arkypita/LaserGRBL

Setting request

Andy-Gadget opened this issue · 7 comments

Andy-Gadget commented

Great software, but could I request a feature :
When engraving on a light coloured material (e.g. birch wood) the laser sometimes does not char quickly enough to start a track so the line isn't engraved. Another GCode generator (I think it's LaserWeb) has a 'delay' setting, which, after a laser off move, energises the laser then waits for a time before starting the engraving move. Sensible default for this would be 0 (i.e. no delay) up to 200 ms or so.
Andy.

arkypita commented

I know the problem, is very common with light coloured materials and low power lasers.
Do you know how LaserWeb create delays? I mean, what is the GCode used? G4?

  • 👍1
Andy-Gadget commented

It wasn't LaserWeb; It's the JTech plugin for Inkscape which has this setting, and looking at the generated code it is as you suggest, using G4 for the delay . In the code below, G4 P1.23... is a 1.23 second delay I set in the configuration. (P sets the delay units to seconds.)

. . .
G1  X13.97 Y32.0322
G4 P0 
M03 S255
G4 P1.2300000190734863
G1 F250.000000
G1  X29.7744 Y12.5589
G4 P0 
M05 S0
G1 F500
G1 X0 Y0
M18

Looking a bit deeper, the laser-on pause with no movement works when using G3 (constant laser power mode). In mode G4 (dynamic laser power mode) the laser is only powered when moving so the G4 pause just waits with laser off. This is by design and in the GRBL 1.1 laser mode documentation.

Andy.

arkypita commented

added to roadmap

minoseigenheer commented

I'm really looking forwad to this feature. When do you expect this?

arkypita commented

a lot of feature request and few spare time now... i cannot tell when I can do this

FrankHovis commented

Has this been implemented or not? I see a few issues opened with the same problem, the laser takes a little while to switch on, but I can't see as there has been any actual way to resolve this using laserGrbl.

sully9 commented

Apologies for the chatter, but I agree this feature would be useful. In the meantime, a tedious, manual workaround I use is:

  1. Load PNG/SVG into LaserGRBL
  2. Save resulting Gcode to .NC file
  3. edit .NC with text editor, add a 'G4 P0.025' command following any spindle(laser) ON command ('Sxxx')
  4. Load the .NC file into LaserGRBL

One of my everyday setups is a very cheap "DIY CNC2418" with a similarly cheap 0.5W laser. The laser is very slow to respond to spindle commands, So if I configure acceleration and feedrates for a tolerable run time, there's a lot of incomplete lines - even on paper. So once I've sorted out all the other relevant adjustments, I use the steps above.