Image2gcode + ghosting/double image

Finally got my laser working thanks to Jeff! Using the Jtech inkscape plugin I got a really nice crown etched into some wood.

I tried using image2gcode to do a rasterized image burn and I’m getting a ghosted or double image: https://imgur.com/a/oGqLZs0

I’ve read that it has to do with the burn being offset on a left to right pass vs right to left. I don’t see where to adjust that in image2gcode, is this something to do with the firmware?

Any help is appreciated.

You are using a Rambo board right?

Did you read this post?
https://forum.v1e.com/t/laser-engraving-not-really-getting-great-results/9402

Remind me. What version of Marlin do you have, and are you using M3 or M106 to turn it on?

I’m using 414D bugfix 2.0

I found that using M42 P45 Sxxx to turn the laser on gave me the cleanest signal on my scope.

I haven’t tried the Marlin.ccp fix yet… I’ll do that this afternoon and see if it fixes the issue.

Yes, I’m using the RAMBo. I had a look through that post. I think the solution is uncommenting some lines in Marlin.cpp I read somewhere that Marlin is running a check before firing the laser which delays it just enough to cause the issue when the laser is running back and forth.

I just ran the g-code with the modifications to Marlin
CPP with similar results. I’m still getting the ghosting.

I’m going to switch the image I’m using to ones used in other threads to make troubleshooting easier.


Here is the Garfield with the Wood laser profile selected. 3000mm/m burn and federate with both decimal value and optimized raster options enabled.

I chose to use cereal box cardboard as well to keep things the same.

It’s a little hard to tell but it seems I’m still getting a bit of ghosting. I’m running the wedding photo now with the same settings to compare.1

Those original pictures were being run at 750mm/m so increasing to the 3000 is really nice.

Getting close. Upper right is the latest burn. I increased gamma and brightness as suggested in another thread. Seems the ghosting is gone as well.

All 4 of the burns were done using Repertier Host over usb. I just read that results nare better on SD card so I’m running the same g-code as the top right again but on an SD card. I’ll post the results right away.

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Blew it back up to regular size and went with the same settings as the previous attempt. Looks like the ghosting is gone. I might have to adjust brightness and gamma a bit more but I’m definitely happy with the improvement. Thanks for your help everyone :+1:

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We didn’t do anything… you did all the reading… :rofl: :grin: :stuck_out_tongue_winking_eye:

BTW,
You made changes to the firmware, did you upgrade the firmware or you still using 414D?

Still using 414D, just made changes to Marlin.cpp

in the Marlin.cpp file.

// Limit check_axes_activity frequency to 10Hz

static millis_t next_check_axes_ms = 0;

if (ELAPSED(ms, next_check_axes_ms)) {

planner.check_axes_activity();

next_check_axes_ms = ms + 100UL;

}

To fix the problem it needs to be changed to this.

// Limit check_axes_activity frequency to 10Hz

//static millis_t next_check_axes_ms = 0;

//if (ELAPSED(ms, next_check_axes_ms)) {

planner.check_axes_activity(); //< THIS IS THE ONLY LINE OF CODE YOU LEAVE UNCOMMENTED

// next_check_axes_ms = ms + 100UL;

//}

I would make changes to the latest Ryan’s firmware (425D ?) if i’m not mistaking.
You will see improvements with router and laser after the changes…

Sweet, I’ll check it out. Thanks!

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I suspect the later versions of the firnware, with the laser pin set to 45, then using M3/M5, might be the best option. I don’t want to blow a workday for you while you are on a deadline, but that should have the latest fixes from mainline Marlin in it. Hopefully, you don’t need bugfix.

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