Tweaked Laser Gcode generation for Inkscape

[keyz182]

Hey, I've just uploaded my changes to the 305 Engineering Laser Gcode generator for Inkscape, that takes advantage of the recent Duet changes to set laser power in the G1 commands. My testing has given much quicker, and cleaner outputs.

https://github.com/keyz182/inkscape-laser-gcode/tree/duet
Make sure to grab the duet branch. It should happily live alongside the original plugin, rather than replace it.

[dc42]

I'm glad to hear that you have it working well.

One firmware feature that I haven't implemented yet is ramping the laser power up and down during acceleration and deceleration. How important do you think this is? The firmware already reduces the laser PWM proportionally if the top speed of the move is lower than the requested speed.

[keyz182]

@dc42 I'm not really sure yet. My usage has been very light.

For reference, this is for raster images, so scanning lines back and forth, traditional inkjet printer style.

This particular plugin is configurable up to 10 "pixels" per mm, so potentially, a 100mm x 100mm image will have 1000 G1 commands per line, with 1000 lines, aiming for 20-30+ mm/s speeds.

So I think this is a different beast to vector based engraving/cutting.

I guess the accel/decel would be important at the start and end of lines, as most of the line (ideally) is a constant speed. Also, it's likely far more important on the more powerful e.g. C02 lasers (mines a "5W" diode, though probably closer to 2W in reality), where there might be even higher speeds in play, where it could end up having a "deeper" engrave/etch at the sides where accelerating or decelerating.

Here's an example of the gcode generated for a 50mm x 50mm image at 10pixels/mm https://gist.github.com/keyz182/b28db30c7ec6b5aae9c1b4723d2dbbd2

[T3P3Tony]

I have heard that for rastering it's common for control software to set a wider movement area than the raster area so that the acceleration is done before the laser is turned on in each pass.

[keyz182]

@T3P3Tony that makes sense, though makes lining up things for cutting/etching a bit more difficult.