How much "backlash" would the rubber teeth on the belt contribute?
> -----Original Message----- > From: Ian Wright [mailto:[email protected]] > Sent: Tuesday, 9 June 2009 8:57 AM > To: [email protected] > Subject: Re: [Emc-users] Mill-Drill needs steppers and servos? > > John wrote... > <<<With the optimistic 50% steel estimate, you have 1 * > 0.065 * 0.5 = > 0.0325 square inches of steel. Assume a load of 200 lbs. > That results > in stress in the steel of 200/0.0325 = 6153 psi. The tensile > modulus of steel is 30,000,000 psi. So under 200 lbs load, > the belt will stretch by 6153/30000000 = 0.0002" per inch. > If you are using that belt for a 100" long linear axis, the > stretch would be 0.020. > > A ballscrew for an axis that long would most likely be over > an inch in diameter. A 1" ballscrew probably has a root > diameter of at least 0.8", resulting in 0.502 square inches > of steel. That is 15 times more steel, or 15 times less > stretch. So a 100" long, 1" diameter ballscrew loaded to 200 > lbs would only stretch 0.0013" instead of 0.020".>>>> > > > Interesting maths but what would the effect of changing > temperature be - which would be the more stable, he belt or > the ballscrew? > > Best wishes, > > Ian > ------------------------- > Ian W. Wright > Sheffield UK > > -------------------------------------------------------------- > ---------------- > 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 > [email protected] > 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 [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
