On Monday 28 September 2009, Sven Wesley wrote: >2009/9/28 Gene Heskett <[email protected]> > >> On Monday 28 September 2009, Andy Pugh wrote: >> >2009/9/28 Sven Wesley <[email protected]>: >> >> I did as you suggested (I'm in the workshop right now) and you are >> >> right! >> >> >> They overshoot with no load at all. >> > >> >So, the good news is that they are probably big enough for the job, as >> >they behave similarly under load and no-load, and have successfully >> >routed wood already. >> > >> >The bad news is that we still have no idea what is wrong: >> >It seems unlikely that both EMC and the tuning software would both >> >produce incorrect pulse trains. >> >All that seems to leave is corruption of the pulse-train between the >> >computer and the drive, or that the drive is not making a good job of >> >driving the servos. >> > >> >If you are in a hurry to have a working system: >> >> http://cgi.ebay.co.uk/3-AXIS-CNC-Router-or-Mill-Stepper-Motor-complete-ki >>t_ >> >> >W0QQitemZ280401285543QQcmdZViewItemQQptZUK_BOI_Electrical_Components_Sup >> >pli es_ET?hash=item41493811a7&_trksid=p3286.c0.m14#ht_1062wt_1172 >> >> This one is similar to the xylotex kit, and looks to be more ready to >> go, at >> a competitive price. >> >> >Your servo system is better in principle, but perhaps you would be >> >better getting a working system then fiddling with the servos when you >> >don't need them? >> >> -- >> Cheers, Gene > >I can cannot see any changes in speed even if I push put all my body weight >on the Z-axis, it just runs super easy and the motors never gets warm. It >doesn't _seem_ to be a force/power problem.
In both directions? Another thing is I'm having a hard time visualizing your setup, a few pix might help clarify what it is that I undertook to pontificate on. The emc sign on logo is runnable, and can be used just to exercise the machine. If you start it after 'homeing' all 3 axis's, but home z on a block an inch high, and run it once with the feed override at 100%, then check the clearance at the end, record that, then run it back to the start position & rehome it on that same 1" tall block, then set the feed override to 10%, and run it again. If you wind up with the same error at the end that you got the first time, then its time to break out the oscilloscope and find the problem, possibly at the output of the parport. The point is that we will then have absolved the motors themselves, and its time to find out if the drive signals are correct. I admittedly tend to treat the scope like a pair of pliers, one tends to do that when one has had a probe in one hand for 58 of my soon to be 75 years. If you can locate one, and its good enough to look at this digital stuff, it can be very educational. Slower, non-triggered sweep models need not bother knocking, something like this needs dual trace, triggered, dc to 50 or more megahertz response, anything slower will lie to you. Oh, and properly compensated 10x probes too. >I have put so much money and time in building a servo system. It's REALLY >annoying if I have to go back to steppers. To me, these eBay-items looks >pretty small too. Are they really going to make it? If that z axis can pick up both itself and you, then I'd have to say they are big enough. But lets do the above comparison anyway. -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) The NRA is offering FREE Associate memberships to anyone who wants them. <https://www.nrahq.org/nrabonus/accept-membership.asp> Publishing a volume of verse is like dropping a rose petal down the Grand Canyon and waiting for the echo. ------------------------------------------------------------------------------ Come build with us! The BlackBerry® Developer Conference in SF, CA is the only developer event you need to attend this year. Jumpstart your developing skills, take BlackBerry mobile applications to market and stay ahead of the curve. Join us from November 9-12, 2009. Register now! http://p.sf.net/sfu/devconf _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
