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arpruss / gcodeplot

Use a 3-axis machine as a pen plotter
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Avoid turning loops? #34

Closed Miq1 closed 2 years ago

Miq1 commented 2 years ago

Hi,

first let me thank you for this convenient way to use my 3D printer as a cutter as well! 👍🏻

I have a question on using it, though. Due to the nature of the blade's point running behind the turning axis, there are loops cut at sharp corners. Is there a way to avoid these? Something one could do in Inkscape to have the blade lifted, moved and lowered again at these corners? grafik

arpruss commented 2 years ago

The offset and overcut options may help with this.

Miq1 commented 2 years ago

Whoa! What a speedy reply! 😆

Well, offset is obvious, 0.5mm in my case with 1mm shaft, 45 degree blades. But what does overcut do? How does the amount influence the tip trace?

Miq1 commented 2 years ago

I had the impression that the commercial plotters are doing a kind of "in place turn" when changing directions, i.e., moving the head in a circle section around the blade tip until it is pointing opposite to the next cut direction. So a tiny hole is cut at best, while maintaining the given paths very well. Do you think this would be possible in GCodeplot as well?

arpruss commented 2 years ago

It's been years since I've used this for cutting. I think overcut may be that kind of circle movement or some other solution to the same problem. I can't remember. I see that I used some code that I didn't write myself for the overcut, and it's pretty complicated code, so a quick glance at the code doesn't answer my question. I suggest the experimental method. You might set the output of gcodeplot.py to HPGL so you can visualize the output.

Miq1 commented 2 years ago

I am a C++ programmer and have never done anything in Python, unfortunately. Else I would try myself understanding and in case modifying the code. Thanks anyway for your support! Danke schön! 😉

arpruss commented 2 years ago

Python is straightforward enough that one can do a lot of code modification without knowing python.

Miq1 commented 2 years ago

Uh, silly me! 😜

When trying to understand the ProcessPath method I noticed that overcut actually is doing what I was suggesting! I was misled by the traces as can be seen in a GCode viewer, showing the strange loops at corners I thought were caused by the trailing blade.

But these traces in fact are drawn because overcut already does the corrections for the blade.

So excuse me for having raised a non-issue... 😊