Check the real size
Set a target size for the object and compare it with your printer's build volume. Confirm that any holes, slots, or moving gaps are large enough for your printer and material. After export, verify the dimensions in the slicer too.
Check that the shape is a solid
A printable object needs surfaces that define a coherent physical volume. Open edges, missing faces, duplicate faces, or unexpected internal geometry may lead to missing walls or strange slicer results. Inspect the mesh closely in edit mode and use a mesh check when needed.
Check thin details and overhangs
Thin walls may vanish in the slicer or print weakly. Long unsupported features may need a different orientation, support, or a design change. There is no single safe thickness for every printer: it depends on nozzle size or resin process, material, and slicer settings.
Use the 3D Print Toolbox as a helper
Blender's 3D Print Toolbox extension includes geometry checks and tools such as Make Manifold. Treat its findings as clues, inspect fixes visually, and keep a saved version before major changes. It cannot guarantee a successful print.
Always inspect the slicer preview
Open your exported STL and step through the layers. Look for missing features, unexpected filled holes, floating sections, and support requirements. The slicer preview is where the intended model meets the actual print process.
Need the export steps? Continue with creating an STL file in Blender.