Infill; Brim - Prusa Research Original Prusa MK4 Handbook

6.5.4. Infill

Another parameter that affects the properties of the printed object is Infill. It affects the printing
speed, strength and appearance of the object. Objects printed with the FFF/FDM method usually
do not have 100% density. Instead, they contain a certain geometric structure inside. It can take
various forms, from simple square grids or hexagons to more complex patterns. The purpose of
the infill is to stiffen the object from the inside. Most models are printed with 10-15% infill, but if
you need a really solid structure, you can choose a higher density.

6.5.5. Brim

The brim serves to increase adhesion to the bed, reducing the risk of warping. A wider first layer
is printed around the model. This makes sense especially if the model only touches the bed in a
small area. This function can be enabled in PrusaSlicer by checking the "Brim" box in the menu in
the right column. After the printing is finished, the brim can usually be removed easily by hand,
or you can use a knife or scalpel.
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