Newbie- Looking for electronic insight

[xtremein]

Hello all,
This is my first post, I just joined the forum. I have been looking around for a few weeks, but was having some issues registering.....anyway. I work for a small company and we had a CNC Router built for us buy a friend of a friend of a friend...... I know very little about CNC's, sorry if I use the wrong termanology. It has Keling Technology KL34H295-43-8A Motors, Intelligent Motion System IB104 Motor Drives, and this one I am not 100% about will have to double check, a CNCPC.cpm C1 Parellel Board. The machine works fairly well. I am having problems with it losing step when both the X and Y axis are in motion during a radius cut, works fine in a straight angled line. The guy that built it came out and looked at it. All he did was slow the motors down to 45 in/m and change the acel/deacel curve. Does anyone have any insight as to what I shoul be looking for/at. If you need more information feel free to ask.
Thanks,
Micheal

[ger21]

Assuming you're using Mach3, open the task manager and check the CPU usage while cutting arcs.

[xtremein]

We are using Mach 2, we have Mach 3 but the guy that built our CNC said it was acting odd so he downgraded. I think the issues were from the CNc itself not the Mach 3, but when that happened I was not involved with the project. What kind of numbers am I looking for and what are my options if they are not acceptable?
Thank you for the prompt reply. It will tomarrow before I will have an answer.
Thanks again,
Micheal

[ger21]

You'll want less than 100% CPU usage. Let's see what you have and we'll go from there. Also, how fast is the PC?

[xtremein]

OK, the computer has a 2.8 GHZ Pentium 4 with 512K of RAM. I ran several different G-code programs and normal CPU usage is between 0-5% with a onetime spike of 27%..........

[xtremein]

Not sure if this matters, but I noticed that all three axis move at different speeds during full jog and while using gcode, X is 38 in/m, y is 78 in/m, and Z is 32 in/m..............

[vger]

I had a missing step issue on my little router at first. It seemed to miss only at at certain feed rates. The fix was to reduce the drive current to the steppers. Motor resonance was the culprit.

Steve

[xtremein]

How would I go about reducing the drive current?

[xtremein]

Thank you everone for your help. I do not know if this is the correct fix, but I have it working now. I went in and redefined the motor settings and now run the CNC at a slower feed rate, was trying to run 60 in/min, then 45 in/min, no down to 40 in/min. If anyone has any more suggestions or insight I look forward to learning and trying to make our machine better.
Thanks,
Micheal