Loosing steps or backlash

[ranchak]

Success at last! I gues I should get at least two parts finished before I start celebrating. It appears that the motor change has made a difference. My finished part is not perfect, but it does fall with + - .005 tolerance. I probably need to check the backlash and see how bad that is. I might try to slow my finishing cuts down a little also. Thanks to everybody who has helped and especially to Hood.

[ranchak]

Should be interesting to see what the new motors will do. A motor that dosen't get warm is not doing any work, the more work the motor does the hotter it will get. As long as the motor is operating in a temp range below the rated insulation you should be ok and with age it would be prudent to operate it taking age into consideration. Greater than 140F  you can't hold your hand on it very long and can get burnt. The motor case temp you see is influenced by the how well heat is being removed from it so dirty fins or evan different paint thickness and location can influence it. So relatively small temp changes of say 10 deg diff is subjective for any conclusion.  I have motors on my mill that are  are older than me and work great. don't be suprised if you see a difference in microstepping position as i found different motors required small change in the steps per unit and would attribute that more to the quality of the motor. Let me remark that it's within a roatation or very small moves.
Just some comments on the motor end they are  generalizations.
RICH

I agree with what you said, I think what was happening is there is a very small amount of error that adds up over time. I normally don't run programs that are this long so I never noticed this problem although I am sure it always existed. Now i need to figure out backlash and see if that changes anything.

[Hood]

Keeping my fingers crossed for you
Hood

[ranchak]

The motors have made a difference, the machine seems to be smoother and I just cut a large pocket 10" x 9.25", I used a 2 flute .500 end mill, .006 cut, 40 IPM, 50% stepover, the cut was extremely smooth and consistent. Well, up until my Smoothstepper lost communication with Mach. This happened 3 times in a row, so I installed my new parallel port card and could not get any movement. I got out the old PC that I was using a few weeks ago that was giving me some problems. I managed to get through the project, but there where 3 times that I saw steps lost. I was able to get back on track and get the job done, but I had to work until very early in the morning. I need to get my new PC running, I still have one job that I have to get done by Monday. Hopefully I can find the mistake that I made and get back on track. The port address is something weird like cc00. Back to the motors, the new motors did heat up to 126 degrees, but they would cool down. If anybody is interested I got them at www.anaheimautomation.com. I paid $245 for a Nema 42 motor.

[ranchak]

Also Steve at PMDX was a huge help in trying to determine the source of my problem as well a number of members here on the forum.