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Why does bed heats when changing filament?  

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adp97
(@adp97)
Active Member
Why does bed heats when changing filament?

Maybe this is a stupid question, but I cannot find any reason why the heated bed should heat when you are only changing the filament. Let say it assumes you are going to print right  after changing the filament, but I still think it is unnecesary to wait until the heated bed reaches for example 85℃, the filament could be loaded in the meantime!

Any other idea?

Posted : 26/01/2023 8:13 pm
JoanTabb
(@joantabb)
Veteran Member Moderator
RE: Why does bed heats when changing filament?

Make a gcode to only heat the nozzle.

Job done

Possibly the controller is short of code space and they use existing code?

 

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 26/01/2023 9:32 pm
adp97 liked
Stefan
(@stefan-3)
Estimable Member
RE: Why does bed heats when changing filament?

Possibly the controller is short of code space and they use existing code?

That is the most likely reason, i think soo too.

And if the nozzle has reached temperature, you can change the filament. No need to wait until the bed has warmed up.

Posted : 26/01/2023 10:26 pm
adp97 liked
fuchsr
(@fuchsr)
Famed Member
RE: Why does bed heats when changing filament?

As Joan said no need to wait until the bed has heated for a filament swap but why it heats the bed up in the first place, no one but the Mighty Jo knows. The main suspect though is the one you figured out yourself, prepare for a print following the swap. But of course I often unload filament without necessarily printing right away with new filament, so it often feels like a waste of electricity dollars...

Posted : 26/01/2023 11:04 pm
adp97 liked
René
(@rene-3)
Reputable Member
RE:

In the eeprom.cpp I encounter the following instruction

Line 61 eeprom_init_default_byte((uint8_t*)EEPROM_HEAT_BED_ON_LOAD_FILAMENT, 1);

I have absolutely no understanding of it,

but if this value is set from 1 to 0,

the bed will no longer heat up with a load filament command via the controller.

Posted : 27/01/2023 12:40 pm
adp97
(@adp97)
Active Member
Topic starter answered:
RE: Why does bed heats when changing filament?
Thank you all for your answers!
Line 61 eeprom_init_default_byte((uint8_t*)EEPROM_HEAT_BED_ON_LOAD_FILAMENT, 1);

 

@rene-3, at which FW did you find the above line?

I am looking for it on latest release 4.4.1, but I cannot find it

Posted : 27/01/2023 2:31 pm
René
(@rene-3)
Reputable Member
RE: Why does bed heats when changing filament?

Sorry my mistake, I come across it in the MK3 Prusa Firmware,

https://github.com/prusa3d/Prusa-Firmware/tree/MK3/Firmware

Posted : 28/01/2023 6:32 am
dpenezic
(@dpenezic)
New Member
RE: Why does bed heats when changing filament?

I ask the same question myself, additional to load, way heat bed when unloading filament to?

Posted by: @adp97

Maybe this is a stupid question, but I cannot find any reason why the heated bed should heat when you are only changing the filament. Let say it assumes you are going to print right  after changing the filament, but I still think it is unnecesary to wait until the heated bed reaches for example 85℃, the filament could be loaded in the meantime!

Any other idea?

 

Posted : 02/02/2023 6:41 pm
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