the accel and decel at each end) I bet the following error is a bit more than that
[16:50:15] <jmkasunich> during less aggressive movement, it might be less, as little as 1
[16:51:15] <jmkasunich> following error is available as a pin or parameter (not sure which offhand, use show) so you can meter it or scope it while running
[16:57:55] <jepler> http://timeguy.com/cradek-files/emc/final-tuning.png
[16:58:09] <jepler> this is cradek's servo lathe tuning
[16:58:23] <jepler> I think the scale for the error is 10 milli-mm
[16:58:37] <jmkasunich> ype
[16:58:39] <jmkasunich> yep
[16:58:52] <jmkasunich> his encoder counts are _very_ small
[16:59:01] <jepler> and the input scale is 6000
[16:59:14] <jmkasunich> 2000 count/rev encoders, 3:1 belt drive from motor to screw, and 20:1 screw (I think)
[16:59:30] <jmkasunich> oops
[16:59:32] <jmkasunich> 1mm screw
[16:59:53] <jepler> I think 1 div would be 60 counts
[17:00:09] <jmkasunich> yeah
[17:26:30] <lerneaen_hydra> I take it pid error is the deviation from where it should be?
[17:27:56] <lerneaen_hydra> so from cradek's lathe it looks like 6 steps when doing rapids and 1-2 with less agressive stuff?
[17:29:21] <JymmmEMC> logger_emc: bookmark
[17:29:21] <JymmmEMC> Just this once .. here's the log: http://www.linuxcnc.org/irc/irc.freenode.net:6667/emc/2007-05-26.txt
[17:36:06] <JymmmEMC> Is there a way to capture/measure mid-band resonance?
[17:40:25] <archivist> yes by a slow frequency sweep through it
[17:41:02] <jmkasunich> which might be hard to do, since the axis will be moving in one direction the whole time, and might run out of travel
[17:41:27] <jmkasunich> if you want to check motor resonance only, decouple it from the screw, then you can check as archivist suggested
[17:41:48] <archivist> also depends on available equipment /me would use a dynamic sysem analyser
[17:41:55] <JymmmEMC> Sorry, I meant when it does stall.
[17:42:44] <archivist> not entirely valid under stall conditions
[17:43:03] <jmkasunich> archivist: doesn't the analyzer need position and/or velocity feedback from the unit-under-test?
[17:43:20] <archivist> yes
[17:43:35] <jmkasunich> dunno if you've been following the saga of JymmmEMC
[17:43:43] <archivist> not really
[17:43:46] <jmkasunich> he has a stepper machine that every once in a while loses steps
[17:44:00] <jmkasunich> he really has no clue as to why, but one suspect is mid-band resonance
[17:44:14] <jmkasunich> he has no feedback devices, and the problem is very intermittent
[17:44:26] <archivist> could be, we had it on a printer we made
[17:45:14] <archivist> full step or microstep?
[17:45:24] <JymmmEMC> Geckos have "Mid-band compensation", altering the phase (somehow), but since geckos don't have any feedback, I suspect it's an electrical thing that's being compensated. I was thinking of somehow reading those, but I dont know what to look for.
[17:45:30] <JymmmEMC> 8 micro
[17:45:49] <archivist> you increase power a bit
[17:45:55] <JymmmEMC> archivist: I have xylotex right now.
[17:46:04] <jmkasunich> archivist: to be clear, JymmmEMC is not using Geckos, he's using something else, and wondering if Geckos would solve his problem
[17:46:16] <archivist> dunno
[17:46:22] <JymmmEMC> archivist: IT's at the limits.
[17:46:41] <archivist> then avoid the noisy speeds
[17:47:20] <JymmmEMC> archivist: I'm just looking to confirm that the issues I've been having are indeed mid-bind, and not the motors, a cable, or something else entirely different. Then I can justify buying geckos.
[17:47:57] <archivist> we evend damped the gears in the drive using thixotropic grease
[17:48:17] <JymmmEMC> archivist: You know the ngc file that loads when you start Axis? I can get even that to stall once in a while, but not all the time and can't repeat it either.
[17:48:31] <archivist> basicly if the drive is noisy its a sign of resonance
[17:49:28] <archivist> check the acceleration rate v the steppers limits bearing in mind the load it has
[17:50:17] <JymmmEMC> http://www.xylotex.com/StepperMotor.htm
[17:50:26] <archivist> Im used to the stepper problems but not used linux emc yet
[17:51:08] <lerneaen_hydra> JymmmEMC: just OOC, what type of speed are you running your motor at? continously sub-critically? or do you jump past often?
[17:51:18] <jmkasunich> since the problem is intermittent, if it is a resonance, it must be one that in most cases the machine passes thru quickly enough that it doesn't show up
[17:52:08] <JymmmEMC> lerneaen_hydra: Can occure even at 40IPM
[17:52:24] <lerneaen_hydra> what type of motor rpm is that?
[17:52:32] <lerneaen_hydra> (stepper rpm)
[17:52:59] <JymmmEMC> 5TPI ballscrew on 2:1 pulleys
[17:53:15] <archivist> hmm whats the curve for the motor
[17:53:33] <JymmmEMC> what's in that link is all I have.
[17:53:48] <lerneaen_hydra> so around 6.5 revs/s?
[17:54:00] <lerneaen_hydra> that sure sounds like supercritical
[17:54:05] <JymmmEMC> lerneaen_hydra: I dont know
[17:54:26] <lerneaen_hydra> maybe you're loosing steps when going between 0 and that speed (like you were hypothesising)
[17:54:40] <JymmmEMC> lerneaen_hydra: I can rapid to 100IPM
[17:55:09] <lerneaen_hydra> JymmmEMC: oh, not bad at all
[17:55:15] <JymmmEMC> Kinda scarry at that speed too.
[17:55:20] <lerneaen_hydra> that's surely super critical
[17:55:21] <lerneaen_hydra> I can imaging
[17:55:23] <lerneaen_hydra> *imagine
[17:55:41] <lerneaen_hydra> 2500mm/min is fast ;)
[17:56:04] <JymmmEMC> I saw it once bounce the machine sideways.
[17:56:14] <JymmmEMC> not by much, but still.
[17:57:38] <archivist> try some different acceleration rates
[17:57:45] <JymmmEMC> I have
[17:59:07] <archivist> I note that the pdf is missing the resonant speed, mass and max step rate of the motor
[17:59:53] <JymmmEMC> Also note the my steppers are square, and the pdf shows them as octalgon
[18:00:19] <archivist> I assume its just a badged motor from some other company I would check a few compatible data sheets
[18:03:03] <JymmmEMC> Ok, say I dont get the curves, then what?
[18:03:07] <JymmmEMC> s/dont/do/
[18:05:30] <archivist> the curve will show the resonance of the rotor (need accelerating through, preferably with plenty of spare power)
[18:06:00] <JymmmEMC> Ok, and if I'm within specs?
[18:06:32] <archivist> the max torque they quote is only stall, it drops with speed so dont go too fast
[18:07:40] <JymmmEMC> So I can rapid at 100IPM, but intermittantly can stall randomly at 40IPM ?
[18:09:42] <JymmmEMC> If I slow it down much more than I already have I start risking it becoming the ultimate of rubbing of two sticks together.
[18:09:48] <archivist> doesnt suprise me mechanical systems have many resonances eg stepper, any intemediate rotating mass and the moving mass
[18:10:42] <archivist> thats why you have to avoid the resonances stay above or below
[18:11:36] <JymmmEMC> And how would you suggest I do that?
[18:11:58] <archivist> play and listen avoid the noise
[18:12:04] <JymmmEMC> If the Geckos resolve the problem once and for all, no problem. But if the issues is something else, say the motors. then I might as well invest is (let's say) servo motors/drives.
[18:12:23] <lerneaen_hydra> or encoders on the steppers
[18:13:15] <JymmmEMC> archivist: it's random, unrepeatable. Yes, I hear it when it does stall. But how would you siggest that I avoid the noise? I have no way of reading (eletrically) .
[18:13:32] <JymmmEMC> lerneaen_hydra: $112.34/ea encoder US Digital.
[18:13:45] <lerneaen_hydra> JymmmEMC: :/ nasty
[18:13:48] <archivist> no scope?
[18:14:08] <JymmmEMC> archivist: What am I to scope?
[18:14:25] <JymmmEMC> archivist: (no, but I've been thinking about getting one)
[18:15:19] <archivist> just listening to the stepper whine and find the quietest speeds
[18:16:29] <JymmmEMC> archivist: Ok, and adjust what? accel? vel? I can't repeat the problem. Even running the say gcode 10 times in a row after warming up the machien for 2 hours.
[18:16:37] <JymmmEMC> s/say/same/
[18:18:21] <archivist> both acc and vel, quietest at max current
[18:19:15] <JymmmEMC> archivist: And when do I know I've hit a limit on either? I have no feedback (electrically) to base the setting son.
[18:19:56] <archivist> when it works best as you cannot measure
[18:20:04] <JymmmEMC> measure what?
[18:21:05] <archivist> when it actually loses step and at what rate
[18:21:35] <JymmmEMC> What and how am I suppose to measure the loss steps?
[18:22:49] <archivist> you dont have feedback from the steppers so you cant
[18:22:59] <JymmmEMC> Then why would you suggest that?
[18:23:34] <archivist> i didnt
[18:24:15] <JymmmEMC> * JymmmEMC FACE PALMS
[18:39:19] <JymmmEMC> 5tpi screws, 2:1 pulley, 8microstep = 16000 PPI ??? I'm asking about the units part (PPI) not the value. Is that correct? 16,000 pulses per inch?
[18:54:38] <JymmmEMC> brb
[19:23:47] <eric_u> seems like if you are building a stepper powered device that you are using in production, Geckos are the minimum you would buy
[19:35:48] <robin_sz> so JymmmEMC , did you get your new drives and psu wired up?
[19:36:27] <JymmmEMC> robin_sz: I didn't get those drives, the seller canceled the auction (fscker),
[19:36:34] <robin_sz> ahh
[19:36:55] <JymmmEMC> and no more to be had (of those model#) on ebay, been looking.
[19:36:56] <robin_sz> shame
[19:37:09] <JymmmEMC> They looked like really nice drives too.
[19:37:11] <robin_sz> better get a gecko then
[19:38:19] <JymmmEMC> Yeah, I'm considering it. But if I'm to spend $500, Id REALLY like to know wth the problem is and not just toss money at it to find out "that's not it" (say the motors themselves or some other issue).
[19:39:18] <robin_sz> 5 axis machine?
[19:41:00] <robin_sz> g201s are only 114 dollars, 350 dollars will do it
[19:41:16] <JymmmEMC> $200 is a lot easier to swallow than $500. No the G203v, $147/ea * 3 = $441 + $20 Shipping + 1.0875% tax
[19:41:16] <robin_sz> thats 175 gbp
[19:41:43] <robin_sz> 203V .. oh the expensive one,
[19:42:03] <robin_sz> nice of you have the money
[19:43:05] <JymmmEMC> I figure if I buy the g203V, and if my motors go out in the future, I'm not out drives too. and I could just buy nicer motors.
[19:43:14] <robin_sz> true
[19:43:34] <JymmmEMC> I don't mind the investment, Just need/want to justify it is all.
[19:43:48] <robin_sz> to be fair, it os often a bewtter idea to buy the best, especially if you can only afford to buy once
[19:44:43] <JymmmEMC> If I buy stepper drives, then find out it's motors that are the problem, then I'm out both. when I could have just gone servo and resolved the problem in the first place.
[19:45:03] <robin_sz> well, servo is MUCH more expensive to do
[19:45:30] <JymmmEMC> Yeah, I understand. But 24+ months of these issues is enough.
[19:45:43] <robin_sz> no kidding
[19:45:58] <robin_sz> did you buy this thing to make money or just for kicks?
[19:46:19] <JymmmEMC> It was to make enough money to but a laser actually.
[19:46:27] <JymmmEMC> s/but/buy/
[19:46:32] <robin_sz> uh huh
[19:46:48] <JymmmEMC> what?
[19:46:53] <robin_sz> so, the sooner you fix it, the sooner you can make money
[19:47:11] <JymmmEMC> yep.
[19:47:25] <robin_sz> how much you think you can make? $100 a week?
[19:47:54] <JymmmEMC> Gawd I hope not =) I'd be broke within 60 days =)
[19:48:14] <robin_sz> ??
[19:48:27] <robin_sz> presumably this will be a sideline, not main income?
[19:48:58] <JymmmEMC> Would be working towards main income hopefully/eventually, I have a couples of products in mind.
[19:49:05] <robin_sz> right ...
[19:49:32] <JymmmEMC> I'll be outsourcing the laser potion I need
[19:49:56] <robin_sz> then just make the investment, its a trivial amount to invest in your business
[19:50:08] <robin_sz> * robin_sz is looking at a new laser too
[19:50:18] <robin_sz> well, a second hand one anyway
[19:50:26] <JymmmEMC> wattage? co2?
[19:50:33] <robin_sz> yeah co2
[19:50:46] <JymmmEMC> wattage?
[19:50:49] <robin_sz> 2k
[19:51:00] <JymmmEMC> Oh nm what I had in mind then =)
[19:51:06] <robin_sz> would have liked a 3k, but ...
[19:51:24] <JymmmEMC> This is 40W 48" x 32"
[19:51:31] <JymmmEMC> for $4000 complete
[19:51:45] <robin_sz> mine will be a bit more than that :)
[19:51:49] <robin_sz> not a lot though
[19:51:53] <JymmmEMC> yeah =)
[19:52:07] <robin_sz> $10K to $14K ...
[19:52:49] <skunkworks> That doesn't seem to bad
[19:52:56] <JymmmEMC> I need acrylic squares (various sizes), but polished edges. and doing it by hand takes way to long especially when I cna cut and polish in one pass of the laser.
[19:53:03] <robin_sz> yeah
[19:53:20] <robin_sz> this one im getting (hopefully) has been cutting acryllic
[19:53:41] <JymmmEMC> robin_sz: Just FYI, you'll be limited to 40IPM
[19:53:47] <JymmmEMC> if you want polished edges.
[19:53:53] <robin_sz> just fyi, I wont
[19:53:59] <JymmmEMC> heh
[19:54:22] <robin_sz> this thing has been cutting acryllic lettering, polished edges, at way, WAY more than that
[19:54:57] <JymmmEMC> Hmmmm, maybe this one shop I talked to is full of shit then =)
[19:55:09] <JymmmEMC> Still getting quotes
[19:55:18] <robin_sz> probably they dont have experience with multi-kilowatt CO2
[19:56:18] <robin_sz> and they probably dotn have precision height feedback ...
[19:56:33] <skunkworks> Our 1k laser polishes edges at 40ipm
[19:56:47] <JymmmEMC> Well, these are small qty jobs lots too.
[19:56:57] <JymmmEMC> This is one place... http://www.sanjoselaser.net/
[19:57:16] <JymmmEMC> We use a 3600 watt Mitsubishi Laser system
[19:57:37] <robin_sz> skunkworks, the 2K im looking at was doing perspex lettering , in 3mm perspex at at least double or more that speed
[19:57:44] <robin_sz> looked polished to me
[19:59:20] <robin_sz> Jeeez
[19:59:34] <robin_sz> NO WAY would they be allowed to perate like that over here
[19:59:43] <JymmmEMC> ???
[19:59:51] <robin_sz> exposed beam
[19:59:55] <JymmmEMC> heh
[19:59:59] <robin_sz> look at theat 5 axis ...
[20:00:12] <JymmmEMC> Yeah, I saw =)
[20:00:12] <robin_sz> operator standing by it ... oops, sorry, was that your leg?
[20:00:12] <skunkworks> This is a prc brand laser.
[20:00:29] <robin_sz> skunkworks, slab?
[20:00:46] <skunkworks> * skunkworks is not up on the lingo - slab?
[20:01:13] <robin_sz> two flat plates, nearly parallel mirrors, beam walks out
[20:01:58] <skunkworks> single tube - forced air - mirror on each end.
[20:03:14] <skunkworks> forced 'gas'
[20:03:30] <JymmmEMC> ew, maint wise.
[20:03:57] <skunkworks> it has a blower similar to what is on drag racers
[20:04:50] <skunkworks> we have had it for about 15 year. blower was replaced once so far
[20:05:21] <robin_sz> 1kw from a single tube?
[20:05:25] <robin_sz> coo
[20:05:33] <skunkworks> it has a large hv power supply with tubes to control
[20:05:37] <robin_sz> ahh, yes a rootes blower
[20:05:45] <robin_sz> right DC excited
[20:06:09] <skunkworks> it is rated at 800w - but we have always been able to get 1k
[20:06:10] <robin_sz> those rootes blowers go on for ages and are self-serviceable
[20:06:26] <robin_sz> basically, just a bearing and seal kit
[20:06:30] <skunkworks> rootes - I could not remember the name
[20:06:44] <robin_sz> the one im looking at is rootes blower
[20:07:04] <robin_sz> better than the turbine ones IMHO, maintenance wise anyway
[20:07:27] <robin_sz> this one is RF excited though, so no electrode sputtering
[20:08:25] <skunkworks> No major problems with it.
[20:08:41] <robin_sz> good
[20:08:54] <robin_sz> is the DC side vacuum tube based?
[20:09:19] <robin_sz> or solid state?
[20:09:52] <skunkworks> it has a control circuit (solid state) that floats at what ever voltage that controls the tubes. run with fiberoptics.
[20:10:02] <robin_sz> right, nice
[20:11:09] <skunkworks> 4 tubes iirc
[20:13:24] <skunkworks> tubes are cooled in a oil bath
[20:31:43] <JymmmEMC> 5tpi ballscrews @ 8microstepping, 2:1 pulley = 16000 PPI. Is the units, not the value correct??? 1600 pulses per inch?
[20:32:02] <JymmmEMC> typo missing a zero there
[20:32:36] <JymmmEMC> 200 SPR motors
[20:39:24] <robin_sz> 16000 steps per inch ...
[20:40:31] <robin_sz> 100 ipm = 1600000 per minute ...
[20:40:51] <robin_sz> 26.666 khz
[20:42:19] <robin_sz> you need a maximum rt period of 19us to do that
[20:42:25] <robin_sz> quite fast ...
[20:43:16] <robin_sz> will your PC run relaibly with 20us period?
[20:44:05] <archivist> will the steppers still have any torque at that speed
[20:44:18] <JymmmEMC> No, No, I mean is 16000 ppi == pulses to move one inch?
[20:45:37] <archivist> only if 1 pulse is one microstep
[20:45:49] <robin_sz> it is
[20:45:52] <JymmmEMC> robin_sz: 15000nS ovr max
[20:46:06] <robin_sz> 15us
[20:46:37] <JymmmEMC> so it's STEPs not Pulses per inch?
[20:46:47] <JymmmEMC> or can the two be interchanged?
[20:46:58] <robin_sz> 200 steps
[20:47:05] <robin_sz> 1600 usteps or pulses
[20:47:31] <JymmmEMC> ah, gotcha
[20:49:12] <JymmmEMC> Wait, no I don't LOL
[20:49:36] <JymmmEMC> 16000 is Steps necessary to move one inch?
[20:49:47] <JymmmEMC> OR
[20:49:57] <JymmmEMC> 16000 is Pulses necessary to move one inch?
[20:50:46] <archivist> what part of 8 microsteps per step is hard
[20:51:20] <JymmmEMC> If I knew, I would not have a need to ask.
[20:54:20] <archivist> they are partial steps, not accurately defined in angle between full steps, done by fiddling with the drive signals
[20:54:43] <JymmmEMC> I'm just asking what units they are in, nothing more, nothing less.
[20:55:10] <jepler> "microstepping" increases the number of pulses the PC has to issue to turn the motor shaft by a varying amount.
[20:55:30] <jepler> er
[20:55:34] <jepler> "microstepping" increases the number of pulses the PC has to issue to turn the motor shaft by a particular amount
[20:56:35] <archivist> its a smoother drive but has lower torque on some intermediate microsteps
[20:57:17] <archivist> and the angle of turn is not exactly 1/8 of a full step it varies
[20:57:35] <jepler> from the standpoint of emc, if you change the stepping from "full" to "1/8", the inifile SCALE is multiplied by 8
[22:12:30] <robin_sz> 16000 is Pulses necessary to move one inch
[22:12:39] <robin_sz> JymmmEMC, ^^ that
[22:12:49] <JymmmEMC> TY
[22:14:37] <robin_sz> you may be better off with a G210
[22:16:07] <JymmmEMC> why the 210?
[22:16:19] <JymmmEMC> 203 is 10microsteps
[22:16:48] <robin_sz> it will smoothly microstep the motor, 10 nice smooth microsteps for 1 pulse
[22:16:55] <JymmmEMC> I'll loose resolution if I use their multipler.
[22:17:00] <robin_sz> correct
[22:17:24] <robin_sz> but you wont be able to drive the G201 at the same speeds with emc
[22:17:52] <robin_sz> s/loose/lose/
[22:18:07] <archivist> JymmmEMC, dont confuse resolution with accuracy
[22:18:07] <JymmmEMC> I have 15500uS ovl max base period with emc, why wouldn't I?
[22:18:13] <robin_sz> the 201 is 10 usteps ...
[22:18:41] <robin_sz> you think you can do 30khz from emc reliably? if you can, then you have it sorted, no worries
[22:19:10] <JymmmEMC> Isn't 16000 about 22KHz (I dont know the math)
[22:19:18] <robin_sz> thats for 8 usteps
[22:19:23] <robin_sz> the gecko is 10
[22:19:27] <JymmmEMC> ah, right.
[22:19:41] <robin_sz> 16000 is 26.666 k .. I did the math for you earlier
[22:19:57] <robin_sz> at 100 ipm
[22:20:09] <robin_sz> of course, you could just do slower G0s
[22:20:24] <JymmmEMC> so 200SPR * 5TPI 2:1 pulley and 10uStep is 20000 base period?
[22:20:35] <robin_sz> errr
[22:20:42] <robin_sz> for 100 ipm?
[22:20:51] <JymmmEMC> no, no, to achive that
[22:21:00] <robin_sz> to achieve what?
[22:21:13] <robin_sz> 100 ipm?
[22:21:49] <JymmmEMC> 200SPR * 10 TPI leadscrews = 2000 * 10uStep = 20,000
[22:22:04] <robin_sz> 20,000 steps per inch yes
[22:22:06] <JymmmEMC> as opposed to my 16000 @ 8uStep.
[22:22:28] <robin_sz> now .. tell me a speed, and I'll tell you a frequency/period
[22:22:36] <JymmmEMC> So, to use those settings, I'd need to reduce what? just accel?
[22:22:48] <robin_sz> potato
[22:23:14] <robin_sz> no, the machine is PHYSICALLY the same
[22:23:17] <JymmmEMC> Well, I'd like to be able to do 80IPm rapids
[22:23:26] <robin_sz> so the physical contraints are unchanged
[22:23:34] <JymmmEMC> I just said that I *CAN* do 100IPM currently, that's all.
[22:24:09] <JymmmEMC> I need to be able to do 40IPM minimally, better with at least 60IPM.
[22:24:21] <robin_sz> well, 80ipm will be 26.66khz, same as before
[22:24:45] <JymmmEMC> Ok, that's cool. Plastic doens't like slow moves =)
[22:24:53] <robin_sz> quite
[22:25:38] <JymmmEMC> As my spindle is limited to 8K-25K RPM's, I don't have alot of room to play on that side of it.
[22:25:49] <robin_sz> single fluyte cutter?
[22:26:48] <JymmmEMC> No, O-Flute cutters, 0.01" top engraving, and V-Cutters.
[22:26:55] <JymmmEMC> s/top/tip/
[22:27:14] <robin_sz> engraving huh
[22:27:20] <robin_sz> floating nose cone?
[22:27:31] <JymmmEMC> Some engraving, no floating.
[22:28:01] <robin_sz> you will need a VERY good machine to do any decent engraving without a flotaing nose cone
[22:28:55] <robin_sz> any vertical movement when it accels/stops ends up as crappy round circles from the engraving tip
[22:29:01] <robin_sz> it needs to be quite rigid
[22:29:28] <robin_sz> and you have to get the alignment of the head and the material very flat
[22:29:36] <robin_sz> or the engraving width changes
[22:29:52] <robin_sz> thats why commercial machines cheat and use a floating nose cone :)
[22:30:30] <robin_sz> it compensates for misalligned material heights, and crappy mechanics
[22:30:32] <JymmmEMC> robin_sz: I havne't had too bad results (excuse the photo, poor lighting made it out of focus) http://farm1.static.flickr.com/84/206158222_cb5c34978c_m.jpg
[22:31:14] <JymmmEMC> That's on a 3" disc.
[22:31:18] <robin_sz> yeah, that looks neat enough
[22:31:30] <robin_sz> machine cant be that bad then
[22:31:47] <JymmmEMC> Other than the stalling, no it hasn't been at all.
[22:32:07] <JymmmEMC> It's not a hass by any means, but...
[23:36:57] <sudo_maddash> where can I find the documentation for 'emc.nml'?
[23:44:38] <JymmmEMC> sudo_maddash: http://www.google.com/search?hl=en&client=firefox&rls=org.mozilla%3Aen-US%3Aunofficial&hs=Gj5&q=emc.nml+site%3Alinuxcnc.org&btnG=Search
[23:46:06] <sudo_maddash> psht. wise guy. I'm only asking because i've grepped the wiki, all 4 .pdf docs and the html man page.
[23:46:40] <JymmmEMC> What? I hate wikis (in general) and google has done a nice job of indexing the site.
[23:47:45] <JymmmEMC> sudo_maddash: http://www.google.com/search?q=sudo_maddash+site%3Alinuxcnc.org&start=0&ie=utf-8&oe=utf-8&client=firefox&rls=org.mozilla:en-US:unofficial
[23:48:28] <JymmmEMC> your words have been immortalized! LOL
[23:48:44] <JymmmEMC> You've been googled! hahahaha
[23:50:26] <sudo_maddash> nada on the 48 results.
[23:53:15] <sudo_maddash> [sigh]. well, back to trial and error.