Heating during z-calibration ok?  

Re: Heating during z-calibration ok?

My comment : No !

While heating the bed and nozzle the pinda probe measuring is affected.

Thomas

Re: Heating during z-calibration ok?

Thanks. Sounds plausible. Is it "backed" by any solid evidence?

Re: Heating during z-calibration ok?

You must heat the bed before the 9-point calibration (G80) ; the nozzle is to a large extent irrelevant.

If you don't heat the bed to print temps then the calibration will be incorrect (variable). You need to ensure the probe is at least 100mm above the bed while heating the bed.

However, I heat the nozzle to 170 degrees while the bed is heating and then to print temp during the G80 just to save time.

If you look at older posts, you will find plenty of evidence.

Peter

Re: Heating during z-calibration ok?

But then the G-code for the printer should do that and also move the probe up? And should you then turn heating off during calibration?

The temperature calibration of the probe - shouldn't that make it possible for the printer to compensate for bed temperature?

So you should use the preheat commands on the printer first then?

Re: Heating during z-calibration ok?

So to incorporate what I found I will start prints like this (see gcode below)

1) Preheat nozzle to 170 and bed to printing temperature
2) Home and wait for temperatures to stabilize
3) Turn off bed and extruder heat
4) Do bed leveling
5) Re-set extruder and bed temperatures and print when reached

Makes sense?

As this:

G21 ; set units to millimeters
G90 ; use absolute positioning
M82 ; absolute extrusion mode
M104 S170 ; set extruder temp to 170 preheat MHP
M140 S{material_bed_temperature} ; set bed temp MHP
G28 W ; home all without mesh bed level
M190 S{material_bed_temperature} ; wait for bed temp MHP
M109 S170 ; wait for extruder temp MHP
M104 S0 ; turn off extruder during bed leveling
M140 S0 ; turn off heatbed during bed leveling
G80 ; mesh bed leveling
M104 S{material_print_temperature} ; set extruder temp
M140 S{material_bed_temperature} ; set bed temp
M190 S{material_bed_temperature} ; wait for bed temp
M109 S{material_print_temperature} ; wait for extruder temp
G92 E0.0 ; reset extruder distance position
G1 Y-3.0 F1000.0 ; go outside print area
G1 X60.0 E9.0 F1000.0 ; intro line
G1 X100.0 E21.5 F1000.0 ; intro line
G92 E0.0 ; reset extruder distance position

Re: Heating during z-calibration ok?

You certainly don't need this:

M104 S0 ; turn off extruder during bed leveling
M140 S0 ; turn off heatbed during bed leveling

I repeat, the heated bed must be at printing temperature during the 9-point calibration.

The built-in probe temp calibration is OK, but it does not take into account changes in ambient temperature. Therefore it's not something I use.

Peter

Re: Heating during z-calibration ok?

You certainly don't need this:

M104 S0 ; turn off extruder during bed leveling
M140 S0 ; turn off heatbed during bed leveling
I repeat, the heated bed must be at printing temperature during the 9-point calibration.
....

Well if the pulses to the bed and extruder disturbs the measurements then I DO have to turn of heating during bed leveling.

kr
Morten

Re: Heating during z-calibration ok?

Well if the pulses to the bed and extruder disturbs the measurements

Why would that happen? The probe (and MCU etc) is powered via a buck regulator so the 5 volt rail is simply not likely to be affected by the heaters. Especially so when the PSU has at least 25% overhead.

Peter

Re: Heating during z-calibration ok?

Do we have a good start and end g-code established yet?

I'm having troubles with getting consistent results with bed levelling, printing with ABS/HIPS