Hey all, I built an OX cnc with the stepper motors Nema 23 with the 542 drivers being driven by an arduino uno. Having problems with it. I think its loosing steps. but only does it if it gets worked a lot. I am doing a star pattern, 50 stars on 7 x 9.5 area carving with a 1/16 in bit. If I take my pattern and carve out he inside of the stars byt the time its done my depth is about half as deep and my starts are not in line any more they start wandering. If I do an outlind cut on the line. the depth is about half as deep but they are about right where I placed them, in 9.5 inches it looses about 1/4 - 3/8 of an inch in length (x plane) in the Y plane they are almost spot on. When it is finished it returns to home but it is off about the 1/4 to 3/8 of an inch. On my machine setup everything is spot on. tell it to move 290mm and its dead on in the x and Y and z is spot on as well. If I go with a 1/8 inch bit my sizes are even close to spot on but its not the look I am going for. My belts are tight Its is driving me nuts I have slowed thing down as far as speed rates and all also bumped up the amps on the drivers but can't figure out what to do. Any ideas or suggestions to help out? Been fighting this for almost 2 months now.
Not saying it'll help, but what are your other specs? Step settings, power supply, software, material, etc. Have you checked all things mechanical like couplings and pulleys?
Apart from the mechanical aspects, as Joe has pointed out, at a pinch it could be a temperature thing. It is a common sign if it starts okay but gradually gets worse as it works longer. Try increasing the airflow through-put.
I once had a similar problem on my z axis, Atkinson. I would start with the bit at material top surface and by the time all the parts where 'cut' the bit was an 1/8" above the top surface. The problem, in my case, was the set screw on the belt pulley was not quite as tight as I thought it was and it slipped a fraction but with all the up and down it accumulated.
