On Wed, 08 Apr 2009 11:45:31 -0500, you wrote:
>> EMC isn't helping. There is no acceleration/deceleration setting I can >> see in the hal or ini files produced and spindle inertia and emc are >> fighting each other. A 30lb chuck slowing from 3000 rpm to 200 rpm >> instantly is never going to happen without a brake, the minimum decel in >> the VFD is 1 second. >> >> >I jus ran into this with a rigid tapping run. I had to put a lowpass >filter between the spindle speed command and the servo amp that is >driving the spindle motor. Thinking about this, I don't know in practice if it's going to cause me a problem for now. For tapping I use an extending nose tap holder and the drag on the cut acts as a spindle brake. Reason - with this lathe the stock 1:1 pulley ratio from motor to spindle is poor design, the 1Kw 3200rpm motor is gutless at low speed. I can stop the spindle from 300rpm by grabbing the chuck! I'm going to have to add a jackshaft and additional pulleys, so I can get up near the motors max speed at two working speed ranges. Also while I'm at it I think I'll replace the stock motor and VFD with a new good quality 480V 1.1Kw 1400rpm 3phase motor and flux vector VFD I have spare. Having said all that I cut a 1.5mm test thread today, I was extremely impressed. I deliberately only had a 5mm lead in, and only had spindle set for 500 rpm. After the first two passes looked so good, I leaned on the chuck and slowed it to 300rpm during the third pass, then let it speed up again - still spot on pitch! The thread turned out absolutely perfect so I'm well impressed :) Steve Blackmore -- ------------------------------------------------------------------------------ This SF.net email is sponsored by: High Quality Requirements in a Collaborative Environment. Download a free trial of Rational Requirements Composer Now! http://p.sf.net/sfu/www-ibm-com _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
