Raster issue

(Marcelo Freitas) #1

Hi all.
I have a k40 upgraded to an Arduino Uno whith shield and GRBL 1.1f. Fimware. The problem is that i can’t do a good raster engraving. I just try to engrave some difrent images but it’s everytime the same. The movements of the machine are not smoth. It jerks and even lose step because of this jerks. Usually i use the speed between 150mm/s and 250mm/s. This problem appears specialy when i set the laser beam to 0.1mm. Anyone has an idea about what is wrong and what can i do to fix this? we can even saw that the machine speed is not constant during the raster movemenst.

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(Claudio Prezzi) #2

The performance of the Arduino Uno is the limiting factor. The maximum speed is depending on the configured laser diameter, picture complexity and CAM params like “join pixels”. With 0.1mm you could probably reach about 20-30mm/s. Try at least 0.2mm laser diameter. The beam diameter of a K40 is anyways between 0.2 and 0.3mm (with optimal focus).

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(Marcelo Freitas) #3

Ok. But can i reach the 250mm/s with 0.1mm beam on smoothieboard, cohesion 3d or other board that run with laseweb?
I just try to engrave with 0.2mm laser beam but you can saw by eyes the laser passes. Specially if i use low power.

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(Claudio Prezzi) #4

No, you probably can’t. Smoothieware will not be much faster than Grbl on Arduino Uno when using LaserWeb (because of communication method). Smoothie can be a bit faster when you run the gcode from the sd card but not 250mm/s with 0.1mm pixel size.
You could install grbl-LPC on a Smoothieboard (or compatible) which is much faster on raster engraving via USB, but I doubt it will reach 250mm/s @ 0.1mm.

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