I am building CNC tool grinder. The feed for tool grinder should be from 0.00025 to 0.001 of the inch per minute. The servo motor must perform at this feed perfect to make a good grinding job. I will use direct drive and my ball screw has 5 pitch per inch. So talking in degrees, 5 times 360 = 1800 degrees of revolution of motor to get 1 inch for linear motion.
To get 1 inch need turn 1800degrees/minute of motor. To get 0.00025 need 0.45 degrees/minute of motor. Is this too slow? I think so. The one solution is to take high end controller and large AC servo motor and that is expensive. Jon Elson said about harmonic drive. I found here www.harmonicdrive.net That gear can reduce up to 1 to 160. If I will put two side by side, it gives to me 25600 to 1 reduction. So 0.45degrees/minute times 25600 equal 11520degrees/minute, or 32 revolution per minute. 32 revolution per minute is good range to any AC servomotor and with 8192 pulse per revolution drive and EMC2 will have enough pulses to be accurate. All harmonic drives have 0 backlash. One piece for NEMA34 cost $1500 and per axis it is $3500 with special plates etc. 5 axis is $17, 500 is to gears a lone to make good CNC tool grinder. I think it is very good idea! Instead of making electronics part and programming more complicated ( and not all can understand that part - I can not for sure) it is much better use mechanical gear reducer and use less expensive and more robust drives and software. I am correct? Aram ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
