[n1tr0]

Hi,
I've got the machine sort of working. The ways are oiled and manually entered moves are working fine. I have the backlash compensation set at about 0.005 and can get repeatable moves x & y at 40ipm within 0.0002x"
When I try to air-cut a circle 'tho, my x-axis stepper chatters and misses steps as it slows down and changes directions. At a feed rate of 40ipm, the x-axis can walk an inch in a half a dozen loops. At F20, it'll chater a bit less and walk a half-inch in the same amount of passes, and if I slow it down to F10 the change is more clunky with fewer misses steps, but it's still a problem. Moving the x-axis by hand (crank) it's smooth and easy moving, same as the y-axis. This isn't a high inertia system and these feed rates feel insanely slow. The motor acceleration is set at 1in/s/s although I've tried it at 0.5in/s/s and that doesn't seem to have any real effect.
I'm wondering if the gecko driver simply can't handle running 3 motors at once, if the power supply doesn't have enough oomph, are the motors just too small, ...?

G1 Z0. F20 <-- feedrate in IPM
X1.5038 Y1.0445
G3 X1.5274 Y1.068 R0.0236
X1.1149 Z-0.0197 R0.2062
X1.5274 Z-0.0394 R0.2062
X1.1149 Z-0.0591 R0.2062
X1.5274 Z-0.0787 R0.2062
...

The computer that came with my machine has/had a few issues, like not having any of the software loaded and it complains about a missing air temp sensor every time it's booted up. If someone has a set of good Mach3 config files for their mill-turn, I'd be interested in trying those out. Thanks

[BlackICE1]

I had a similar problem on the Patriot and fixed it by changing the configution.

Check Shuttle Accel under general logic configuration and under than backlash settings as a % of max. I'm not near the machine now so don't know what I did but I will get them numbers later if needed.

[instructor37]

Go to CONFIG>GENERAL CONFIG and look at SHUTTLE WHEEL SETTING--- set this to 0.0001
Also go to the setting LOOK AHEAD--------LINES and set that to 5
Set Debounce Interval to 500
Set Index Debounce to 0
Go to BACKLASH and set the % of Max to 100

If you are doing strictly circular interpolation you will get better results with BACKLASH turned off. The setting for % of max, if too low makes the stepper work in a "jerky" motion as the backlash compensation runs at a speed less than the regular feedrate. Setting it to 100% will eliminate that .
For stepper systems, your best way to avoid lost steps is to find the max rapid feedrate then drop your settings down to about 75-80% of that number.
If the LOOK AHEAD number above is too high, your computer may not have the speed necessary to process too many lines.

[n1tr0]

I still haven't found any settings that allow the machine to really work with backlash compensation on, but at least turning it off has cleared up the lost steps. Thanks for the help.

[walters474]

Making sure that the pulley allen set screws, on the stepper motor shaft, are tight might help. I had a intermitant crashing sound on the Z axis (mill) in the middle of travel (cutting air so far). Intermitant as it was, it seemed to correct this problem.