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Prusa Mini End G-Code Problems  

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Eric Eichstaedt
(@eric-eichstaedt)
Eminent Member
Prusa Mini End G-Code Problems

Hey,

at least since the release of the firmware 4.1.0 it is known, that there is a bug that triggers a strange behavior at the end of a print.
The printer executes G-Codes which are not part of the end G-Code,  i.e. homing, mesh bed leveling or purging, which can damage the printer massively.

It only accrues when you change the start or end G-Code. Many users of the Mini change the e-steps in the starting g-code when they are using the bondtech extruder or when they are just not pleased with the overall accuracy of the firmware e-steps.
For example, I´m using it for a warm-up routine of the P.I.N.D.A because of the horrible temperature dependence.

I didn't upgrade the firmware since 4.0.5, which released at the 6th of april 2020 (so well over a year passed)

I decided to upgrade to the newest version, because I thought the bug, which is commonly known, might be fixed...
but it isn't.

What's going on?

I also didn't find an official statement from Prusa, which alerts users that they shouldn't change the starting g-code or otherwise they could damage their Mini irreversibly.

 

I would love to hear that the development team is working on it or that I just did not find the official statement.

Greets
Eric

 

 

Electrical EngineerWorking on master’s degree in electrical engineering...
Posted : 12/07/2021 7:24 pm
Eric Eichstaedt
(@eric-eichstaedt)
Eminent Member
Topic starter answered:
RE: Prusa Mini End G-Code Problems

Github:

https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/864
https://github.com/prusa3d/Prusa-Firmware-Buddy/issues/733

Videos of it:


 

It as well happened several times to me but I didn't capture it on video.

 

Electrical EngineerWorking on master’s degree in electrical engineering...
Posted : 12/07/2021 7:31 pm
Eric Eichstaedt
(@eric-eichstaedt)
Eminent Member
Topic starter answered:
RE: Prusa Mini End G-Code Problems

It just happened to me again:

G-Code:

Faulty_G-Code

 

Electrical EngineerWorking on master’s degree in electrical engineering...
Posted : 12/07/2021 7:48 pm
Jerry liked
fuchsr
(@fuchsr)
Noble Member
RE: Prusa Mini End G-Code Problems

Interesting. I use both custom startup and custom end gcode but never seen any of this behavior. Some weird edge condition, perhaps?

Posted : 13/07/2021 12:41 am
Eric Eichstaedt
(@eric-eichstaedt)
Eminent Member
Topic starter answered:
RE: Prusa Mini End G-Code Problems

@fuchsr

What do you mean by "edge condition"?
Did you find any problems in the G-Code?
It doesn't mention anything after the End G-Code that should be executed.

Some people say that the starting g-code, which is commented out at the end of the print for some kind of information is interpreted wrong by the parser and gets executed. Sometimes it's mentioned that it only appears when the comment is longer than 95 characters.

 

Electrical EngineerWorking on master’s degree in electrical engineering...
Posted : 13/07/2021 5:07 am
fuchsr
(@fuchsr)
Noble Member
RE: Prusa Mini End G-Code Problems

My definition of "edge condition" is one that occurs under rare and/or unusual circumstances. I know a lot of people in these forums here use modified G-code, but this was  the first time I've heard about such strange behaviors. So my assumption was it's not a common occurrence and probably only happens under specific circumstances (such as the >95 character comments you mentioned). I use start and end gcodes modified to change the startup temperature behavior, position of the print head and bed before and after the print, esteps for Bondtech, etc. So far so good, no issues. Appreciate this report -- should I ever run into issues there's a place to check I would never have expected.

And I totally agree,  even if it's a rare condition it ought to be fixed to avoid damage.

-r

 

Posted : 13/07/2021 11:04 am
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