all grinders have linear incoder and all feed back comes to computer not from revolution of ball screw but from actual move of the table. in that case the accuracy of ball screw can not make table move faster or slover. grinder usually program with 0.001-0.003 per minute when grind ceramics.
> Aram, >>From your numbers it could take over a month to traverse the entire table > and perhaps four days to grind a single end mill. Does this sound > excessive > to you? > > On anther thread, you say accuracy is not as important as speed. Do you > mean smoothness of travel is more important than accuracy? Why? > > Glenn > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > [EMAIL PROTECTED] > Sent: Thursday, May 22, 2008 9:36 PM > To: Enhanced Machine Controller (EMC) > Subject: Re: [Emc-users] Harmonic gear and EMC2. ???? > > Machine make up to 1 inch in diameter and 6 inch long end mill. max travel > is 12-13 inch > > >> Aram, >> What is the total travel distance of the grinding table? >> Glenn >> >> -----Original Message----- >> From: [EMAIL PROTECTED] >> [mailto:[EMAIL PROTECTED] On Behalf Of >> [EMAIL PROTECTED] >> Sent: Thursday, May 22, 2008 6:59 PM >> To: Enhanced Machine Controller (EMC) >> Cc: emc-users@lists.sourceforge.net >> Subject: [Emc-users] Harmonic gear and EMC2. ???? >> >> 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 >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> >> ---------------------------------------------------------------------- >> --- 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 >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > > > ------------------------------------------------------------------------- > 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 > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > > > ------------------------------------------------------------------------- > 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 > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------- 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 Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
