On Jun 10, 2009, at 8:39 PM, Neil Macintosh wrote: > Gentleman > I have finished my lathe and now wish to start on the 5-axis mill. > > I have been reading all that I can find with regards to dc brushed > servos vs steppers, I used steppers on the lathe with DIY driver > boards > from Oatley Electronics. Results were very satisfactory with the only > steps being missed when the swarf wrapped around the job. However > with > the 5-axis the work will be a lot bigger with much more expensive > consequences for missed steps. I am hoping to use the DIY UHU servo > controllers but I have a few questions for the gurus. > > Do I need to gear the motors down to increase the holding torque. > Do I need servos to drive 200kg's+ of gantry and head and attain > reasonably high feedrates +- 10m/min so that I don't spend to long > cutting air. > Can I use rack and pinion drive to cut down costs on the XYAC, Z would > obviously need to be ballscew with counterbalance of some type. > > The machine will be mostly aluminium extrusion for the moving parts > with > some type of linear guide, maybe igus polymer bearings. The table > will > be fixed and the entire gantry assembly will be attrached to pillars > either bolted to the floor or roof. I have run a Rambaudi H60 which > worked in this way but that machine cost A$2 000 000, obviously right > out of my budget. > > I am hoping to first build a prototype using aluminium and acetyl for > the bearing surfaces,gears etc to test the concept with a working area > of 1000m x 500mm x 600mm. I know that I can easily drive this with > steppers but the final build will be an envelope of +- 3000mm x > 1500mm > x 1500mm. > > All answers would be greatly appreciated. > > Regards Neil Macintosh > > The difference between theory and practice is a lot smaller in theory > than in practice.
Here is one servo example. http://www.lmwatts.com/cnc.html Les made a pile of turkey calls on this one. HTH Dave > > > ---------------------------------------------------------------------- > -------- > Crystal Reports - New Free Runtime and 30 Day Trial > Check out the new simplified licensing option that enables unlimited > royalty-free distribution of the report engine for externally facing > server and web deployment. > http://p.sf.net/sfu/businessobjects > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
