I put this in the Bar, as it primarily involves Inkscape, as the Ardino hardware has not yet arrived.
has anybody used Inkscape to create DXF files? i have a DXF to GRBL converter, but whatever i use to open the DXF file, it shows nothing.
All i want to do is learn how to create the DXF files correctly, so i can convert them to GRBL. I can export from Inkscape to DXF, but i don't think i am doing it correctly. either i have the sizing incorrect, or i really don't know what i am doing (the later is most likely).
Thoughts? ideas? suggested tutorials? Suggested anything, that doesn't include adding the idea to the circular file?
I am just trying to make sure i know what i am doing first, while i wait for the parts to arrive.
Inkscape can write HPGL files which are very close to GCode. I wrote a Python program to convert from HPGL to GCode.
I wanted to mill some very simple shapes from thin brass sheet on my small lathe. It worked OK but then I discovered electro-etching which is a lot less trouble. I can cut an etch mask from self-adhesive vinyl with my Silhouette Portrait cutter.
The motor, drivers and controller is 1% of CNC.
The important part is the lead screws and bearing surfaces and control software is the other 99%.
I have a scope, soldering station, signal generators, powers supplies, analyzes, all purchased.
What you do with them is what DIY is about.
Same with CNC.
Mine came in semi-kit form and it was clear that building one from scratch would require a fairly sophisticated shop. But, if your goal is to build a CNC machine and not use a CNC machine it would sure be a challenging project.
travis_farmer:
I have an old version of SolidWorks that was given to me due to it being outdated. but i have not found a way to generate GRBL code from there.
I know nothing about SolidWorks and I have never put in the time to learn proper 2D Cad, never mind 3D. I do my 2D drawing with LibreOffice 4.3 Draw which I think is better than InkScape and which can export SVG files that Inkscape can use. I had a problem with the SVG files from a newer version of LibreOffice.
I reckon it would help if you explain the sort of tasks you want your CNC to do.
I added 3 stepper motors (X, Y and Z axes) to a small lathe (Sieg C1). I wrote a simple Arduino program to control them. And I wrote a Python program for my PC to allow manual control and to interpret simple GCode and convert it to numbers of steps for the motors (actually the total time for a move and the time between steps for each motor) which it sends to the Arduino. It seems to work properly but I have actually used it very little. I had started adding a sensor to detect the position of the chuck so as to synchronize the feed for screw cutting - but like a lot of my things the need evaporated before I got that finished
Making a robust machine that can handle the heavy loads for metal cutting would be a major task.
I wouldn't worry too much about backlash. You can make your program allow for that by adding some extra steps when the direction changes - as long as the backlash is consistent.
Lead screws are direct connectable to stepping motors.
You get huge mechanical gain advantages.
Very accurate linear movement, better than 1/2 thou.
With backlash nuts, negligible forward to reverse slack.
Easy to mechanically connect to.
Easy to maintain/clean.
Low wear.
Put a bearing to the frame on the non business end is all the support necessary.
Great for X Y and Z axis.
travis_farmer:
I am thinking of starting with just 2D engravings, to begin with.
That should be perfectly possible with GCode derived from HPGL output from Inkscape.
One of the things that has put me off GRBL (and the LinuxCNC etc) is the absence of simple advice explaining how it "knows" where the tool tip is so as not to crash into the work piece and how the zero position is set for measurements against each different piece of material that is to be cut. It has always seemed to me that the authors assumed a level of knowledge bout the process of CNC machining that I don't have. My solution was to write my own Python code.