Common Problems with 3D Printing Models
Some common defects in STL files can lead to the rejection of models by 3D printing services. STL files, essentially the building blocks of 3D models, demand precise optimization in calculations. Failure to achieve this precision may result in problems such as unclear exterior details and subpar rendering performance in the printed design.
In the context of submitting files for 3D printing, the following outlines five of the most common mistakes made by customers in their STL files.
Incorrect file resolution
Achieving functional 3D printed parts relies heavily on accurately setting the resolution of the STL file. If the resolution is too low, the product may lose definition and print unevenly due to larger triangles. However, extremely high-resolution STL files can be difficult to upload to other 3D printers. The number of details may overload the printer, causing downloading and processing issues. To achieve the best results, speak with your 3D printing service beforehand to select the appropriate file resolution.
source: i.materialise
Consider the visual representation of three globes: the left one in its original 3D modeling software format, the middle one as a high-resolution STL export, and the right one as a low-resolution STL export. When submitting an STL file for printing, the choice of resolution is critical for achieving a high-quality print.
Disregarding the thickness of the walls
The main issues with 3D printing often revolve around the thickness of the walls in a model. If the walls are too thin, it can lead to warp or unprintable small parts.
source: i.materialise
Overlapping triangles
Since your STL file is essentially made up of a mesh of triangles, you might face issues related to the triangles themselves. Problems such as intersecting or overlapping triangles can occur when two surfaces overlap or cross each other. Identifying these errors may become more challenging as the complexity of your model increases.
source: additive3d
Inverted normals
Before 3D printing, make sure to check the direction in which the triangles in the STL file are facing. Sometimes, they can be flipped inward instead of outward. This is called inverted normals and can cause problems, especially with hollow designs. If the normals are facing the wrong way, the 3D printer might get confused and try to fill in the inside of your object, leading to a failed print. So, if you detect any inverted normals, flip them in the correct direction before printing.
source: additive3d
Noise shells
The outer layers of a 3D model are called shells, and having more shells makes the surface of the model denser and smoother. However, if a shell is too small, it doesn't really contribute to the design and is called a "noise shell." These noise shells can be removed by fixing inverted triangles to create a solid structure before exporting the model. Removing unnecessary shells can make the 3D printing process faster, especially when there are too many shells in the design.
source: additive3d
Gaps in a mesh
For 3D printing machines to work well, the model needs to be a solid volume with no openings, like a sealed container. The problem occurs when nearby triangles in the model don't share enough common points.
source: openFOAM
Bad Edges
This issue occurs when there are more than two shapes sharing the same edge or when an extra surface is inside the model. The first case confuses the 3D printer about how to handle the shapes, and the second case creates a confusing path for the machine or laser. While not as critical as some errors, it's still a good idea to fix it by adding thickness to connecting edges or increasing the gap between edges to avoid potential problems.
source: foxdoc
