This guide illustrates a solution to the issue where the top surface has line defects due to raised text causing the base model top surface to be broken up by the space left under the letter, like shown in the following slicer preview.
Here are some examples of what the top surface defect looks like that I found from other Bambu forum posts.
To solve this issue do the following steps. I used Autodesk Fusion to make the model.
Autodesk Fusion
Make a sketch on the base part and use the text tool to write your text.
Right click the text and select Explode Text to convert it to a sketch
Extrude the outline to half your layer height. (0.2mm layer height : 0.1mm). Make sure to extrude it as a new component in the Extrude dialog box Operation field.
Use the same sketch to Extrude the full letter, but make sure to activate the new text component before extruding so it is part of the text component and not the main model. Also make sure to start the extrusion on top of the outline by choosing Object in the Start field and selecting the top of the outline extrusion.
In the objects tab, select the color you want for the text.
Use Classic wall generator, not Arachne. Arachne is more likely to make defects on the top surface in the slicer preview.
Print it! It will print the top surface perfectly, and the next layer will print the full letter. Since the outline height was less than the layer height, the outline layer is not printed.
I noticed in one of the forum posts I linked above, that @CanDo said:
I looked into this feature, it is available in developer mode. The interface shells option only works if the letters are a different color than the base model, otherwise it just prints it the default way.
I tested the interface shells option in Bambu Studio. As a reminder, this is what happens to the top surface under normal settings without my fix or Bambu’s interface shells.
For interface shells, it adds a wall around the letter and fills in the the top surface under the letter like the picture below.
Here is a comparison of the three methods. The picture on the left is my technique, the middle one is Bambu’s interface shells and the third one is the Bambu Studio’s default handling of text. I added two pictures to highlight the differences.
Other than the normal FDM imperfections, my version is flawless. Bambu’s interface shells version seems to lessen the prominence of the defects a little but they are still noticeable. Also, the default version has one additional defect on the top left that is not visible in the interface shells version. The additional defect is definitely a more problematic defect, so interface shells will likely eliminate the worst defects that people experience, but not all.
Bambu’s interface shells version is still in development, but unless they make the top surface solid and uninterrupted like mine, I don’t think there will be a significant improvement to the defects that still exist.
Let me see if I have an understanding of why this works. You’re creating a half-layer line gap under the letter and connecting it to the subsurface using only the walls. That means the offset, or thin-extrude of the text can be up to the size of your outer-wall width. Does this sound right?
The exact size of your line width, not wall. The wall width is too wide and will cause an artifact on the top surface. I tested two line widths and it caused artifacts on the top surface.
I figured that the slicer probably wouldn’t see a need to cut or make a wall on the top surface to accommodate a single line of plastic, so it would just print it over top of the surface. Since it is raising the letter above the surface it has to create bottom surface layers at the bottom of the letter instead of infill. And by only using half of the layer height (less than half may also work and may actually be better if it does work), the space under the letter is too short to create a layer of just the outline so it prints the full bottom surface layer of the letter.
I think we are referring to the same thing, but I want to make sure because I use other size nozzles and what to make sure I understand. I am talking specifically about the outer-wall line width. for a .4 nozzle I think it is 0.42mm.
What if you don’t select one wall on top and bottom surfaces?
Actually, it has to be less than the wall width. When I did my test, I forgot that the wall width was a little larger than the nozzle, so I made it the nozzle width. I tried using the wall width 0.42 and it didn’t work as well, at least in the slicer preview. It didn’t disturb the top surface, but the first layer was the outline of the letter partially drawn with lines and seams. Making it 0.4 works much better, the first layer is just the full bottom layer of the letter.
