K40 Laser Software: K40 Whisperer, LightBurn, CorelLaser and Inkscape

You will find one of three things:

• An M2 Nano from LiHuiyu Labs, the classic K40 board, often with a USB key in the box. It runs K40 Whisperer, LaserDRW and CorelLaser.
• A GRBL board, as in the OMTech K40+, or an aftermarket swap such as the MEFORE H2. It runs LightBurn and LaserGRBL.
• A Ruida or other DSP controller, rare in a K40 but common after a big conversion. It runs LightBurn on its higher license tier.

Take every K40 laser software download from the people who make it, never from a mirror site. K40 Whisperer comes from Scorch Works at scorchworks.com, LightBurn from lightburnsoftware.com, Inkscape from inkscape.org and LaserGRBL from lasergrbl.com. LaserDRW and CorelLaser ship with the machine on a disc or USB stick.

Do not flash or replace a board to fix a software problem until you are sure the board is at fault. A dead USB cable, the wrong driver or a missing USB key explains most classic K40 connection trouble.

Setup on Windows includes swapping the stock USB driver for a libusb driver, following Scorch Works' instructions. After that, LaserDRW no longer sees the board until you switch the driver back, so commit to one or the other.

K40 Whisperer reads colour, not layers. Draw your file with these conventions:

1. Red lines: vector cut, the beam follows the path.
2. Blue lines: vector engrave, a lighter line traced at a faster speed.
3. Black fills and images: raster engrave, scanned line by line.

Set speed per operation in K40 Whisperer, and power on the machine's panel. The M2 Nano only switches the laser on and off, so the knob or buttons set one power level for the whole job. For a light engrave and a full cut in the same file, run them as two jobs and change the panel setting between them.

Gray images engrave by dithering: the program turns shades into dots of full power. It works well on wood and anodized aluminium, less well on materials that need true power control.

• Home the head before each job.
• Use the frame button to trace the job outline with the laser off.
• Save your speed settings per material in a notebook, since the program does not keep a material library.

In Inkscape, K40 laser files start with the document set to millimetres at a scale of 1, then pure colours. Pure red (#FF0000) for cuts and pure blue (#0000FF) for vector engraves keep K40 Whisperer from guessing. Convert text to paths before you save, so fonts cannot change on the way.

On a K40 laser, CorelDRAW sends jobs only through CorelLaser, a plugin that needs the M2 or M3 Nano's USB key plugged in. Many classic K40s ship with an old CorelDRAW installer on the disc. Do not assume that copy is properly licensed; if you want CorelDRAW, buy it from Corel.

• Lose the USB key and CorelLaser and LaserDRW stop working.
• K40 Whisperer and Inkscape need no key and cost nothing.
• CorelLaser suits owners who already work in CorelDRAW every day.

Three routes lead to a K40 that runs LightBurn:

1. Buy a K40+: OMTech's K40+ runs LightBurn and LaserGRBL on its stock controller, and one bundle includes the license.
2. Fit a drop-in GRBL board: the MEFORE H2 shares the M2 Nano's 97×64mm footprint and mounting holes, so no drilling. Other K40 conversion boards exist too; match the connectors to your machine.
3. Go to a DSP controller: a bigger job, usually part of a full rebuild, and it needs LightBurn's higher license tier.

For a GRBL machine, the lower LightBurn license tier covers it. Tier names have changed over the years, so read LightBurn's current description of which controllers each license covers before paying. The free trial runs the full program, which is the best way to confirm your board connects.

For a K40 laser, LightBurn setup comes down to three settings: add the machine as a GRBL device, set the work area to the real travel, about 300 by 200mm, and set the origin to match your homing corner. Then cut a small test square and check its size with calipers.

Power control is where LightBurn earns its keep. Each layer gets its own maximum and minimum power, so a single file can engrave, score and cut in one run. On a K40 tube, keep the maximum well below what your ammeter shows as the tube's limit.

• Classic K40, hobby use: K40 Whisperer with Inkscape. Free, reliable and good for cutting and simple engraving.
• Classic K40, photo engraving or mixed-power jobs: a GRBL board plus LightBurn. The board costs less than a new machine and changes how the K40 works.
• OMTech K40+: LightBurn for everything, or LaserGRBL if you only engrave images on Windows.
• Existing CorelDRAW user on a stock board: CorelLaser, keeping the USB key safe.

LaserGRBL deserves a word. It is free, Windows only and aimed at GRBL lasers, with good image conversion for engraving photos. Its layout tools are basic, so many owners design in Inkscape and use LaserGRBL only to send the job.

Whichever you pick, the habits that keep a K40 safe stay the same. Safe K40 setup lays them out, the upgrade order places the board swap among the other jobs, and the materials guide lists starting settings.