Elegoo Neptune 4 PRO Printing Issues: No Preheating and Extruder Crashes

[xenos92 0]

Hello everyone,

 

I'm facing several issues with my Elegoo Neptune 4 PRO 3D printer that I'm hoping to get some help with. I've been experiencing some challenges with the G-code not preheating the printer as expected, which leads to errors and the printer beginning the print job without reaching the necessary temperatures. Here's what's been happening:

 

Preheating Issue: When I send a print job to the printer, it doesn't preheat automatically. Unless I manually preheat the printer, it starts printing directly, leading to a "temperature too low" error and the printer beeping with an error message.

 

Extruder Crashing: Occasionally, the extruder head crashes against the metal plate, causing the printer to stop. The error displayed is from the Klipper firmware:

 

// MCU 'mcu' shutdown: Stepper too far in past
// This generally occurs when the micro-controller has been
// requested to step at a rate higher than it is capable of
// obtaining.
// Once the underlying issue is corrected, use the
// "FIRMWARE_RESTART" command to reset the firmware, reload the
// config, and restart the host software.
// Printer is shutdown
!! MCU 'mcu' shutdown: Stepper too far in past

 

Missing Purge Line: Additionally, the printer is supposed to execute a purge line on the side before starting the main print to ensure the filament is flowing correctly. However, this isn’t happening.

 

Printer Model: Elegoo Neptune 4 PRO

Cura settings:

Version: 5.7.1

 

Printer settings: 235mm x 235mm x 270mm

 

Printhead Settings:

X min = -20

Y min = -10

X max = 10

Y max = 10

Gantry height = 270

Apply extruder offsets to Gcode = true

 

Extruder settings:

Nozzle size = 0.4

Material diameter = 1.75

 

 

My start G-code:
 

;ELEGOO NEPTUNE 4/4Pro
G21 ;Metric values
G90 ;Absolute Movement
M82 ;Absolute Extrusion
M220 S100 ;Set the feed speed to 100%
M221 S100 ;Set the flow rate to 100%
G28 ;home

M104 S150 ; Set Extruder temperature for bed leveling
M140 S{material_bed_temperature_layer_0} ;Start heating the bed.
M109 S150 ; Wait for Extruder temperature for bed leveling
M190 S{material_bed_temperature_layer_0} ;Wait for the bed to get to the set point.
G92 E0 ;Reset extruder position

BED_MESH_CALIBRATE  AREA_START=%MINX%,%MINY% AREA_END=%MAXX%,%MAXY%

M104 S{material_print_temperature_layer_0} ; Set Extruder temperature
M109 S{material_print_temperature_layer_0} ; Wait for Extruder temperature
G92 E0 ;zero the extruder

G0 F3000 X-20 Y-10 Z20 ; Move to wait position considering printhead settings
G130 X20 Y20 Z20 A20 ; Lower stepper Vrefs while heating
M105 ;Report temperatures

G130 X127 Y127 Z40 A127 B127 ;
G92 E0 ;zero the extruder

G1 F900 E10 ; purge nozzle
G92 E0 ;zero after purge

G0 F3000 X10 ; move over
G0 F2400 X25 Z0.3 ; drop to wipe height
G1 X245 Y10 E15; Slow wipe
G0 F2400 Z10 ; Raise Z

 

I would appreciate any advice or suggestions on how to fix these issues. Has anyone experienced similar problems with their printers?

What could be causing the extruder to crash and the printer not to preheat as commanded by the G-code?

 

Thank you in advance for your help!

[Slashee_the_Cow 483]

Afraid I can't solve all your problems... or maybe many of them. I'll go over my best guesstimations then I'll go over some things I see in your gcode:

 

Preheating: This one I'm not sure I can explain. There's an M109 and M190 so it should have waited for both extruder and bed temperature.

Extruder crashing: That error message makes it seem like you're trying to print/move the head the head too fast on at least one axis (possibly Z, given the crash). You can't change the maximum Z speed by default, meaning you'd have to either change your definition file or download the Printer Settings plugin (mandatory shoutout to @ahoeben for his fine work):

That will give you options for maximum speed for each axis:

Make sure your Z is low enough. In theory a printer shouldn't try and follow a command to move faster than it's supposed to be able to, in practice... 🤔

Purge line: I cover this in my gcode section below.

 

About your startup gcode: I seem to be a bit of a startup gcode snob😏 so please don't take it personally:

G130 X20 Y20 Z20 A20 ; Lower stepper Vrefs while heating
M105 ;Report temperatures

G130 X127 Y127 Z40 A127 B127 ;

According to the RepRap wiki, neither Marlin nor Klipper support a G130 command. Could be that an unrecognised command is making it not follow the ones afterwards (including the nose wipe)? Also the comment says to lower them while heating, but that code occurs after all of the heating commands. In fact, those commands should run pretty much one straight after the other so the second (if it does anything) would cancel out the first one anyway.

 

Although if those commands are affecting it, it could affect the printhead crashing because it would be changing the voltages on which the stepper motors run.

 

M104 S{material_print_temperature_layer_0} ; Set Extruder temperature
M109 S{material_print_temperature_layer_0} ; Wait for Extruder temperature

Shouldn't cause any problems, but the M104 is pointless, in theory. M104 tells it to heat to a certain temperature; M109 tells it to heat to a certain temperature and then wait until it reaches it, so it doesn't need an M104 to tell it how hot to get.

 

G0 F3000 X-20 Y-10 Z20 ; Move to wait position considering printhead settings

The "apply extruder offsets to gcode" setting only applies to multi-extruder printers where each extruder has a nozzle in a different position (i.e. doesn't share a nozzle). Regardless of what your print head dimensions are set to, X0, Y0 is always going to be the corner for a single extruder printer.

 

Some printers can move their heads past the extremes at one or both ends, but it's often a bad idea (i.e. my Ender-3 V3 SE can go to negative X coordinates but that results in the print head pushing against the homing switch for that axis).

 

This might have something to do with your nose wipe problems if it's trying to wipe from invalid coordinates (since it's trying to start at Y -10).

 

Also, one thing which shouldn't affect prints but annoys me about so, so many startup gcode sequences (i.e. probably feel free to ignore this particular rant 🙂)

RED = You haven't extruded yet, why do you think it's necessary to reset the extruder position? Like, maybe one I could understand in case it doesn't reset from a previous print.

YELLOW = You have extruded, you should probably reset that before you print.