50W CO2 laser not engraving full image

nickz · February 17, 2021, 7:06am

Hi There,

Firstly…
Laser: Chinese 50W 5030 Blue/White
Controller: Ruida 644XS
Firmware: LightBurn 0.9.20

Problem: I have tried to engrave several different images with all only engraving certain parts, while leaving other sections white with no dots whatsoever. There isn’t even one dot in these completely white sections. Tried using different computers, new USB cable, all different combinations of speed/power/DPI.
Below is the image being engraved (the Chris Walken one LB did way back, so the image itself has no issues), what the preview shows, and what is engraved. Settings for machine located below said images. Any help would be appreciated, at first i thought it was a firing rate issue and slowed the speed right down, but that wasn’t the case…laser can engrave great detail as seen.

Image:

Preview:

Engraved on white card at 200mm/s, 14% power, 0.175mm LI
Even the dots for the background around his face aren’t there.

Settings:

Pls help, I think i’m going insane trying to figure this out.

Cheers

ferg · February 17, 2021, 7:19pm

I definitely am a novice but it looks to me that you are negating most of your power setting by setting Minimum power the same as Max. Plus: I think you are trying to engrave too fast. Slow it down.

nickz · February 18, 2021, 2:11am

Regarding the max/min power, I believe the dithering works by optical illusion by increasing or decreasing the density of dots to create shades, unlike diode which changes power. I did lower the min power just incase (as seen below) but this didn’t affect the final image. I have lowered the speed as suggested to 150 and 50mm/s respectively, however this did not fix the issue either. The dots are darker than before and you can see some of the detail better, but the large blank white spaces are still there (chin, lips, nose, cheeks)…it’s like the controller doesn’t know to fire in these sections?

Any further suggestions would be great, even if they seem minor.

Cheers

TomWS · February 18, 2021, 2:43am

Well, I suppose you can believe what you want, but I think @ferg 's point is valid. You’re essentially killing the software’s range of choice to nil.

Establish the limits. Set your min to the lowest value you can get on your laser (8-10% probably) then up the max a bit from 14% to darken the dark areas. I wouldn’t slow down the speed, 200mm/s might even be too low for white chip board.

ferg · February 18, 2021, 2:41am

Your laser is interpreting the light area as no burn or slight burn. Did you try raising the power to, let’s say 25%. Leave the speed alone.

nickz · February 18, 2021, 4:23am

Ah, I didn’t know that the software chose from a range of powers for each dot. I thought it just applied one set power (max) to all positions it’s told, my bad.

The lowest power for my tube is 12%, anything under that and nothing happens. Tried with 12% as minimum and even lower at 10% to see what would happen.

Raised power to 25% as seen above, also tried one at 100mm/s, any slower and dots would just burn straight through.

I guess the areas are still being interpeted as no burn? Might grab a piece of wood and try a higher powered min% as the white card is too thin.

Thanks

Enno · February 18, 2021, 5:26am

200mm/s is not a problem for that machine, I think the single dots are just evaporating the material without time to darken, could try to go a few mm out of focus

Enno · February 18, 2021, 5:31am

If you want to use the min / max for engraving try the greyscale setting, not the dithering. I will burn each dot with max.

Kris1 · February 18, 2021, 1:55pm

Have you tried the settings in ‘shape properties’?

joel1 · February 19, 2021, 2:16am

When doing an image in dither mode there is no shading, laser is either on or off, nothing in between, setting min and max the same is fine.

As mentioned, settings in shape properties might help.

You might also try a higher DPI

LightBurn · February 19, 2021, 2:20am

When dithering, Min Power is ignored, so any suggestions to the contrary are incorrect. You have Max Power or zero, and that’s it, so setting Min the same as Max is correct (when dithering).

What Enno says is correct - if you are going fast enough, it’s possible that the smallest dots are firing too quickly to darken your material, so you may need to increase power or slow down, or both. What’s the material?

nickz · February 19, 2021, 6:02am

Well, I have now gotten it to work. Changing shape properties and DPI had no effect. What did work was changing to a thicker material (3mm ply) and setting speed to 80mm/s and both min/max power to 60%. The dots that were missing now make a mark however it carves through half of the wood lmao. Will keep fine tuning from here. I guess the problem was just the white card i was using was too thin? But then again many other people seem to have no issues engraving on similar materials.

Thanks for the help guys.

joel1 · February 19, 2021, 4:39pm

If that’s the case, What Oz said might help you.

So try a much slower speed and lower power. Maybe try finding the lowest power your laser fires reliably at, use it. Set the speed to control the burn. You are searching for the speed and power that will fire all dots and not burn deep.

joel1 · February 19, 2021, 5:52pm

I’m doing some quick test just to see how things look ( I’ve been playing more with 3D engraving ). I used your test image scaled to 150mm wide.

This image on my laser is 400mm/S, 20% power ( 80W laser ) using Jarvis dithering.

I’m doing others, the one running now at 15% power and 300mm/S looks worse than what you started with.

This is on white posterboard

Once my array is done, I’ll post all of it.

joel1 · February 20, 2021, 12:37am

Here’s my test, I tend to like Stucki better. 500mm/S and 600dpi I think push my laser too far.

There are a few that are OK.

TomWS · February 20, 2021, 1:54am

Nice set! As you, I like the Stucki best. This set definitely establishes a benchmark. Thanks for you effort!