¶ Fault Symptoms
- Poor first-layer adhesion
- Visible layer lines
- Severe stringing
- Under-extrusion / layer separation
- Surface defects such as particles, bumps, or spots
¶ Possible Causes
- Incorrect heated bed leveling or Z Offset setting
- Loose mechanical structure or assembly deviation
- Extrusion system abnormality
- Filament issue
- Incorrect slicer parameter settings
¶ Required Tools
- 2.0 mm Allen key
- 2.5 mm Hex Wrench
- A4 paper
- Wrench
- ELEGOO Slicer software
¶ Troubleshooting Steps
Note: Please turn off the printer power before performing the following inspections and adjustments.
¶ 1. Check the PEI Build Plate
¶ 1.1 Confirm PEI Build Plate Installation
Please install and fit the PEI build plate correctly according to the figure below.
Otherwise, the proximity switch may not correctly detect the position of the PEI build plate, resulting in poor first-layer printing quality.
¶ 1.2 Clean the PEI Build Plate
It is also recommended to clean the PEI build plate to prevent surface oil or contamination from affecting adhesion.
- Use a lint-free cloth or tissue with IPA (isopropyl alcohol, recommended alcohol concentration above 75%) to wipe the surface.
- If there is heavy oil contamination, clean the surface with warm water and a small amount of mild detergent, then dry it completely.
- After cleaning, avoid touching the printing surface directly with your hands.
¶ 2. Check Whether the Tool Head and Heated Bed Are Loose
¶ 2.1 Check Tool Head and Heated Bed Movement
Check whether the heated bed and tool head carriage have noticeable looseness or abnormal resistance during movement.
If any abnormality is found, adjust the eccentric nuts on the POM wheels to ensure smooth movement without noticeable gaps.
Reference video:
¶ 2.2 Check Heated Bed Fixing
Ensure that the PEI build plate is flat and firmly attached to the heated bed.
Also check whether the heated bed fixing screws are loose.
¶ 3. Check the X-axis Parallelism
¶ 3.1 Check X-axis Parallelism
Move the X-axis close to the top of the Z-axis lead screws, and check whether the X-axis profile is parallel to the top frame.
¶ 3.2 Measure X-axis Height
If it is difficult to confirm visually, use a ruler to measure the distance from both ends of the X-axis to the heated bed.
Confirm whether both sides have the same height.
¶ 3.3 Recalibrate X-axis Parallelism
If the X-axis is confirmed to be not parallel, recalibrate the X-axis parallelism.
Note:
The following video is the Neptune 3 Pro X-axis parallelism calibration tutorial.
The adjustment method is basically the same for the Neptune 3/4 series. You can refer to the steps shown in the video for adjustment.
Video:
https://www.youtube.com/watch?v=lbeevQxRwlI
¶ 4. Check the Proximity Switch
¶ 4.1 Remove the Auxiliary Cooling Fan Assembly
Use a 2.5 mm Allen key to remove the auxiliary cooling fan assembly.
¶ 4.2 Remove the Tool Head Rear Cover Assembly
Use a 2.0 mm Allen key to remove the three screws securing the tool head and rear cover assembly.
¶ 4.3 Remove the Ribbon Cable Assembly
¶ 4.4 Remove the Tool Head
Use a 2.0 mm Allen key to remove the two screws securing the front cover of the tool head, then remove the tool head.
¶ 4.5 Check the Proximity Switch Cable
Check whether the internal proximity switch connection cable is damaged, loose, or not properly secured.
¶ 5. Check the Z-axis Structure
¶ 5.1 Check and Adjust the Z-axis Structure
Check and readjust the Z-axis uprights, couplers, and lead screw fixing screws to ensure the Z-axis structure is secure and free of looseness.
Note:
Do not fully tighten these screws. Otherwise, it may increase Z-axis movement resistance and cause the Z-axis to become stuck during upward movement.
¶ 5.2 Power On the Printer
¶ 5.3 Perform Auto Leveling and Reset the Z Offset
Perform auto leveling and reset the Z Offset value.
Use A4 paper to assist in adjusting the distance between the nozzle and the PEI build plate.
Reference video:
Start from 7:35 for the leveling operation.
¶ 5.4 Fine-tune the Z Offset Value
-
If the nozzle is too far from the PEI build plate, causing the first-layer lines to not be pressed properly or leaving obvious gaps, decrease the Z Offset value (make it more negative) to move the nozzle closer to the PEI build plate.
-
If the nozzle is too close to the PEI build plate, causing excessive first-layer compression or preventing normal extrusion, increase the Z Offset value to move the nozzle farther away from the PEI build plate.
Please refer to the following video:
¶ 6. Check the Filament
¶ 6.1 Check Filament Condition
Check whether the filament is stuck together, bent, brittle, or has other issues.
¶ 6.2 Check Whether the Filament Is Tangled
¶ 6.3 Check Filament Diameter
Check whether the filament diameter is 1.75 mm.
¶ 6.4 Check Whether the Filament Is Damp
Typical symptom of damp filament:
- Bubbles appear during extrusion.
¶ 7. Check Slicer Parameter Settings
¶ 7.1 Check the Printer Model and Filament Type
- Check the filament type and recommended printing temperature on the filament label.
- Open the slicer software, import the G-code file, and check whether the printer model matches the actual machine and whether the filament type matches the loaded filament.
¶ 7.2 Check Nozzle Temperature
Check whether the nozzle temperature is within the recommended range.
Example:
- PLA: 190℃~230℃
¶ 7.3 Check Model Cooling Fan Speed
Check whether the model cooling fan speed is set correctly.
Example:
- PLA recommended model cooling fan speed: 100%
¶ 7.4 Check Printing Speed
Check whether the printing speed is set correctly.
Example:
- PLA recommended printing speed ≤300 mm/s
¶ Still Not Resolved
If the printing quality still cannot be improved after following the above steps, please provide the following information and contact our technical support team at:
for further assistance:
- STL file
- G-code file
- Filament label
- Machine SN code
SN code format:
NEP X.XXXXX.XXXXX
¶ Help us improve
If you have any ideas about the wiki pages, please let us know via ELEGOO official feedback channel