Inspection for perfect first layer
Follow these points before setting Z offset:
A. Effector Inspection
Inspection 1 :
Ensure the side fans aren't making contact with the central hub to prevent interference during the auto leveling process.
Inspection 2 :
Ensure the hotend assembly is securely
fastened to the hub cover.
Inspection 3 :
Ensure hub cover securely fastened to the central hub.
Inspection 4 :
Ensure that there is a washer between the spring (mounted on the M3 20mm screw) and the central hub.
Inspection 5 :
Ensure the appropriate sleeves and washers are properly installed between each side fan and the hub cover.
B. Ensure the plate cannot be shifted:
Ensure that the screws and nuts are securely fastened to the 2020 extrusion.
Ensure that the plate cannot be shifted in any way when force is
applied in any direction (from any side and from the top).
The build plate is made from tempered glass so it can easily endure the pressure caused by the glass holder.
C. Clean the residual filament from the hotend's nozzle
Using the preheat function, wait for 5 minutes and use a paper towel to wipe away the residual filament.
D. Ensure that the glue is spread evenly over the build plate
Ensure the glass print bed is cleaned and gluestick is well spread on glass evenly.
Gluestick may be uneven after many times uses, use towel to wipe up the residual glue on plate is recommended
E. Distance between end stop and screw
Adjust the nut holding the spring on the underside of the effector. Loosen the nut until you here a "click." Then tighten the nut until you hear another "click." Now when you apply light pressure to the hotend nozzle, you should hear a "click" each time. If not, tighten the nut slightly until you here the "click" each time you apply pressure to the hotend nozzle. DO NOT touch the hotend when it is hot. You may get burned!
Adjustments can be made on the machine or on the software. The following will be the method of adjusting the machine :
After the screw (shown in red in the image on the top) has just touches to limit switch, the following steps can be carried out: turning the screw in the clock-wise direction so that the extruder comes closer to the print bed during printing, or; turning screw in the counter clock-wise so that the extruder becomes further away
from the print bed during printing.
Turning the screw by 1 full turn will move the the extruder by 0.5mm in perspective direction, hence directly correcting the distance between the print head and the print bed.
Setting Z Offset
Follow the steps below to set the optimal gap between the hotend and print bed.
This update allows your machine to remember the optimal gap in the firmware as soon as you are finished, so that you won't need to autolevel every time you print. Please make sure that the firmware version is 2.0.3 or above. Latest firmware can be downloaded in the Support Section.
Before you get started, please ensure that you have gone through the steps in Inspection for perfect first layer thoroughly, otherwise the auto level will not reach its optimized performance.
It is recommended to execute the following steps before first time use or everytime the glass build plate is removed. Make sure the nozzle and the glass build plate is clean and the build plate is securely fastened. Follow these steps to clean the nozzle: preheat to 200 C and wait until the filament leaks out from the nozzle ( about 3 minutes ) then wipe clean.
Auto Leveling Steps:
1. Go to [ Setting Z-offset ] in menu.
2. Select [ Auto Level ]
3. Select [ Go to Zero ]
4. Place a regular copy paper between the nozzle and the build plate. Obverse if the nozzle touches the paper lightly, just enough to generate friction yet still allow the paper to easily move back and forth.
5. Decrease [ Z offset ] value if nozzle is too far away, and repeat step 3~4 until gap is well adjusted. Increase [ Z offset ] value if nozzle is too close, and repeat step 3~4 until gap is well adjusted.
6. You can start printing after reaching a suitable Z offset. Please note that G29 is no longer required in the Gcode. Happy printing!
For current users:
Simply delete the G29 lines to use your new settings.
If you have already generated a .gcode file then you can delete the G29 lines to use your new settings.
command and make changes to it.
If you are satisfied with current way (Set g29 value or Z offset in KISSlicer), it is fine to upload the firmware, cause
it will still follow the Z value of your files' G29 settings.
About Layer Build Quality
The integrity of every layer in a print job is important, but the first layer is the most critical layer. The path should be straight, clean and have a consistent width. There should be no gaps between the paths as well as between the perimeter and the infill.
If the pattern is correct but there is a gap between the infill and perimeter, the hotend assembly may not be securely fastened (pg.9) or the amount of flow coming out of the hotend is restricted or set too low.
fig.1 Having the optimal amount of gap between the hotend and print bed will result in the best print. The material is neatly laid down on the print bed along the designated path.
fig.2 If the gap between the hotend and the print bed is too large, the material will not stick to the print bed properly, as it will loosely hang out of the hotend when it comes out before touching a surface to stick on. This will result in wrinkling, curling or deformation.
fig.3 If the gap between the hotend and the print bed is too little, the material coming out will be restricted or even flattened by the hotend as it goes along its path, resulting in broken and inconsistent print results. If there is no gap between the hotend and the print bed, then no material will be extruded and the hotend tip may even scrape on the print bed.
Challenge: Perfect First Layer
Generally speaking, as long as the first layer adheres securely to the build plate, the imperfections on the layer will not affect the overall quality of the print. However, if the machine is not assembled properly, the first layer will have imperfections. Complete the following check-up to perfect your first layer.
Auto Leveling Mechanism G29
At a micro level, print bed surfaces are usually not perfectly flat and even and because of how it is mounted on the printer, it is not always level.
The G29 command is a special G-CODE designed for compensating both non-level surfaces and local deformities of the print bed surface. In printers without the G29 function, you would have to manually adjust the print bed to be level or to be normal to the nozzle. 3D printers that support the G29 command instead use a probing mechanism to find micro-differences in height in an imaginary grid of points on the surface of the print bed.
ATOM 2’s “probing mechanism” consists of an end-stop in the effector, a screw that triggers the end-stop, the hotend and the hub cover that it is mounted on.
During the [Auto Level] process, the effector assembly will move down towards the print bed until the hotend touches the surface, where it will trigger the end-stop, telling the printer to retract and move to the next point along the grid.
In ideal circumstances, the hotend should touch the print bed at Z=0, but because the end-stop button has a compression range of 0.2mm, the printer will think the surface of the print bed is 0.2mm below the actual surface of the print bed. This absolute error can be further increased if the print bed if you decide to use a layer of
tape to bind the printed object to the bed.
Theoretically, the optimal gap between the hotend tip and the print bed for ATOM 2 printers is 0.2mm, therefore we must set the printer to offset Z by about 0.4mm (filament extrusion gap + end-stop compression range) above the surface. This value varies slightly between each printer.