To my knowledge GIMP does not support laser engraving machines like Legend Helix 24 Laser.

The spesifications for Legend Helix 24 Laser: http://www.epiloglaser.com/legend_helix.htm

There exists a backend named epilog-cups for the legend brand of engravers/lasers, but it seems fiddly to use and no GUI or PPD files exists to my knowledge. I think that the epilog-cups backend only works
with inkscape, but i am unsure because i dont have a Legend laser so i cannot test it.

At present state, the user of epilog-cups needs to set up and make a printer for each typer of material.

That has some advantages, but the power and resolution and speed apparently cannot be adjusted with ease. Anyway, it should be possible to add a suitable plugin with a GUI that can store the settings for a type of material.

examples: 1mm beech plywood, cutting.
Ti6Al4V (titanium,polished) engraving etc..
etc..

epilog-cups is located here + some info on how to set it up: http://www.as220.org/labs/wiki/index.php/Laser_Cutter_Technical_Info_Links cups-epilog.c is here:
http://aaisp.net.uk/free/cups-epilog.c

The AS220 CUPS-Epilog driver converts postscript input into a .PJL file, that is sent to the Laser Cutter/engraver. Apparently the Epilog uses this HP printer control language! ( source=
http://wiki.laoslaser.org/index.php/PrinterDriver#Example_code )

Epilog laser engraver

The Epilog laser engraver comes with a windows printer driver. This works well with Corel Draw, and that is about it. There are other windows applications, like inkscape, but these rasterise the image before sending to the windows printer driver, so there is no way to use
them to vector cut.

information on cups-epilog follows:

The cups-epilog app is a cups backend, so build and link/copy to /usr/lib/cups/backend/epilog. It allows you to print postscript to the laser and both raster and cut. It works well
with inkscape.

With this linux driver, vector cutting is recognised by any line or curve in 100% red (1.0 0.0 0.0 setrgbcolor).

Create printers using epilog://host/Legend/options where host is the hostname or IP of the epilog engraver. The options are as follows. This allows you to make a printer for each different type of material.af Auto focus (0=no, 1=yes) af optimise vectors (0=no, 1=yes)
r Resolution 75-1200
rs Raster speed 1-100
rp Raster power 0-100
vs Vector speed 1-100
vp Vector power 1-100
ov Re-order vectors to reduce time
vf Vector frequency 10-5000
sc Photograph screen size in pizels, 0=threshold, +ve=line, -ve=spot, used in mono mode, default 8.
rm Raster mode mono/grey/colour

The mono raster mode uses a line or dot screen on any grey levels or colours. This can be controlled with the sc parameter. The default is 8, which makes a nice fine line screen on 600dpi engraving. At 600/1200 dpi, the image is also lightened to allow for the size of the laser point.

The grey raster mode maps the grey level to power level. The power level is scaled to the raster power setting (unlike the windows driver which is always 100% in 3D mode).

In colour mode, the primary and secondary colours are processed as separate passes, using the grey level of the colour as a power level. The power level is scaled to the raster power setting. Note that red is 100% red, and non 100% green and blue, etc, so 50% red, 0% green/blue is not counted as red, but counts as "grey". 100% red, and 50% green/blue counts as red, half power. This means you can make distinct raster areas of the page so that you do not waste time moving the head over blank space between them.

It seems to me that the epilog-cups does not support 3D engraving. 3D mode looks at the dots and the dot patterns in a very different way than Basic raster engraving mode, especially where it concerns either color, or grayscale images.

In 3D mode, instead of looking at the dots and determining where to fire the laser based on the dot spacing, Epilog Laser look at the dots and determine how much laserpower (wattage) to apply to each dot, and that’s the big difference between Basic raster engraving mode and 3D. In Basic raster engraving mode, every dot is fired at the same laser output (wattage). In 3D mode machine have the ability to adjust the laser output for every dot.

An additional aspect of 3D mode is that, unlike Basic mode, the laser fires continuously between most dots – even if it is engraving from a 10% fill pattern to a 30% fill pattern. This is by design so there is a
gradual change in the depth of engraving when the artwork transitions from one shade of gray to another. The only time that this is not true is when the artwork changes from 100% black to 100% white (or visa versa).

Any opinions ?

www.ecpur.com

http://www.ecpur.com/40-watt-co2-laser-cnc-router-engraving-and-cutting-machine-cutter-engraver-usb-port-us1-p-5.html

CO2 LASER ENGRAVING CUTTING MACHINE Laser Type CO2 Gas
Laser Power 40W
Tube Trigger Volt 20KV
Tube Operating Volt 15KV
Current 0-22mA
Interface to Computer USB Port
Maximum Item Size to Engrave 320mm * 220mm * 70mm (12.6W * 8.7L * 2.8H in ) Laser Tube (life hours) 1100-1400 Hours Engraving Speed 0-350mm/s (0-13.8 in./s ) Cutting Speed 0-35mm/s (0-1.38 in./s) Minimum Shaping Character 1mm * 1mm (0.04 X0.04in ) Resolution Ratio 0.026mm (0.001 in ) / (1000dpi) Resetting Positioning ≤0.01mm (0.0004 in ) Motor Type Stepper Motor
Software Supported MoshiDraw / CorelDraw software Power Consumption ≤250W
Operating Temperature 0-45℃ (32-113℉) Graphic Format Supported .PLT / .DXF / .BMP / .JPG / .GIF / .PGN / .TIF etc.. Water Cooling Water Pump include
Recommended Spare Parts / Consumables Laser Tube, Focal lens, Reflection lens Product Dimensions 800mm * 500mm * 250mm (31.4in * 19.6in * 9.8in.) 3 years factory warranty and life time free maintenance service FDA Compliant : YES
CE Certification : YES
ISO9001 Quality Certification : YES
* Japan imported main board and chip which can control the engraving more precise * Germany imported bearing and high accuracy stepping belt which not only make the engraving more precise, also make the machine life time twice to three times than other ordinary CO2 LASER Engraver. * High Precision Stepping motor makes engraving more precise. * Graphic format supported CorelDraw / AUTOCAD * Mainly used for engraving of non-metal materials: such as Rubber / Ox horns / Wood / Plexiglass / Atomic materials / Crystal / Bowlder / etc...