> I am a "servo bigot", and just don't want to do anything like > machining metal while "flying blind", which is how I think of > stepper systems. > > Jon
I cant let this pass without a comment. As someone said earlier this is 'holy war #1' in the CNC hobby. It is a fact, not disputable, that thousands, maybe 10's of thousands, of large, even Bridgeport machines use steppers. They make parts every day, day after day and never loose a step. It is clear that a stepper system will always cost less- assume the motors could be built for the same cost- they are similar lumps of wire, magnetic material and bearings. Assume the drive module could be built for the same cost, the servos will always require an encoder and extra logic for it. Servos always cost more- the IMserv kit for Sherline is over $1000, a Xylotex kit is about $400. A stepper motor operated within its torque rating will never loose a step. If you overload it by trying to go to fast, or take to big a cut it could loose steps. I don't do that to my machines. Servos are sensitive to failures of the encoder and its logic. The result of that is often a runaway motor crashing at full speed into its limit. Id rather have a machine loose a step or two than crash at high speed. For a Sherline size machine steppers will work just fine. Use the rest of the money to buy a lathe or tooling for the mill. clearly for large machines where the table motion needs over 300-400 watts then servos are the only choice. Below that use steppers, simplify the machine and save your money. ron ginger ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
