First, I’d like to thank @Gero and everyone who helped me learn this, in addition to this Tutorial. I thought I’d write it up with some screen shots to help anyone else learn without as much Q&A. This is a simple example of a small wheel. You can make it a bit more complex as in the Tutorial if you want, but it helps to go through once with a simple object before trying more complex creations.
Part 1: Create the Sketch
Step 1: Open FreeCAD, create a new document, and save it.
I’ve also created a maslow_post.py for FreeCAD. It doesn’t do anything special, except it removes all unsupported codes and I updated the Pre and Postamble. Also, it says Maslow in the GCode now. If there are any suggestions for improvements, please let me know.
Ok, there’s a couple of things I have noticed here. First, the feed rates are a little high in the tutorial. 42mm/s for cutting and 100mm/s are too fast for Maslow. The maximium speed is about 40ipm, which is about 1220mm/min or 20mm/s. Based on discussions elsewhere, a good cutting speed is around 30ipm or lower, which is 760mm/min or 12.7mm/s
Secondly, internally, FreeCAD stores speeds in mm/s, so this must be converted by the post-processor into mm/min for Maslow. So the Python post-processor (maslow_post.py) must be edited, around line 266 to multiply the speed by 60. Like this:
Sliptonic is a major contributor to FreeCAD CNC tool path generation and a pretty dedicated communicator. I follow his youtube channel for walk through tutorials.
That’s good to know, however, I suspect that that setting only changes the display units, so internally it’s still mm/s therefore the post-processor must still multiply by 60.
Haven’t heard from @waltmoorhouse regarding this, but my patched version of his post-processor works for me.
Right, because you selected “Metric small parts” to change FreeCAD’s display as you mentioned above, and because the grbl post-processor has a line that multiplies the feed speed by 60 to convert from mm/s to mm/min. That’s how I knew to edit the Maslow post-processor- I checked what the grbl one did.
Is there a way to cut a ring without using a pocket tool path in the center? To cut out the inner-diameter with a similar spiral as the outside with tabs?
Welcome to the Forum!
I do not understand the question, sorry, my mind seems blocked.
Edit: I think I got it. Let me open FreedCAD and draw the ring for a screen shot to confirm i understand correctly.
Edit2:
Does this come close 2 what you are looking for?
Using the ‘Profile based on edges’ choosing the outside/inside edges and setting outside/inside?
