#linuxcnc | Logs for 2012-03-29

[00:34:57] <ssi> super impressed with this machine
[00:35:30] <ssi> even with the loss in resolver precision, I can turn .100 off the diameter of cold roll in one pass and hit the number within 0.0002"
[00:45:42] <Nick001> that's why I have 3 of them - I can do that in SS when I'm in a hurry
[00:46:51] <ssi> :D
[00:46:55] <ssi> I'm very very happy with it
[00:47:05] <ssi> if i get all my configs dialed in just so, I think it's going to make very nice parts
[00:47:14] <ssi> I need to start running feeds and speeds numbers for it
[00:49:13] <ssi> my first real parts are going to be drill bushings :)
[00:49:20] <ssi> I started making some tonight
[00:49:26] <ssi> but I only could center drill it
[00:49:33] <ssi> I have a drill bushing with a center drill in it, and that's it
[00:50:17] <ssi> https://p.twimg.com/ApIat1ZCQAE13f1.jpg:large
[00:50:34] <ssi> surface finish is ugly again
[00:50:37] <ssi> need to play with feeds and speeds
[00:50:44] <ssi> plus I don't have a cutoff tool that I can use on this machine yet
[00:50:54] <ssi> just ordered one from shars, as well as a 3/8" chuck and a 5/8" straight shank for it
[00:52:16] <Nick001> really starting from scratch -)
[00:53:01] <Nick001> Using an insert or hand ground tool?
[00:53:25] <ssi> insert
[00:53:33] <ssi> I have tons of lathe tooling
[00:53:38] <ssi> but it's all qctp style stuff
[00:53:46] <ssi> 5/8 and 3/4 shank
[00:53:55] <ssi> tooling for the turret machine is very different
[00:54:58] <Nick001> I usually use them for roughing. when I need a teally good finish - Hand ground on a diamond wheel and hone the corner
[00:55:16] <ssi> shame on me, I've never really properly learned to grind lathe tools
[00:55:55] <Nick001> you'll learn now - hehe
[00:56:02] <ssi> yeah maybe so
[00:56:13] <ssi> perhaps I should just buy a box of 3/8" tool blanks
[00:57:15] <Nick001> they last a long time if you don't push them
[00:58:22] <ssi> what I really oughta do is figure out a fixture to put the lathe tools on my surface grinder
[00:58:29] <ssi> so I can get precision rake and clearance angles :)
[00:58:34] <ssi> OVERKILLLLLLL
[00:59:11] <Nick001> toolmakers vise and protractor
[00:59:57] <Nick001> also need a baldor diamond grinder
[01:00:33] <ssi> I don't have any diamond wheels on anything
[01:00:40] <ssi> I do have toolmakers vises though
[01:00:47] <ssi> including some teensy ones and one adjustable angle vise
[01:01:01] <ssi> my bench grinder has crap coarse chinese wheels on it
[01:01:07] <ssi> what do diamond wheels cost?
[01:01:40] <Nick001> 50 - 200 depending on hitting sales
[01:02:15] <Nick001> not chinese though
[01:02:29] <ssi> my surface grinder has norton wheels
[01:02:57] <ssi> what grit diamond wheel do you like for tools?
[01:03:07] <ssi> mcmaster has red, blue, and orange
[01:03:10] <ssi> (100, 180, 320)
[01:03:57] <Nick001> i use cup wheels on the surface grinder - 240 for finish 100 ok for roughing
[01:04:26] <ssi> $180ish at mcmaster
[01:05:06] <Nick001> i'd have to look to be sure of the grits. I go a lot of years before having to replace a wheel
[01:05:33] <Nick001> sound high - try MSC or travers
[01:06:52] <ssi> mcmaster is usually high
[01:07:09] <ssi> but they're the first place I look, because they have everything, their website is awesome, and I can get anything I need overnight :)
[01:08:04] <ssi> ok bedtime
[01:08:06] <ssi> talk to you tomorrow
[01:08:23] <Nick001> same here later
[02:05:51] <Jymmm> SWPLinux: http://www.surplusplanet360.com/Tobago-Cargo-Tactical-Pack-Voodoo-Tactical-15-7866.html
[02:05:56] <Jymmm> SWPadnos: http://www.surplusplanet360.com/Tobago-Cargo-Tactical-Pack-Voodoo-Tactical-15-7866.html
[02:24:29] <DJ9DJ> moin
[02:51:31] <Loetmichel> mornin'
[06:46:32] <Paragon-ws> Hi Everyone. I hope someone could give me some pointers regarding the Mesa 7i43 io card and VHDL. I have downloaded Xilinux development environment so as to learn / play with programming vhdl on the 7i43 card but am a little confused about how to program it! The support software downloaded from Mesa is a bit thin on the ground. Could some please give me some pointers on how to program it...
[06:46:34] <Paragon-ws> ...via the USB port? BTW all jumpers are configured correctly.
[06:47:46] <Paragon-ws> (I meant to say the support software from Mesa is a thin on the ground regarding documentation)
[06:50:35] <archivist> some clue http://www.linuxcnc.org/docs/2.5/html/drivers/hostmot2.html
[06:50:47] <awallin> for use with linuxcnc you don't have to compile vhdl->bitfile yourself. I guess xilinx should have some tutorials if you really want to do this
[06:53:00] <Paragon-ws> Thanks Guys. I confess my question was not specific to EMC per say but rather towards programming, compiling and uploading to the 7i43 (more from an interest point of view)
[06:54:15] <archivist> see how it loads the config at boot
[07:03:22] <Paragon-ws> Thanks again!
[07:15:43] <Paragon-ws> Would you know of a usb loader for the 7i43 that runs under windows (don't shoot me) :-)
[07:16:45] <Paragon-ws> Tried google but no joy at this time.
[07:36:39] <CareBear\> Paragon-ws : what is used on linux?
[07:37:52] <Paragon-ws> CareBear\: Sorry what do you mean?
[07:38:27] <CareBear\> usb loader for the 7i43 for linux
[07:40:56] <Paragon-ws> Is there one? I could use it under linux but the Xilinx IDE platform runs under windows and rather than move the hex over to linux I thought there may be a loader under windows.
[07:41:20] <CareBear\> oh ISE runs on linux as well
[07:42:21] <mozmck> hey CareBear\! haven't noticed you here before, do you have a cnc machine?
[07:42:40] <CareBear\> no
[07:42:54] <CareBear\> Paragon-ws : http://peter.stuge.se/spartan-3e-logic-analyzer
[07:44:11] <Paragon-ws> Wasn't aware of that. Thanks for the link!
[07:58:35] <jthornton> what does "thin on the ground" mean?
[07:59:07] <Paragon-ws> jthornton: lacking
[08:01:10] <Paragon-ws> jthornton: Probably a better description being 'scarse'
[08:04:27] <Paragon-ws> For example the downloaded zip file from Mesa has very little details about the programs, what they do and how to execute them. Looking in the utils\usb directory there are the following files but what do they do? ldpcom.exe, readhmid.exe, rpd.exe, rpo.exe, SC7i43W.exe, SCM7i43W.exe, wpd.exe and wpo.exe! Any ideas?
[08:06:33] <frysteev_> mesa has great technical support, but their documentaion could use some work for non-engineers :P
[08:08:29] <Paragon-ws> It would be helpful :-)
[08:10:48] <Paragon-ws> For example the pluto-p board that I possess has some great examples to get you started (led blinking) and so on. It has a windows loader also. But I can't seem to find one for the 7i43. I know this is off topic but I thought I would post the question here as you folks have been very helpful in the past :-)
[08:12:30] <frysteev_> im still waiting to order some mesa gear myself, and i have hit the same roadblock in my reasearch,
[08:12:46] <frysteev_> I know it can do what i need, but I dont know how to make it do what i need
[08:17:51] <Paragon-ws> The Mesa 7i43 works great with EMC, but I am looking to use it to control a homebuilt induction heater. Upto this point I have used a PIC MCU and PLL combination with moderate success. But wish to use the 7i43 to monitor current phase and produce an offset so as to keep the tank circuit in tune as the workpeice is heated. I would also use it for current limiting temp sensors and so fourth.
[08:20:37] <Paragon-ws> It may appear to be a bit of an overkill but I wish to do this as project so as to learn VHDL as I go.
[08:22:46] <frysteev_> 7143 seems sort of overkill for that
[08:22:59] <frysteev_> seems like something an arduino would be better suiter for
[08:23:04] <jthornton> Paragon-ws: thanks
[08:23:17] <jthornton> sounds like a neat project
[08:23:18] <CareBear\> Paragon-ws : I'd suggest a papilio board if you'd like to do VHDL
[08:23:31] * jthornton hangs up here
[08:24:38] <Paragon-ws> CareBear\: I'll take a look at that. Thanks.
[08:26:25] <frysteev_> induction heater for what?
[08:28:58] <Paragon-ws> frysteev_: To heat and melt => cast metal components see http://www.mindchallenger.com/inductionheater/induction2.html
[08:31:33] <Paragon-ws> http://www.youtube.com/watch?v=PVtcp4JZ8FA
[08:34:43] <frysteev_> cool
[08:35:58] <JT-Shop> I have a project where I need to fire a solenoid at positions called out in a recipe, the axis is powered by AC motor and VFD with encoder position feedback
[08:36:16] <JT-Shop> any thoughts on what/how to proceed?
[08:36:38] <Valen> perhaps some kind of spindle synchronised motion?
[08:36:46] <Valen> I'd use an AVR myself lol
[08:41:28] <JT-Shop> I'm thinking of using a custom GladeVCP GUI to display the recipes etc
[08:41:53] <JT-Shop> the positions vary with each recipe
[08:42:33] <JT-Shop> I'm guessing some kind of HAL connections atm
[08:47:20] <frysteev_> i wish there was a hal for dummies
[08:48:46] <JT-Shop> there is
[08:50:26] <ssi> http://a4.sphotos.ak.fbcdn.net/hphotos-ak-prn1/529499_818700965252_71107655_35508767_1301398710_n.jpg
[08:50:30] <ssi> :D
[08:54:13] <ssi> ok commuting, back in an hour
[09:10:05] <frysteev_> morning
[09:10:13] <JT-Shop> morning
[09:11:19] * JT-Shop heads for the other shop for a whil
[09:11:21] <JT-Shop> e
[09:11:39] <frysteev_> i need to find out what the weight rating for redi rrack is :P
[09:12:26] <Loetmichel> sooo... slowly it it gets to look like a HexaCopter... just have to get/mount some Tabletennis-balls as feet and i am ready for test-takeoff ;-) -> http://www.cyrom.org/palbum/main.php?g2_itemId=12985 http://www.cyrom.org/palbum/main.php?g2_itemId=12988
[09:18:29] <Loetmichel> *grrr* 24h disconnect
[09:18:51] <mazafaka> Loetmichel: flying camera?
[09:19:33] <Loetmichel> something like it
[09:20:04] <Loetmichel> multirotor stabilized platform with about 1kg max. payload
[09:35:19] <mazafaka> Loetmichel: I doubted in passibe safety of the vehicle unless I have decided to move the seats back a little and flatten the floor at the front of the van. Also plan to bind the body with a frame with some sort of bounding the frame elements thingies which are bolted to reinforced bottom of the van. I also plan some safety cage which will not bee seen from inside
[09:35:47] <Loetmichel> ?!?
[09:36:36] <A0Sheds> liuxcnc might get slashdotted today
[09:36:47] <mazafaka> some rally SUVs have ropes which bind their body to frame in front, back and middle of the car. This helps in case of crash.
[09:36:58] <awallin> A0Sheds: really? why now?
[09:37:13] <A0Sheds> there's a story about needing something like "LAMP" for robots
[09:37:35] <mazafaka> Loetmichel: how don't you know of words like 'half-a-meter to death' about the fron seats of the vans ??
[09:37:37] <A0Sheds> linuxcnc is already mentioned
[09:40:16] <Loetmichel> mazafaka: because i have worked on "vans" wiht a rigid body... maybe you can scrape me from the windshield in case of an accident, but the passenger cell is normally sufficient rigid to allow for survival space in any accident
[09:40:42] <Loetmichel> ... exept hitting a activated trash compactor
[09:40:44] <Loetmichel> ;-)
[09:41:11] <mazafaka> Loetmichel: there are many of photos of framed vans which passive safety is nothing but 'unsafety'
[09:41:30] <Loetmichel> mazafaka: so be it
[09:42:25] <mazafaka> Loetmichel: so be another (because even on the MTB, I have 'stories' with drivers which are brain-stiffed maybe)
[09:42:51] <mazafaka> Loetmichel: let me show you one photo of the van during its restoration
[09:45:38] <mazafaka> http://s3.images.drive2.ru/car.journal.photos/x1/4400/000/000/313/ae8/88cdee6849559812-large.jpg <-- where are the legs of the driver? I plan to lift the body a little and flatten the arc above front wheel, and move front seats a little back to the cabin
[09:47:37] <mazafaka> Even on the mountain bike, on regular roads at regular day, there are stories in which you will have to protect yourself or attack first. Drivers, even with the air conditioner, are greasy morons, who might have a weapon, otherwise whatever happening is their problem.
[09:48:14] <mazafaka> Real life and collisions make thoughts about the situation to appear.
[10:06:17] <Loetmichel> mazafaka: easy solution: http://www.landscaper.de/Fahrzeugdaten/Fruhere_Fahrzeuge/HTML%20Fruhere%20Fahrzeuge/tatra_1_koffer_16.html
[10:06:18] <Loetmichel> :-)
[10:06:33] <Loetmichel> http://www.landscaper.de/Fahrzeugdaten/Fruhere_Fahrzeuge/HTML%20Fruhere%20Fahrzeuge/tatra_1_koffer_13.html
[10:07:02] <Loetmichel> that deals with the problem of compressing the footspace of the driver.
[10:07:22] <Loetmichel> (at the expense of some 450kg additional weigth, of course ;)
[10:07:44] <mazafaka> yeah, I nevertheless will have added a robust front bumper suitable for the installation of the winch
[10:08:31] <ssi> back
[10:08:55] <mazafaka> Loetmichel: photos of crash tests show the body of the van moves along the frame and front part of the body deforms too much
[10:09:34] <mazafaka> this front bumper will be really rigid and self-made, not bought.
[10:10:02] <Loetmichel> mazafaka: like i would do it
[10:10:27] <Loetmichel> the main tubes of the tatra "bumper" are 120mm steel tube with 40mm wall
[10:10:30] <Loetmichel> ;-)
[10:10:43] <mazafaka> but I do ot really have a garage, although plan to buy that tall van with gas equipment
[10:11:12] <mazafaka> 40 mm wall?
[10:12:15] <mazafaka> I think of some steel profile welded with some steel tube and such
[10:14:44] <Loetmichel> mazafaka: right, 40mm "hole" left in the middle ;-)
[10:15:38] <Loetmichel> a BIT heavy... but on 17 ton truck the half ton front bumper is negligible ;-)
[10:15:45] <mazafaka> but such a rigidity is at certain height only, not higher
[10:17:31] <Loetmichel> and it was even adjustable. there were 2 9 ton hydraulic cylinder beneath the chassis which could swivel the "cow bar" all the way down to the ground, even lift the front two axles completly off the ground
[10:19:06] <Loetmichel> because on the roof of the truck was a 6 meters grid pylon to be mounted on the bumper with a hook on the top end, so the bumper could double aas a crane ;-)
[11:00:58] <mazafaka> what a vehicle! nteresting
[11:12:42] <JT-Work> anyone have a favorite place to get laptop batteries in the US?
[11:13:16] <cradek> I've never successfully bought a good replacement laptop battery.
[11:13:54] <cradek> if I needed one for my thinkpad I'd call up lenovo and get it right from them, even if it's $200
[11:14:03] <cradek> every other (ebay) attempt has failed for me
[11:16:22] <skunkworks> I have had good luck with dell batteries on ebay... atleast 90% good :)
[11:17:21] <JT-Work> I bought one in 2007 for the other laptop and it still works but I can't remember where I got it from
[11:18:49] <Jordan_> would acme 5/8-6 G2 be good enough for linear motion?
[11:19:17] <JT-Work> sure if your not wanting smooth precision motion
[11:19:49] <Jordan_> i want smooth precision
[11:21:13] <Jordan_> maybe it is good enough
[11:23:02] <SolarNRG> ballscrews are better than acmethread for precision
[11:24:01] <jdhnc> s/for$//
[11:24:26] <Jordan_> is it hard to tap AL for an acme screw
[11:24:50] <JT-Work> not if you have an acme tap $$$$$
[11:25:27] <skunkworks> or a lathe and a properly ground cutter...
[11:26:30] <JT-Work> I think I have some inserts for that somewhere for my grooving holder
[11:27:07] <Jordan_> kind of new to this, would a AL tslot with a slide block that's tapped for an acme screw work?
[11:27:38] <Jordan_> not looking for the highest precision but i don't want to make it crappy either
[11:28:27] <Jordan_> there isn't much load on it either
[11:30:04] * JT-Work heads back to the shop
[11:39:44] <jdhnc> because an acme tap is $80-100 and an acme nut is cheap?
[11:40:10] <Jordan_> ok how do you fasten it to slide block
[11:40:23] <Jordan_> but anyway that's irrelavant i want to know how accurate it could be
[11:40:30] <jdhnc> glue, weld, bracket, compress
[11:40:32] <Jordan_> and it's weaknesses
[11:40:38] <frysteev_> gravity,
[11:41:09] <jdhnc> offset force will tend to make the slide bind. A longer slide would help with that.
[11:41:24] <jdhnc> is this like a T-bolt, or a 8020 slide fixture, or what?
[11:41:54] <Jordan_> i don't know haven't picked one out
[11:42:02] <jdhnc> a t-bolt loose enough to slide would probably bind
[11:42:29] <Jordan_> no i don't want anything loose, it's a cnc type machine
[11:42:54] <jdhnc> http://www.8020.net/Solution-8.asp
[11:46:52] <Jordan_> do you know where you get the slide blocks?
[11:47:01] <jdhnc> from 8020 distributors
[11:47:52] <Jordan_> good place for it? do you know the price ranges?
[11:49:45] <ssi> it's spendy
[11:50:00] <Jordan_> jdhnc, do you think that maybe the screw could be used as a guide itself?
[11:50:41] <jdhnc> I don't understand what you mean.
[11:51:11] <Jordan_> no guide rails just attached the nut
[11:51:19] <jdhnc> what is the nut attached to
[11:51:31] <Jordan_> the lead screw
[11:51:44] <Loetmichel> Jordan_: make the slide from POM
[11:51:54] <jdhnc> the nut has to be attached to something that won't rotate.
[11:52:04] <Jordan_> there will have to be a flate plate on back
[11:52:21] <Loetmichel> then you can make the tap yourself, using an angle grinder, some acme thread rod and a Burner/oil
[11:52:23] <Jordan_> i'm thinking it will be just a square block with a flat peice on the back
[11:52:42] <Loetmichel> http://www.cyrom.org/palbum/main.php?g2_itemId=356
[11:52:56] <Loetmichel> like i did here ;-)
[11:53:06] <Jordan_> Loetmichel, how much and where do you get POM
[11:53:15] <Jordan_> i read it does have some really good properties
[11:53:22] <Loetmichel> ebay
[11:53:31] <Jordan_> how much sir?
[11:53:38] <Loetmichel> i think in america its calles "acetal"
[11:53:43] <Loetmichel> called
[11:53:52] <Jordan_> jdhnc, so i guess the guide could be considered just a flat piece of aluminum
[11:53:56] <Loetmichel> here in germany on ebay its more or less cheap
[11:54:17] <jdhnc> Delrin(tm) is acetal copolymer
[11:55:10] <Jordan_> jdhnc, or just and flat peice on the back, but the nut will be a big square block that rides on that flat peice
[11:55:31] <jdhnc> something has to resist the rotation
[11:55:37] <Jordan_> would it be straight enough
[11:55:40] <Loetmichel> http://www.ebay.de/itm/POM-Block-77-x-63-x-40-mm-0-32-kg-Schwarz-B-/390391880016?pt=Rohstoffe_Materialien&hash=item5ae52b5950
[11:55:44] <Loetmichel> thats in euro
[11:55:53] <Jordan_> jdhnc, the flat piece on the back...
[11:56:49] <Loetmichel> jdhnc: delrin, POM and Acetal are the same, just different names/trademarks
[11:57:23] <Jordan_> the other problem is how do you fasten the ends of a lead screw?
[11:57:31] <Jordan_> cheaply
[11:57:35] <Jordan_> and securely
[11:57:41] <Loetmichel> woth a block of aluminium?
[11:58:06] <Loetmichel> http://www.cyrom.org/palbum/main.php?g2_itemId=3494
[11:58:09] <Jordan_> it will not wear?
[11:58:22] <gene_> got head scratcher here. 1.000" of carriage motion is about 17.75 turns of the lead screw, what tpi is this POJ?
[11:58:22] <Loetmichel> http://www.cyrom.org/palbum/main.php?g2_itemId=755
[11:58:39] <Jordan_> do you have the same design as what i'm talking about
[11:58:50] <Jordan_> Loetmichel, there is no bearing in them/
[11:58:52] <Jordan_> ?
[11:59:20] <Loetmichel> have you looked at the link bevore wirth the schematic?
[11:59:24] <Loetmichel> before
[12:00:12] <Loetmichel> the leadscrew in the last photo is made this way at the ends: http://www.cyrom.org/palbum/main.php?g2_itemId=2991&g2_imageViewsIndex=1
[12:00:28] <Jordan_> oh
[12:00:34] <Jordan_> it is milled down
[12:00:43] <Loetmichel> so beneath the aluminium spacer there are TWO 10mm bearings
[12:01:13] <Jordan_> do all lead screws come like that with the ends like that
[12:01:24] <Jordan_> or is it a lot more expensive
[12:01:34] <Loetmichel> if you order them this way: yes ;)
[12:01:43] <Loetmichel> and no, not really
[12:01:49] <Jordan_> not expensive
[12:01:52] <Jordan_> i doubt that
[12:02:10] <Jordan_> what about a smooth round nut
[12:02:16] <Jordan_> you could fasten on the end
[12:02:18] <Loetmichel> i payed about 50$ for machining the 4 leadstews for that machine
[12:02:49] <Jordan_> like one with only one hole
[12:02:57] <Jordan_> and just tighten it down on the end
[12:03:29] <Jordan_> could probably even use the POM
[12:03:29] <KimK> gene_: Could it be 1.5mm/turn and minus about 5%? (1.430985915 mm/turn) If the screw was rolled insteat of ground (common in low-cost screws), that might account for the error.
[12:03:30] <Jordan_> for that
[12:04:02] <KimK> s/insteat/instead
[12:04:56] <Jordan_> but the larger point is would the G2 lead screw be straight enough to be the guide
[12:05:58] <Jordan_> the way the nut won't turn is a flat peice of metal along the screw
[12:06:08] <Jordan_> maybe a c channel
[12:06:21] <Jordan_> and the nut is a big block of POM
[12:06:47] <jdhnc> that would work as long as the thing it is moving is captured from rotation
[12:07:24] <Jordan_> wow
[12:07:29] <Jordan_> that's awesome
[12:07:39] <Jordan_> jdhnc, G2 is good enough?
[12:07:50] <Jordan_> 5/8-6
[12:07:51] <jdhnc> heh, for what?
[12:08:00] <Jordan_> its a 3d printer
[12:08:12] <Jordan_> i needs to be fairly accurate
[12:08:21] <Jordan_> not NASA accurate
[12:09:01] <jdhnc> nasa hubble accurate? nasa challenger accurate? nasa mars rover accurate?
[12:10:17] <Jordan_> well i guess i could try it
[12:10:29] <Jordan_> won't be too expensive
[12:11:26] <gene_> kimk, don't know. its std 7x12 lead screw
[12:11:39] <Jordan_> 7?
[12:11:42] <Jordan_> 7 inch
[12:12:11] <Jordan_> that is a huge lead screw
[12:12:16] <gene_> yup, mini lathe, in this case wearing a Speedway label
[12:12:22] <Jymmm> that's what she said
[12:12:59] <Jordan_> i though 7 was the diameter
[12:13:11] <gene_> of the lathe :)
[12:13:23] <Jordan_> i want a mini lathe
[12:13:48] <gene_> no you don't! Its a PIMA!
[12:13:49] <Jymmm> 7x14mm
[12:13:51] <Jordan_> maybe a t slot would be better for framing options
[12:14:35] <gene_> the screw isabout 3/4" in diameter, acme thread
[12:14:56] <Jordan_> you think the bigger the better?
[12:15:01] <Jordan_> for accuracy
[12:15:02] <frysteev_> anyone here have expereince rigigng heavy loads?
[12:15:21] <Jordan_> since it would not be subject to bending
[12:15:25] <Jymmm> JT-Shop: frysteev_ is looking for you
[12:15:35] <frysteev_> lol
[12:15:41] <IchGuckLive> Jorden why not standart Trapezional scew and tread
[12:16:14] <IchGuckLive> Jordan_: this may give you 0.05mm acuracy at all time
[12:16:30] <Jordan_> what?
[12:16:38] <IchGuckLive> even les if you catch better stuff
[12:16:58] <Jordan_> .05mm is pretty dag on good
[12:17:13] <Jordan_> but IchGuckLive what are you talking about
[12:17:23] <IchGuckLive> 3 standard nema 23
[12:17:34] <Jordan_> what
[12:17:39] <IchGuckLive> somthing like reprap
[12:17:43] <Jordan_> i'm using nema 17
[12:17:47] <Jordan_> yes like reprap
[12:18:00] <gene_> actually I just measure it, its .620" in diameter
[12:18:01] <Jordan_> i found cheap nema17's
[12:18:07] <IchGuckLive> they use 12x3mm in there europ standard kit
[12:18:20] <Jordan_> i still don't know what you are talking about
[12:18:31] <Jordan_> .05mm for what
[12:18:36] <Jordan_> the g2 lead screw?
[12:18:39] <ssi> frysteev_: I'm driving my forklift up to you, but I've been on the road three days and I only made it as far as tennessee
[12:18:41] <IchGuckLive> the Epson NEMA23 laser sreppers have 3Nm at a 15Euro prise
[12:18:53] <Jordan_> too expensive
[12:19:14] <frysteev_> lol
[12:19:18] <Jordan_> IchGuckLive, you talking about my idea for leadscrew and c channel
[12:19:21] <IchGuckLive> but accurat and tourch enoph
[12:19:35] <frysteev_> so anyone here use belt drive?
[12:19:48] <frysteev_> i keep eyeing up the belt they use for garage door tracks
[12:19:51] <IchGuckLive> frysteev_: Timebelt yes
[12:20:05] <Jordan_> i have a mxl belt and pulley
[12:20:10] <Jordan_> for my 3d printer
[12:20:30] <Jordan_> but GT2 is supposed to be slightly better
[12:20:33] <IchGuckLive> frysteev_: what size of movement are we talking
[12:21:34] <IchGuckLive> frysteev_: or yust between leadsrew and motor
[12:22:24] <IchGuckLive> Jordan_: the leadscrew TR12x3 Trapez is 8Euros per meter
[12:22:41] <IchGuckLive> if you go direct for 400steps its 3/400
[12:23:10] <IchGuckLive> thats 0.0075mm step with
[12:23:12] <Jordan_> what's tr stand for?
[12:23:18] <IchGuckLive> Trapez
[12:23:24] <Jordan_> what quality?
[12:23:27] <Jordan_> g2
[12:23:31] <Jordan_> or c
[12:23:50] <IchGuckLive> let me have alook at the supplyer
[12:24:59] <IchGuckLive> Jordan_: http://maedler.de/Article/64001200.aspx
[12:25:31] <IchGuckLive> Tolerance 7e
[12:25:44] <Jordan_> so is that better than g2
[12:25:59] <Jordan_> i don't know what all these things mean
[12:26:11] <IchGuckLive> i will see one moment
[12:26:40] <Jordan_> what oh that mm
[12:27:10] <Jordan_> so is that 3 threads/cm?
[12:28:43] <IchGuckLive> 3mm/revolution
[12:29:10] <IchGuckLive> if you take the TR14x4 you are exactly at 0.01mm per step
[12:29:23] <frysteev_> i grabbed a bunch of those chamberlin quiet drive belts from home depot, NOS sale, 10 each they are like 16 weet long each
[12:29:36] <IchGuckLive> 7e is Zero -0.015mm
[12:30:12] <IchGuckLive> G2 is the Hole +0.03+0.05
[12:31:23] <Jordan_> i think i'll just try g2 i found a cheap place for it like 5USD for 3 feet
[12:31:27] <IchGuckLive> if you take a standard bronz Nut it is at 7H so it is +0.01-+0.03
[12:31:47] <IchGuckLive> ok it is up to you
[12:32:09] <Jordan_> but i don't feel like spending on a tap
[12:33:05] <Jordan_> but i'll keep that source in mind
[12:33:09] <IchGuckLive> http://maedler.de/Image/250-250/Bilder_Ecomm%5CProductpics%5CRunde-FlanschmutternV2.jpg.ashx
[12:33:11] <Jordan_> but i'm in US
[12:33:21] <IchGuckLive> Jordan_: this is what you search for
[12:33:22] <Jordan_> that's a nice nut
[12:33:34] <Jymmm> that's what she said
[12:34:40] <IchGuckLive> Jordan_: cheesCNC verses a Pricise one Good-Precice-Hevy-not cheep
[12:35:16] <Jordan_> i was thinking of a delrin nut
[12:35:21] <IchGuckLive> cheesCNC-gauging-onefinger pull-cheep
[12:35:40] <IchGuckLive> if it fits your need
[12:36:42] <IchGuckLive> Jordan_: http://www.cncroutersource.com/acme-nut.html
[12:37:41] <IchGuckLive> http://www.cncroutersource.com/precision-acme-leadscrew-nut.html
[12:38:34] <Jordan_> Constrictor Back Lash Compensation Constricting is what i want then?
[12:39:01] <Jordan_> i think i like plastic the best
[12:39:04] <frysteev_> Jordan_: how big of a machine you trying to make?
[12:39:18] <Jordan_> not big, like 1 cu foot
[12:39:27] <Jordan_> or 1.5 cu foot
[12:39:54] <IchGuckLive> frysteev_: Nema17 in place
[12:40:14] <IchGuckLive> so jorden not able to pull the world !
[12:42:54] <IchGuckLive> Hi WalterN
[12:43:31] <Jordan_> no i won't be pulling the world
[12:43:41] <IchGuckLive> B) O.o
[12:44:18] <IchGuckLive> Jordan_: the glue is only on 0,1mm pricise or
[12:44:32] <Jordan_> glue?
[12:44:39] <IchGuckLive> from the printer
[12:44:42] <Jordan_> oh yea
[12:44:48] <Jordan_> yea probably
[12:45:11] <IchGuckLive> so dont care go as cheep as you can go
[12:45:50] <frysteev_> 3d printer? go belts, you want speed
[12:46:28] <IchGuckLive> 3d printer does not need 6m/min speed
[12:46:41] <IchGuckLive> there is 250mm limit on the glue
[12:53:38] <Jordan_> so the lead screws are going to be too slow you think
[12:54:12] <Jordan_> i was looking at a 5/8-6
[12:54:16] <IchGuckLive> no al that is on the market will fit your need
[12:54:19] <Jordan_> 6 turns/inch
[12:54:30] <Jordan_> that's pretty quick
[12:54:52] <IchGuckLive> Jordan_: thats good
[12:54:55] <Jordan_> how fast do the steppers turn for nema17
[12:55:07] <IchGuckLive> max 15rev/sec
[12:55:16] <Jordan_> so that's plenty fast
[12:55:26] <Jordan_> that's like 3"/s
[12:56:06] <Jordan_> only 75mm/s though
[12:56:26] <Loetmichel> hmm, didnt find any Tabletennisballs... so i took some 3mm PVC foam and made some "custom Feet".... -> http://www.cyrom.org/palbum/main.php?g2_itemId=12991
[12:56:28] <Loetmichel> ;-)
[12:56:31] <Jordan_> are the double starts much more expensive?
[12:56:55] <IchGuckLive> times 60 makes you 4.5meter per min you need 250mm
[12:57:41] <Jordan_> the max is 250mm/s
[12:57:44] <Jordan_> which i'd like to try
[12:58:02] <IchGuckLive> Loetmichel: quad+2 copter
[12:58:46] <Loetmichel> IchGuckLive: hexacopter
[12:58:47] <Loetmichel> ;-)
[12:58:52] <IchGuckLive> B)
[12:59:49] <JT-Shop> Jymmm: I'm here now
[12:59:53] <IchGuckLive> Jordan_: is that on your gluesystem 250mm/sec
[13:00:15] <Jordan_> yea i think that is considered really fast
[13:00:19] <Jymmm> JT-Shop: frysteev_ wanted you
[13:00:25] <Jordan_> 80mm/s is probably more standard
[13:01:54] <IchGuckLive> Jordan_: isend the basic reprap on 269USD why are you going for your own
[13:02:13] <Jordan_> no it's much more than that
[13:02:51] <IchGuckLive> the small one 0.75c Foot kit
[13:03:11] <frysteev_> JT-Shop !!
[13:03:26] <frysteev_> as told you knew about heavy things
[13:03:56] <Jordan_> IchGuckLive, are multiple starts more expensive or same?
[13:04:01] <JT-Shop> well maybe
[13:04:38] <IchGuckLive> Jordan_: thats of my limit
[13:04:39] <frysteev_> i need to do osme rigging this weekend,
[13:04:51] <JT-Shop> what are you moving?
[13:04:57] <frysteev_> like 2000lbs or so,
[13:05:03] <frysteev_> laser head onto its stand
[13:05:26] <frysteev_> thinking about using redyrack as a frame..
[13:06:04] <JT-Shop> I'm not familiar with redyrack
[13:06:22] <frysteev_> pallet racking.
[13:06:54] <JT-Shop> ok, like warehouse racks
[13:07:42] <frysteev_> ya
[13:07:59] <frysteev_> weight wise i think its ok.
[13:08:22] <JT-Shop> most of them hold quite a bit of weight
[13:08:26] <frysteev_> but its not what it was designed for, and i have like no ceiling height for typicaly methods like a forklift
[13:08:56] <JT-Shop> we took the rack off of our forklift so we could lift much higher
[13:09:41] <JT-Shop> so what is your question?
[13:10:07] <frysteev_> am i nuts?
[13:11:08] <JT-Shop> well you might be... but I don't see a problem if properly rigged to use a rack as a crane boom
[13:11:19] <JT-Shop> what are you lifting with
[13:12:36] <JT-Shop> my 3 ton chain falls take up 2' of vertical height
[13:12:39] <frysteev_> couple of 3 ton harbour freight like chain hoists
[13:13:12] <frysteev_> was debating picking up acouple of 2000lb truck winches and using tho :P
[13:13:13] <JT-Shop> are you going to lift the part then move the stand under it then lower it down?
[13:13:21] <frysteev_> exactly
[13:14:25] <JT-Shop> do you have enough height left after subtracting your rigging to get the part high enough?
[13:14:57] <frysteev_> http://www.flickr.com/photos/megacyclelabs/6836727761/
[13:15:02] <frysteev_> i think so...
[13:15:12] <frysteev_> thats a buddy being blurry beside it in the truck
[13:15:39] <JT-Shop> got some beams to go across the racks to hang the chain falls on?
[13:15:55] <JT-Shop> I'm still on dial up so it will take me a while
[13:15:57] <frysteev_> thats what i was thinking
[13:16:12] <frysteev_> you can use your phone to connect to the internet?
[13:17:02] <JT-Shop> I have a 4s so no, not without paying
[13:17:22] <JT-Shop> my neighbor can use my cell booster and get almost 1meg download speed
[13:17:47] <JT-Shop> is the photo what your lifting up?
[13:17:56] <frysteev_> yup
[13:18:08] <frysteev_> that is the laser head on the stand, before we took it off to move it
[13:18:23] <JT-Shop> looks like lots of places to tie your rigging chains to
[13:18:35] <JT-Shop> the top part?
[13:20:27] <frysteev_> and the bottom, there is a metal subframe underneith it
[13:22:45] <JT-Shop> don't look too awkward to lift
[13:23:13] <frysteev_> its just hefty :P
[13:23:35] <frysteev_> its the last big obsticle to getting the machine all setup
[13:24:12] <JT-Shop> all I can say is triple check everything and lift slowly checking everything as you go
[13:24:44] <frysteev_> *nods
[13:25:05] <JT-Shop> make sure your chains and chain falls can't slide in any direction as you lift
[13:25:14] <frysteev_> more worried about the chain fall taking up 2 feet of lift...
[13:25:32] <JT-Shop> yea, you do need to do some measuring
[13:26:30] <JT-Shop> for your amusement notice about the 4th from last photo http://gnipsel.com/shop/gantry/gantry.xhtml
[13:27:07] <Jymmm> http://gnipsel.com/shop/gantry/gantry-11.xhtml
[13:27:18] <Jymmm> cheap bastard!
[13:27:23] <JT-Shop> you take all the fun out Jymmm
[13:27:53] <Jymmm> =(
[13:28:53] <Loetmichel> JT-Shop: harhar... perfectly normal "workaround" ;-)
[13:29:12] <frysteev_> http://www.flickr.com/photos/megacyclelabs/6836766573/
[13:29:14] <JT-Shop> yea, I had to get my chains off somehow
[13:29:37] <frysteev_> i see your engine hoist pic. and raise you that, it buckled real good,
[13:30:04] <frysteev_> http://www.flickr.com/photos/megacyclelabs/6836757415/
[13:30:13] <frysteev_> do use your engine hoist for that.....
[13:30:28] <frysteev_> load shifts, and make your hoist asymetrical
[13:30:34] <trwags> Hi, is there some pin in HAL that goes true, with a fault is precent, axis.N.f-errored is not working for my, i can see the display alarm in AXIS but the pin never goes true, i wanth to put a ligth for the operator to know there is a fault
[13:31:16] <JT-Shop> I would guess that the axis enable goes false during a fault
[13:32:18] * JT-Shop waits to see what experience frysteev_ got
[13:32:55] <frysteev_> waiting on the pic to load?
[13:33:19] <JT-Shop> yea, that looks a bit of a stretch for an engine hoist
[13:33:20] <JT-Shop> yea
[13:33:26] <JT-Shop> finally did
[13:34:23] <JT-Shop> here is how I unloaded my VMC http://gnipsel.com/shop/unload-308/unload-308.xhtml
[13:35:06] <JT-Shop> I really should do some work but... back to this mornings question
[13:35:37] <JT-Shop> I move a part along a rail with a VFD driven motor and have encoder feedback
[13:36:07] <frysteev_> thats more of a statement then a question
[13:36:15] <JT-Shop> what would be a slick way to fire a solenoid valve at precise positions with a recipe of positions?
[13:36:20] <JT-Shop> HAL only?
[13:37:09] <JT-Shop> I also need to vary the speed of the motor driven by the VFD as the position changes
[13:37:10] <frysteev_> drive the solozoid as its own axis?
[13:37:32] <JT-Shop> and I'm talking about +- 1/8" of accuracy on firing the soenoid
[13:38:38] <JT-Shop> not sure what you mean
[13:38:57] <pcw_> so HAL only no gcode?
[13:39:11] <trwags> ok, axis.N.amp enable out could work i will tray
[13:39:28] <JT-Shop> well it could be g code but the simpler the better
[13:39:29] <frysteev_> you theoretically COULD drive it az its own axis, like A axis, then fire it from gcode
[13:40:33] <pcw_> are the waypoints fixed?
[13:40:52] <JT-Shop> no, I need to have a table or recipe for each one
[13:41:05] <JT-Shop> a look up table or something
[13:41:39] <pcw_> I guess user adjusted I what I really mean mean
[13:42:13] <JT-Shop> the gantry runs down to one end firing the solenoids at predefined positions then comes back to the home position and repeats
[13:42:25] <JT-Shop> yes, the user needs to be able to change positions
[13:43:14] <JT-Shop> I guess something like when encoder count = nnn fire
[13:43:37] <frysteev_> what do these solenoids do?
[13:44:03] <JT-Shop> sorry, not allowed to say
[13:44:33] <frysteev_> i will then assume they spray cheese on the worktable
[13:44:58] <JT-Shop> that would work or cheese blobs
[13:45:35] <pcw_> yeah maybe a comp that reads from a table of waypoints and advances when enabled and gets a position match
[13:45:47] <frysteev_> my machine has too many solenoids, abit over my head with it
[13:46:05] <JT-Shop> that's a good idea pcw_
[13:46:06] <pcw_> position match being a fairly hairy concept in real time
[13:46:20] <pcw_> probably > compare
[13:47:51] <pcw_> so comp has enable, position, reset inputs and fire output (one comp invocation per solenoid)
[13:48:20] <JT-Shop> I'll have to twiddle with that a bit and see what I come up with
[13:49:11] <pcw_> (and some clever way of loading the table I leave as an excercize to someonw who knows what they are doing)
[13:49:29] <JT-Shop> I was just pondering how one might do that
[13:49:41] <pcw_> halui?
[13:49:46] <JT-Shop> like a screw comp file kinda
[13:49:53] <pcw_> yeah
[13:50:25] <JT-Shop> one file per part...
[13:51:03] <pcw_> halstreamer?
[13:51:42] <JT-Shop> yea, that might work COOL!
[13:52:09] <pcw_> (thats may be sort of overkill as you dont need much data)
[13:53:05] <pcw_> just a way to load some arrays from a user specified file
[13:53:26] <pcw_> This really needs a HAL guru
[13:53:49] <JT-Shop> it would be pretty simple data just a list of positions maybe 40 at the most
[13:57:48] <Jordan_> what are the fastest lead screws they make in TPI?
[13:58:49] <Jordan_> turns per inch
[13:58:54] <pcw_> multi-start lead screws can get pretty fast
[13:59:10] <Jordan_> do they also get pretty expensive
[13:59:28] <pcw_> probably
[13:59:47] <pcw_> I've seen 2 TPI
[13:59:56] <Jordan_> where, how much?
[14:00:52] <pcw_> I have no idea how much, just saw them on a machine
[14:02:40] <Jordan_> about 6 turns per inch is pretty cheap
[14:02:47] <Jordan_> but kind of slow
[14:06:34] <pcw_> Direct step motor to shaft?
[14:06:51] <Jordan_> what
[14:08:37] <pcw_> well 6 turns per inch is not slow at 3000 RPM or so RPM so I guessed that you are using step motors
[14:09:01] <Jordan_> yes stepper motor
[14:09:51] <pcw_> and step motor drives screw direcctly?
[14:09:57] <Jordan_> yea
[14:10:30] <pcw_> so you can go only faster if you have more torque than you need...
[14:15:18] <Jordan_> well the best that i can find that's pretty cheap is 1x4, 6foot for 10.73
[14:15:27] <Jordan_> stil 4 tpi is slow
[14:16:47] <Jordan_> if i ran the motor at 5 revs/sec which is 1000 steps/sec, that's 127mm/sec
[14:17:02] <Jordan_> i guess that's not too bad
[14:17:21] <Jordan_> no wait
[14:17:26] <mrsun> hmm making a concrete base for the lathe, should be a good idea right? :)
[14:17:34] <mrsun> atleast then i can twist the bed of it to wherever i want! :P
[14:17:36] <pcw_> well a decent step drive/motor should at least get to 600 RPM so possibly double that
[14:18:11] <Jordan_> no that's a little over 25mm/s
[14:18:15] <Jordan_> that's too slow
[14:18:28] <frysteev_> a lathe for concrtete would be cool
[14:18:38] <Jordan_> 60revs a second?
[14:18:45] <frysteev_> cnc jackhammer would be cool for making parkinglot art
[14:18:58] <Jordan_> no i got a cheap nema17 stepper
[14:19:11] <pcw_> 60 revs/sec it out of stepmotor territory
[14:19:17] <pcw_> is out
[14:19:24] <ssi> pcw_: so Nick001 had an HNC resolver in hand, and claimed that it said 6V output 12V input on it :/
[14:19:47] <ssi> 23:50 < Nick001> Harowe Servo Control
[14:19:47] <ssi> 23:51 < Nick001> Rotor 1 Phase Output 6.0 V
[14:19:47] <ssi> 23:51 < Nick001> Stator 2 Phase Input 12v
[14:19:47] <ssi> 23:51 < Nick001> 2500 HZ
[14:20:02] <pcw_> Well not sure theres any guarantee they are all the same
[14:20:10] <ssi> absolutely true
[14:20:13] <Jordan_> you just said 600 RPM that's 10rps
[14:20:47] <pcw_> yes that should be OK for a good stepmotor/drive
[14:21:15] <pcw_> ssi did you try 2500 Hz? (I forget)
[14:21:17] <Jordan_> ok still slow at about 2.5 in/s that's about 60mm/s
[14:21:52] <ssi> pcw_: no, originally I was using a firmware which wouldn't allow me to change freq
[14:21:56] <ssi> pcw_: and I haven't tried since
[14:22:03] <pcw_> (well 2400 Hz on the 5I23)
[14:22:25] <Jordan_> i need a 1 or 2 tpi
[14:22:52] <pcw_> you will have very little torque
[14:23:27] <Jordan_> yea
[14:23:41] <pcw_> err i should say cutting force
[14:23:49] <Jordan_> i'm not cutting
[14:24:08] <Jordan_> it's just a positioner really
[14:24:16] <pcw_> if its speed your after what about a belt drive?
[14:24:25] <Jordan_> yea i know
[14:24:32] <pcw_> you're
[14:24:52] <JT-Shop> my plasma cutter can go 500IPM with nema 23 steppers and belt drive
[14:25:05] <frysteev_> ooooo
[14:25:21] <frysteev_> is this going to be a 'my cnc is faster then yours' match?
[14:25:53] <JT-Shop> no, just saying belts can be fast and cheap if you don't have side loads such as a plasma
[14:26:09] <frysteev_> ya
[14:26:23] <frysteev_> i still wanna try out my garage door belts, they are long and cheap
[14:26:35] <frysteev_> hard finding gears for them tho
[14:26:38] <pcw_> probably much faster and cheaper than an exotic leadscrew
[14:26:59] <JT-Shop> I used timing belts you get by the foot
[14:28:10] <frysteev_> http://sanforddoors.files.wordpress.com/2012/02/gdo-belt-drive.jpg
[14:30:57] <Jordan_> pcw_ i was going to try to combine the screw into drive and guide and frame
[14:31:35] <JT-Shop> like a linear actuator?
[14:33:28] <Jordan_> i guess
[14:40:21] <Jordan_> does driving motors faster make the driver hotter
[14:42:29] <mrsun> stepper driver?
[14:42:46] <JT-Shop> probable as you will need higher voltage to go faster
[14:42:52] <mrsun> driving them to fast will lose steps as they cant feel every pulse :P
[14:47:15] <ssi> JT-Shop: man o man I love my HNC... we're going to make beautiful chips together
[14:50:44] * Jymmm steps WAY BACK from ssi!
[14:51:33] <frysteev_> ummmm
[14:52:01] <frysteev_> no having sweet love with the HNC
[14:52:19] <ssi> WHY NOT
[14:52:22] <ssi> DON'T JUDGE ME
[14:52:41] * Jymmm turns the firehose on ssi
[14:52:46] <JT-Shop> a man and is machine
[14:52:58] <Jymmm> ^rusted
[14:52:59] <JT-Shop> s/is/his
[14:53:18] <ssi> even with crappily tuned servos and insufficient resolver resolution, it's turning within two tenths of the commanded diameter
[14:53:34] <ssi> that's pretty amazing IMO
[14:55:30] <JT-Shop> that's pretty good
[14:55:38] <frysteev_> ssi: just cuz its ronf, dont stick it in the chuck
[14:55:45] <frysteev_> err round
[14:56:11] <ssi> JT-Shop: it cut two tenths under my commanded diameter on a .050" depth of cut (.100 off diameter) in cold roll
[15:08:02] <JT-Shop> nice!
[15:08:17] <JT-Shop> leave a nice finish?
[15:09:15] <ssi> nope!
[15:09:23] <ssi> I haven't tried to figure out feeds and speeds yet :)
[15:09:33] <ssi> I don't have spindle speed feedback yet, and I don't have scaling for gearchanges
[15:17:44] <TekniQue> http://a2.sphotos.ak.fbcdn.net/hphotos-ak-ash3/543187_10150630012308042_159553408041_9155648_811947044_n.jpg
[15:17:58] <TekniQue> nice, a rotary spindle in a laser cutter
[15:18:05] <TekniQue> to cut steel tubing
[15:18:21] <ssi> yea
[15:18:29] <ssi> that plus a barfeeder = airplane kit making heaven :)
[15:18:49] <JT-Shop> no more hand fitting joints
[15:19:05] <ssi> http://www.cartesiantube.com/
[15:26:33] <syyl> ever seen a real tube cutting laser? :D
[15:26:38] <syyl> they have barfeed...
[15:27:11] <syyl> http://www.youtube.com/watch?v=6NLgA1DVD3Y
[15:27:17] * syyl wants one ;)
[15:28:41] <DJ9DJ> hmm, nice
[15:28:53] <JT-Shop> nice plane
[15:29:36] * JT-Shop needs to stop looking at plane kits
[15:29:42] <syyl> i dont like planes, they are always prone to gravity
[15:30:08] <syyl> newton is always against yout ;)
[15:30:14] <Loetmichel> syyl: a plane can soar if the motor fails.
[15:30:27] <Loetmichel> a helicopter wil inevetably go down ;-)
[15:30:35] <Loetmichel> ... FAST...
[15:31:52] <JT-Shop> I used to land my XCel heli with the engine at idle most of the time... more fun
[16:22:29] <DJ9DJ> gn8
[16:31:48] <Jymmm> JT-Shop: ever heard/used this? http://www.amazon.com/Bernzomatic-HC9X12-9-Inch-12-Inch-Cloth/dp/B003ZDO1EK
[16:33:21] <JT-Shop> nope
[16:33:36] <Jymmm> k
[16:46:01] <djdelorie> for those curious about what it's like to work "under the hood" on the electronics of my CNC machine: http://www.delorie.com/photos/cnc/img_2600.html
[16:46:35] <djdelorie> just did my first test run with the 1/8" air die grinder cutterhead. Needs light passes, but the intention was to use it to drill PCBs anyway
[16:48:13] <djdelorie> the new ferrites showed up, so I was testing them. Ferrites on the motor and power wires made a big difference, but not 100%. Good enough that I'm back up to 120VDC for the motors
[16:57:18] <JT-Shop> I like 2579... saw horses
[16:58:17] <JT-Shop> very neat workmanship!
[17:04:49] <djdelorie> yeah, I haven't built any legs for it yet
[17:04:52] <djdelorie> thanks!
[17:05:29] <djdelorie> http://www.youtube.com/watch?v=AHQffhbGyRE&feature=youtu.be
[17:05:43] <djdelorie> die grinder in action
[17:13:33] <JT-Shop> should take about an hour for me to download :/
[17:43:10] <A0Sheds> PCW pcw_ whats the fastest toggle speed for the 7i37 outputs? ~1MHz?
[17:43:56] <PCW> much slower its a power output card for relays etc maybe 10 KHz max
[17:44:04] <A0Sheds> ah ok
[17:44:17] <A0Sheds> whats the approx on/off times?
[17:45:04] <A0Sheds> 25us or so?
[17:45:20] <A0Sheds> i can look up those optos
[17:45:53] <PCW> the outputs dont use OPTOS
[17:46:04] <A0Sheds> SSR's?
[17:46:07] <A0Sheds> I forget
[17:46:17] <raynerd> hello...sorry for those of you who I asked a similar question to last week, but what type of tool would you be using to cut something like this engraved sign: http://i16.ebayimg.com/04/i/000/b8/cd/e063_1.JPG
[17:46:44] <PCW> no they use little Ethernet like transformers
[17:46:46] <JT-Shop> an engraving bit
[17:46:51] <raynerd> please don`t say engraving bit
[17:46:51] <A0Sheds> ah ok'
[17:46:59] <A0Sheds> hehe
[17:47:13] <A0Sheds> tiny cutting bit
[17:47:24] <raynerd> lol, so what is an engraving bit...angle, cutting tip length...
[17:47:47] <raynerd> you google engraving bit and you get about 100 different looking tools popping up.
[17:47:49] <PCW> so gated ~8MHz osc --> transformer --> fullwave rect --> MOSFET gate
[17:48:01] <raynerd> I`m basically wanting to order some now off ebay but don`t know which to go for
[17:50:13] <raynerd> ?
[17:50:15] <djdelorie> you'll probably break a few anyway, but a variety and see what you like
[17:50:35] <raynerd> unfortunately, my budget can`t stretch to a variety.
[17:50:52] <archivist> you can make your own bits
[17:51:05] <raynerd> has anyone ever actually done any engraving, fine, like in the picture?
[17:51:15] <djdelorie> buy a variety of cheap bits, see which one you like while you break the rest, then buy one good one ?
[17:51:17] <raynerd> Archivist
[17:51:49] <raynerd> "cheap" ?? it seems most are £15 for 5!
[17:51:56] <raynerd> that is enough for now..!!
[17:52:21] <archivist> use an old jobber drill and grind to the shape you want
[17:52:52] <JT-Shop> go to Onsrud
[17:53:13] <JT-Shop> raynerd: yes, I do engraving on brass tags all the time
[17:53:17] <raynerd> I was quite hoping someone had done some finer engraving and could advise me on what they used..hey ho! Archivist: would be a good experiment, but not for now as still troubleshooting my machine
[17:53:50] <JT-Shop> single flute engraving bit, the tip width and angle depends on the results required
[17:53:54] <archivist> helps to have a tool and cutter grinder :)
[17:54:04] <JT-Shop> I need one
[17:54:35] <raynerd> JT-Shop - so, if I wanted to replicate the image I posted, what width and angle would you recommend
[17:54:40] <archivist> start from cheap d bits
[17:55:30] <archivist> that image a bit like a stamped one
[17:55:44] <raynerd> Onsrud is USA and I`m UK :-(
[17:56:46] <archivist> measure the impression on the tag to decide what bit you want
[17:57:02] <JT-Shop> what ^^ archivist said
[17:57:54] * JT-Shop listens to Kraftwerk...
[17:58:21] <raynerd> lol.. so JT, which do you use or have you a diverse range?
[17:58:30] <raynerd> clearly I have`nt the tag.
[17:59:11] <asdfasd> raynerd: could you please send another link, I cant open that
[17:59:12] <JT-Shop> I use 37-05, 37-07, and 37-11
[17:59:18] <archivist> so some experimentation required
[18:09:41] <asdfasd> I need to make some improvements soon, It will be a lot of wasted time for me to make it, just to check if that already exist, I need in AXIS screen to add separate touch off button for each axis
[18:11:02] * djdelorie wants a way to rotate the part coordinate system for when I bolt the blank down wrong...
[18:11:18] <JT-Shop> you can
[18:23:18] <cradek> djdelorie: http://linuxcnc.org/docview/2.5/html/gcode/gcode.html#sec:G10-L2_
[18:25:00] <djdelorie> I was hoping for a button, like the "touch off" button
[18:25:19] <Valen> hard part would be determining the actual rotation angle
[18:25:20] <cradek> there isn't one
[18:25:25] <cradek> I agree with Valen
[18:25:43] <djdelorie> even a simple 90 degree rotation would be nice :-)
[18:25:44] <cradek> simple probing and atan can do it
[18:25:50] <cradek> not so simple if you don't have a probe
[18:26:11] <Valen> probing might not be "simple" even with a probe
[18:26:12] <cradek> I've used 90 degree rotation to make a fixture fit more than once
[18:26:34] <djdelorie> but a way to "touch off" XY by locating three points would be useful too, to compensate for... well, stuff.
[18:26:34] <cradek> yeah if you don't have a known flat part to probe...
[18:27:59] <djdelorie> today I could have used a feature to set the Z axis at a non-flat angle
[18:28:31] <djdelorie> my board was a little higher on one side, made a big difference when you're only taking 0.01" off
[18:29:07] <cradek> that feature you want is a 5 axis mill :-)
[18:29:42] <cradek> if you can't tilt the tool, there's usually not much use in tilting the work
[18:30:00] <djdelorie> what I *need* to do is mill my table flat :-)
[18:30:11] <cradek> heh
[18:30:15] <cradek> is it wood or something?
[18:30:18] <djdelorie> yes
[18:30:32] <Valen> wood and .01"
[18:30:37] <djdelorie> cheap knotty pine, too. The boards weren't flat to begin with, but they were cheap and available
[18:30:42] <cradek> I agree with Valen
[18:30:45] <cradek> haha
[18:30:51] <Valen> sure on tuesday this side is high, next week the other side will be high
[18:30:57] <djdelorie> Valen: my router table is precise down to 0.001" - you need that with hardwoods and dovetails
[18:31:29] <cradek> if it's wood, that seems extremely doubtful to me
[18:31:29] <djdelorie> well, it was 0.15" higher one one side, so it was cutting 0.01" here and 0.16" there
[18:31:30] <Valen> if its made out of wood it'll move by more than that if its raining outside
[18:31:39] <cradek> I agree with Valen
[18:31:52] <djdelorie> yes, everyone says that, but none of those people do dovetails
[18:32:10] <Valen> your misunderstanding accuracy and repeatability
[18:32:20] <djdelorie> a few thou makes a HUGE difference in the fit, and the two pieces move the same anyway so it doesn't matter if they move
[18:33:01] <Valen> I use .001mm linear glass scales on a 300kg cast iorn base mill
[18:33:09] <djdelorie> Valen: no, I can take a few thou at a time off with my router table. It's very repeatable, accurate, and precise. And expensive.
[18:33:23] <Valen> and made out of wood?
[18:33:24] <cradek> it's easy to cut a few thou off something
[18:33:38] <Valen> as in the load bearing members are wood
[18:33:38] <cradek> it's hard to make a cut that gives you a plane surface that's flat to a few thou
[18:33:54] <cradek> one has almost nothing to do with the other
[18:33:57] * Jymmm spits on the wood! There, I added a few thousands!
[18:34:02] <djdelorie> well, the router table is a combination of hardwood plywood, solid hardwood, and aluminum
[18:35:44] <djdelorie> the cnc table top is a couple of crappy weathered cupped pine planks that I didn't bother to try to flatten
[18:36:03] <Valen> i believe that you can cut a part, then cut a mating part and it'll fit fine
[18:36:21] <Valen> if you cut the mating part in a few weeks then your tollerences will be off
[18:37:24] <djdelorie> I understand that, I usually do mating parts at the same time, and keep my shop at a relatively stable temperature and humidity. Why are you all being so anal about this? I know all about wood movement and how to mitigate it.
[18:37:52] <Valen> you said it was "accurate" to .001, that has a very specific meaning when machining stuff
[18:38:11] <asdfasd> my experience with wood is that it is too flexible, if you are routing with V bit that pushes the table down, that force is changing with feedrate, so all tolerances too
[18:38:15] <djdelorie> today's problem had nothing to do with humidity, and everything to do with using crappy wood. I just need to use something flatter, or at least mill the surface to be flat relative to the Z axis
[18:38:27] <djdelorie> the 0.001" accurate parts are aluminum. Please don't spit on my aluminum
[18:39:41] <djdelorie> the router table toolkit includes a dial indicator to zero out all the bits and fences, and has an 0.001" indicator on the height adjustment
[18:39:42] * Jymmm tosses JetFuel on the aluminum and ignites it!
[18:39:49] <Valen> Jymmm: that wont do it
[18:39:53] <JT-Shop> Jymmm is a bit crude sometimes
[18:39:58] <Valen> use thermite!
[18:40:01] <ssi> ever tried to light jet fuel?
[18:40:08] <Jymmm> Valen: 20 gallons would!
[18:40:19] <Valen> eh, probably not
[18:40:25] <Valen> it doesn't really burn that well
[18:40:31] <ssi> it's diesel
[18:40:34] <JT-Shop> kerosene
[18:40:36] <ssi> yep
[18:40:58] <JT-Shop> a bit higher on the cat cracker
[18:41:20] <Valen> i think it has additives specifically to make it hard to light too?
[18:41:22] <Valen> jet-A
[18:41:56] <JT-Shop> did you see the 707 that they tested hard to light JetA with?
[18:42:11] <Valen> heh and then they fluffed it anyway
[18:42:18] <JT-Shop> yea
[18:42:56] <PCW> high flash point is probably the main thing (if atomized in a crash its different though)
[18:43:12] <ssi> there's nothing all that glamorous about jet-a
[18:43:16] <ssi> it has anti icing additives in it
[18:43:22] <ssi> and avation taxes added :P
[18:45:06] <PCW> I saw some show that explained how jelled fuels are safer (since they dont atomize)
[18:45:32] <ssi> I should retrofit my plane to run off sterno cans :D
[18:45:43] <ssi> really really big sterno cans
[18:50:11] <frysteev_> or methane
[18:56:11] <Valen> hydrogen its the way of the future
[18:56:50] <Valen> (except its all made from fossil fuels currently and uses 4x the fuel to make the hydrogen as just burning the dinos in the first place)
[18:57:26] <Jymmm> Valen: The ocean is made from dinos?
[18:57:55] <Valen> Jymmm: no, but if you go to the gas shop and get a bottle of H2 it comes from dinos not the ocean
[18:58:18] <Jymmm> Valen: H2 O
[18:58:25] <Valen> thats great
[18:58:40] <Valen> commercially hydrogen is produced from oil
[18:59:13] <Valen> everybody blathers about electrolysis, but nobody uses it on commercial scales
[18:59:25] <djdelorie> iceland?
[19:00:40] <Jymmm> I thought they use geothermal
[19:01:23] <djdelorie> I thought I saw a show about hydrogen in iceland, and that they used electrolysis because electricity is so cheap there
[19:01:37] <Valen> could do
[19:01:47] <Valen> but then as i recall population there is what 50k>
[19:01:48] <Valen> ?
[19:02:19] <Jymmm> http://en.wikipedia.org/wiki/Renewable_energy_in_Iceland#Hydrogen
[19:03:38] <Valen> thats the thing, hydrogen (from water) isn't a fuel source, its an energy storage medium people seem to generally gloss over that
[19:03:57] <Jymmm> and your point is?
[19:04:06] <Valen> batteries are probably better than H2 in the general case
[19:04:24] <Jymmm> and heavy, and toxic, and must be replaced
[19:04:27] <Valen> burning H2 still produces nitrous oxides and such
[19:04:44] <Jymmm> nuttin wrong with a lil laughing gas ==)
[19:05:00] <Valen> except it destroys the ozone layer and makes acid rain?
[19:05:13] <Valen> recycle them, A123 chemistry lasts ~10 years or so and aren't actually that heavy
[19:05:39] <Jymmm> Valen: Yeah, tell every Toyota hybrid owner that.
[19:05:44] <Valen> also less likely to cause a hydrogen explosion when somebodies car leaks in an underground carpark
[19:06:18] <Jymmm> they seems to be very well tested for that more than anything else.
[19:06:21] <Valen> prius isn't A123 chemistry, they are NIMH
[19:06:33] <Valen> old and very heavy
[19:06:48] <Jymmm> LiFePo is what I prefer
[19:06:58] <Valen> thats what A123 developed
[19:07:38] <Valen> thundersky makes lifepo4 for traction packs, quite cheap but not the same quality. ~10% the price though
[19:08:00] <Jymmm> traction?
[19:08:18] <Valen> for pulling stuff, like cars, forklifts and submarines ;->
[19:08:34] <Valen> I have helped a few people do EV conversions with thundersky packs
[19:08:35] <Jymmm> like used for taxing jets?
[19:09:25] <Valen> http://www.evworks.com.au/index.php?product=BAT-LFP90AHA
[19:09:55] <Valen> a battery pack designed as the primary motive power in a car/whatever is often called a traction battery
[19:10:19] <Jymmm> silly aussie!
[19:10:53] <Jymmm> 90Ah eeesh
[19:10:54] <Valen> its from old stuff, like a traction engine
[19:10:58] <Valen> http://www.evworks.com.au/index.php?product=BAT-LFP200AHA is a bigger one
[19:11:09] <Valen> but most people seem to use 90 or 160's
[19:11:22] <Valen> they have a 2000Ah one for subs, but not through this reseller
[19:11:24] <Jymmm> That be a fun flashlight
[19:12:17] <Jymmm> no weight listed =(
[19:12:35] <Valen> they feel like a block of plastic
[19:12:44] <Valen> lighter perhaps
[19:12:57] <Jymmm> ah
[19:13:06] <Valen> weight is listed on the 90ah
[19:13:08] <Valen> 3.3kg
[19:13:17] <Valen> 7.9 for the 200
[19:13:27] <Jymmm> I guess I'll stick with my 18650's for now.
[19:13:37] <Valen> touch more spendy
[19:14:12] <Jymmm> Yeah, but more things are using them, I can find battery holders for them, etc.
[19:14:46] <Valen> you generally build a frame for these batteries, they come with screw terminals that take M8 bolts as i recall
[19:15:00] <Valen> thats one cell keep in mind
[19:15:04] <Valen> 3.6V 200Ah
[19:15:05] <Jymmm> Valen: I got one of these for $10USD and it has an 18650 in it =)
[19:15:11] <Jymmm> http://www.amazon.com/Sony-CP-ELS-Portable-Charger-Battery/dp/B005XJWS30
[19:19:07] <SolarNRG> Why do some stepper motors have 6 wires and some have 8 wires, what is the difference?
[19:19:30] <djdelorie> "the wiring" duh :-)
[19:19:58] <djdelorie> there are four coils in a stepper, eight wires. Sometimes, wires are combined internally to save on external wiring
[19:22:52] <SolarNRG> So on my little stepper motor, red and green go to +5v, the other 4 must be fired in sequence
[19:23:15] <djdelorie> assuming red and green are the commons, probably
[19:23:24] <SolarNRG> With my BIG stepper motors, does this mean 4 of them go to +24v and still four are fired in sequence?
[19:23:49] <djdelorie> if they're split out you have more options. You *could* connect them that way, or use an H-bridge
[19:24:12] <SolarNRG> I'm guessing because you're using higher voltages and currents an H bridge might be sensible
[19:24:36] <SolarNRG> But I discussed this idea and an H bridge made from TIP BJTs would be slow compared to a gecko drive
[19:24:42] <djdelorie> an H bridge lets you use all the coils all the time, doubling the torque generated
[19:27:38] <SolarNRG> Thanks for your advice
[19:35:59] <Jymmm> H Bridge? Are you serious? I'd use a 90 degree phase offset I bridge instead
[19:38:38] <djdelorie> it's a stepper, you should use an S-bridge ;-)
[19:39:22] <djdelorie> Or, to make a long story short, you could use an A-bridge
[19:39:50] <Jymmm> For stepper, you really ned an L bridge
[19:42:09] <Jymmm> as in london
[19:43:00] <djdelorie> avoid those, they keep falling down
[19:43:34] <Jymmm> Ah, yes, good point!
[19:46:35] <SolarNRG> Could I make my own "gecko" drive
[19:46:44] <SolarNRG> dj, ur pretty good with pcbs
[19:46:57] <djdelorie> you could, but what's the point?
[19:47:10] <SolarNRG> cheaper
[19:47:17] <djdelorie> unlikely
[19:47:18] <SolarNRG> I don't want a chinese board
[19:47:27] <SolarNRG> everyone tells me they smoke, not much else
[19:49:45] <Valen> cheaper until you blow stuff up and take your time into account
[19:50:34] <SolarNRG> Can you make your CNC machine do the mario theme?
[19:50:43] <SolarNRG> http://www.youtube.com/watch?v=Kh2AWswAMvw like this
[19:50:56] <djdelorie> probably, the PWM for the motors is well past human audio range
[19:51:45] <SolarNRG> How can you turn a midi into stepper motor music?
[19:53:39] <Tom_itx> http://www.synthgear.com/2009/strange-weird/midi-stepper-motor-music/
[20:24:09] <Jordan__> would it be stupid for the motor to move?
[20:24:26] <Jordan__> instead of using a belt system?
[20:24:42] <Jordan__> so the motor moves itself along the track
[20:54:54] <Jordan__> anyone got anything against acetal gears?
[20:56:21] <Jymmm> Other than a pipe cutter, is ther eany other cutting tool like a can opener?
[20:56:25] <Jymmm> any
[20:59:46] <Tom_itx> jaws of life
[21:00:07] <Tom_itx> tin snips
[21:00:09] <Jymmm> More hand tool
[21:00:20] <Jymmm> needs to be rotary
[21:00:26] <Jymmm> like a can opener
[21:00:41] <Tom_itx> paper cutter
[21:01:16] <Jymmm> What I need is a hand can opener that will leave a about 1/4" lip inside the lid.
[21:01:23] <Jymmm> err the can that is
[21:01:40] <Tom_itx> i think you can buy them
[21:01:50] <Jymmm> I have to find them first
[21:01:55] <djdelorie> nibbler?
[21:02:12] <Jymmm> djdelorie: too fugly of a finished cut
[21:02:29] <djdelorie> you want to get the food out, leave a pretty edge, and not be standard?
[21:02:47] <Jymmm> I never said anythign about food =)
[21:02:59] <djdelorie> mount the can in a lathe ?
[21:03:18] <Jymmm> it'll crush it, and no lathe
[21:03:41] <djdelorie> is there food in the can?
[21:03:53] <Jymmm> no, empty.
[21:04:01] <djdelorie> *can* you put something in the can?
[21:04:13] <Jymmm> sorta
[21:04:14] <djdelorie> I'm thinking, fill it with fluid, freeze it, and use a forstner bit
[21:04:30] <djdelorie> you need something behind the metal to push against
[21:04:34] <Jymmm> Ew, I just tried a step bit, not a pretty sight
[21:04:41] <djdelorie> a wheel cutter might work
[21:04:44] <Jymmm> swarf everywhere too
[21:04:52] <Jymmm> wheel cutter?
[21:04:59] <Jymmm> like a can opener?
[21:05:36] <djdelorie> http://www.rockler.com/product.cfm?page=11196
[21:05:55] <Jymmm> oh gawd no
[21:06:04] <Jymmm> I dont want Any swarf
[21:06:15] <Jymmm> I have one of those btw
[21:07:09] <djdelorie> cnc laser ? ;-)
[21:07:25] <Jymmm> I have one of those too, but it dont cut metal
[21:08:44] <Jymmm> this is a comercial can opener http://www.costco.com/Browse/Product.aspx?Prodid=11490617&whse=bd_827&Ne=2286%204000000&eCat=bd_827|11113&N=4007132&Mo=298&No=9&Nr=P_CatalogName:BD_827&Ns=P_Price|1||P_SignDesc1&lang=en-US&Sp=C&topnav=bd
[21:08:51] <Jymmm> bbiab
[21:28:16] <Jordan__> is there not supposed to be any pressure on the rack and pinion gears? are they supposed to kind of float together
[22:02:15] <mozmck> Jordan__: some of the ones I've seen use a spring to keep the pinion pulled tight against the rack.
[22:03:17] <mozmck> I guess it also would allow for a less than perfectly straight rack over a long distance.
[22:04:52] <Thetawaves> is there a way to set maximum duty cycle on a pwm output?
[22:05:42] <Thetawaves> i want to use a 170v power supply to run a 100v motor, this should be possible with proper filtering and not more than 58% duty cycle
[22:07:26] <Thetawaves> any comments as to if this is even a good idea
[22:08:29] <Thetawaves> could there be glitches where the pin may accidentally be held high?
[22:08:43] <pcw_> asplode!
[22:09:08] * Thetawaves would like to run 100v motor without spending 500$ on a 100v power supply
[22:09:41] <djdelorie> Thetawaves: the motor will still see 170v part of the time, if the insulation isn't rated for that, it might short
[22:09:54] <Thetawaves> not if you filter properly
[22:10:32] <Thetawaves> a pi filter should do a pretty darn good job at eliminating the transients
[22:10:48] <pcw_> Brush motor?
[22:10:57] <Thetawaves> i understand your concern and will make sure when it is built
[22:10:59] <Thetawaves> yeah
[22:11:13] <Valen> generally it'll be ok, though you may see more arcing
[22:11:44] <Valen> might put an additional inductor in the line and a condensor cap
[22:12:09] <Thetawaves> before the filter?
[22:12:18] <Thetawaves> a pi filter is a series of capacitors and inductors
[22:12:36] <Valen> to make the filter
[22:12:47] <Thetawaves> ahhh yeah, thats the plan
[22:13:14] <Valen> put an inductor in the line, the motor itself is an inductor
[22:13:28] <pcw_> you dont want a PI filter (capacitor input)
[22:13:56] <Valen> putting a cap across the terminals of a motor can help reducing arcing
[22:14:01] <Thetawaves> pcw_, you advise against first leg in the pi filter?
[22:14:32] <pcw_> Yes you cant drive a capacitor with a PWM source
[22:14:44] <Thetawaves> huh?
[22:16:05] <Thetawaves> the simplest filter is a resistor + capacitor
[22:16:22] <Thetawaves> that is the usual way to smooth a pwm signal
[22:17:04] <Thetawaves> that is the younger sister of LC based filters though
[22:17:30] <pcw_> The current in the capacitor will by C dv/dt and dv/dt is very high for the square wave edges
[22:17:35] <Valen> Thetawaves: if your feeding a motor PWM you need to look at whats actually going on and what cares about the voltage
[22:18:25] <Valen> the windings in the motor are the most sensitive, however the voltage across them is going to be nice and smoothed do to the motor itself being a huge inductor
[22:19:16] <pcw_> inductor input will work but I suspect you are better just lowering your power supply voltage
[22:19:16] <Valen> the brushes may see full line voltage, this can cause excessive arcing
[22:19:16] <Thetawaves> pcw_ how do you lower your power supply voltage?
[22:19:16] <pcw_> (the current is smoothed, not the voltage)
[22:19:23] <Valen> putting a small cap across the motor can help to quench the arc
[22:19:33] <Thetawaves> Valen, if you produce a filtered signal, there will be no 170v transients reaching the motor
[22:19:51] <Thetawaves> in essence we are saying exactly the same thing
[22:20:09] <Valen> I'm saying I'd run it without any filtering and a small cap across the motor
[22:20:26] <Thetawaves> NOW YOU"RE TALKING SCARY
[22:21:07] <Thetawaves> i think these motors burn through brushes fast as it is
[22:21:09] <Valen> I often run low voltage motors at 4x their "rated" voltage ;->
[22:21:12] <pcw_> how big a motor?
[22:21:17] <Thetawaves> 300w
[22:21:55] <pcw_> 170V is rectified/filtered line voltage?
[22:22:04] <Thetawaves> will the additional arcing cause the brushes to deteriorate?
[22:22:09] <Thetawaves> faster*
[22:22:15] <pcw_> yes
[22:22:16] <Thetawaves> pcw_, yeah
[22:22:26] <Valen> yeah arcing is bad mmkay
[22:22:31] <Thetawaves> then i would much rather design the system to work at lower voltages**
[22:23:03] <Valen> I say try it and see what it looks like
[22:23:05] <pcw_> also the ripple current will be higher at a given PWM frequency
[22:23:22] <pcw_> what is the PWM frequency?
[22:23:35] <Valen> arcing is a product of voltage, current and RPM (not the simple product though)
[22:23:53] <Thetawaves> what frequency can i produce on the parallel port?
[22:24:05] <Valen> ok, thats not going to work then lol
[22:24:29] <Thetawaves> think i can produce 5khz?
[22:24:30] <Valen> 300W motor 3Khz or so would be the minimum PWM frequency I'd use
[22:25:03] <Valen> note thats PWM frequency, at low duty cycles the effective "frequency" can be much higher
[22:25:23] <Thetawaves> the entire goal of this little thought exercise is to get away from writing code on one of the avr to produce fast pwm
[22:25:33] <Valen> use a hardware PWM port
[22:26:16] <Valen> 3Khz at 256 levels of PWM means a minimum pulse is equivalent to 768khz
[22:26:17] <pcw_> also you will only have about 10 steps of PWM from aparallel port (3+ bits)
[22:26:53] <Thetawaves> alright, my hopes are crushed
[22:27:13] <pcw_> thats a little beyond what software pulsing (from a PC) can do
[22:27:37] <pcw_> use an arduino
[22:27:40] <Thetawaves> do you get more resolution if you reduce the frequency?
[22:27:46] <pcw_> yes
[22:28:29] <Valen> pcw_ you should be telling him to use mesa boards ;-> they will do PWM at stupid fast speeds
[22:28:41] <pcw_> but the ripple current will get out of hand
[22:29:10] <Thetawaves> mesa won't work because my atom computer's pci slot is already occupied
[22:29:27] <Valen> if its not occupied with mesa it could be put to better use ;-P
[22:29:29] <Thetawaves> ...or i could replace it
[22:29:54] <jdhnc> I have a mesa 7i43 on my Atom parallel port
[22:32:33] <pcw_> or if you are just poking about, run the motor from a safe voltage and use software PWM and see how you do
[22:33:05] <Valen> whats the motor for?
[22:33:09] <Thetawaves> spindle
[22:35:00] <Thetawaves> simplest sounds like using an avr to convert the low speed pwm from the computer into higher speed to run the igbt
[22:36:35] <pcw_> if its a spindle why not just use the AVR to control it and send serial/modbus/analog/ whatever from LinuxCNC to set the speed
[22:42:17] <Thetawaves> serial would be the easiest
[22:43:26] <Valen> I'd also look at using one of those hobby brushless motors
[22:43:31] <Valen> and controllers
[22:44:03] <Thetawaves> back to using parallel port, no serial port
[22:45:19] <Valen> many of the itx boards have a serial port, its just on a header
[22:45:30] <Valen> also for that application usb > serial would do
[22:45:44] <Thetawaves> ahh yeah, i'll open it up and take a look
[22:45:46] <Valen> (heck use a usb AVR + lufa and you don't even need another item)
[22:46:02] <Valen> just usb > avr > pwm out
[22:46:22] <pcw_> someone on th mailing list (maybe Kirk Wallace?) had a bit banged SPI comp for the parallel port as well
[22:46:28] <Thetawaves> i actually have most of the parts to do that
[22:46:43] <Thetawaves> would have to make a pcb for the smd avr chip though
[22:46:45] <Valen> (don't use v-usb ;->)
[22:47:10] <Thetawaves> it has been on my to-do list to make a usb avr work
[22:47:13] <Valen> ahh well i better head out and do some work
[22:47:22] <Thetawaves> thanks
[23:42:30] <ssi> http://a1.sphotos.ak.fbcdn.net/hphotos-ak-ash3/553744_819270538822_71107655_35511698_1208677495_n.jpg