Issues with lightburn 1.3.01 and 1.3.0

we’ve encountered a couple of problems with either of the above mentioned versions. Lightburn is running on Windows 10, the laser unit used is a NEJE 3 Max with the N40 630 laser.

One problem that has occured with either of the above versions is related to the speed (mm/s) with which the laser head is moved. For example, an edge with a length of 160 mm completes in 95 seconds, even though speed has been set to 1mm / sec. so,… way of.

Another problem which is accuring at irregular intervals with version 1.3.01, is that Lightburn, while cutting, freezes towards the end of the streaming process. The program then has to be terminated and restarted to solve the problem.

Presently, the faulty speed control is our main concern. Any ideas as to the cause of this issue and as to what can be done to correct it are greatly appreciated.


Grbl controllers count their own timing from a Crystal Oscillator on the control board. LightBurn can change the commanded speed but the calibration of clock timing is up to the manufacturer or their firmware team.

LightBurn can access the $100,$101 (steps per mm) which allows us to precisely recalibrate a distance along an axis but without clock calibration in Machine Settings, the clock is inaccessible - regardless of which software is commanding the motion.

The controller, has maximum speeds that are available in Machine Settings, $110, $111 (mm/min) The minimum speeds are most often set by the manufacturer and hard-coded like the clock calibration, when the Firmware is compiled. Your example of 60mm per minute should be well inside the max and min speeds.

There’s a remote chance that the ‘Cornering algorithm’ is adjusting the speed. The engraver applies the acceleration values $120, $121 when changing direction and when changing from a Travel move to an Engrave move. It’s worth testing to confirm the Cornering algorithm is not in play. Setting both $110 and $111 to the speed you have selected for engrave speed should take a majority of the acceleration (or more accurately deceleration) out of your distance vs. time test. Be sure to convert speed to mm/min when adjusting the setting as the controller is not likely to interpret mm/second correctly.

Newer 32 bit controllers like the NEJE 3 Max are often based on GrblHal or other firmware. Custom Machine Settings are being added by almost every manufacturer so it may be worth reaching out to NEJE about their clock settings after further testing.

LightBurn shouldn’t Freeze, Crash or Hang.

There’s a decent chance that this is either a communication setting (DTR) or the Windows 10 USB Suspend select setting.

Communication Between LightBurn and the control board can pause when sending large files as the buffer on the control board starts to get full. If the controller doesn’t resume communication Windows can put the USB ports to ‘sleep’.

Have a quick look at the USB Suspend Select:

After confirming the USB Suspend Select is correctly set (to disable) It may be worth toggling Enable DTR Signal on or off in Device Settings (in LightBurn) then retesting with a file that caused the hang condition.

If this doesn’t resolve with these first two checks, please reply here.

If you’re willing and inclined to share the file we can invite more folks to test this further.

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