On Friday 30 November 2007, W. Jacobs wrote: >Hello All, >I am new, real new to the cnc world. I want to convert a small bench >top mill into a cnc machine. I have wanted to do this for a long time >and about a week or two ago, I found the linuxCNC.org web site. I have >not at this time found a computer I want to use and am looking for one. > >I have wanted to do this project for a long time. Because of that, >Years ago, I found 3 rather husky stepper motors that I thought would be >usable and bought them. They have been sitting on a shelf for a long >time. > >I looked at stepper drivers the other day and thought they were rather >expensive. A 3 axis unit was just over $300. That seems like a lot of >money to me. It is my understanding that the printer port of the >computer has 2 lines per axis. One line tells direction and the other >says to take a step now. That seems pretty elementary to me. It should >use a small micro controller, and 4 transistors for each axis. > >I had planed to belt drive the lead screws with a timing belt and use a >stepper motor that has 200 steps per revolution. This will give >resolution of about .0005 inch per step. I may half step, but I see no >reason to micro step. > >Am I missing something? Is there more here than I think? Is my concept >of the data on the printer port wrong? Any light on the situation would >be helpful > >Thanks >bill > No, your general view of the parport is correct. The devil is of course in the details. As for microstepping, it has the advantage of removing large amounts of resonance vibrations at middle speeds of the motors, thereby enhancing the torque available to do real work quite a bit.
I'm running the xylotex 3 motor kit running in 8x microstep mode on a micromill that's been expanded and modified quite a bit, the most recent being a whole new z axis drive that puts the driving screw in front of the post and above the head, removing about .020" of give in the head sled gibs, backlash is now about 2 thou and compensatable for in emc. I can now drill small holes under emc control. I also have a 4 motor kit with the 450oz motors to do my small lathe with eventually, but that's all in a box till warmer weather now. Very little heat in my shop & I'm diabetic so my feet get cold easy. -- 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) <Joy> that's a Kludge(TM) <knghtbrd> It Works(tm) <Joy> AIX works(TM) <knghtbrd> no it doesn't <knghtbrd> => ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
