The mill-drill which I'm starting to convert to CNC has 0.2mm (0.008") backlash in the Z feed, making it a much better candidate for stepper control than servo, IIUC. There is though, sufficient in-built upward spring-loading for the quill to retract if the feed worm is disengaged. I wonder if that would permit servo control, without hunting?
My brand new rotary table has almost 0.1° backlash, so I guess it has to be a stepper axis? It's a 970 kg machine, with a 1m long table, so even when I stump up for ballscrews, the thought of trying to drive X and Y with steppers is daunting, and I fear lost steps, so expect I'll have to go with servos there. I've found some servos with attached encoders here: http://www.oceancontrols.com.au/motors/servo/servo_motors.htm but they look rather wimpy. On the other hand, I'd be amazed if I was outputting 150W when doing manual rapids, even with the acme leadscrew. Add some HTD pulleys, to increase the torque, and take what rapids I get, maybe? At least the motor compares favourably with the one Kirk found recently: http://www.cadcamcadcam.com/motorservoglobepm-dc.aspx giving 3.5 times the torque at 2800 RPM. Now, if only the appreciating A$ had brought the local price down. Erik ------------------------------------------------------------------------------ OpenSolaris 2009.06 is a cutting edge operating system for enterprises looking to deploy the next generation of Solaris that includes the latest innovations from Sun and the OpenSource community. Download a copy and enjoy capabilities such as Networking, Storage and Virtualization. Go to: http://p.sf.net/sfu/opensolaris-get _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
