Hi, Just finished building my 4x2. Took me a while to figure out wit=ring etc but have got there. I'm running Mach3. I can get it to cut squares etc fine but circles are miles out. I don't know where I am going wrong. I will post photos below shortly. Any tips would be greatly appreciated.
Generally flat spots on circular cut-outs are caused by back-lash (slack) in the system. From your photo the flat appears parallel with the Y axis - if this is the case then check your X axis - the most common cause is the pulley slipping on the stepper shaft (possibly a loose grub screw ?). Tweakie.
That's what I thought but I have ground a flat spot on the shaft and thread locked the screws etc to make sure it isn't slipping.
Check your asymmetric bearings are not too tight. I was making great circles until I decided to tighten it all up a bit. This led to some very blobbish shapes. Slackening off back to where I was, got my circles back.
Hoping someone could help point me in some direction. Ive attached a video below of the machine cutting a circle. Its almost as if its skipping steps. Do you think its the physical machine or cheap drivers and control board? Thanks Aaron
What kind of controller are you using? I had a similar issue with xPro CNC Controller. One of the Y axis drivers would go into thermal shutdown. The other would keep working fine, and was strong enough to move the Y axis, so it wasn't immediately obvious that one of the motors was not working. Copper heat sinks fixed it for me. -- John
Its a Hytechworks usb board http://www.hytechworks.com/Products/HyCnc/index_e.html I suspect this may be part of my problem with pibot driver boards.
Mechanics I would look at first before assuming electrical: With power to the steppers is there any play in the x and y. when pushing by hand. stepper mounting bolts are all tight. eccentrics are set nicely against the extrusion. check belt tension near both sides of the pulleys. Are the belts and pulleys compatible. Belt ends aren't moving with direction change. does this happen the same all over the work area. work is fixated well to the spoilboard. good luck. keep us updated.
Everything is tight. and no play. Work is screwed down to eliminate this. Every circle cut is identical to another (Not round) It almost looks like the motor skips a step now and again when moving. But not a belt slipping.
It does look like lost steps in both axis. Are you using shielded motor cable? Do you have separate drivers on the long axis? Which variant controller are you using? Post your M3 xml
Having played about with the micro stepping its running better but still no difference to circles. Is it possible the hytech control board is complete rubbish?? I have spare pibot driver boards and have swapped these out and it makes no difference.
Its probably the cheap tb6600 on those drivers. Up your pulse and direction widths! they need a 3.3 usec min. If 5 doesnt work then try circles in sureline mode and see if they get round. edit; clarity.
Finaly got it sorted. Thanks to Joe and a few other tweaks. Just need to work out how to stop the burr on the edge of the cuts. Im using a 3mm single flute up cut. Should I try a down cut? Thanks everyone for your suggestions!
Glad you got it sorted. I reread my last post and it was pretty ambiguous. Must've been beer involved in that one.
