#emc | Logs for 2007-10-01

[19:58:42] <cradek> machinery's handbook recommends drilling/reaming Aluminum at 300-400 sfm. does anyone really do this?
[19:59:34] <alex_joni> hello
[19:59:42] <cradek> hi
[20:00:07] <cradek> that means 3200 rpm for a .5 inch hole
[20:00:36] <cradek> and it said .031 per rev, so that means 100ipm feed!
[20:00:58] <cradek> I think I'd want to be standing pretty far away to try that
[20:01:06] <Roguish> cradek: i usually go more on chip load, rather than pure sfm.
[20:01:33] <cradek> yeah I kept the same load (.031) but MUCH slower
[20:01:57] <cradek> maybe I did about .020, I don't remember
[20:02:10] <cradek> I experimented quite a bit because I had a part I wanted nicely finished holes in
[20:02:27] <Roguish> ya definitely should spin the bit, but that high is for big ENCLOSED machines with lots of rpm and power.
[20:02:29] <cradek> I can't imagine running a .5 inch reamer at 3200 rpm
[20:02:55] <Roguish> with really good (expensive) tools.
[20:03:14] <cradek> ok so the answer is "no" :-)
[20:03:38] <cradek> I think I'll continue trusting my gut instead of the book
[20:03:59] <Roguish> hey, in pyvcp, is there a way to have text change on a pin change?
[20:04:26] <cradek> I don't know for sure, but probably not
[20:04:36] <cradek> alex_joni: are you home now?
[20:05:18] <alex_joni> close enough
[20:05:22] <alex_joni> sweden :D
[20:05:29] <cradek> ha
[20:05:41] <alex_joni> I was during the weekend
[20:05:44] <Roguish> i would like one big led to change color with jogging on/off, and have the axis label change on the selected axis.
[20:05:58] <anonimasu> cradek: Yes..
[20:06:16] <anonimasu> cradek: well, reaming anything is done with a high feed..
[20:06:31] <cradek> anonimasu: my reamer didn't like it at all when I tried that
[20:06:41] <alex_joni> Roguish: what do you mean jogging on/off ?
[20:06:42] <anonimasu> cradek: I go by my manufacturers spec..
[20:07:09] <cradek> I dropped down to 200rpm and about 2ipm like I would do by hand on a drill press and got a very nice finish
[20:07:27] <alex_joni> hi mgouget
[20:07:30] <mgouget> Hello!
[20:07:30] <anonimasu> cradek: the machinist handbook probably dosent have a clue..
[20:07:37] <Roguish> i have a rotary switch for my jog wheel. when i change axis i would like the text on a label to change.
[20:07:37] <alex_joni> mgouget: great timing
[20:07:46] <anonimasu> cradek: :p seriously though, I thinkthe tool manufacturer has a better idea about it
[20:08:01] <alex_joni> mgouget: can you /join #emc-devel ?
[20:08:30] <mgouget> alex_joni: ok, going there
[20:08:40] <cradek> anonimasu: this is just plain old HSS tools cutting Al, no idea who the manufacturer is...
[20:09:09] <anonimasu> cradek: random reamers?
[20:09:25] <cradek> yeah pretty much
[20:10:10] <skunkworks_> The only experiece I have had with reamers is running too slow makes a bitter than wanted hole. ;)
[20:10:30] <anonimasu> hm..
[20:10:41] <anonimasu> cradek: how big reamer?
[20:10:47] <cradek> about .500
[20:10:47] <skunkworks_> -bigger
[20:11:01] <anonimasu> 12.7mm?
[20:11:20] <cradek> skunkworks_: interesting, I should measure it
[20:11:32] <cradek> anonimasu: uh yeah
[20:11:37] <anonimasu> 0,38mm/rev is what dormer recommends..
[20:11:47] <anonimasu> 525mm/min
[20:12:12] <cradek> at what rpm or surface speed?
[20:12:39] <anonimasu> 0.38mm/rev..
[20:12:42] <anonimasu> that's whta matters..
[20:12:45] <anonimasu> err what..
[20:12:54] <anonimasu> 1363rpm..
[20:13:11] <anonimasu> though thoose are recomendations, slower/faster isnt as critical as long as you maintaing the same feed per tooth..
[20:13:13] <anonimasu> err fpr..
[20:13:33] <cradek> ok that seems fast to me! I've always reamed slowly with plenty of oil
[20:13:44] <anonimasu> this is with flood coolant :p
[20:13:51] <anonimasu> we ream some 50mm holes at work..
[20:13:53] <anonimasu> in iron..
[20:13:57] <anonimasu> drill 49 ream 50
[20:30:21] <Paragon37> I have been looking at the Gecko stepper drives has anyone used these or does anyone recomend any other?
[20:30:49] <alex_joni> nope
[20:37:47] <anonimasu> Paragon37: I have used them
[20:37:50] <anonimasu> they work great
[20:38:28] <Paragon37> Anonimasu which model would you recommend?
[20:39:53] <anonimasu> the "ones with v in the name"
[20:40:02] <cradek> I think everyone recommends the geckos
[20:40:10] <anonimasu> I guess..
[20:40:14] <anonimasu> I havent used thoose
[20:40:17] <cradek> (but I have not used them for anything yet)
[20:40:21] <anonimasu> only the older ones, and they work great
[20:44:36] <alex_joni> * alex_joni has a small tabletop mill
[20:44:52] <alex_joni> XY with G201 and Z with L297/298 (pminmo design)
[20:45:00] <alex_joni> XY are ages better than the Z
[20:46:13] <alex_joni> although I wouldn't get the G201 now, I'd get the 210 or the 203V
[20:51:34] <Paragon37> Just took a look at the differences between the 203v and 210 the 203v has a lot of functionality but the 210 does full / half/ 5micro and 10 Micro what are the benfits for each?
[20:52:22] <SWPadnos> the 203v can do that as well. either with the g902 (?) or it may be part of the CPLD
[20:52:52] <SWPadnos> are you using a parallel port for step generatin?
[20:52:55] <SWPadnos> generation
[20:52:57] <Paragon37> What does the 5micro and 10micro steps signify?
[20:53:09] <Paragon37> Yes with EMC2
[20:53:32] <SWPadnos> all the drives are 10x microstepping. some of them have a pulse multiplier that allows you to send one step from the PC, and have the drive go more than 1 microstep
[20:53:52] <alex_joni> that's for overcoming the output limits of the parport
[20:54:17] <Paragon37> So one can get very smooth and accurate motion?
[20:54:51] <alex_joni> if your motor can do 100kHz microsteps, but your PC only can output 33kHz
[20:55:03] <alex_joni> then you would set the multiplier, and have higher motor speeds
[20:55:08] <SWPadnos> all the drives are microstepping from the drive to the motor
[20:55:34] <SWPadnos> as Alex said, it's to allow a slow PC to make the motors go fast
[20:56:25] <Paragon37> The ones I am using currently is based on the L297 / L298 circa 1988 which only do half stepping. I guess I should see a massive improvement using microstepping
[20:56:41] <SWPadnos> the anti-resonance of the geckos will provide a nice improvement, I think
[20:56:51] <alex_joni> otoh the 210 also does mid-band resonance damping
[20:56:58] <alex_joni> the 203v doesn't? as far as I can tell
[20:57:01] <anonimasu> err all geckos do.
[20:57:47] <alex_joni> anonimasu: are you sure?
[20:58:01] <SWPadnos> they all do mid-band damping
[20:58:10] <anonimasu> yes
[20:58:24] <SWPadnos> if anything, the 203v will be better, since it has more logic available to make deicsions
[20:58:25] <alex_joni> hmm, nothing in the docs of the 203v
[20:58:32] <anonimasu> even g201...
[20:58:40] <anonimasu> g203 is the MOST advanced drive they have so far.
[20:59:18] <Paragon37> how can I tell what max frequency the motors can handle?
[20:59:41] <Paragon37> as mentioned they are circa 1988
[20:59:44] <alex_joni> g203V: step frequency: 0 to 333kHz
[21:00:13] <Paragon37> can all motors handle that?
[21:00:38] <SWPadnos> it's unlikely the motors can move as fast as the geckos are capable of driving them
[21:00:44] <SWPadnos> certainly not while doing useful work
[21:01:30] <Paragon37> guess I better inquire on shipping costs to the UK then :-)
[21:01:39] <anonimasu> Paragon37: 25$
[21:01:46] <anonimasu> it's mentioned on the page..
[21:01:51] <anonimasu> though you will pay VAT on it..
[21:02:23] <Paragon37> No escaping that one ... :-(
[21:05:54] <Paragon37> anonimasu: can't see that shipping cost anywhere on there page.
[21:06:52] <anonimasu> click ADD TO CART
[21:06:56] <anonimasu> on a drive.
[21:07:19] <anonimasu> oh they've changed it, but it's usually around 25.
[21:07:20] <anonimasu> $
[21:07:47] <Paragon37> I thought it was me ...
[21:42:15] <Paragon37> what do you think of these £33 on ebay http://cgi.ebay.co.uk/4-2A-50V-Microstepping-Stepper-driver-ideal-for-CNC_W0QQitemZ130154526059QQihZ003QQcategoryZ42899QQrdZ1QQssPageNameZWD1VQQcmdZViewItem
[22:09:47] <fenn> Paragon37: they look cute, but no mid-band resonance damping
[22:15:54] <Paragon37> What does that give me sorry for naive?
[22:16:30] <SWPadnos> read this: http://geckodrive.com/photos/Step_motor_basics.pdf
[22:17:09] <SWPadnos> and possibly this: http://geckodrive.com/photos/How_the_G203V_gets_the_most_from_your_motor.pdf
[22:20:13] <fenn> are there drives besides gecko that do mid-band damping?
[22:20:30] <fenn> sub-k$
[22:20:39] <fenn> (or is that $k)
[22:23:21] <skunkworks> if you keep an eye on ebay - parker oem750 drives do. (although I have not had issues with microstepping drives without it.)
[22:49:51] <JymmmEMC> fenn: Yes, the parker compumorot does
[22:50:00] <JymmmEMC> OEM750
[22:50:25] <JymmmEMC> the OEM650 do NOT
[22:51:08] <JymmmEMC> OEM750 brand new from Parker are $550/ea worse case scenario.
[22:53:17] <JymmmEMC> SWPadnos: With your video stuff, do you do any bandwidth monitoring?
[22:53:45] <Paragon37> Thanks for the links.... What does mid-band damping do in a real world sense
[22:54:10] <JymmmEMC> Paragon37: Read the links that SWPadnos gave you, it explains it very well.
[22:54:46] <Paragon37> Oh OK it's in there ... Thanks