hotend over 150 degres before bedmesh in print start

[Pepeuch]

Klippain branch

• I confirm using the main branch

Version

v4.2.0-16-ga207639

Describe the bug and expected behavior

hello, I noticed in your print start that the temperature of the nozzle is higher than 150°C during the meshing of the bed, is it possible to modify the print start so that the meshing is done with an adequate temperature?

thank you again for your work.

Additional information and klippy.log

No response

[Frix-x]

What kind of probe are you using?

If using TAP it should not be the case as there is some safety included in Klippain and this would be a bug.
If using another kind of probe this behavior is normal to measure the bed at the printing temperature to be as close as possible as the printing conditions.

[Surion79]

I use tap and haven't had the issue with an overheated nozzle.

[EricZimmerman]

It's all managed appropriately depending on the configuration selected

[Pepeuch]

hello, so I have a classic inductive probe, and I think it doesn't like the hotend to be too hot, and I think that this generates measurement errors, that's why I was wondering if it was normal for the temperature to increase just before the bed mesh. while for the QGL the temperature is indeed at 150. Perhaps add a temperature for the mesh not only the TAP.

Generalizing the safety temperature to 150 for the QGL/bedmesh would surely be simpler, regardless of the probe used. No?

[Surion79]

Could you please describe in which case it is over 150 degrees? (I mean steps done to have it over 150)

[Pepeuch]

So it's over 150 degrees when he meshes the bed; in fact the nozzle heats up to printing temperature at the time of purging but does not come down for the mesh. while it should be at a value of 150 (I specify that I use the original macros from klippains without any modification); and that I test all the macros to see if there are any inconsistencies/errors before launching large prints.

I also specify that I have been using klipper since v0.6 (a long time ago), but I wanted to test klippains for the first time, and which seems to me to be an excellent alternative to standardize use and configuration printers.

[Surion79]

Could you add a klippy log until the start with the mesh? Can you also give an example gcode file which includes the 'misbehaviour'?
(E.g. a voron cube at 300% size to habe a bed mesh call)

[Surion79]

hmm, reading your last comment again: You do a primeline and after that you do a bed mesh?

[Pepeuch]

hello and happy new year to the whole team;
excuse my late response, the problem (it is not necessarily one), but the order of actions which is faulty, once the QGL is made at the correct temperature (150°C), the nozzle starts to heat to the printing temperature (200°C), then purge, clean the nozzle, do a homing, until then OK everything is good.

From this point on, the macro should lower the nozzle temperature to 150°C before meshing the bed (which is generally the backup temperature for the probes). But since this step is missing, the mesh of the bed is done at printing temperature (I specify that I am talking about the temperature of the nozzle).

I therefore ask if it was possible to add this instruction in the startup macro and even add a user variable for the temperature of the nozzle to carry out the meshing of the bed and this whatever the probe used.

[Surion79]

your order is wrong. mine does primeline right before the print start. QGL, Bedmesh comes always before that.
can you please attach a klippy.log?

your startprint_actions seems out of order
mine is
variable_startprint_actions = "bed_soak", "extruder_preheating", "chamber_soak", "clean", "tilt_calib", "z_offset", "bedmesh", "extruder_heating", "purge", "clean", "primeline"

[Pepeuch]

Mine is:
HEATSOAK_BED
HEATSOAK_CHAMBER
TILTING
EXTRUDER_HEATING
PURGE
CLEAN
Z_CALIB
BED_MESH
PRIMELINE
EXTRUDER_PREHEATING

and the temperature of the hotend does not go down before the BED_MESH

I will post the klippy log tomorrow, I have a print in progress and it may be quite long.

[EricZimmerman]

Why not swap preheat and heating? Meshing at 150 is fine and then it doesn't need to drop.

[Pepeuch]

the problem with preheating is that it does not allow purging to clean the nozzle.
there may be a small modification to make in your start_print to ensure a good bed mesh.

here is my klippy log
Uploading klippy.txt…

[EricZimmerman]

I've not seen a Need to purge with klippain since it does retractions at the end of a print, personally

[Surion79]

hmm, i understand if someone with a Voron Taps wants to purge/clean nozzle before a bed mesh, But I don't see the reason to do it on an inductive probe.

I have Voron Tap and don't do a prior purge/clean as it is the same for me as for Eric. I have perfect first layer

[Surion79]

please change order to

HEATSOAK_BED
HEATSOAK_CHAMBER
TILTING
EXTRUDER_HEATING
PURGE
CLEAN
EXTRUDER_PREHEATING <<<<--- ADD
Z_CALIB
BED_MESH
EXTRUDER_HEATING <<<- change to heating and before primeline
PRIMELINE

PREHEATING issues a M109 S150 which is then waiting to reach 150 degrees up from the previous heated value

[Surion79]

putting primeline before extruder_heating won't work as the function does not have any temperature commands afais

[Surion79]

you added no klippy log, just a link to this issue.

if the print_start action is really as you describe, the print can never begin, since the extruder is at safe temperature, not at printing temperature.
if you manipulated the value for variable safe_extruder_temp to the printing temperature then your request will never work