@NeverDie I've got this one several months ago, I couldn't say it's a good one though.
here is the list of drawbacks I've had/have:
- spindle fixed speed 12000RPM. I added automatic circuit breaker to it so it won't put home on fire when it rams into the table. (threw away DC connector on top as it wasn't reliably holding both sides to begin with and then it was burned a bit after spindle stall). Runout is about 50um. + whatever collet would add (cheapest ones from aliexpress were disappointment in a range 50~100um, so I've got precision one locally)
The only thing I'm going to invest into this machine is 24K spindle + vfd with small runout. (it just arrived but still unpacked, it will need adapter plate to mount it on Z plate, hopefully I'll make something with adjustable tilt to simplify tramming)
- it was poor assembled, one has to disassemble and put it back properly tightening screws and making sure belts are not loose (that solved lost steps issue)
- it uses lead screws with bronze nuts like in 3D printers and a plastic spacer between nuts (to counter backlash).
- axis plates are attached to nuts via that same plastic spacer (not sure how it would do with milling aluminium)
- there was (still is) some backlash (~40-60um) left after tightening nuts,
one could tighten it further but that would come at cost of lower speeds as no-name steppers start stalling (currently I have 2300mm/min max on XY plane, and one would wish for more rapids if one would wish to try milling plastics)
- squaring it is nightmare, basically the only option you have is adjusting X pillars and try to square XY and YZ at the same time (and there isn't much space to play with it). For tramming spindle on XZ plane, I had to move up one side of X support plate as there isn't sufficient play in spindle mount and then level sacrificial board to make X axis square to the table.
As result of several iterations, I've got ±40um difference in hight across the table. XY axises still not square ~0.5mm on opposite sides of of the table on X axis, but I don't have heart to repeat whole procedure again (yet).
- controller dial is way too sensitive, so I practically don't use it at all. Ribbon cable to SD card fell appart, USB connector for PC doesn't work reliably (but mostly works if you got it in working position).
The whole setup was bought to prototype PCBs and later on learn how to mill other stuff (plastics/aluminium) for casing prototypes.
So far I've managed to mill reliably 0.3mm isolation paths with 60*0.2 engraving bit (but as you did, I've redesigned board with wider traces to reduce failure chances). In Flatcam, I had to add runout value to tip diameter to avoid track thinning. Perhaps I could do more fine traces now (after all the tuning) with more fragile 30 or 15 degree bits, but I won't try till I get current project out of the door (at least hardware part of it).
and here is my 1st attempt to mill the case part