Controller miscalculates run time

Dear Readers,
I made a little test today to see how the laser could react to some settings.
I loaded the file on the USBstick and uploaded the file.
Estimated run time 1h27 min.
It took 4h37 min !!!
Is this a Luban problem ? Should I rather write in the Luban topic section ?

Kind regards,

What is the version of Luban you are using? Maybe post the source file here for testing?

Runtime is a known problem to be calculated, same at 3d printing.- I don´t know if this calculation could be adjusted. The controller calculates for itself, same does Luban.

I calculate for myself, for example i do many small tests before laser engraving a huge thing, so i multiplicate the factor of size to the original test-file time taken.
Hope this could be understood.

Makes sense to me. But luban and the firmware must each have a algorithm to estimate job time (probably based on the linear distance of the tool path and the running speed. With some other factors thrown in?) So it doesn’t supprised me that predicted time and actual time are different. But as I read your post @xchrisd it sounds like your saying the predicted time in Luban is different them the predicted time in the controller? Why would snapmaker use different algorithms?

I have yet to have the estimated time match the actual print time. I’ve only used the laser module so far. I printed a picture that was estimated at 3 hours 26 minutes. It actually took 9 hours 18 minutes. I had to pause it at 7 hrs as I didn’t want it running overnight while I was sleeping, resumed in the morning just fine. Even short prints, on the order of less than 2 minutes, take longer than the estimate.

I have no idea how it calculates the print time, but somewhere there must be an error in the formulas.

I now assume twice the print time it says, even three times for longer prints.


Same here! What could be the cause of this? Could it be related to the working parameters inserted in Luban? I used the settings as provided in the Definitive Guide for Laser Engraving and Cutting.

edit: sometimes the ‘Time remaining’ even counts upwards instead of down

Hi Potter, Luban 3.7.0. the .nc file is too large to post here. Is there another way to post the file ?

Thank you

@phil Wetransfer or any other cloud or one click hoster would work, just share the link :wink:

I had the opposite on the latest big laser print I did - 12" x 12" Said 42 hours. Ended up being less than 24. Seems like the laser should be pretty simple to estimate.


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Thanks xchrisd ! Yes i think i get it…
Throughout other tests i have been able to notice that the calculated time on the controller corresponds to the runtime of the first layer (in a multi-layer file).
From then on the settings make the difference of how many extra hours it goes…

That’s a nice surprise :slight_smile:
I read somewhere that the max runtime of the laser should be 5h… which is disappointing if it takes so many hours to do something not close to the bed size.

Link to file :
Looking forward & Thank you for your feedbacks !

Where did you read this? I have not heard of a laser time limit.

I can’t find it anymore, but ill keep an eye open for it and post a link when/if i do.

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Hi Atom, ran into it again… N°3

So you know that is for the sampamker original. And while the focusing instructions certainly apply to both SM1 and SM2.0 im not sure the time limit would. But its good to keep in mind.

thank you for this clarification !

But you have made me curious @JKC20 is there any run time limitations for the laser on the SM2.0? I would hate to ruin my laser module by running a project that is too long.

found this on the store…
For general understanding, as numbers vary, may i ask if it makes a difference : 445nm or 450nm?

Not for run time.
Not for ability to cut.
Technically it can make a difference for which safety glasses (and windows) are compatible with it. I wouldn’t want to have glasses that didn’t cover both though just to be safe.