I’m running into issues with the Material Test in Lightburn and the results are far darker than
expected. Hoping I can start here but if appropriate I can take this question to a Lightburn forum.
Based on the OF “Pew Pew! Laser Shootout” video I was expecting something like this …
(e.g. 175/10% to be very light, 100/50% to be darker and 25/50% to be quite dark but not burnt. My results are MUCH darker (Note: I realized the material engraved will impact the results but am experiencing darker than expected results on scraps of standard ply, pine and other wood materials)
My setup: JTech 7W+. BB controller 1.6.2. Lightburn 1.7.08. Material shown is MDF
I believe I have followed all the available instructions from OF and JTech (max svalue = 1000, and machine is configured for GRBL-m3, laser focused, etc…).
I also tried the “Fun with Lasers” example in the OF setup video - selecting “Standard Ply” from the 7W materials library and get this as a result
Looks like you are on the right track you just need to experiment with speed and power a bit more to find the optimal combination for the material you are using. Its not as simple as just choosing MDF and letting lightburn burn away, thay is only a starting point.
Thanks for the encouragement and info Scott. I will try to grab some Baltic birch and see if I get somewhat closer to the results shown for the 7W laser in the Pew Pew video. Failing that I will just keep experimenting as you suggest.
I’m leaning toward this being a controller or laser issue. My test using Baltic birch yielded the same results - even when doubling the top speed to 400 inches/min. Hopefully Onefinity support or JTech can weigh in with some thoughts.
My laser turns on with m3 s0.01 and marks at that level (as seen in the lower left as I moved the laser to set X and Y)
Check your settings within lightburn. You 7w shouldn’t be able to burn anything like that at those settings. In fact, your laser shouldn’t even turn on with a S.01 command.
My set up is OF woodworker pro, Makita router and 7W+ laser with BB controller. I used the OF “set up” to configure lightburn.
I found the interval needs to be at least 0.006-0.01 inch for wood as the lines “overwrite” each other with smaller setting, increasing the “burn”. Also I found using the lightburn test patterns, 5-10mm squares are too small. With all the mass of the z20/makita/laser that the laser cannot accelerate fast enough. You need bigger sample squares and set the overscan as high as possible to stop the laser spending too much time in the same spot while it decelerates/stops/reverses/accelerates. Generally I have found 10%overscan to be the minimum with a 10-20mm sample square. The Onefinity simply cannot move fast enough compared to an equivalent open frame laser.
FYI, I use m3 s1 for setting the laser up and even then I lift the z axis to defocus it otherwise it marks the wood.
Hope this helps
Exactly - it should not turn on with S0.01… but it is. This is why I am concerned I may have a defective laser or controller.
The M3 S0.01 is entered directly from the Onefinity MDI interface… no lightburn involvement at all - so I don’t think it is lightburn settings that are the issue. It is a simple gcode command and yet it makes the laser do something that shouldn’t happen. Thus my concern the laser driver or the laser itself is not operating correctly.
Lightburn is new to me but I have checked and double checked the settings and all seems fine.
max S-value = 1000 ; confirmed
laser configured as GRBL-M3 as required for OF; confirmed
Well this hurts to admit but I’m running fine now and the issue was operator stupidity.
Thanks to all who provided suggestions. I’m certain I changed the tool type to JTech when first setting up the laser but somehow it reverted back to Makita Router and that was at the heart of the issue.
I’ve stopped making charcoal and am now happily making Material test boards for my projects.
If you need anything else, just ask. I struggled for several days and every sheet of whatever seems to need different settings. The biggest thing for me was the acceleration and overscan. For one burn I even went 15% overscan and I seldom go over 150 inches/ minute.
