manuel.r6
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Re: Bed preheat error with v3.5.x

Jan 18, 2019 11:40 am

Hi. Yesterday I was trying to print an ABS piece. When de bed temperature raised to 100ºC began the first layers , the layer ends and the bed set for the second was 110ºC, before reach this bed temperature the display showed “BED PREHEAT ERROR” I try to print again and the same error was displayed . Today I download to my printer(i3-MK3)the firmware V3.4.1 and don’t show the error. Is a firmware bug?

dominique.l3
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Re: Bed preheat error with v3.5.x

Jan 19, 2019 9:14 am

Same issue here.
Printing ABS, first layer (bed temp. 100C) prints ok, at second layer bed temp. is set to 110C (Slic3r PE default), temperature rises very slowly to 108 or 109C and then, bang ! BED PREHEAT ERROR, and the print is killed.
Going back to FW 3.4.2 does help.
Occurs with some parts, and not with others.. very strange !
Room is at 16-17C, heating to 20C or more could help, but this is not an issue for me.

The print could be ok with bed at 108C, but the software does kill the prtnt !!! Stupid, no ???
This error could be changed to a warning, with printer set in pause mode for example.
HTH

kai.s9
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Re: Bed preheat error with v3.5.x

Jan 25, 2019 9:13 am

Hi Kai,

The default PET settings are just not good.
Set nozzle temp to 240C for first layer and other layers. Set bed temp to 85 for the first layer and other layers.
Depending on your environment, the object you're printing and the PID settings of your printer, the higher target temperature can't be reached fast enough.

No design issues, just regular configuration tweaking in the slicer.
Right, meanwhile I did sort that out too :-).
Unfortunately the PETG starts stringing on very small objects 0.4 nozzle with 240C - were ~225C works...
Had the hope Prusa team would set these defaults suitable for their filament... ?! 8-)

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PJR
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Re: Bed preheat error with v3.5.x

Jan 25, 2019 9:31 am

FWIW, I "upgraded" to FW 3.5.x a few days ago.

Now I am getting "PREHEAT ERROR" when printing a model with PLA, always at the same point (Z=1.2) and always during a tool change, at the point the temperature is increased by 2 degrees in preparation for loading the new filament.

This is definitely firmware related. For me, the work-around was to keep the temps constant (which can cause slightly worse tips). The other work-around is to revert to 3.4.x until this fault is fixed.

Peter
Please note: I do not have any affiliation with Prusa Research. Any advices given are offered in good faith. It is your responsibility to ensure that by following my advice you do not suffer or cause injury, damage or loss.

greg.p2
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Re: Bed preheat error with v3.5.x

Jan 26, 2019 10:11 pm

I am having the same issue with 3.5.1, Prusa PETG default settings, Extruder 230C first layer, 240C other layers, Bed first layer 85C, other layers 90C. Cooling fan disabled for the first 3 layers.

On the third layer, the fan comes on. In a few seconds, I get the "Bed Preheat Error". I tried this last night and this morning.

Note that the fan remains on after the error. I think the fan not turning off is a benign "bug", but would be nice not to have my fan running until I start preheating for another print or cycle the power.

This same problem happened on a previous version of firmware when I printed items with a small x-y footprint in the center of the build area. The problem went away by offsetting the print away from the center, where the temperature probe is located.

So I tried that again just now, moving the item printed to the side of center on the build plate. Note that I did not power cycle the printer between prints. This time, the printer did the Z calibration, went to the front corner and lowered to do a wipe. Paused maybe 10 seconds, then powered down the bed and hotend heater. No error messages. Just displaying "Prusa i3 mk2.5 Ready" like nothing happened. Another sign that the "Bed Preheat Error" is not cleaning up correctly.

I power cycled the printer. Retried the same print. The hotend dropped 5 degrees when the fan came on, but the bed stayed steady at 80C. Did not get the error. Printing fine.

kai.s9
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Re: Bed preheat error with v3.5.x

Jan 31, 2019 9:54 am

Ok, seems to fix the 'problem' mostly.
What I do not understand: Why does (sometimes) an error occur if the 1st to 2nd layer temp difference is 10°C or more... .
It seems that if the bed does not heat up fast enough this happens. But if so: Why can you define a 10°C spread in the Slicer?
THX
Kai

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nikolai.r
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Re: Bed preheat error with v3.5.x

Jan 31, 2019 4:47 pm

kai.s9 wrote:
Jan 31, 2019 9:54 am
Ok, seems to fix the 'problem' mostly.
What I do not understand: Why does (sometimes) an error occur if the 1st to 2nd layer temp difference is 10°C or more... .
It seems that if the bed does not heat up fast enough this happens. But if so: Why can you define a 10°C spread in the Slicer?
Current firmware is very aggressive on the bed temp check. If you print PLA, you're turn the fan on from the second layer. In case you're printing small object, you're blowing cold air on the bed and trying to heat it up at the same time. But if you print a big object, the bed is covered with plastic and can is able to heat up fast enough.
Slic3r does not limit you in your settings. Maybe you want to achieve something special (not common) and Slic3r shouldn't be in your way. In general I don't understand the default setting with this 10C temp difference.

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TickTock
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Re: Bed preheat error with v3.5.x

Feb 13, 2019 1:37 am

I had this problem,too. Small part in center = Bed preheat error. Just moving it off center eliminated the issue. With bigger parts I guess the fan doesn't dwell long enough on the area around the sensor to trip it.

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carlos.b6
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Re: Bed preheat error with v3.5.x

Feb 13, 2019 9:27 am

WhatsApp Image 2019-02-11 at 20.01.45.jpeg
WhatsApp Image 2019-02-11 at 20.01.45.jpeg (115.58 KiB) Viewed 21 times
10 minutes to go in a 47 hour print I get this PREHEAT ERROR
Could it be more depressing?
I do think it is software related more than a hardware issue
Print failed with hotend over the wipetower. It had been 100k times over that area in the same print with no error
BTW - I am not using PRUSA's FW, but Zero's. Slicing was done with 1.42 alpha3

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