Hi there after a little help I have built my 3axis CNC and using Arduino to run it I have 3 Nema 23
running off 40v power supply. I have now got it up and running but am having trouble when I try carve or cut any thing the steeper on the y axis seems to skip or stutter it happens in the same place most times and gives me strange results when trying to run Code the answer is probably simple but I can not figure it out for the life of me . Any help would be greatly appreciated.
You are loosing steps.
Possible causes, single or combination of:
Current limit of stepper drivers set too low
Feed rates too fast / depth per pass to deep
Spindle not 90deg true relative to waste board
Pulleys loose/slipping
Hi thanks HaldorLonningdal
I am thinking that I will try increase my current to the stepper am I right in thinking that the 40 volts is plenty but mite need more current I am running t8 lead screws and they are very powerful so it moves the gantry with ease it just starts missing steeps when moving the x and y axis at the same time thank you for your help I will try that tomorrow 
Ok trouble shooting to day I increased the current to steppers. No luck still missing steeps I replaced the driver. No luck replaced the stepper. No luck so then I separated the leads incase there was some interference this made no differents. so then I increased the feed rate and dropped it back a bit so runs a bit faster now but is still dropping steeps. I am at a loss now. it happens at the same place every time.
I do not think your current limiters are hitting max temp because that would giv you a straight line in either the horizontal or vertical plane.
The circles are deformed due to flex, if you by hand pull on the bit with say a 2kg force, what kind of deflection do you see? (Disconnect spindle power before doing so)
What kind of bit do you use?
If you insert a ball point pen or pencil into the collet, how do the circle look like then?
haha year my thought’s as well checked that to day is all solid as. when I tried a new stepper motor I did not mount it back on cnc and it also stuttered in the same way. It is all ways when y moves back or ‘’-’’ direction that’s what made me think it was electrical interference’s. I will have a another look and see if I can get it on video thanks
Looks like backlash, have you tightened the bolts on the nut on the Y axis?
Also check for a squished spot on the underside of your belts, I had that happen to me.
One thing your can try for testing is to reduce your depth of cut. The depth of cut has a real impact on the load and flex on the mechanicals (you can only slow the feed rate down so far before you can star having issues from the bit rubbing on the same spot of the material.
HaldorLonningdal ErikJanssen AaronMatthews
Thanks for all your suggestions I have been over every thing again to night all think I have narrowed it down to something electrical. I removed all the X and Z axis and ran the same code and it was still jumping steps. So I hooked up a spear stepper and tried that still looked to be missing steps so I tried the driver off the Z axis same thing SO I’m thinking it must have something to do with the Arduino I am still finding this hard to believe tho as all the other Axis are running fine and never miss a beat.Olny the Y Axis mabe I will try running the X axis in the Y axis ports and see if I have the same problems ( Just want to get carving )
Tried loading a vid but wouldn’t work sorry 
I’ve had similar trouble occasionally. I usually start by seeing if it’s hardware or electrical by swapping the wiring between the x and y axis, and see if the problem swaps from the x to y or stays the same. This helps narrow down whether it’s a driver or power issue, software issue, or belt issue.
Also if you’ve got 3 motors for your machine is the Y-axis a single motor setup that moves the bed/material?
You can usually see if it’s an issue with belt slipping by lowering the feedrate and depth of cut right down so it’s not meeting much resistance.
best of luck!
Hey finally good news after trying every thing and I mean every thing! I have finally fixed my machine
it turns out the only way to fix the missing steeps was to change the micro steep size from 1/200 to 2A/400 and recalibrate steep size and bobs ya uncle.
Big thanks to every one for there help hope this post may help others as well:+1:
