Laser: True grayscale instead of dithering?

Do we know what version of marlin is running on SM1? How do I find out by myself? I am also trying to trial some laser software that looks really promising and the 30 day free trial is really helpful. I cannot get it to recognise my Snapmaker original yet it knows Marlin and Grbl. I think I will do a firmware update and try again because the software has many really useful facilities. Four different image burning modes for example. I think a license is around $40 and if I can get it to work with SM1, I will probably buy a copy.

This may help you: FYI:Source code of Snapmaker Firmware
Most software I have seen yet allows you to select the “flavour” of the G-Code, and if so, select Marlin would be my suggestion.

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Hi folks,
I played around a bit more:


Bottom line: I start left with the focus way off (10 mm), laser at 100%, and then close in into focus on the right. As you can see the transistion from “not scorched at all” to “totally black” is happening relatively fast.
Second line: Started left, increasing laster power in 1% steps to reach 100% on the right, and dwell with the laser for 1 millisecond on each pixel. Again, quick transition.
Top line: same, but laser a bit out of focus (2mm out of focus).
I also tried the grayscale square on very white photo inkjet paper, and there its either white or black, no grayscales possible.
What I infer is: There is the assumed exponential effect: First the laser is reflected very much by the unscorched surface - the whiter, the more is reflected. Slowly heat builds up, and the material starts to darken. Darken means better absorption of light, heat builds up quicker, dakrening fastens, heat builds up even quicker, and ere you can say “Fire!” you have reached complete black.
In that sense my greyscale squeres were kindof a lucky shot I’d say!
I’d tend to give up here and say: Too many variables and to fast effects to keep control of it, but I have found a few examples that tell a different story:

So after all, I suppose my original approach would work if I did not run into the PWM problem. And it’s there - I played around with the grayscale square, and here it’s clear to see:

I gues I’ll contact support and ask for options. It would be sooo cool if we all could use the fast method I used for the square…

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Ah, and by the way: If I try sub-millisecond dwell, the program crashes :slight_smile: A G4 M0.1 and the laser is stuck…

Thank you very much @Hauke; I have just updated the firmware to GD32 Base 2.11and I chose Marlin when initiating the software. It has to be connected for the software to run so it must sense something because it lets me specify Snapmaker manually and add the x & Y dimensions and the software version Marlin.

An odd coincidence is that earlier today I chose to download the 30 day trial of Lightburn. It looks really comprehensive so I am a little frustrated that I cannot get it to connect to the Snapmaker, having followed all of the installation instructions. I checked and I was able to use Luban to talk to Snapmaker over the USB/Serial port on my Mac but Lightburn resolutely refused to connect.

On the Lightburn forum a staff member said that they had only just included the Snapmaker name for manually adding the machine so I guess a version 2.0 person requested it/and possibly helped them with some parameters.

EDIT
Here is a verbatim response to my Snapmaker questions…

2nd Edit
I have been experimenting with Lightburn and have managed to drive Snapmaker v.1.0 with it. The controls which are provided over every imaginable value for laser creation work are excellent. I will try and produce some work in a few days because I am rather busy at this time with house renovations. I may even make a screen video for assistance with understanding what facilities may be useful in Luban and worth aiming to produce.

I was very pleased to note that you can set the software to overscan the image by a numerical percentage value, which would really help with turning the laser beam off before it stops and changes direction and turning it on again once it has started moving again and velocity is up to speed.

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Interesting work here @Hauke; and thanks for the useful links.

Yep, thanks again @Hauke. In May it was Marlin 1.8.0.0 and is possibly still there. At least I have a starting point now.

I’ve noticed this same thing when using paper, either regulator printer stock or thicker card stock, and I think you’re reasoning for why is spot on. I had much better success with your techniques to get a “gray” when testing on wood, as it can singe and darken before going black, and doesn’t start out with such a dang high albedo (it’s less white).

I have a million questions for you @Hauke and @jepho , you guys are trying to tackle alot of the things I’m concerned about as well.

I will just start with one, is the snapmaker (2.0) a grbl capable device ?
I found a program called LaserGRBL and it looks promising, but I need to dig into alot of the settings.

I will refrain from adding more questions for now,(perhaps just one more:)
Maybe we can start another topic?

like, alternative laser controlling software and settings?

Hello @Galduron: There is a vast array of choice for controlling the laser. Much of it is available via Github for open source stuff and Grbl control. It has to depend on what your future needs are likely to be. If you want to do any sort of production work, then open source may not offer the best solutions, purely because response times to problems can vary widely.

Production capable software will require a fee but it will usually have a GUI that is less clunky and the response to issues is good. As an example, I have been testing Lightburn and putting it through its paces. The interface is clean and logical and the developers are very responsive. There are two of them and they have two admin assistants. The forum they run has over 7,000 members.

The software is around £31 for a year from the UK. It is highly capable and can run CO2 or Diode lasers and I do believe that fibre lasers is on the to do list. The developers are very knowledgeable and friendly. I have recently started to look at it in relation to SM1. You may find this link helpful.

Hello @jepho, thanks for responding.

At the moment I am diving feet first into laser engraving, greyscale images, and have had time to find my settings in Luban, made some awesome engravings, posted some of them on Facebook snapmaker group. The only thing that bugs me is that the way Luban creates the dot mode gcode files.
It takes too many hours to create an engraving when the laser does the move,stop,burn,move motion at high detail. I love the resolution this thing can make, but I am looking for an alternate approach.

I believe that by alternating pulses fired by the laser while the gantry has a steady motion going from point A to point B, the same effect could be achieved.
Is lightburn hooked up to snapmaker capable to do this?
Their fee is reasonable enough for me to use their software if that’s the case.

I have been reading up on you and @hauke 's discussions on several post, learning what I can, trying to understand (most of the time successfully). I am willing to learn so much more, but most of all I need to know if that time will be rewarded with more speedy results, my wife is complaining about my ‘research time’.

Hello @Galduron. Well… the first thing to say about Lightburn is that you take advantage of a 30 day trial period; without any need to purchase the software. During the 30 day trial period there are no artificial limits placed on what the software can do.

I like the ability to overscan in Lightburn. Where the laser module has to change direction, there is an unavoidable amount of speed change with the head slowing down then speeding up. Lightburn permits a setting of at least 2.5% overscanning so that the burn is done when the head is moving at a constant speed. It also provides several useful modes for image processing, including halftone & greyscale.

I am still trialing the software and have not discovered all that I need to know as yet. It is very capable software and could be used in a commercial environment. I am currently busy with other things but I intend to do some image processing next. My thought is that you lose nothing by trialing Lightburn. It is likely to prevent you spending rather a lot of time trying to make Luban do what you want.

Okay guys. I have successfully printed a more true, variable-powered greyscale laser engraving using a local copy of LaserGRBL that I modified to work with our machine. I have some cleanup work but I’ll have something up soon. It was interesting coming across your posts and you had all had the same questions and discoveries I had. @Hauke if you want to provide the GraySquare image for me to convert as a test, I can print it and put my results here. Right now I just have a random desktop background image I printed as a test. I want to print it again at a slightly lower power level since it burned too dark, but there is so much more detail than I could get with dithering. For now maybe I’ll use the one from trotec and maybe a random gradient from somewhere. Anyway. Keep an eye out here for my latest changes to the software. I haven’t uploaded the changes yet. It wasn’t too difficult. I’ll try to update here when I finish.

Unfinished Sample Attached.
Left: Luban Atkinson Dithering Dot mode
Right: LaserGRBL Line2Line Tracing modified for Snapmaker 2.0
Max laser power for both set to 18%

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That’s incredible. Interested in knowing how Lightburn does with an image like that. Clearly LaserGRBL does great.

WOW !!! Really Cool @MadHatter !!!
Thank you for this personal investment of yours ! For what it’s worth, you made my day and give me hope to be able to use the laser freely.

I am a newbie in all of this and have defiantly understood that Luban is not really a way to get the results someone like, except maybe for simple things.

Does your programming only concern greyscale ? or does it give control in things like cutting too ?

I know its relative… but do you guys think LaserGRBL is the better way to go than Lightburn? It looks convincing !!!
I downloaded the trial of light burn but communication with my machine is not yet set up and it seems to be an issue for many.
I would change software again and be happy to settle with it ! i guess like many other out there…

Kindly,
phil

Hi @MadHatter, thanks for sharing this! How long actually did the print run, compared to Luban?

Regarding grayscale square, I need to create the image :slight_smile: Will do and put it somewhere.

@phil I didn’t know Lightburn could produce gcode compatible with the machine. The changes I made were only to get greyscale working in LaserGRBL. I found it silly that with other software options such as Luban, I could only burn in black and white (calling dithering greyscale is a lie) so I wanted to confirm that the machine is capable of more. I wasn’t too concerned about getting the connection working either since I can connnect in Luban if I want and that seems to work just fine. Even if you could get LaserGRBL to connect I know it would need some additional tweaks. I suppose you could always produce the gcode in something else then run it in Luban or whatever else connects to it easily if you don’t like running from the machine.

@Hauke It took quite some time I hate to say. Just as long as from Luban if not longer to do the dot mode. Luban looked like it was going to be at least a little faster in line mode but was still hours for this image. Luban’s line mode looked pretty bad though. I could see the lines in a 10/mm print bleh. I don’t see any in these. I do have this printing in both directions for now. Supposedly you can get better quality only turning the laser on in one direction according to the LaserGRBL settings… that setting may or may not work with my changes… I haven’t tested it. Unless I’m mocking something, I prefer to wait for the quality. I’m not trying to mass produce anything.

I’ll compile the code optimized in release mode and throw it in releases. Just extract and run the exe. For now I won’t build the installer. You might need to delete C:\Users[user]\AppData\Roaming\LaserGRBL\LaserGRBL.Settings.bin because if you have run it before and changed the settings, it won’t get the new header and footer due to the ability to customize the header and footer. Not good…

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Thank you for this explanation @MadHatter ! Does this also work for mac ?
I don’t know what lightburn can do either… Its more cause i’ve been reading it’s name frequently and seeing that people are trying to figure thing out, there too.
I would just like a piece of software where i can create and get the g-code on the stick, run it and be happy with the result. Ignoring Luban…

Try a 30 day free trial of Lightburn. Works fine on a Mac. Baud rate with my SM1 was 115, 200. Lightburn filetype is .gc. Change it to .nc and it will run on Snapmaker from a USB stick.

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Thankyou @jepho !!! that’s great news for me !
is it the same Baudrate for SM2 ? A350.

Can i assume that Lightburn can produce the same type of results as the one shown from MadHatter with LaserGBRL ? or would i have to have both softwares depending on what i wanna do ?
Sorry for being so ignorant and maybe wanting it too simple but im learning so much at the moment… i guess you ve all been through this before… and we never stop learning each one at his level :slight_smile:
Thank you for all for helping !!!

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