Nozzle temperature changing while printing

Martín

Hello, Im using prusaslicer to slice my stl and I set up 215ºC to print, but I saw that while printing the part, the nozzle temp changes for no reason, suddenly its 220ºC, then 225, then 215, and I don't know why is this happening

droftarts

@Martín If the temperature is changing suddenly, most likely it is either interference or a poor connection. Check your wiring thoroughly, and make sure it isn't shorting/grounding out on other wiring or hardware. Move or shield the wiring from heater and motor wires.

If that doesn't help, please supply more information. A screen grab of the temperature changes would be useful. Also your config.g (so we can see what type of temperature sensor you use, and how it is set up) and send M115 in the console and post the response, so we can see what hardware and firmware version you are using.

Ian

Martín

Hello @droftarts, the machine never did it again so I guess it could be a problem with the GCode.

What I wanted to ask is if there is a way to set this on the machine.

Heat Bead -> BLtouch -> Heat Nozzle -> Print

This is because the extruder is making a lot of ozooing while passing the BLtouch and is being an issue

Thanks!

Phaedrux

@Martín said in Nozzle temperature changing while printing:

What I wanted to ask is if there is a way to set this on the machine.
Heat Bead -> BLtouch -> Heat Nozzle -> Print

You can control this in your slicers start gcode. It will depend on your slicer how you would go about doing that.

Martín

@Phaedrux I thought I had to do it with the Duet Config.. interesting

I'm using PrusaSlicer but with a custom printer, and in my initial Gcode in PrusaSlicer is just:
G28
G29

Martín

I'm gonna try this starting G-Code, how do you see it?

M104 S0
G28
M109 S0
G29
M109 S200

droftarts

@Martín The commands to know are:
M104 - Set Extruder Temperature
M109 - Set Extruder Temperature and Wait
M140 - Set Bed Temperature (Fast) or Configure Bed Heater
M190 - Wait for bed temperature to reach target temp (set temperature and waits)

For M104 and M140, the temperature is set and heating starts, but then control is returned, ie it will do the next Gcode straight away, without waiting for the heater to get to temperature.
For M109 and M190, you can't control the printer while the heater heats up.

If you want to do it in the order: Home -> Heat Bead (to temperature) -> BLtouch -> Heat Nozzle -> Print, then:

M104 S0   ; set nozzle temp to 0
G28       ; home
M190 S60  ; set bed temp and wait
G29       ; mesh compensation after bed has heated up, in case it moves
G28 Z     ; rehome Z, to take account of bed moving when heated, and to set mesh compensation at the correct height
M109 S200 ; set hot end temp and wait

I've set the bed temperature before doing the mesh, and added an extra home Z.

In Prusaslicer you can use the parameters from the filament you have selected to fill the numbers in, eg

M190 S[first_layer_bed_temperature]
M109 S[first_layer_temperature]

See https://help.prusa3d.com/article/list-of-placeholders_205643 on how to find and use these.

This is my start G-code in Prusaslicer. I tend to do the mesh compensation beforehand. It also extrudes a thick line at the front of the bed (my X0 Y0 is in the centre of the bed) to get the nozzle going:

T0
M190 S[first_layer_bed_temperature]
M109 S[first_layer_temperature]
G28
G1 X-80 Y-80 Z0.3 F6000 ;Move the platform
M83 ;relative extrusion mode
G92 E0
G1 X0 F500 E20
G92 E0

Ian