Ryan, I think you guys talking about buffer issues, have nailed it. I’m convinced.
Shades of gray… opened ImageToGcode and created 3 quick files… changing only the travel and burn rates. I used 0.2mm resolution for all files… and 50mm/s, 25mm/s, and 20mm/s for the rates. Slowing the rates definitely darkened the image and did away with the “acceleration effects” we’ve been seeing.
[attachment file=89407]
[attachment file=89408]
[attachment file=89409]
[attachment file=89410]
Well done!
– David
Am I understanding it correctly that “Feed Rate” is the speed when the laser is on and “Travel Speed” is when the laser is off?
That’s my understanding. I’ve only set them both to the same rate in tests so far.
Nice, thank you David. So it looks like 20mm/s is primo right now. I do suggest keeping both numbers the same for now until we get things sorted out more clearly.
We do have the option to increase the buffer, but I do not know what consequences might come of it or if it will actually help.
Hello, guys! You, this forum and this thread are awesome! :)At the beginning, as I wrote my app, I had a cheap 1W UV laser (but it was actually less than 0.5W). I made really good results with it. But with max engraving speed of 250 mm/min. I unfortunately broken this tiny laser (it was really small) and bought a real (I think) 0.5W EleksMaker laser module and with it I got the same good results but with speed of 1000 mm/min. Then I bought a new 2.5W EleksMaker laser module in hope I can engrave much faster, but if I go faster then ~25 mm/sec my X-axis begins to stutter. I engrave with 0.07mm resolution. If I change the resolution to 0.3mm I can engrave with faster speeds without stuttering. So it seems (like Jeffeb3 said) to be a buffer and planner issues. I am not frendly to Marlin firmware to fix this issue, but I can change the Gcode 
So my idea is to adjust X- and Y-axis resolution separately. I will make some tests and post the results.
Hi, Ryan!
I have done two pics, one with 200mm/s travel speed, another with 25mm/s. The feedrate was 25mm/s for both pics. Engraving time was 5:01 and 22:40. Can you see the difference?
Victor you are using Marlin? With the tweak we are doing pretty good with M106/7 now.
yes, I am using Marlin 1.1.9
but in this version marlin.cpp does not exist, so I am not able to try it out.
If I understand it right, you can go over 25 mm/s without stuttering? Which resolution do you use?
Ok. Here are a few tests I have done with the same images. The far left image, where it looks like something was started was done at .2 resolution at a FR of 20mm and TS of 20mm. I seriously cannot get a usable image at all at .2 resolution. Maybe I’m misunderstanding something. The .12 resolution looks ok. The bottom 2 tests are run at the same settings. The wood I’m using is birch I believe. I got them from Hobby Lobby.
The .12 looks pretty good to me but I’m not 100% sure what I should be looking at/for. It could just be the wood. Did you try on cereal box cardboard? Did you sand the wood before burning?
Really I’m wondering if I’m misunderstanding something. At .2 resolution I can’t even make out a picture at all, it just looks like some random burn mark’s. Are you guys bumping .02 resolution at a time, from .1, or actually going .1 to .2 to .3 resolution? ?
I was only ever using the gcode files that were posted in this thread so as to eliminate variables. I’m not sure what resolution they were set up at off hand. Are you using those files?
I did use the gcode files that David posted, and they were fine. I was just experimenting with the settings others were using.
Hi, Kelly D
I had the same problems with a piece plywood. On the same sheet, but on different places the results were very different. Now I get the best results on hardwood and cardboard. And on cardboard I can get an interesting effect if I engrave with smaller laser power. The surface becomes lighter 
Just wanted to Thank everyone for this post! I was wracking my brain trying to figure it out, I am so thankful for the work you guys put in on this!
TEN PAGES of posts is a LOT to weed through if you an ignorant s[l]ob like me… Can I simply ask what the final summary was? I’m going to try to use my Rambo with Marlin v2.0…Dual Endstop version FW with an Endurance 10W+ Laser… did you guys ever figure out the Marlin changes, and can anyone summarize them in idiot format? (simple, no acronyms or abbreviations) Has anyone compiled the code and offered it for sale?
I’m really quite ADHD so I’m as lost as hell but happily hard headed enough not to quit! I’ve been lurking on these pages for a couple of days now… still in the dark.
—Thanks in advance.
Hahaha…you know, when I first came to V1 I remember seeing two threads. Jeffe’s MP3DP build thread and Dui’s Made in China thread. They had multiple pages and I was like “Wow, these cat’s must be super active…I hope I get a long thread going one day.”
And now I feel bad for the pain you are experiencing because I too felt it trying to make my way through those other two threads. I got my setup to the point where I finally had a hallelujah (post #88402) and then my life got crazy busy (went out of town for a ten day carve). Thing is, when I left the whole crew kept at it, digging deeper and deeper into stuff I can only nod my head over and pretend like I’m still in the conversation.
Check post #88406 for the answer and then refer back to post #88349/50 and #88353
Remember, this is on the miniRambo without dual endstops so your setup may yet need to be different. I don’t know. I assumed all things would be the same but just 20 minutes ago discovered that with dual endstops set up there is no moving of axis in the negative direction with the LCD controls (I was so scared I messed something up in the wiring!). I don’t know if that’s a RAMBO thing or an endstop thing.
Sorry Mark. I thought the link to this bug fix was more clear. Give me a minute. I’ll see what I can do to make this easier.
Okay, here it is as simple as I can make it. If you want to apply this bug fix to a working copy of Marlin 2.0 firmware use the attached zip file. in other words you will need to have downloaded one of Ryan’s copies of the correct firmware for your control board.
extract the marlin.cpp file from this zip file and use it to replace the marlin.cpp in you copy. this file will be located in the following location.
RootFolderwithBoardName/Marlin/Src/Marlin.cpp
compile and upload like normal.
Marlin.zip (7.59 KB)
Wow… Service above the call of duty, Thanks Aaryn!
I had to buy a Pololu AVR Boot loader to get the original DE firmware loaded so this should be easy. So many posts, contradicting each other or correcting each other etc… I could not find the ‘final solution’!
I will try this tonight. Thanks again, I owe you!
Mark
Wow, looks like I got in here as actvity is picking back up. I went through this entire thread. I’m only at the basic assembly of the MPCNC itself so far. What got me interesed was a buddy of mine got a glowforge, than someone on the 3d printing FB group brought up the MPCNC…went down the rabbit hole…2 days later had 4 of my FDMs printing all my parts off. I’m so stoked.
Does any of this apply at all to say the TenHIGH 40w laser? I would not think so but I have no clue whatsoever…I only know I want that laser but if its actually overkill for what I need I will gladly use something with less wattage.
Anyhow, wanted to say hi as this is my 1st post and to thank all of the contributors!
