Hello there!
I hope, and I can imagine, that this is the right forum where to find people who have gained some experience with devices like this.
I've done some little research lately about those different kinds of chinese CNC *routers*.
Basically, there seem to be two kinds:
1) newer, usually weaker ones, sold as wood engravers, which already have support for GRBL control, and you can see people on youtube runnig open source software that captures a heightmap of e.g. a copper board with a simple electrical contact, befor the actual milling, to get more precise results and all that.
These are called e.g. cnc 1610, 3018 (for 16x10 or 30x18 cm² max. work piece size)
and have something like a 150W motor driving the tool. Often there are many plastic parts holding the corners together.
2) older style, usually more metal, less plastic, at least 300W, up to 2.2kW motor, sometimes up to 4 axes, and people do actually use them to mill softer metals.
They are called e.g. CNC 3020, or 6040, for their resp. sizes in cm.
They come with either parallel port or USB control, but as I understand, they get direct commands via their comm port and if the host OS has timing issues, this might mess up the routing accuracy.
Which is why you can buy, on ebay china, arduino based PCBs with motor drivers as addons that implement GRBL control (buffering data on the controllers - or so I'd hope, LOL!).
Now what I want to do with it, and the questions.
My best compromise of size vs. price is the 3018 or 3020 one, I pretty much settled on that rough format.
I could mill PCBs for most of my devices' front panels.
And, given the stronger one, 3020, perhaps even actually mill fader slits, and rectangular openings for e.g. LCDs, into some 2mm aluminium sheet?
I started off wanting one of those 3018 cheaper things (between 160..300 EUR, depending on seller... I tried dealextreme and now cancelled, boy have they sunken low with their service, totally unable to understand basic english to solve problems... *sigh* I digress...),
then discovering the sturdier 3020.
Note: comments about "use OSHpark or Seeed studio, you fool!" are 100% off topic and *not* appreciated. I know what I want in this regard, for certain scenarios, which do not involve waiting 2 weeks for a supposed weekend circuit that I don't want to wild-wire solder without DRC, or paying insane money for even 2-layer PCBs of front panel size like 30x18 cm² - and then shipping for those...Now, the 3018 seems pretty much ready-to-go and will do the most important of the jobs, i.e. milling PCB layouts. Time involved getting things up and running *is* relevant, as of course taking time out of my freetime for projects if the tool is it self too much of a project is a disadvantage.
*BUT* if the 3020 "full metal" thingy with, say 300W motor and 3 axes, could *realistically* do things like making aluminium panel cutouts for me without the direct-connection-no-bearings motor breaking after doing 10 panels (but still in hobby quantities), and perhaps as a bonus, mill some plastic parts (even if it's just voxel style "3D" with 3 axes
) this would be a really nice thing and would perhaps make me willing to invest the time & money to get all the extra stuff mentioned to improve their control hard- & software.
As for axes - so if I had 4 instead 3, does that mean I could do really smooth curves along one axis? (I don't think it's that important to me, but nice to know, should I encounter a good offer somewhere)
Also I wonder about accuracy of those both models against each other.
The 3018 has the base plate as one of the moving axes, whereas the 3020 moves the tool / motor spindle on both axes. I imagine this results in potentially more play vs. the flat base plate comfily sliding on 2 "threaded rods" ? With the 3018 or 1610 routers, I saw people doing traces for even QFP parts, hell I would be happy if it did SOIC well, at least I may not have to mess with UV-lighting hand-applied soldermask or nasty stuff like that with that format ;-) (I mean to aid soldering ICs. Spraying the whole board with cheap PCB insulation spray after assembly will probably solve the oxidation, and "I can make shorts easily" problem).
So - I'd like to know:
Is my general perception of these things about right?
What can you say about the points I am not sure about?