Advice for buildinf cnc for pcb

[alfadex]

Hi, i want to make a cnc for pcb milling and holes. I have design this



and parts i have bought are those




Any advice or something i should avoid, do you think i wil have good result or should i change something


My previous milling maching was Portalcyclone CNC with 3d printed parts, but now i need something better with aluminium parts



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[blinkenlight]

I'm not sure the frame change will make as much of a difference as you might think. Sure, the more rigidity the better, but PCB work cutting forces are really small. Backlash matters a lot, but I don't know how much difference there is with that compared to your current nut. Spindle runout matters too, but it seems to me you plan on using a similar spindle (and faster spindle is always better). Finally, so does flatness of the table, but at the 35 micron levels we're talking about here NO hobby level CNC will ever be flat to any usable degree, so you just map the PCB on the run and compensate in software anyway. At any rate, good luck!

[joeavaerage]

Hi,
I isolation route PCBs all the time, and I think your machine as pictured will do nicely.

As blinken has already posted backlash in any of the ballscrews just will not do, they must be backlash free. Likewise spindle runout must be good to very good, 5um
or there abouts otherwise you'l break tool tips all the time and that ruins the cut finish and accuracy.

The hardest part is getting the PCB blank perfectly level....no matter how good the machine you'll never get it good enough, and that does not count any bow or warp in the blank,
and every blank has some. I use Autoleveller, a software utility that probes the blank in a regular pattern and uses the height variation data to modify the Gcode slightly to follow
the bow/warp/uneveness of the blank. I couldn't make decent PCBs without it.

I suggest get Autoleveller, work out how it works and design your machine to take advantage of that. For instance Autoleveller can manipulate Gcode for Mach, TurboCNC, and LinuxCNC,
and that would suggest you use one of those controllers.

Craig

[alfadex]

thank you guys, i am in progress now, i will take into consideration backlash and pcb flatness and i will post news in a few days