Noob Query : Regarding CNC software and its hardware

[junior85]

Hi,

Im a final yr engg student in India. I have taken up a project which involves Fabricating a 3axis CNC machine (basically for routing on wood).

I am completely unaware of the options available to do the software job.
I mean what all software will be needed in the first place ?

If i wish to convert a 2D drawing into G code.... what do i need ?
I know a lil bit of AutoLisp, C++ ...can i do the coding myself
Is there any tutorial or something i can see to start off the coding in the right diection?

Another thing that is troubling me is that after i have the NC code for a drawing ready do i need one of those big CNC controllers ( Fanuc etc) to execute the code? ( i dont think i can buy one of those )

Are there any other options to carry out the CNC machining using something simpler ??

If I havent made something clear pls feel free to put in ur queries
Thx

[Wun Fungi]

I'm still a relative NOOB, but I've studied everything that's free (I think), so I can probably answer most of your questions. If I do it backwards:

The machine will "typically" have three stepper motors driving the X, Y, and Z axis.

Driving the steppers is the machine controller. Typically connected to the parallel port - though there are exceptions.

The machine controller is driven by software which interprets the Gcode.

The Gcode is the result of software that converts from one of various formats: .dxf, .jpg, .bmp, etc... This is where you'll really need to do some homework.

If you know CAD, you probably know DXF files come from AutoCAD. I'm using simple line drawings that my Mrs. creates in Corel and outputs as DXF-12. From there, I run the file through a converter to create the Gcode. Then I run the code on a simulator to check for potential problems. Lastly, I move the file to the PC that runs my router, and run it on a Gcode interpreter.

I'm using and can recommend these freebies:

Machine controllers (Also look at Mach 2):
EZCNC http://www.accesswave.ca/~blandry/ezcnc/abimp.html
DeskNCrt http://www.deskam.com/

Simulators (Also look at back plotters):
CNCSimulator http://www.cncsimulator.com/
AutoEditNC http://www.cnczone.com.com/autonc.htm

Gcode converters:
Ace Converter http://www.dakeng.com/ace.html

And of course, for some very reasonable prices, there are packages that combine some/all of these functions. Mach 3 is very popular on this site.

I just haven't bought anything because I'm still refining my first router, completing my second, thinking about my third, making sawdust, and wasting wood!

An informative link:
http://www.cadcamcadcam.com/hobby/cr..._CNC_parts.htm

Anyway, I hope this was, at least, some help.

Steve in NM

[ger21]

Since you know Autolisp, I'll assume you use AutoCAD. Here's a VBAmacro that will write the g-code from AutoCAD. http://tinyurl.com/35uart

To run the machine, look at TurboCNC, www.dakeng.com or mach3, www.artofcnc.ca

[junior85]

thanx guys for ur response....

I have already seen one or more softies mentioned here and am now looking for a 3 axis controller board circuit which can work with the software...

Any suggestions..

Thx a ton for the valuable input n time

[Wun Fungi]

First, study up on the differences between bi-polar and uni-polar motors. The choice, at least to me, seems to be personal. I believe bi-polars are supposed to be more efficient, and tend to cost a little more, negating the difference – IMHO.

For me, the high end would be Gecko G201 drives @ $200 per axis:
http://www.geckodrive.com/product.cfm?pid=9

Then there are what would seem to be Chinese knock-offs for roughly half that amount:
http://www.kelinginc.net/KLDriver.html

A more economical choice here at $155 for three axis:
http://www.xylotex.com/3axBoard.htm

If you want to assemble it yourself, at $80 for three axis:
http://www.hobbycnc.com/hcncpro.php

If you want REALLY cheap, at $16 per axis:
http://store.qkits.com/moreinfo.cfm/QK179

These things, at under $20 per axis, have something of a cult following:
http://www.piclist.com/techref/io/st...step/index.htm

Note that Keling, Xylotex, HobbyCNC, and others offer “packages” that’ll save you few bucks, and possibly a few headaches. Also note that, depending on the route you choose, you may or may not need to build or buy a parallel port breakout board.

Hope this is helpful.

Steve in NM