New Machine Build- Low Cost Desktop CNC for Drilling PCBs

[Robotics Guy]

I finally finished my super-cheap CNC machine and thought I'd post some pictures on here. Everything was built from scratch. I wrote all of the software as well.





This is an older picture, but shows the whole machine:



The PC program that controls the machine:



And video of a test run:



I'm having a problem with accuracy on the y-axis and the drill sometimes is off by about 1mm. I'm wondering if the cheap threaded rod I'm using might have worn down in places affecting the machine's accuracy? Other than that though, the machine seems to run pretty smoothly.

[keith20mm]

Considering that it appears to be centered at the beginning and end of run, I'd guess the threaded rod is the cause of your positioning error. You should be able to inspect the threads with a magnifier to find any bunged threads, though.

[RomanLini]

Nice simple machine! Complete with home sensors and everything it needs to work...

I'm not sure why your Y axis is out 1mm, that is quite a lot. You're using a 1/4" threaded rod for leadscrews? Or is that 6mm threaded rod? Either way it can't have 1mm backlash at the nut. You might have slop at the thrust bearings (those nuts at the end of the screws).

And I would question the need for those rubber bushed couplings on the stepper motors, there might be some slop there. Solid couplers may improve accuracy there.

Maybe the Y axis error is caused by some binding and/or flex of the whole assembly, you might check that if the motors are turned by hand that everything glides freely and doesn't stick or flex.

I like your electronics too, it's good when people build something and make it work, and then worry about "making it pretty" later... Or maybe not bother. Sounds like some of my quickie electronics projects.

(edit) Sorry Keith20mm I hadn't seen your post when I wrote this (about the threaded rod).

[DIYedInTheWool]

Looks really nice. I'd love to see/hear more about the software you wrote and the electronics it looks like you built yourself. I'm in the planning phase of a very similar project and trying to figure out the best way to get started with software development for hardware control.