On Sunday 16 March 2008, Patrick Ferrick wrote: >Hello again, > >[Machine-related, but off topic, so I'm really looking for someone to steer > me toward a good reference on the subject, or to communicate off-list.] > >I'm thinking about replacing my Z-axis leadscrew with a larger diameter one > that will have less backlash. I'm trying to figure out how to calculate > how much (linear) force a certain stepper will provide with the new screw. > >The screw's pitch is such that one turn gives 0.2" of travel, or 5 turns per > inch. That would seem to give it a mechanical advantage of 5, but what has > me a little bit confused is the translation of a torque (from the motor) to > a linear force (by the nut). > >I believe it is correct to say that a 200 oz.-in. motor, for example, can > exert a force of 200 oz. (12.5 lb) at a distance of one inch from the > center of its shaft. > >Since the leadscrew has a mechanical advantage of 5 and is 0.5" in diameter, > does that mean that I should expect (200 oz. / 0.5") * 5 = 2000 ounces (or > 125 pounds) of push? > >thanks again, >Pat
You might be able to get into that region with ball screws, but with acme, nuh huh. I have a 425 on my z axis, with a 17 tooth sprocket on the motor, and a 30 tooth on the ball bearing supported nut carrier, with a 1/2" acme of 10 tpi doing the honors. With that, I can just hit 155 pounds of z push on the bathroom scales. By your frictionless reasoning that might SWAG at 7500. There's a lot of friction loss in screws when under load. >.................... >Patrick Ferrick >Town of Webb School >Main Street >Old Forge, NY 13420 > >(315) 369-3222 >(315) 369-6216 >.................... > > >------------------------------------------------------------------------- >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 -- Cheers, Gene "There are four boxes to be used in defense of liberty: soap, ballot, jury, and ammo. Please use in that order." -Ed Howdershelt (Author) Nobody ever forgets where he buried the hatchet. -- Kin Hubbard ------------------------------------------------------------------------- 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
