#linuxcnc | Logs for 2012-03-30

[00:15:30] <cradek> ssi: nice knurl!
[00:15:30] <ssi> thx :D
[00:15:36] <cradek> what is it?
[00:15:42] <ssi> hnc drill bushing blank
[00:16:17] <cradek> oh 5/8 to random drill size?
[00:16:21] <ssi> yeah
[00:16:50] <ssi> working on a program to churn them out
[00:17:03] <cradek> what a pain! I have a jacobs chuck mounted.
[00:17:13] <cradek> I have a few of their drill holders too, but they're so finicky.
[00:17:24] <ssi> I'm gonna mount a jacobs chuck also, but I don't have one on there yet
[00:18:30] <ssi> I'm a bit worried about the overall length of a jacobs chuck plus a typical drill bit
[00:18:38] <ssi> especially getting up in the 3/8" to 1/2" range
[00:18:57] <cradek> yeah I always use ... uh whatever the short ones are called
[00:19:01] <cradek> screw machine drills
[00:19:03] <ssi> ahh
[00:19:23] <cradek> for me they're usually better for everything
[00:32:24] <Jymmm> WOOHOO! tinder tubes done and work nicely =)
[00:38:28] <cradek> what's a tinder tube?
[00:46:07] <Jymmm> cradek: Watch this real qick, then I'll tell you 012-03-28 10:29:21 Jymmm: TML: FWIW, this works GREAT!!! http://www.youtube.com/watch?v=-6FNCS7de_A
[00:46:11] <Jymmm> bah
[00:46:16] <Jymmm> just the video
[00:49:42] <Jymmm> cradek: see it?
[01:42:10] <DJ9DJ> moin
[02:03:10] <Loetmichel> mornin'
[05:09:17] <mazafaka> evenin'
[07:04:55] <asdfasd> I have a lathe with spindle controlled by step/dir signals, is it possible to configure emc2 to use it as rotary axis and same time as spindle and control the RPM witn step/dir?
[07:06:26] <cpresser> asdfasd: that would give you two conflicting inputs?
[07:07:04] <asdfasd> inputs?
[07:07:11] <cpresser> but you might use two different 'configurations' for your machine, one 'spinde' and one 'axis'
[07:07:28] <asdfasd> no I need both together
[07:07:45] <cpresser> waht if you set "G0 X10 A20 S1600" (speed 1600, move to 20degrees). how is that going to work??
[07:07:50] <asdfasd> then with G code I will choose which one to control
[07:08:11] <asdfasd> Im not going to use that kind of G code
[07:08:23] <asdfasd> only M3 s1000
[07:08:30] <asdfasd> or only G0 A100
[07:08:52] <cpresser> how does the software know which command to follow?
[07:10:01] <cpresser> you could wire this up in hal with a mux to switch between the two options. but personally i think this is bullshit. two conflicting input options are not a good idea
[07:11:05] <asdfasd> it is not such bullshit, currently working with mach3, spindle and axis A configured on same outputs, I write the G code manually to avoid all conflicts
[07:11:17] <frysteev_> anyone have a machine with mulriple spindles i wonder?
[07:11:48] <asdfasd> so working good, but I like emc2, it is making more smooth movements
[07:11:58] <cpresser> thats why i wrote 'personal opinion' :)
[07:12:49] <asdfasd> ok, can you help me, how to do that, I dont really understand hal
[07:13:04] <asdfasd> I tried to read something but it is new for me
[07:13:12] <cpresser> you need to solve problems like 'reindexing the axis after it has been used as spindle', its not an easy task
[07:13:36] <asdfasd> I dont use houming on A axis
[07:14:48] <cpresser> take a look at the "mux2" module. it has two input signals and one output (plus a signal to control which input is used)
[07:15:43] <asdfasd> first of all I didnt found how to control step/dir spindle
[07:16:09] <cpresser> pwmgen? http://www.linuxcnc.org/docs/2.5/html/hal/rtcomps.html#sec:PWMgen
[07:16:10] <asdfasd> there is only outputs for spindle on/off CW and CCW
[07:16:39] <cpresser> am.. meant stepgen. sorry
[07:17:32] <cpresser> you can use the halui- and motion pins for that
[07:18:42] <cpresser> the pins "motion.spindle-speed-out" tells you how the programmed rpm
[07:19:25] <cpresser> "halui.spindle.runs-forward" tells the direction
[07:19:39] <cpresser> take those pins and hook em up to a stepgen
[07:19:48] <asdfasd> wow
[07:19:59] <cpresser> http://linuxcnc.org/docs/html/man/man9/stepgen.9.html
[07:20:40] <cpresser> stepgen has a velocity mode suitable for this usecase
[07:21:46] <asdfasd> ok, I understand now, still not clear, but now I have what to read, thank you very much
[07:22:11] <asdfasd> it looks like linux is always complicated :)
[07:22:37] <cpresser> its powerfull^^
[07:22:44] <asdfasd> much powerfull
[07:24:44] <asdfasd> recently I had a chat with cradec, for few settings, before I use mach3 on my mill, but I wanted to increase the feedrate, and I changed to emc2, much better movements
[07:25:20] <asdfasd> with same G code almost twice increased feedrate
[07:25:48] <asdfasd> now I think to change to emc2 on my lathe too....
[07:45:04] <asdfasd> I think I found something
[07:45:20] <asdfasd> http://wiki.linuxcnc.org/cgi-bin/wiki.pl?KX3
[07:45:48] <asdfasd> the last example says ..... to add a 5th stepper generator controlling the spindle.
[07:46:58] <asdfasd> after changing that in my hall file should I be able to control the spindle RPM with step/dir?
[07:48:43] <asdfasd> is that the only I have to do?
[08:21:05] <Tecan> anyone here laser ?
[08:24:27] <frysteev_> i have lasers im working on getting operational..
[08:27:16] <JT-Shop> you start raising the bar yet?
[08:27:32] <Valen> frysteev_: they had better be friikin lasers
[08:29:23] <Tecan> frysteev where does the wire go after it comes from the red wire to the tube ?
[08:30:16] * Tecan pokes frysteev_
[08:36:14] <frysteev_> yo
[08:36:24] <frysteev_> to the exciter,
[08:36:44] <frysteev_> its going to be high voltage RF i believe,
[08:36:45] <Tecan> http://i.imgur.com/Hdpo1.png
[08:36:52] <Tecan> this is what im working with
[08:37:05] <Tecan> i know where to put the red wire
[08:37:14] <Tecan> but after that ide assume the ground
[08:37:21] <frysteev_> building one from scratch?
[08:37:24] <Tecan> ya
[08:37:36] <frysteev_> so you have the tube?
[08:37:39] <Tecan> ya
[08:37:50] <frysteev_> but no circuitry to drive it?
[08:38:04] <Tecan> i have a motor driver and pwm for the laser
[08:38:23] <frysteev_> the pwm would go to the laser driver,
[08:38:25] <Tecan> i just need to connect the end of the tube to something
[08:38:42] <frysteev_> the laser driver is what you need, to take the pwm and excite the tube
[08:38:54] <Tecan> yeah thats the power supply
[08:38:55] <frysteev_> not a homebrew item
[08:39:33] <Tecan> i bought the laser power supply, im trying to connect the tube
[08:39:50] <Tecan> where does the wire from the end of the tube go ?
[08:40:23] <frysteev_> im assuming this is an elcheapo china laser?
[08:40:27] <Tecan> mhm
[08:40:32] <frysteev_> (i have a 40 watt elcehapo one at home)
[08:40:47] <Tecan> i shoulda bought 80w for metal
[08:40:50] <frysteev_> i found it was cheaper to buy the whole thing, then buy the parts seperatly
[08:41:08] <Tecan> thats good an all im ready to go i just need to put this last wire somewhere
[08:41:17] <frysteev_> i will take a look at mine late and grab some pics for ya
[08:41:22] <Tecan> thanks
[08:42:01] <frysteev_> you have pics?
[08:42:35] <Tecan> my camera sucks, might try with the phone
[08:42:49] <Tecan> http://i.imgur.com/Hdpo1.png << this is the power supply though
[08:43:11] <Tecan> aha the laser tube circuit loop
[08:43:17] <Tecan> thats where the last wire goes
[09:52:20] <ssi> HI
[09:52:27] <frysteev_> ola
[09:52:33] <frysteev_> are you here yet?
[09:52:37] <ssi> kentucky
[09:52:46] <ssi> I told you it was slow
[09:53:49] <ssi> you laserin yet?
[09:55:58] <frysteev_> hoisting it up tongiht hopefully
[09:56:02] <ssi> sweet
[09:56:04] <ssi> any new pics?
[09:56:43] <frysteev_> nope
[09:56:47] <frysteev_> ill be taking some tho
[09:56:58] <ssi> good
[09:57:05] <ssi> I wrote a program to cut drill bushings
[09:57:09] <ssi> it's working pretty well :D
[09:59:41] <frysteev_> for the lathe?
[10:00:16] <frysteev_> web gui done now too?
[10:32:37] <ssi> yea for the lathe, and no, no web gui :)
[10:33:28] <ssi> and btw, this lathe can part like nobodys business
[10:33:30] <ssi> amazing
[10:33:48] <ssi> parting cold roll at like 8ipm
[10:39:56] <Tecan> frysteev_ can i just tie the 5v to the signal to get the laser to fire ?
[10:40:31] <Tecan> its pwm so i'll be getting 100% power
[10:43:39] <frysteev_> um. not neccasarily
[10:43:59] <Tecan> im trying to test fire it and i put 5v to the in and 5v to the signal and nothing happened
[10:44:06] <frysteev_> if you were to do that i would only do it momentarily for quick tests
[10:44:39] <frysteev_> you have an arduino or soemthing that you can drive a pwm signal with?
[10:44:45] <Tecan> ya
[10:45:06] <Tecan> i duno what im doing though
[10:45:24] <Tecan> its asking for 2.2w to 5 w to fire the laser
[10:45:41] <Tecan> or pwm
[10:46:10] <frysteev_> my cheapo has a rest fire button right on it
[10:46:23] <Tecan> oh wait maybe mine does too
[10:46:28] <Tecan> theres a test thingi
[10:46:30] <Tecan> brb
[10:48:05] <frysteev_> http://megacyclelabs.com/?p=44
[10:48:05] <frysteev_> theres some pics of my cheapo
[10:48:05] <Tecan> sweet tits
[10:48:05] <Tecan> it worked
[10:48:05] <Tecan> burnt a hole in my dvd case
[10:56:54] <Tecan> frysteev_ can you turn the laser really low to set the focal point ?
[10:57:04] <Tecan> so i dont set everything on fire
[10:59:16] <frysteev_> well on mine, you set the power control with the stupid pot, then there is a signal to turn the laser on or off, not pwm
[11:00:39] <Tecan> ew, so grey scale pictures are done with motion speed and hand controll ?
[11:00:54] <Tecan> that sounds tricky
[11:01:13] <Tecan> when you crank the pot way down can it hardly burn anything ?
[11:02:15] <frysteev_> there is a reason that project is sitting on a shelf atm,
[11:09:03] <Tecan> http://www.youtube.com/watch?v=Jm_6U-MWmXk << Vexare - Firing My Lazer
[11:55:18] <cpresser> Tecan: most laser gray scale pictures are dithered (like in newspapers) and engraved with constant power
[12:03:38] <IchGuckLive> hi all around the globe
[12:17:52] <Tecan> so what advantage would having control over it be ?
[12:18:08] <pcw_> IchGuckLive: was that you doing the giant foam statue?
[12:18:34] <IchGuckLive> yes
[12:19:12] <IchGuckLive> therfor i made also the axis hack for xyuv foam view
[12:36:18] <SolarNRG> Hi guys
[12:38:23] <DJ9DJ> Hi guy :)
[12:39:23] <ssi> SolarNRG: melted anything yet?!?!
[12:39:37] <SolarNRG> I want my arduino to drive a stepper motor with my PC 12v power supply, my stepper motor is a 439oz/inch or 3.1NM stepper it has 8 wires. What is the cheapest way to make the motors turn back and forth circuitwise?
[12:40:25] <ssi> SolarNRG: H bridge
[12:40:44] <ssi> but if you're not well versed in circuits, you're likely better off buying a commercial driver
[12:41:44] <SolarNRG> I built a BJT H bridge but it has two NPN 4Amp BJTs and two PNP 4 amp BJTs, I'm guessing this won't work and I need 4 BJTs all the same for steppers, am I righT?
[12:41:53] <SolarNRG> The H bridge I made was for a windscreen wiper motor
[12:42:06] <frysteev_> SolarNRG: you can buy 3 or 4 axis stepper controls cheap online
[12:42:25] <frysteev_> i got a funch of 4 axis ones, 2.4A per motor for like $60
[12:42:35] <SolarNRG> I'm thinking now of using my steppers to drive my solar dish instead of a CNC machine for now
[12:42:39] <SolarNRG> I only need a 2 axis one for this
[12:42:54] <SolarNRG> I can get more steppers if needbe, I think a CNC machine may be a few months away
[12:43:04] <frysteev_> http://www.cncgeeker.com/index.php?main_page=product_info&cPath=1&products_id=41&zenid=91d309d9fb0ddafddf82a4b6b40ccb0f
[12:43:22] <frysteev_> i have a few of those too, which i got cheaper buy buying like 5 of them
[12:44:25] <frysteev_> http://www.aliexpress.com/product-gs/357533544-5-axis-cnc-controller-TB6560-3-5A-stepper-controller-handle-controller-wholesalers.html
[12:44:33] <SolarNRG> Its not as nice as a gecko drive
[12:44:40] <Jymmm> Who needs a plasma cutter http://www.youtube.com/watch?v=kDxJVKymqY4
[12:50:20] <mrsun> did he say lead ?
[12:50:29] <mrsun> or whatever its called in english
[12:50:31] <frysteev_> Jymmm: yours?
[12:50:36] <mrsun> vaporized i dont think its very healty
[12:50:47] <Jymmm> frysteev_: nah
[12:54:21] <djdelorie> maybe it's a pencil lead, which is mostly carbon
[12:55:40] <djdelorie> SolarNRG: the easiest way is to wire the stepper as bifilar, and use four NPN (or better N-MOSFETS) driven by logic
[12:57:32] <frysteev_> the EASIEST way to drive a stepper is turning it by hand :P
[13:01:07] <SolarNRG> DJ, have you got a circuit partslist/schematic to make said ultra cheap-crap but operational device?
[13:02:17] <mrsun> http://www.youtube.com/watch?v=PMXEfDoH1ho&feature=g-vrec&context=G2e1cc6dRVAAAAAAAABg lets destroy a milling machine ? :P
[13:02:25] <mrsun> look at the column guideways ...
[13:06:12] <TekniQue> yeah that's not good for your guideways
[13:06:23] <TekniQue> the abrasive dust
[13:15:09] <djdelorie> http://www.delorie.com/tmp/bifilar.pdf
[13:17:27] <mrsun> driving them non bipolar leaves you with alot less holding torque etc
[13:17:54] <mrsun> my motors are rated 1.85Nm at bipolar and 1.24 or something unipolar
[13:17:57] <mrsun> sucks =)
[13:41:12] <skunkworks> does anyone have any links on how to setup a pci parallel port to epp?
[13:41:16] <skunkworks> on ubuntu
[13:41:22] <skunkworks> I am coming up blank
[13:42:14] <awallin> bios?
[13:42:20] <cradek> the drivers should do it for you
[13:42:27] <cradek> are you having trouble?
[13:42:29] <skunkworks> I don't think pci ones show up in the bios
[13:42:33] <cradek> no, they don't
[13:43:04] <skunkworks> No - but this is the 2nd or 3rd time I have read of people having problems with the g540 and pci printer port cards.
[13:44:13] <cradek> it doesn't use EPP does it?
[13:44:42] <skunkworks> seems the g540 needs epp because it must change the pin configuration.. (thinking a push pull instead of open drain with pull up)
[13:44:44] <cradek> thought it was just dumb step/dir
[13:45:15] <cradek> ok you're above my pay grade now, no clue what it wants
[13:45:31] <skunkworks> yes - it is. It isn't using EPP per say - but it seems to change how the pins act... From what I have read. And in the g540 manual - it specifically says to use epp mode
[13:45:51] <cradek> I just found that too
[13:46:15] <cradek> no idea why it would need that
[13:46:59] <skunkworks> pcw theorizes that maybe it changes the pin config from maybe open drain with pullup to push pull or such.
[13:47:09] <cradek> sounds flaky
[13:47:29] <cradek> not pcw
[13:47:30] <skunkworks> I wish I had one here. It seems people get stuck and then give up.
[13:47:34] <cradek> that requirement (if real)
[13:47:41] <skunkworks> right
[13:48:09] <skunkworks> http://linuxcnc.org/index.php/english/component/kunena/?func=view&catid=38&id=14788&limit=6
[13:48:11] <skunkworks> one example.
[13:48:18] <cradek> hal_parport surely doesn't try to force the port into epp mode
[13:48:30] <skunkworks> Everything seems to work except the charge pump
[13:48:47] <cradek> what do you mean?
[13:48:54] <skunkworks> someone on the yahoo list had the same issue.
[13:49:26] <skunkworks> The step/dir pins and such work - it is the charge pump input that doesn't seem to work without being set to epp
[13:49:45] <skunkworks> *parallel port set to epp.
[13:49:53] <SolarNRG> Would an L298 chip drive these from an arduino? http://i.imgur.com/aJvY1.jpg
[13:52:00] <skunkworks> cradek: could the hal_parport have an option to try to set the parallel port to epp?
[13:52:26] <cradek> anything is possible
[13:52:29] <skunkworks> heh
[13:53:00] <jackc> haha
[13:53:29] <jackc> SolarNRG: likely, perhaps not at full current
[13:54:00] <SolarNRG> Is there a bigger badder brother of the L298?
[13:54:48] <skunkworks> You would think someone made a utility to do that...
[13:55:36] <jackc> SolarNRG: youd thinks someone made stepper drivers or something... :-p
[13:55:39] <jackc> *think
[13:55:43] <archivist> SolarNRG, use a bipolar driver for those motors, more torque, better top speed
[13:56:05] <jackc> im a big fan of the gecko drivers
[13:56:23] <PCW> skunkworks: I think Kirk Wallace from the list has such a parallel port util
[13:56:26] <SolarNRG> I can't afford a gecko :(
[13:56:39] <SolarNRG> I'm looking for a big L298 to make a very basic CNC machine with
[13:56:40] <skunkworks> PCW: ohh. I will check the wiki
[13:56:41] <archivist> http://www.arceurotrade.co.uk/Catalogue/Stepper-Motors/Stepper-Drivers
[13:56:42] <jackc> SolarNRG: ah. if you were really motivated, you could build drivers from parts
[13:56:50] <SolarNRG> I'm game for that
[13:56:52] <jackc> SolarNRG: i THINK actually, you can rock L298s in parrallel?
[13:56:59] <jackc> can someone back me up on that?
[13:57:04] <SolarNRG> ??
[13:57:07] <jackc> SolarNRG: were you planning to use the L297 also for stepping?
[13:57:17] <SolarNRG> Yeah
[13:57:29] <cradek> looks like you'd change the hal_parport_get call and add a write to set 0x80 in ECR
[13:57:36] <SolarNRG> I just want to plug this into my arduino and power supply so at least I can get the motors turning
[13:57:40] <cradek> if you had one, you could try that.
[13:58:09] <archivist> SolarNRG, no need for arduino, drive from the parallel port
[13:58:09] <jackc> SolarNRG: one L297 and 298 pair will do that
[13:59:04] <skunkworks> PCW: http://wiki.linuxcnc.org/cgi-bin/wiki.pl?Startech
[13:59:06] <frysteev_> i wanna make a really clunky stepper driver with relays :P
[13:59:22] <SolarNRG> I can't afford a desktop with a parallel port either
[13:59:26] <SolarNRG> But I have a usb port and an arduino
[13:59:47] <Jymmm> SolarNRG: desktop with paraports you can get for free
[13:59:52] <jackc> SolarNRG: cant use cnc over usb since its polling based
[13:59:56] <jackc> BUT you can get them moving, sure
[14:00:02] <SolarNRG> That's fine for now
[14:00:02] <frysteev_> SolarNRG: grab an old laptop with a parrell port
[14:00:29] <SolarNRG> But what if I want to make my stepper motors rotate a skydish instead of a CNC machine for this?
[14:00:38] <SolarNRG> From a car battery
[14:00:57] <SolarNRG> Do you think 2 L298s in parallel would do this?
[14:01:08] <SolarNRG> 1 stepper makes it move left right
[14:01:10] <SolarNRG> one up down
[14:01:31] <SolarNRG> Like this: http://www.youtube.com/watch?v=sDnCqVxtr3k
[14:01:35] <SolarNRG> This is my solar project
[14:02:15] <SolarNRG> But I want to give it some more powerful steppers and I need drivers that won't cook my arduino
[14:05:02] <Jymmm> SolarNRG: $7 http://www.suntekstore.com/goods.php?id=14002580&utm_source=gbus
[14:05:23] <frysteev_> make some servos
[14:05:44] <frysteev_> we turned a $50 2000lbs winch into a servo
[14:07:36] <SolarNRG> Jymm that looks very good, are you sure it will work with an arduino a car battery and my big steppers?
[14:08:05] <Jymmm> SolarNRG: I'm not sure of anything, just first hit on google for "stepper driver".
[14:09:44] <Jymmm> The manual has the schematic though.
[14:12:36] <Jymmm> shit, even has FREE SHIPING to the US/UK
[14:13:07] <frysteev_> us/uk same thing
[14:13:22] <Jymmm> Yeah, it's just a lil pond in between
[14:13:39] <SolarNRG> And those little things I screw my wires straight into right?
[14:13:45] <SolarNRG> What do I screw into VCC?
[14:13:54] <Jymmm> But is that uni or bi polar?
[14:14:02] <SolarNRG> I have 8 wire unipolars
[14:14:13] <SolarNRG> Here are my steppers http://i.imgur.com/aJvY1.jpg
[14:16:28] <SolarNRG> Can I plug my car battery + and - into VCC and GND respectively with your suntekstore stepper driver?
[14:16:44] <Jymmm> SolarNRG: I'm not sure of anything, just first hit on google for "stepper driver".
[14:17:26] <SolarNRG> It says max power consumption 20W, is that enough for these big steppers?
[14:17:40] <SolarNRG> I'm scared I might buy it and it draws too much power
[14:17:56] <ssi> frysteev_: how fast is your winch servo?
[14:19:10] <mrsun> SolarNRG, voltage/current rating ?
[14:19:16] <Jymmm> Awwww, isn't that cute... it has a PWR switch right on the PCB
[14:19:22] <mrsun> oh a stepper driver :P
[14:19:39] <SolarNRG> I honestly don't know
[14:19:46] <mrsun> SolarNRG, motor current rating and driver current rating ? :)
[14:19:53] <SolarNRG> All I know is the steppers are big, heavy, have 8 wires and are rated to 439 oz/inch
[14:19:56] <SolarNRG> or 3.1NM
[14:19:57] <frysteev_> ssi: we still used it as a winch sortof, was like 60-100 rpm
[14:20:06] <mrsun> as long as the driver can output the current, depending on type
[14:20:14] <ssi> frysteev_: I want to build a cable robot like a skycam
[14:20:32] <frysteev_> but those winch motors draw 50A no load and 100A full load
[14:20:34] <ssi> frysteev_: and I was thinking about maybe building a GODDAMN BIG ONE that could act as a 3D crane up to 500lb
[14:20:43] <Jymmm> ssi: talk to alex_joni then
[14:20:47] <mrsun> if its a chopper you can have any voltage to the rated voltage for the driver realy (according to geckodrive you should calculate maximum stepper voltage as sqrt(mH) * 31 or something like that)
[14:20:47] <ssi> Jymmm: oh yea?
[14:21:00] <ssi> I'm still trying to figure out wtf you call that kinematic
[14:21:06] <mrsun> if its a simple full step driver with no chopping you need to know the rated voltage of the motors
[14:21:08] <Jymmm> ssi: talk to alex_joni then
[14:21:12] <mrsun> else you will burn them =)
[14:21:22] <ssi> alex_joni: talk to me then!
[14:21:36] <Jymmm> alex_joni: dont talk to ssi
[14:21:40] <ssi> having something like that in my hangar that can position a 500lb load anywhere in the space would be awesome
[14:21:48] <ssi> great for things like hanging engines :)
[14:21:49] <SolarNRG> What are most stepper motor's rated voltages typically
[14:22:01] <Jymmm> ssi: 500lbs? WTF
[14:22:15] <ssi> Jymmm: what?
[14:22:32] * Jymmm just shakes his head.
[14:22:36] <ssi> I'd probably do a little one first that can follow me around with a work light and a fan
[14:22:39] <ssi> that'd be pretty good too :)
[14:23:08] <ssi> three or four 2000lb winches oughta be able to support 500lb
[14:23:14] <ssi> might be balls slow, but I bet it'd work
[14:23:18] <frysteev_> ssi: i build a small cablecar once,
[14:23:26] <Tecan> how do i use a usb to db25 printer adapter ?
[14:23:28] <Jymmm> ssi: and you are going to get elecricity to the payload how?
[14:23:39] <ssi> Jymmm: what makes you think the payload needs electricity?
[14:23:41] <Tecan> i cant find the base address
[14:23:47] <Jymmm> ssi: light, fan
[14:23:47] <Tom_itx> Tecan, you don't
[14:23:59] <Tecan> my port is fried though and i need to
[14:24:05] <ssi> hell those could be battery powered
[14:24:19] <Jymmm> Tecan: You use a PCI paraport card
[14:24:28] <ssi> or one of the cables could carry power
[14:24:32] <ssi> there's lots of ways to skin that particular cat
[14:24:42] <frysteev_> ssi: i build a small cablecar, with two aircraft cables, and drove 12V down the lines
[14:24:48] <ssi> frysteev_: yep
[14:24:49] <Jymmm> ssi: Uh huh, you keep thinking that!
[14:25:00] <ssi> Jymmm: so I have a question for YOU
[14:25:07] <Jymmm> ssi: No
[14:25:11] <frysteev_> this was inside, and for fun, wouldnt use it in a shop
[14:25:13] <ssi> Jymmm: do you ever actually contribute anything here, or do you only serve to shit on everyone else's ideas
[14:25:15] <Tom_itx> drumroll
[14:25:25] <Tom_itx> he shits alot
[14:25:40] * frysteev_ gets some ice for ssi's face
[14:25:48] <Jymmm> ssi: Oh, have you actually come up with an idea yet?
[14:25:56] <Tom_itx> ssi, ask him about his laser table
[14:26:12] <SolarNRG> Are any of you familliar with the K179
[14:27:00] <ssi> I'm not concerned about his laser table
[14:27:03] <ssi> just his attitude problem
[14:28:14] <Tom_itx> i'm not too concerned about either one
[14:28:15] <Jymmm> ssi: Maybe you were embelishng a bit (I would hope so), but to lift, carry, and move a 500lbs load on wire skycam overhead, would be HUGE! And the safety factor alone if a cable broke came loose etc would surely bug a big undertaking. Unless you just dont give a fsck.
[14:29:15] <mrsun> filesystem check ?
[14:29:23] <Jymmm> ssi: So, to me that is just talking out your a55, not "an idea" at this point. Yes, maybe I am full of shit here, but I call em as I see em. and I haven't seen anything practical so far.
[14:29:26] <mrsun> thats nice to give away :P
[14:29:56] <ssi> Jymmm: I'm aware of the difficulty of the problem, and even of the safety aspects of it. And I certainly wasn't suggesting that I'm going to offer such a thing up for sale
[14:30:10] <ssi> 15:15 < Jymmm> ssi: Uh huh, you keep thinking that!
[14:30:22] <ssi> re powering a fucking 1lb light over a cable
[14:30:28] <ssi> gosh, that must be an IMPOSSIBLE Task
[14:30:31] <Jymmm> ssi: a 500 lb pendulum
[14:32:00] <mrsun> SolarNRG, stepper voltages vary alot =)
[14:32:05] <mrsun> so does the current rating
[14:32:12] <mrsun> no info from where you bought them ?
[14:32:23] <mrsun> also differnt current for bipolar series/parallel connected
[14:36:22] <Jymmm> SolarNRG: If your motors are 400 oz/in, I seriously doubt that lil driver would even come close. My 260 oz draws 3a alone and that driver maxes at 2a and I'd suspect that includes BEMF as well.
[14:36:54] <SolarNRG> I was guestimating about 4 amps
[14:37:04] <Jymmm> SolarNRG: dont guess, do the math.
[14:37:12] <mrsun> my 1.85 draws 4A in bipolar connection
[14:37:14] <Jymmm> read the spec sheets, etc.
[14:37:20] <mrsun> bipolar parallel
[14:37:25] <mrsun> 1.85Nm
[14:37:36] <SolarNRG> This was a fleabay jobby, no ddatasheet
[14:37:42] <SolarNRG> Right mrsun, these are 3.1Nm
[14:37:48] <SolarNRG> They are unipolar
[14:37:49] <Jymmm> SolarNRG: Find it online then
[14:38:21] <mrsun> SolarNRG, you need to check, but from what ive seen the amps doesnt go very high over the holding torques in higher torques, the voltage goes up more =)
[14:39:13] <SolarNRG> 13.-4.5 amps
[14:39:14] <Jymmm> Hey guys... http://www.suntekstore.com/goods-14002019-lm8uu_8mm_linear_ball_bearing_bush_bushing_.html
[14:39:23] <SolarNRG> 24-50v
[14:39:30] <mrsun> SolarNRG, huh ?
[14:39:50] <SolarNRG> NEMA 23 439oz/inch stepper does 1.3amps to 4.5 amps and 24 to 50 volts
[14:40:05] <mrsun> 1.3 to 4.5 ? :P
[14:40:15] <mrsun> thats not e very good spec
[14:40:28] <Jymmm> mrsun: ya think? lol
[14:40:33] <mrsun> thats like saying the atlantic is somewhere betwene the north and south pole
[14:40:42] <Jymmm> mrsun: It might of well said 1 to 1000v =)
[14:44:26] <Jymmm> Interesting, they have end blocks too http://www.suntekstore.com/goods-14003980-4pcs_20mm_aluminium_shaft_support_pillow_block.html
[14:45:39] <Jymmm> wasn't somone looking for Solenoids?
[14:49:14] <Jymmm> ssi: Here ya go when you get your power situated http://www.suntekstore.com/goods-14002878-22lbs_dc_24v_holding_electromagnet_lift_solenoid_%28zye1-p3022%29.html
[14:50:45] <Jymmm> $4 USD SHAFT COUPLERS http://www.suntekstore.com/goods-14000192-one_aluminum_flexible_coupler_for_stepper_motor_1in_x_075in.html
[14:52:20] <SolarNRG> Can I make stepper motors work on less than their rated voltage?
[14:52:27] <SolarNRG> Or will they not work properly?
[14:52:47] <cradek> usually you want to run a stepper with about 10x its rated voltage
[14:53:00] <mrsun> SolarNRG, you will lose power
[14:53:21] <mrsun> cradek, if you have a chopping driver yes =)
[14:53:27] <Jymmm> mrsun: I thought speed at lower voltage? torque at lower current
[14:53:29] <mrsun> make sure he has that before you recomend 10x rated voltage :P
[14:53:51] <mrsun> Jymmm, if its a constant voltage driver you will lose current with lower voltage
[14:53:58] <mrsun> anything under rated voltage you will lose current
[14:54:25] <Jymmm> mrsun: Right, but lower voltage == lower speed
[14:54:31] <mrsun> Jymmm, yes
[14:54:36] <Jymmm> lower current == lower torque
[14:54:38] <mrsun> as it cant load the magnetic fields as fast
[14:55:17] <Jymmm> anyone need er16 collets?
[14:56:09] <mrsun> sigh
[14:56:17] <mrsun> i dont get people
[14:56:30] <Jymmm> WOW, that's cheap... http://www.suntekstore.com/goods-14002020-dual_digital_pid_temperature_control_controller.html
[14:56:38] <Jymmm> mrsun: ?
[14:56:47] <mrsun> you try and help them, and they dont even answer back with good answers, atleast give links to the products you have bought if you dont get what the peopkle trying to help is saying =)
[14:57:25] <Tecan> awe sweet i can use the prolific 2305 chip with usb2lpt
[14:57:37] <Tecan> they have a eeprom writer for it
[14:58:27] <Tecan> to see if it works in linux after will be another thing
[14:59:04] <Jymmm> mrsun: I think SolarNRG is really enthusiastic, but technically and (seriously) financially challeneged,so he's just trying to get by on doing anything with pennies. Then we show him the stuff to use and it's all $$$ and instead of responding, he just remains silent.
[14:59:40] <mrsun> Jymmm, yes but he had motors and drivers? :)
[15:00:12] <mrsun> almost always you can make do ... like limiting the current, losing torque, like i did in the beginning before i could afford big drivers =)
[15:00:15] <Jymmm> mrsun: Sure, but he didn't even know what motors he had, so they might have been $2 off ebay with free shipping or whatever.
[15:00:58] <mrsun> Jymmm, yeah sure ... i wonder if you can calculate the voltage for them somehow, using a motor tester or something =)
[15:01:14] <mrsun> or hell, just try, start with 2V or so and see how strong they are/hot they get
[15:01:16] <mrsun> =)
[15:01:19] <Jymmm> mrsun: or just find the dtasheet online
[15:01:43] <mrsun> Jymmm, very true, but if its totaly unknown .. but he did know the holding torque so i guess its not totaly unknown :P
[15:02:01] <Jymmm> mrsun: =)
[15:02:16] <mrsun> hope he comes back, i dont like it when people get scared to ask :(
[15:02:50] <mrsun> trying to be as little elitistic as i can ... =)
[15:02:58] <Jymmm> mrsun: he will eventually, his ISP might have jsut went poof too
[15:03:25] <Jymmm> mrsun: nah, go ahead be the motor-nazi you want to be!
[15:04:00] <mrsun> Jymmm, haha im not a natzi, but realy need specs to be able to help people ... took me a long time to start to understand all this even when i had the specs for the motors =)
[15:04:12] <mrsun> and alot of people here has been patient with me also =)
[15:04:31] <Jymmm> mrsun: Mybad, I meant to call you a driver-nazi, not motor-nazi!
[15:04:37] <mrsun> haha :P
[15:04:51] <mrsun> Jymmm, imo just buy the biggest freakin drivers you can get your hands on and never ahve a problem anymore :P
[15:04:58] <mrsun> just set the current and drive! =)
[15:05:14] <Jymmm> mrsun: 440 3ph and some REALLY fast relays?
[15:05:35] <Jymmm> HAWT FSCKING DAMN!!!!! http://www.suntekstore.com/goods-14002287-lm2577s_dc-dc_adjustable_step-up_power_supply_module.html
[15:05:38] <mrsun> or like the motors where im "working" atm .. 200kw etc =)
[15:05:46] <mrsun> and some very beefy relays ;P
[15:06:12] <Jymmm> DAMN DAMN DAMN no manual
[15:06:46] <Jymmm> Ok, how shitty can a step-up really be?
[15:07:06] <mrsun> depends on the girls doing the stepup ;)
[15:07:07] <Jymmm> Yeah yeah, EMI shielding and heatsink needed, but still
[15:08:01] <Jymmm> mrsun: I was being serious actually. Been looking for years
[15:09:59] <Jymmm> mrsun: My netbook will run on 12V, but will not charge unless is see's 15.1VDC. So, step-up from 13.8VDC (car) to 15.1VDC at less than 2A works for me
[15:10:35] <Jymmm> hi JT-5i25
[15:11:06] <Jymmm> JT-5i25: I found you a new welder
[15:11:27] <Jymmm> JT-5i25: well, plasma cutter the is
[15:20:05] <raynerd> Can someone on here talk to me about BOBs. I`m using a cheapo TB6560 and I`m going to move over to M452 drivers but I`ll need a BOB and I`ve read as much as I can, but I don`t get what I`m paying for! They seem to be from 10 to £80 - I don`t know how a relay would be used, as some of them advertise. Some of them say they have charge pump... is this useful and necessary?
[15:29:20] <awallin> raynerd: optical isolation is useful, if you run high voltages on the motor side..
[15:43:19] <Jymmm> CHEAP 3 axis stepper driver and breakout board all in one WITH paraport cable... http://www.suntekstore.com/goods-14002539-3_axis_stepper_motor_driver_controller_board.html
[15:44:30] <Jymmm> 5 AXIS driver for $17USD http://www.suntekstore.com/goods-14002537-5_axis_interface_board_for_stepper_motor_driver_cnc_mill_w_cable.html
[15:45:06] <Jymmm> mybad, 5 axis breakout
[15:48:45] <JT-Shop> this is going to suck if it keeps resetting my connection
[15:49:00] <Jymmm> JT-Shop: dsl?
[15:49:09] <JT-Shop> satellite
[15:49:24] <Jymmm> JT-Shop: is that new, or you've had it for a few months?
[15:49:34] <JT-Shop> about an hour now
[15:49:48] <Jymmm> JT-Shop: Oh, they JUST installed it today?
[15:49:56] <JT-Shop> yea
[15:50:18] <Jymmm> JT-Shop: what speeds?
[15:50:40] <JT-Shop> 9 down and 2 up
[15:50:53] <Jymmm> JT-Shop: satellite or microwave?
[15:51:03] <Jymmm> a square antenna?
[15:51:04] <JT-Shop> satellite
[15:51:13] <JT-Shop> wildblue
[15:51:27] <Jymmm> is the antenna square or oval?
[15:51:31] <JT-Shop> ain't no microwave out here
[15:51:38] <JT-Shop> oval
[15:51:39] <JT-Shop> why
[15:51:41] <Jymmm> k
[15:51:54] <JT-Shop> why
[15:51:57] <Jymmm> just gives me an idea
[15:52:01] <Jymmm> of what you have
[15:52:10] <JT-Shop> wildblue satellite
[15:52:46] <JT-Shop> seems like every few minutes it resets the IRC connection...
[15:53:26] <Jymmm> you might increase the ping time or keep alive
[15:53:48] <JT-Shop> in chatzilla?
[15:54:06] <Jymmm> in whatever, it's probably seeing you as idle and disconnects.
[15:55:50] <Jymmm> JT-Shop: maybe stream some music and see if that makes a difference
[15:58:19] <Jymmm> JT-Shop: maybe stream some music and see if that makes a difference
[15:58:44] <JT-Shop> I don't know how
[15:59:06] <Jymmm> JT-Shop: http://www.pandora.com/
[16:06:45] <DJ9DJ> gn8
[16:08:43] <JT-Shop> nope...
[16:08:51] * JT-Shop heads out for a while
[16:15:12] <TRWags> Hi, some body knows if its posible to force the state of an inpunt in classicladder, for debuging?
[17:08:10] <Tecan> is 5000 pretty standard for driver timing
[17:08:48] <Tecan> whats the 20000 for ?
[17:09:26] <Tecan> i upped the amps and volts to the driver board now im able to get like 2.4 out of them
[17:09:37] <Tecan> anything more and the steppers slip
[17:52:57] <Tecan> wholy jesus
[17:53:06] <Tecan> my mechantronics driver kicks ass
[17:53:10] <Tecan> aliencnc sux
[18:10:45] <ssi> what's the right way to scale a spindle encoder
[18:10:52] <ssi> such that 1 unit of position == 1 revolution?
[21:19:42] <Jymmm> Poor JT... couldn't get online even if he had viagra
[21:19:54] <Jymmm> s/get/stay/
[21:39:05] <Jordan__> would a scissor jack work for z axis?
[21:41:10] <KimK> Yes, it would go up and down; No, it would be non-linear with regard to distance per shaft rotation. That's probably no help to you at all, though?
[21:41:34] <KimK> Maybe you could compensate for it in "kins", but I don't think I'd bother.
[21:41:37] <Jordan__> well is there a formula to us
[21:42:00] <Jordan__> if it isn't linear
[21:42:05] <KimK> How would you make it zero-play?
[21:42:26] <Jordan__> You mean the stage or the z movement
[21:42:45] <KimK> The overall Z travel/position
[21:42:48] <Jordan__> z would be all in one direction
[21:43:04] <KimK> Not if you're doing any cutting. Is this a laser?
[21:43:41] <Jordan__> no
[21:43:44] <Jordan__> 3d printer
[21:43:52] <Jordan__> there is no force on it
[21:44:23] <KimK> Oh, OK, well, if it's never a "rough ride", maybe it would be OK?
[21:44:58] <Jordan__> nah i don't like the non linear
[21:45:03] <Jordan__> i think of something else
[21:45:08] <KimK> Wait, if there's no force, why do you need a scissor jack to begin with?
[21:45:38] <Jordan__> what do you mean
[21:46:31] <KimK> Well, people usually select a scissor jack when they need a mechanical advantage (over a heavy weight that wants to fall).
[21:47:24] <Jordan__> yea well the current system uses two threaded rods and two motors
[21:47:25] <KimK> (And they need it to be self-locking in position)
[21:47:43] <Jordan__> all it does is lower is lift 1 layer at a time about .1mm
[21:47:49] <KimK> Ah, excellent, a gantry system. Often a wise choice.
[21:48:11] <Jordan__> you like two rods & motors
[21:49:03] <Jordan__> trying to get out of a second motor
[21:49:47] <KimK> Yes, I do. It makes motion easier over whatever is serving as ways/rails/tracks/whatever. Rather than forcing one side and hoping the other one slides freely. It never does.
[21:50:05] <Jordan__> i see
[21:50:52] <Jordan__> what about a single z line and it has kind of L on the top for x/y
[21:50:53] <KimK> Well, I shouldn't say that. Maybe I should say, it may or may not slide freely enough for your purposes.
[21:51:35] <Jordan__> well if a second is good that's fine with me
[21:52:13] <Jordan__> well not L, its one line for x one y slides on x
[21:52:24] <Jordan__> xy slide on z
[21:52:24] <KimK> I shouldn't be discouraging you, maybe you will find a new, efficient, and simple design.
[21:53:09] <Jordan__> do you think a free floating overhand is bad idea or should go with bridge?
[21:53:22] <Jordan__> overhang*
[21:54:20] <Jordan__> i definitely came up with something unique
[21:54:51] <Jordan__> i should say unique everything has already been thought of but i haven't seen it yet
[21:55:00] <Jordan__> shouldn't*
[21:55:33] <Jordan__> hard to compete with 6Billion people
[21:55:48] <KimK> You mean that Z carries the entire X/Y carriage assembly, and lifts it as it builds the "pile"? That's an interesting idea. But I don't look at reprap much, so I can't say if anyone has done that before.
[21:55:51] <ssi> good thing it's not a competition :)
[21:56:24] <Jordan__> that's true
[21:57:05] <ssi> KimK: btw thank you for the resolver driver :D
[21:57:10] <KimK> There may be some tilt/slope as X/Y hangs there, but at least it should be relatively constant. Well, except for the head moving around, however much that affects it.
[21:57:20] <Jordan__> well i don't care if they've done it i'm wondering if there is going to be tilt as you say
[21:57:54] <Jordan__> it's going to be 250mm high, y has to be 200mm but only move 100mm, and x only move 100mm
[21:57:56] <KimK> ssi: Thank Andy, he did everything on it so far. I'd like to develop it further, though.
[21:58:01] <ssi> Jordan__: have you seen the way that people use tensioned cables to slave a side without a motor?
[21:58:10] <ssi> KimK: I would like to thank Andy, but he's out playing sea captain
[21:58:50] <Jordan__> yea i'm going to try to make the head as light as possible
[21:58:56] <KimK> ssi: Ha, yes, that's right, any word from the "Derry-Londonderry"?
[21:59:06] <Jordan__> but kimK it is only 100mm movement in x/y
[21:59:12] <Jordan__> the overhang has to be 200mm
[21:59:23] <ssi> KimK: we were kicking around ideas on how to do gated index (my machine has like 5 resolver cycles per screw rev, and there's a fine home prox-switch on the screw)
[21:59:36] <ssi> KimK: no, I'm not up to date on what's happening in the race
[22:00:07] <Jordan__> KimK is this a dumb idea is what i'd like to know or should i make a bridge
[22:00:17] <ssi> KimK: we were thinking it could maybe be handled in the resolver driver. I have been looking at the source but so far I don't have a full enough understanding of how it all works to be useful :/
[22:00:59] <ssi> Jordan__: gantry is a tried and true method, and slaving a second motor is usually cheaper and easier than trying to slave it mechanically
[22:01:23] <KimK> Jordan__: As you do your calculations, try (just for an experiment) adding an "opposite side" to the Z lifter, I think you'll be amazed at the improvement in "droop". As in one of those horizontal-section lifting-bridges to let ships underneath.
[22:01:38] <ssi> what if you had like a four post arrangement, where the posts are screws
[22:01:49] <ssi> and you put sprockets at the top or bottom, and run a chain around all of them
[22:02:01] <Jordan__> interesting
[22:02:07] <ssi> then you can drive one screw and it lifts the whole X/Y assembly
[22:02:11] <Jordan__> but i was trying to get out of the bridge
[22:02:31] <ssi> or maybe it just drives the TABLE
[22:02:34] <ssi> and the X/Y is fixed
[22:02:37] <Jordan__> i can make it much smaller without the bridge
[22:03:31] <ssi> Evening pcw
[22:03:35] <Jordan__> but ssi why would i do four i could do that with two
[22:03:47] <ssi> Jordan__: fore/aft stability?
[22:03:47] <Jordan__> KimK, probably will
[22:04:14] <Jordan__> that should be fine
[22:04:54] <Jordan__> but my bet is a second motor may be cheaper
[22:05:12] <ssi> probably so
[22:05:23] <ssi> when I built my plasma table, I thought about all sorts of ways to try to slave the other side of the gantry
[22:05:31] <ssi> and at the end of the day slaving a second $40 motor is MUCH easier
[22:05:42] <Jordan__> yup
[22:06:19] <Jordan__> a belt and pulleys would be way more than the $7 motors
[22:06:22] <Jordan__> i'm using
[22:07:04] <Jordan__> the only way is if it isn't a bridge at all
[22:07:44] <Jordan__> it is only moving 100mm in x and y
[22:08:07] <Jordan__> but the x line goes out 200mm
[22:08:50] <Jordan__> 100mm is a little less than 4"
[22:09:00] <Jordan__> i mean come on that's not a lot
[22:09:42] <Jordan__> yea i'm not going to do bridge i have other plans ;) for stability
[22:09:57] <KimK> ssi: I don't think you need to do anything special except include both switches in series (they're normally-open, right?). So that both switches must be on to find home. "The first blade shaves you close, the second blade shaves you even closer". Oh crap, now they have five blades. Nevermind.
[22:11:55] <KimK> ssi: OK, wait, your coarse-home switch would have to go on only in a limited area (off on both sides) which means if it doesn't find home it will hunt all the way to the end if you don't stop it. OK, maybe that's not the best.
[22:14:42] <Jordan__> what's a plasma table
[22:16:56] <Jordan__> KimK, would it be better to move the bed down or head up?
[22:17:03] <KimK> ssi: There is a special function for resolver that would solve your problem that I would like to add. Hang in there, it will happen eventually.
[22:17:21] <Jordan__> basically would it be better to fix the z on the bottom or the overhang
[22:19:02] <KimK> Jordan__: Since your X/Y travels are so small (and I'm guessing your Z travel is in the same range) maybe no big deal? What is the smallest filament you plan to extrude?
[22:19:15] <Jordan__> 3mm
[22:19:28] <Jordan__> well that doesn't matter
[22:19:35] <Jordan__> the z needs to go 200mm
[22:19:49] <Jordan__> the filament isn't really an issue
[22:19:59] <Jordan__> you mean the layer height
[22:20:06] <KimK> OK so you are making relatively "tall" objects?
[22:20:11] <Jordan__> i think that is typically .1mm
[22:20:14] <Jordan__> maybe
[22:20:52] <Jordan__> but in general would it be better to move bed down or head up
[22:21:10] <KimK> Oh? You can extrude a 3mm filament with only a 0.1mm step rise? That seems odd, have I got it wrong?
[22:22:02] <Jordan__> the filament is 3mm, but it comes out of a .5mm nozzle
[22:22:19] <KimK> Oh, I see. And the step rise?
[22:23:02] <Jordan__> i'm not sure but i thought for the outer edges of object it uses a smaller step like .1mm and the inner like .3mm
[22:23:06] <djdelorie> the nozzle points down, the diameter of the hole is independent of the thickness of the ribbon it extrudes
[22:23:27] <djdelorie> the diameter determines the *width* of the ribbon, not its thickness
[22:23:33] <Jordan__> anyway back to my question
[22:24:17] <KimK> djdelorie: OK, thanks. I don't completely follow, but I haven't done anything with reprap.
[22:24:24] <Jordan__> my gut says to move the bed down
[22:24:48] <Jordan__> but most the others move the nozzle up
[22:25:27] <KimK> Jordan__: You may be right, the plastic (plus heated table?) should be much lighter than the X/Y carriage assembly.
[22:26:05] <Jordan__> yea but i was planning to move the extruder off of it
[22:26:19] <djdelorie> KimK: imagine a 10mm nozzle 1mm above a surface, aiming down. As it moves *sideways*, it leaves a ribbon of goo 10mm wide and 1mm thick
[22:26:23] <Jordan__> so it would be pretty light hot end on the top
[22:26:39] <djdelorie> much like a paintbrush can be 3" wide but doesn't leave paint 3" thick
[22:26:52] <Jordan__> So the factor is which is lighter to move
[22:27:19] <ssi> KimK: right now I'm doing it with a set/reset flipflop... seeing both home switches sets it, and the coarse home going low resets it
[22:27:33] <ssi> KimK: it's working ok for now, but I think a gated index might be the way to go for the future
[22:28:54] <Jordan__> but it would also have 2 motors on top
[22:29:19] <ssi> Jordan__: plasma table is a CNC machine with a plasma cutter on the head
[22:29:24] <Jordan__> i'm kind of torn maybe ill see which i could do smaller
[22:29:29] <ssi> Jordan__: not terribly unlike what you're trying to do, but much bigger :)
[22:29:50] <ssi> mine is a 54x54" table with a gantry
[22:29:58] <ssi> I have about 48x42" working area
[22:30:18] <Jordan__> that would make one hell of a reprap
[22:30:44] <ssi> perhaps it would :)
[22:30:52] <KimK> djdelorie: Ah, OK, "...like a paintbrush can be 3" wide but doesn't leave paint 3" thick...", thanks, that helps a lot.
[22:30:53] <ssi> I don't think it's precise enough to be honest
[22:31:02] <Jordan__> you could print out buildings with that
[22:31:14] <Jordan__> well maybe tree houses
[22:32:20] <Jordan__> actually more like dog houses
[22:32:31] <ssi> hehehe
[22:32:54] <ssi> my machine wouldn't be great as a reprap because it's only got 3" or so of Z travel
[22:32:58] <Jordan__> i can only print out bird houses
[22:33:08] <djdelorie> or really big gears
[22:33:17] <Jordan__> i see
[22:33:21] <ssi> yeah I could make a hell of a plastic planetary gearset :D
[22:33:56] <ssi> I want to add a plate marker and/or drill head to my plasma table
[22:34:02] <ssi> biggest problem with plasma is small holes
[22:34:19] <Jordan__> is plasma for cutting metal
[22:34:20] <ssi> if I had a plate marker, I could sorta centerpunch all the drill locations
[22:34:22] <ssi> yeah
[22:34:28] <Jordan__> what about laser
[22:34:38] <ssi> laser that'll cut metal is $$$$$$
[22:35:00] <djdelorie> plasme that'll cut metal is like "well, duh"
[22:35:04] <ssi> yeah :)
[22:35:15] <KimK> So, back to Jordan__'s question... If the finest step you wanted was 0.1mm (~0.004"), and the tilt/slope/mismatch/error was +/-0.01mm (~0.0004"), that would be +/- 10%, would that be OK (good enough)?
[22:35:15] <ssi> plasma won't cut anything but metal
[22:36:14] * KimK is just trying to find a "ball-park" figure
[22:36:18] <Jordan__> KimK i'll be using g2 5/8-4 drive screws
[22:36:33] <ssi> g2?
[22:36:36] <Jordan__> by g&g manufactoring i think
[22:36:49] <Jordan__> g2 is a quality lowest general
[22:37:00] <ssi> what kind of screw is it
[22:37:02] <ssi> acme? ballscrew?
[22:37:12] <KimK> 4 TPI?
[22:37:12] <Jordan__> acme
[22:37:16] <Jordan__> yeea
[22:37:33] <KimK> You might be better off with 1/2-20 allthread?
[22:37:51] <ssi> better off with allthread?!
[22:38:00] <Jordan__> why?
[22:38:05] <Jordan__> you know how slow that would be
[22:38:16] <KimK> Over a 4 TPI acme? Yeah, maybe.
[22:38:23] <ssi> Jordan__: well speed isn't everything, you gotta take into account your minimum step size
[22:38:32] <ssi> most steppers are what, 1.8deg/step?
[22:38:42] <Jordan__> yes 200 steps
[22:38:43] <ssi> 200 step/inch
[22:38:50] <Jordan__> and there are 1/16 micro steps
[22:38:56] <ssi> forget micro steps
[22:39:04] <KimK> You only have to rapid at the end, right? And during set-up?
[22:39:32] <ssi> so your inch is 800 steps
[22:39:33] <Jordan__> the normal repraps run about 80mm/sec
[22:39:45] <ssi> which makes your minimum positioning accuracy like 0.0012
[22:40:10] <Jordan__> it has to be 4tpi to get anywhere near that fast
[22:40:34] <Jordan__> some run 250mm/s
[22:40:46] <ssi> 80mm/s isn't infeasible with a 10tpi screw I don't think
[22:41:00] <ssi> and the really fast ones are probably belt driven rather than screw driven
[22:41:04] <Jordan__> no the motor max you want to run is 15rps
[22:41:12] <djdelorie> I'm getting almost that with a 16tpi screw
[22:41:34] <Jordan__> well the motor i'm using won't be able to do that it's $7
[22:41:45] <ssi> I made the mistake of trying to build a machine once with 2tpi, 5 start screws
[22:41:46] <ssi> it was FAST
[22:41:48] <djdelorie> mine is more than that, and takes up to 160 volts...
[22:41:49] <ssi> but imprecise as hell
[22:41:54] <KimK> You can only rely on microsteps for positioning accuracy to about the half-step level. Even quarter-steps get iffy. Beyond quarter-steps, it's a coin toss. Although steps up to about 10, 12, 16, even sometimes 20 can be good for smoothness, anti-resonance, etc.
[22:42:26] <Jordan__> yea i think they recommneded that for smoothness
[22:42:37] <djdelorie> my motors are effectively 333 microsteps, but I have an encoder to keep the position where it's supposed to be
[22:43:08] <Jordan__> i have to use 4tpi
[22:43:16] <Jordan__> i think it will be fine
[22:43:19] <ssi> I think you'll be unhappy with the precision of the parts you can make
[22:43:27] <KimK> Jordan__: OK, then 4 TPI it is.
[22:43:39] <ssi> why is 80mm/s a requirement, btw?
[22:43:40] <Jordan__> really
[22:43:50] <Jordan__> it's not but i don't want that sllow
[22:44:01] <ssi> maybe not... I don't really know what the precision requirements for 3d printed parts are
[22:44:04] <KimK> Maybe you can use a timing belt and gear your screw down?
[22:44:10] <Jordan__> 4 tpi is 800 steps an inch
[22:44:16] <Jordan__> how is that imprecise?
[22:44:23] <KimK> s/a timing belt/some timing belts/
[22:44:23] <ssi> that's 1.25 thousandths per step
[22:44:46] <Jordan__> ssi that good
[22:44:57] <Jordan__> KimK, i don't want to add more costs
[22:45:02] <Jordan__> the screw is the drive
[22:45:03] <ssi> even my plasma table has better precision than that, and it's rack drive
[22:45:17] <Jordan__> ssi this is a 3d printer
[22:45:27] <Jordan__> it squirts goo out
[22:45:29] <KimK> Jordan__: OK, but you were saying earlier that you wanted to step in layers of 0.1mm (~0.004")?
[22:45:33] <Jordan__> it doesn't have to be that precice
[22:45:35] <ssi> well that's fine then
[22:45:52] <ssi> seems like it'd need to be more precise, but I've never worked with one
[22:46:38] <Jordan__> KimK, .00124 is less than .004
[22:47:13] <Jordan__> and half steps would double that too KimK
[22:47:34] <Jordan__> to 1600 steps/inch
[22:47:59] <Jordan__> but i think it will be running in 1/16 steps
[22:48:06] <KimK> Jordan__: What if you were printing, and you found that 0.1mm (0.1000mm) was too thick? What would you want as the next available choice? 0.09mm? 0.099mm? 0.0999mm?
[22:48:44] <KimK> s/too thick/too much/
[22:49:26] <Jordan__> wouldn't a drive screw be much more precise than a belt and pulley
[22:49:36] <Jordan__> even at 4tpi
[22:49:44] <ssi> not necessarily
[22:49:52] <ssi> timing belts are quite precise
[22:50:01] <djdelorie> ha!
[22:50:15] <ssi> ha!
[22:50:20] <ssi> :'(
[22:50:30] <djdelorie> they're OK if you get all the slop out and tension them just right...
[22:50:33] <Jordan__> yea but it is probably 1 inch diameter, for one rotation so yea
[22:50:42] <Jordan__> 200 steps/inch
[22:50:56] <Jordan__> much less than 800steps/inch in a 4tpi drive screw
[22:51:22] <djdelorie> no, 1 inch circumfrence, not diameter. That's about 0.32 inch diameter
[22:51:23] <Jordan__> not diameter, perimeter
[22:51:35] <Jordan__> yea sorry
[22:52:14] <Jordan__> so is this matter settled or is there something i should know
[22:52:37] <ssi> if you already have the parts, then it's moot
[22:52:38] <ssi> build it
[22:52:54] <djdelorie> build one crappy machine, use it to build a better one :-)
[22:52:56] <Jordan__> no i don't have parts, i want to make sure what i'm doing is not stoopid
[22:53:13] <ssi> if it were me, I'd be using 10tpi acme screw
[22:53:37] <Jordan__> you know how slow that would be, you know how slow they already are
[22:53:48] <Jordan__> it takes 12 hours to print out the parts for one prusa
[22:53:51] <ssi> I don't think it matters that much
[22:54:10] <ssi> what's your actual feedrate while printing
[22:54:46] <Jordan__> not sure
[22:54:55] <ssi> rapid speed is irrelevant, especially for that machine
[22:55:14] <ssi> if it's gotta feed at 25mm/s, then what difference does it make how much faster it can go?
[22:55:16] <KimK> There are always engineering tradeoffs. If you know that you want (about) a 0.1mm (0.004") step layer, then 0.01mm (0.0004") allows a 10% adjustment, 0.001mm (0.00004") allows a 1% adjustment, etc.
[22:55:29] <djdelorie> ssi: speed might be required to bridge big gaps
[22:55:36] <ssi> djdelorie: maybe!
[22:55:47] <ssi> speed is an issue for my plasma cutter, because you need feed rate to cut thin metal
[22:55:52] <ssi> that machine'll run 600ipm
[22:56:34] <Jordan__> well i'm not concerned about it 4tpi would be higher res than what the hole community uses
[22:56:45] <Jordan__> whole*
[22:57:00] <KimK> Jordan__: Why, what are they using?
[22:57:09] <Jordan__> belts and pulleys
[22:57:28] <KimK> And what resolution are they getting?
[22:57:45] <ssi> http://wiki.makerbot.com/faq-frequently-asked-questions
[22:57:49] <ssi> Accurate to 0.08mm (.003") Minimum feature size is 0.08mm.
[22:57:53] <ssi> 33mm/sec (1.3"/sec)
[22:58:12] <Jordan__> yea people laugh at that makerbot
[22:58:20] <Jordan__> for how slow it goes
[22:58:29] <ssi> I'm just trying to get an idea of some numbers
[22:59:02] <ssi> what's a "good" machine
[22:59:27] <Jordan__> the belt i got is about 12mm diameter. so its about 200steps/3inches
[22:59:34] <Jordan__> i mean pulley
[23:00:09] <djdelorie> 12mm diam = 1.5in around
[23:00:48] <Jordan__> oh right
[23:01:01] <Jordan__> still that's worse than a 4 tpi drive screw right?
[23:01:38] <djdelorie> depends on whether "too slow" makes it worse for its intended purpose or not
[23:01:57] <Jordan__> i mean as far as resolution
[23:02:03] <Jordan__> not talking about speed
[23:02:37] <djdelorie> well, yeah, a screw would give you more precision. But whether that's "better" or not depends
[23:03:05] <Jordan__> ok so 4tpi will have more precision than what they currently have so it's fine
[23:03:17] <djdelorie> but it's also slower, which may not be fine
[23:03:24] <Jordan__> yea that part i hate
[23:03:30] <KimK> Looked at another way, if your machine has 0.1mm step size, and you are making a part with 0.1mm layers and find them too thin (maybe your part was designed to be 5cm high, but it's coming out short, say, only 4.8cm. So your other choice would be to add another whole 0.1mm step, probably making the part come out 9.6mm instead. Is that close enough?
[23:04:01] <djdelorie> KimK: the trick there is to tell the software how thick the layers really are, and let it recompute the layer stack
[23:04:17] <KimK> Or redesign your part and hope you can "sneak in" some more layers?
[23:04:50] <djdelorie> but consider, the design of the Z axis is independent of the X and Y axes.
[23:04:55] <KimK> djdelorie: Yes, I think we're on the same track there.
[23:04:58] <Jordan__> oh well i'll try it anyway, ill show you guys when i'm done if you are around
[23:05:12] <djdelorie> the Z axis can be slow and precise, where the X and Y axes can be faster
[23:05:13] <ssi> please do
[23:05:40] <KimK> Jordan__: Yes, please, we'd like to see it. Don't take our comments as criticism.
[23:05:53] <Jordan__> the z axis uses off the shelf M8 threaded rod
[23:06:09] <Jordan__> that would be excruciatingly slow
[23:06:13] <djdelorie> right - the first step in design is to understand the goals and reasons, not to understand the steps to get there :-)
[23:06:15] <Jordan__> for x and y
[23:06:37] <djdelorie> Jordan_: the Z axis need not be fast in a makerbot - it steps once per layer
[23:06:48] <djdelorie> the X and Y have to draw each layer, they need to be fast
[23:06:53] <Jordan__> yea i know, z axis can be slow
[23:07:20] <djdelorie> so generic 1/4-20 for the Z is probably fine, but would make XY unusable
[23:07:44] <Jordan__> yea i'll use 4 tpi for xy
[23:07:57] <Jordan__> so 20 is "fully threaded"?
[23:08:19] <djdelorie> or belts. Remember, you're painting with an 0.5mm nozzle, making X and Y much more precise than that might be unnoticable
[23:08:29] <djdelorie> 1/4-20 is a standard US thread size, that's all
[23:08:46] <djdelorie> (for generic hardware store all-thread rod, that is)
[23:08:50] <Jordan__> is it acme
[23:09:05] <Jordan__> you wouldn't use acme?
[23:09:35] <djdelorie> generic hardware store all-thread? No. Standard 60 degree triangular. Dirt cheap
[23:10:01] <djdelorie> it's not needed for Z
[23:10:12] <ssi> seems like acme oughta run smoother
[23:10:25] <ssi> and is still pretty durn cheap
[23:10:32] <KimK> Jordan__: 1/4-20 should be something like 6mm-0.8mm(?) Good luck, I'll check back later. djdelorie: Thanks for your explanations. ssi: We'll talk more later.
[23:10:47] <ssi> KimK: thanks :)
[23:10:52] <Jordan__> ok thanks
[23:10:53] <djdelorie> ssi: acme is chosen when efficiency is needed - it transfers more power to the output, less waste
[23:12:31] <KimK> Jordan__: Oops, sorry, more like 6mm-1.25mm
[23:13:00] <Jordan__> is that 1.25mm per turn?
[23:13:09] <KimK> Yes, approx.
[23:13:12] <ssi> so my spindle feedback from the resolver doesn't look too happy
[23:14:01] <ssi> I'm graphing the resolver velocity in halscope, and it's a big nasty waveform whose amplitude is bigger than the velocity itself at max speed
[23:14:51] <ssi> I need to put a real scope on the resolver outputs I think
[23:15:04] <KimK> ssi: Is it a sin or cos waveform? Or something else?
[23:15:52] <ssi> looks more like spiky noise
[23:16:18] <KimK> ssi: OK. I'll have to check back later.
[23:16:30] <ssi> ok no problem
[23:22:05] <Jordan__> djdelorie, but the g2 acmes should be higher tolerance than off the shelf screws
[23:22:16] <Jordan__> for straightness and such
[23:22:26] <djdelorie> probably
[23:22:26] <Jordan__> right
[23:22:52] <Jordan__> i don't want any wobbly z screws
[23:24:21] <KimK> BTW, before I go, any eBay fans around? I sometimes run across a seller that uses those "mouse over image to zoom" photos. If I try to print the first page (Ubuntu 10.04, Firefox 11.0), there's no photo, only the text. I was wondering if there's a way to fix this (without printing a screen shot). Are there any Firefoxscript-blockers or Java-killers that make this go away? Example at http://search.ebay.com/220988456703
[23:26:10] <Tecan> do they do 1/8 step ?
[23:28:01] <Jordan__> would acetal work well with the acme screws? can i make those myself out of acetal blocks
[23:28:19] <Jordan__> i don't want any play in them
[23:28:32] <djdelorie> my Z axis uses solid maple with all-thread, works fine
[23:28:51] <Tecan> http://www.easy-cnc.com/4axisdriver.html << these boards are awesome
[23:28:57] <Jordan__> mine is only 4tpi
[23:29:15] <djdelorie> you need a way to tap it
[23:30:10] <Jordan__> where do you get taps?
[23:30:33] <djdelorie> for acme? No idea. One bonus for using generic all-thread is that generic taps work :-)
[23:31:38] <Jymmm> Tecan: Fro the specs, I suspect that board uses the ahtena (?) chipset which are prone to heat issues. NOT a good thing.
[23:31:47] <Jymmm> Same as the xylotex board.
[23:32:10] <Jordan__> how big of a problem is backlash of screws compared to belts?
[23:32:46] <djdelorie> if you care about backlash, you typically use an anti-backlash nut on a screw anyway
[23:33:02] <Jordan__> yea but what if you didn't have it
[23:33:43] <djdelorie> then it depends on the specifics of your machine, I suppose
[23:34:44] <Jordan__> but in general is backlash a bigger problem in belts and pulleys?
[23:34:49] <Tecan> allegro
[23:34:50] <djdelorie> I don't know
[23:35:27] <Tecan> they manage fairly well without heatsinks
[23:35:27] <cradek> quality toothed belts and pulleys set up at the proper tension do not have backlash
[23:37:15] <Jordan__> how much backlash can i expect if i didn't use antibacklash nutes
[23:37:18] <Jordan__> nuts*
[23:42:27] <Jordan__> what about acceleration, screws would have advantage over belts
[23:42:38] <djdelorie> depends on the belt
[23:44:05] <Jordan__> just in general