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Topic: Arduino Addict (SMALL CNC Rounter attempt) (Read 3 times) previous topic - next topic

myersweb

Dec 29, 2008, 08:52 pm Last Edit: Dec 30, 2008, 03:45 am by Myersweb Reason: 1
Hi everybody, I am a total NEWB when it comes to this kind of stuff. I have been a fan of the "hack type websites" for years now. I have built a few projects in my time, by reading tutorials. This Arduino thing really got my attention, so I made the leap and bought one not knowing what I want to do with it, other than messing around with LEDs and things like that. I also bought a motor shield (thanks LadyAda).

I have done all the easy tutorials for both Arduino and the Motor sheild, and everything works. So now I have this idea that I want to build a SMALL desktop CNC type router. Do you guys think it will work? I have searched Google with some success but nothing that really covers it top to bottom.

I guess my biggest hurdle is getting the machine to take commands from the software. I downloaded the software called MACH3 (because it was free) Anybody ever here of that? I looked at the RIPRAP or what ever its called but I dont think thats what I want.

I feel like I am going about this in the wrong order because I dont know anything about programming C let alone electronics. But with the small progress I have made makes me think I might be able to do it. So its either the small CNC, or a laser guided gun turret with a camera. lol. Any and all advise welcome. I could become the Adruino case study if I got the working.

Dave


SunboX

hm, a good starting point could be these "Lego Technik Plotters".

for example this one: http://kisd.de/~krystian/nxt/

ciao andré

scootabug

Hey Dave,

I too have been musing over a desktop CNC router of late.  They'd be perfect for making your own CNC routed PCBs quickly and easily, which would be my intended purpose.

I think the hardware side of it would be quite simple.  You need say 2 stepper motors or 2 servos to move the bed around, plus a solenoid (or something better) to push the router/motor down (for drilling holes).  Plus the router (I've seen/heard of people using dremels?) and the gear to hold it all together.  Wouldn't be hard using 3D CAD software to design the parts and/or utilise existing parts.

The more difficult part as you've discovered is the software and communication.  I'm yet to look into the contents of a DXF file, but my initial stage 1 thought was using a monochrome bitmap.  In VB.Net it's extremely easy to iterate through the pixels of a bitmap and determine what the pixel colour is.  So, for instance, if you were to draw your PCB (or whatever it is) and made the bitmap black where you wanted it routed and white where you didn't, you could translate the relationship between the black pixels and the material you're routing.  Simple commands could be sent to the Arduino over serial to tell it to lower or raise the router and which X,Y coordinate to move to.  This basic method would make it work like an inkjet printer (left to right, top to bottom)...wouldn't be much good for line work, this would be more complex.

I'd like to see the router follow paths, to create smooth arcs and solid lines in a single route.  That's where you'd need to use more advanced file formats and command routines with the Arduino.

I'm going to make this thread a favourite, so keep it updated with your progress/or lack there of!

Cheers,
Scott

scootabug

Well, I just checked out the contents of a DXF file and it looks pretty simple...so there's some good news!

drone

Scoota - why not use the text-based G-Code like most other CNC routers?

http://en.wikipedia.org/wiki/G-code

Funny enough, I was considering making a "travel size" pcb router myself last night, as I wished I could just test out what I was working with in Eagle w/o waiting for a PCB service. =)

!c

harry

Would looking at the rep-rap project offer some inspiration? surely what they can do in 3-d can be turned into a 2-d version?

drone

Harry - a 3d printer is basically just a cnc router/mill with a dispenser instead of a cutting bit.  You can even add such heads to many existing systems - so yeah, what they do is directly applicable =)

!c

halley

#7
Dec 30, 2008, 09:59 pm Last Edit: Dec 30, 2008, 10:00 pm by halley Reason: 1
One big difference between additive (depositing) and subtractive (milling) systems is the way you have to adjust the tool paths.  It can be a significant software problem.  A milling tool isn't a zero-radius needle, and a depositing jet can't produce zero-width material either.

scootabug

#8
Dec 30, 2008, 11:56 pm Last Edit: Dec 30, 2008, 11:58 pm by scootabug Reason: 1
Quote
why not use the text-based G-Code like most other CNC routers?


Never heard of it! Looks pretty straight forward going by the Wikipedia article. We could do it either way I suppose...use someone elses or make up our own.  Either way, it'd work.  Just not sure which would be easier but it'd make sense to at least follow the basic method and logic they use but this would still be something we'd need to implement manually on the Arduino side.

Better yet, is there software available that will output serial commands for a CNC router that we can interpret?  That'd be ideal.  They probably all do this...I have had no experience with CNC routers.

Quote
Would looking at the rep-rap project offer some inspiration? surely what they can do in 3-d can be turned into a 2-d version?


I'm sure they'd have some functions that would be very handy.  3D is only 2D with an extra axis.  Seems like an obvious statement but if you look at how they build 'up' with the Reprap, they appear to handle the STL files in layers..X and Y for each Z. No doubt there's more to it than that.

Quote
One big difference between additive (depositing) and subtractive (milling) systems is the way you have to adjust the tool paths.  It can be a significant software problem.  A milling tool isn't a zero-radius needle, and a depositing jet can't produce zero-width material either.


I agree.  I had thought of this, which is where I had initially thought for the PCB, you can subtract everything you don't want very easily.  It's much more complicated to do anything beyond that, but certainly not impossible.

In my case, I'd rather have the PC control the CNC router (aka Arduino)...which will make it a ton easier to handle all of the data by sequencing the commands and having the Arduino execute 1 command at a time.  Seems a little inefficient but I'm sure it'd work fast enough for this little black duck.

One thing is for sure, it's certainly going to be of huge benefit to work with a common file type like a DXF or whatever else is more appropriate.  The ability to work/operate for various platforms would be crucial.

Anyone have mad Java programming skills?

myersweb

WOW, that lego deal is pretty cool. I have been looking at those projects as well, I just cant bring my self to spend the cash on "legos". After looking at REPRAP again, that might not be a bad way to go after all. The problem would be that I already have most of the stuff to start the build. (I think) I have 6 or 7 steppers that I have acquired... RIP all the printers and scanners in my house! i have even more DC motors, and I have 4 good servos, and 4 not so good servos. The ladyAda shield only supports 2 steppers, and I want 3. So thats kinda problem one. I guess I could use a servo for the Y axis. For the frame, I want to do something like the EASY CNC project. (The guys who uses round pipe on youtube) For the cutting head.... I may just start out with a pencil, so I dont do too much damage. Then maybe a dremmel tool w/ the flex extension. Remember I plan on a small machine. Maybe 1 x 1 or something. You can see how well thought out this is. Anyway, I try to make a little progress every night, so I will keep this thread updated.

BTW, last night, I tried the Wii nunchuck with 2 servos that I ordered from Trossen Robotics with the pan & tilt. 99% success. The code I found has the vertical servo reversed. Of course I cant find where in the code it calls for that. Its pretty cool code, it has 7 levels of smoothing, lots of LEDS (one I replaced with a laser pointer that I can turn off and on with the wii controller.) If I posted that code here, would you guys take a look at it? or is this not the place?

Dave

scootabug

@Dave: Great work!  I've got a few old servo's laying about too, I'll have to dust them off.  Create another thread for the code, or PM me, I'm interested to see it.

You should be able to handle your third motor with one of these: http://www.sparkfun.com/commerce/product_info.php?products_id=8368

@Drone: Seems you're on it with the G-Code.  There's plenty of cheap software available that will send out G-Code commands that we can interpret with the Arduino.  Awesome stuff.

There are a ton here: http://www.probotix.com/cnc_software/

And this one looks like a great place to start: http://www.kellyware.com/kcam/index.htm

SunboX

that sounds really cool. Would be a nice way to prototype PCBs. Where can i buy such a nano cnc? :D

myersweb

I made some progress on the X Stage of my TOY Machine. The video shows single steps and micro steps. Still not much progress on the software /  firmware side. I got the Raprep host running. The Firmware compiles with no errors. Im not not sure what to do next other than start reading up on the raprep controller. Do you think that can cross over to the LadyAda motor shield?

Heres the video.
http://www.youtube.com/watch?v=DsQsao-d2ho

scootabug

Looks awesome.  How are you controlling the movements?

myersweb

Just a few lines of code from the motor shield tutorial. I was trying to figure out how to control with a pot. I can do it with out the shield, but not with. Im sure its just pins and wiring.

Dave

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