Infill Density and Pattern Settings Explained

Infill is the internal lattice inside a print, and its two settings — density and pattern — trade off print time, material use, strength and (less obviously) how good the top surface looks. Bambu's stock 15% is a reasonable default for most prints, not a number to treat as fixed.

Density: the strength/time/weight trade-off

Bambu Studio's stock 0.20mm profile ships at 15% % sparse infill density — light enough to print quickly and use little material, dense enough to support the shell and top layers for typical decorative and light-functional prints. Functional parts under real mechanical load want more (30–50% is a common range for parts that need to resist bending or impact); display models and prototypes that will never be stressed can often go lower without any visible difference.

Pattern: not just an aesthetic choice

• Grid / line patterns print fast and use little material — the right default for most non-structural prints.
• Gyroid prints reasonably fast while distributing strength evenly in all directions, because it has no straight lines to concentrate stress along — a strong general-purpose choice when a part might see load from an unpredictable direction.
• Honeycomb and other high-strength patterns trade print time for higher strength-to-material ratio — worth it for load-bearing parts, wasted time on a display piece.

The connection to top-surface quality

Infill density and pattern interact directly with pillowing and pinholes on the top surface: sparse infill under too few top shell layers leaves gaps for the top surface to sag into during cooling, which is exactly the failure mode covered in the top surface guide. Raising top shell layers (Bambu's stock default is 5) is usually a more effective fix for a poor top surface than raising infill density across the whole part — it solves the problem exactly where it shows up instead of adding weight and print time everywhere.

Practical starting points

• Display models / prototypes: 10–15% grid or gyroid — fast, light, plenty strong enough for handling.
• Everyday functional parts (brackets, clips, organizers): 20–35% gyroid — good all-direction strength without a heavy print-time penalty.
• Load-bearing or impact parts: 40%+ with a stronger pattern, plus checking interlayer bonding — infill density doesn't help if the layers themselves aren't welding well.
• Top surface still pillowing despite good infill: raise top shell layers before raising infill density further.