Nozzle is scratching on the bed

Frank01x

Hi to the community,
I own a JGAurora A5S since April 2019 and have printed various things, mostly PLA, without any problems with the original firmware.
At the end of July, at the end of a project, I wanted to change the firmware to the Marlin version of Samuel to use bed mesh leveling. After a test print had succeeded, I saw that a new update was available for download at the end of July. With this latest version, I can no longer print, because the Nozzle after the leveling and saving the configuration, the print bed damaged! I use the JG Slicer (a modified version of Cura). The start code entered there reads:

G28; Home
M420 S1
G1 Z15.0 F6000; Move the platform down 15mm
                                                            Prime the extruder
G92 E0
G1 F200 E10
G92 E0

Does anyone know this problem? I am full of hope!
(My native language is german, sorry!)

Samuel Pinches

Frank01x, I'm sorry to hear of your bed being damaged. I will look into this and reply to you soon. Thank you for letting me know of this issue.

axell

Hi, 

I have the same problem. Is there a solution for this issue? 

Many thanks,
Axel

GTA99

Same Problem, and this after i replace it with a new heating bed!
I installed the community Firmware, did the mesh bed leveling and add 

M420 S1 after G28 gcode command.
What is wrong with the Firmware and how can i fix it.

Samuel Pinches

• Did you mesh level the bed with the bed hot?
  
• Did you save the configuration after doing the levelling?
  
• Are you using the same SD card with the eeprom.dat file (which contains the saved settings) on the card?
• After mesh levelling, you can enable mesh levelling in the menu, and then manually move the print head around and see how accurate the mesh is
  

GTA99

• Did you mesh level the bed with the bed hot?

  Yes at 50 Degrees

• Did you save the configuration after doing the levelling? Y

  es i pushed the "Store Settings button after mesh leveling

  n".
  
• Are you using the same SD card with the eeprom.dat file (which contains the saved settings) on the card?

  I only use one SD Card. Same that i use to flash Community Rom. But i will check after print is done.

• After mesh levelling, you can enable mesh levelling in the menu, and then manually move the print head around and see how accurate the mesh is.

  Didn't try this out. But i will. Thanks :)

I used the baby step function to check the the hight.
Totaly 0.5625 to deep

This is how i modify my Start Gcode

G28 ;Home
M420 S1
M117 Use Mesh
M290 Z0.5625 ; move up 0.5625mm on the Z axis
M117 BabyStep 0.5625
M500
G1 Z15.0 F1500 ;Move the platform down 15mm
;Prime the extruder
G92 E0
G1 F200 E10
G92 E0

gsokky

Hi,
Unfortunately, I encountered the same problem. As I was late for abort the print, the scratched area is bigger than @Frank01x's. I plan to buy a bed surface, because first layer does not stick to scratched area properly. I installed the community firmware 3 days ago for trying mesh bed leveling. It did well for 2 days, but then this issue happened. 
How can I fix this? 
Thanks

Samuel Pinches

Hi @gsokky - I am sorry to hear that. Unfortunately, the worst damage will be to the nozzle, as the ceramic coating will damage the brass nozzle orifice, so you will probably need to replace the nozzle as well. Some spare parts are linked on the wiki here.

Its confusing to me, I don't understand why it would work fine the first time, and then happen later on. The important thing is to save the settings (SD card in!) after doing the mesh bed level, and to ensure the SD card is in the printer when you turn it on so those settings are properly loaded again when you come to print.

I'm sorry that I don't have more information. You can manually enable mesh levelling in the leveling menu and check that it is moving correctly using the manual move commands, before printing. I suggest doing that to be sure, if you're having any doubts.

Please let me know if you have any other questions, or findings on this issue.

chang69

I have the same issue. I was totally clueless as to why, but luckily I found your @Frank01x post. I registered on this forum just to say thank you. I just replaced all the parts this afternoon. New level bed, glass and nozzle. My damages where big as didn’t watched the printing at all. 

I propose to take the firmware offline till this issue has been located, otherwise a lot of people get damages. I will rollback to the original firmware.

Samuel Pinches

Thanks for your report @chang69 - can you please be specific to describe your issue? It may not be the same.

chang69

The issue is:
-Calibrated the levels using the sheet and the 5 corners/area.
-When printing, after heating the Z level is a lot lower and scratches the nozzle into the bed.

The first time I had it, I thought I made an error. I already have this printer for approx 1 year and never did I had this issue.
Then the 2e time the scratch was so deep that the entire glass was damaged

Then I saw this post and suddenly recall that all this only happened after I upgraded the firmware. I have now rolled it back to the factory version.

This costs me 2 nozzles, 1 glass bed and one heated bed. :-(

Samuel Pinches

I am truely sorry to hear of that damage to your printer. I know that replacing the bed in particular is quite expensive.

I agree the current situation is not ideal. It is extremely difficult as one person to do everything, I wish there were other willing volunteers. If I had more time, I would like to create a video showing how to use the mesh bed levelling feature, and how to double test if it is actually working before running a test print. Maybe that will be possible in early November.

I’m particularly concerned about the reports of mesh bed levelling failing to enable intermittently. However, intermittent issues are really the most difficult of all to solve, and at this time I don’t have anything left to give at the moment - I’m writing this message at 2am. 😞

I don’t think pulling the firmware does any good at this point. Perhaps I could put a warning there? If you have a suggestion I’m all ears.

Finally, I would suggest trying the “beta 6” version and seeing if you have different results with that one.

Best regards,
Sam

Laser8302

A couple ideas.
1) After flashing firmware, run M502, M500, M501 in that order.
2) Connect to printer using prontorface. Send M851 (Z-offset) see if it is a negative number. I would send M851 Z0 to make sure it's set to 0. Then store EEPROMs again with M500.

chang69

@Samuel Pinches thank you for developing this firmware for the community. I understand how difficult it is to do this all by yourself and flush out bugs. I think a warning would be great. 

One another note, because my 3D printer was broken I ordered a Prusa MK3S. I honestly must say the difference with the jgaurora is day and night. 

With the jgaurora more than 50% of the prints failed. I have now a 100% success rate and focus on creativity. 

I still keep my jgaurora and might give it to my nephew. ;-)

Samuel Pinches

Thanks. I've added a warning on that page now, and wrote up some brief instructions on how to use mesh bed leveling here.

The MK3S is not comparable as it is significantly more expensive, but you definitely get a more polished product as a result for your money. Happy printing!

rhythmdave

I had the same problem with scratching the bed. Turned out the hot end carriage wasn't level (x axis).  Was able to level it by turning off printer and hand turning z axis motors by hand.  After leveling the carriage and perfoming the leveling, it worked fine.  I got a new glass from JG for $35 (said it was shippng cost) and in the mean time you can turn the glass over an print directly to glass,

Richy_T

Perhaps advise people not to print on the factory glass with the new firmware until they are comfortable with it. a 30cmx30cm piece of glass from a home improvement store is a lot cheaper.