I built a DIY CNC router (gantry type) a couple of years ago. Built from MDF, 1" and 3/4" gas pipe, aluminum runners, skate bearings, etc. I purchased a Keling bundle of a Gecko 540, PSU, and 3 370oz motors (about $500 total). Got it working somewhat.
My problem was always repeatability. Meaning, I would make the first cuts, then when my G-code would go back and make the second and third deeper cuts, when it should have gone back to the same spot to start making the deeper cuts, it would not. When I was making only one shallow cut, the letters or whatever I was cutting would not be symmetrical. It wouldn't be off much, but enough to mess up my work. The computer I was using was a 2.4 GHz Intel system with 1GB memory and I also tried several different video cards (never used the built in video on the motherboard). I tried the trial Mach3 with WinXP and Linux/EMC, and always had high latency (approx 22K ns or whatever it measured in, if I remember correctly). After asking questions on this forum, we all decided I was losing steps. Not wanting to invest in another computer, I finally gave up and dismantled the whole system.
Now, I'm ready to try again. So my questions. Was I correct in that the high latency was causing the motor step loss, which in turn was causing my repeatability problems.....and what are some suggestions for a decent computer and operating system to run the system. I'm willing to spend a small amount on a computer, but I'm just scared whatever I end up with will have the same latency problem. As the topic title says, I need some advice.
P.S. I still have the original computer system stored in my attic just waiting to go back into action if anyone can offer some advice on how to lower the latency.