When most people think about making their 3D prints stronger, their first instinct is to crank up the infill percentage. After all, more plastic inside must mean more strength, right? That’s the infill lie. In reality, strength comes from other factors—walls, orientation, material, and bonding—not just filling your part solid.
We’ll break down the myth, show real test results, and walk through the settings and design tricks that actually matter when you want durable, reliable prints.
Walls Beat Infill Every Time
In our test, a part with 50% infill and only two walls failed quickly under pressure. Meanwhile, a 25% infill part with six walls held up much better. Why?
Because walls do the heavy lifting. Think of them as the armor of your print. Infill is scaffolding—it keeps the shape from collapsing but doesn’t carry the main load.
Adding more walls (four to six is a sweet spot) has a bigger impact on strength than pushing infill past 25–30%.
Orientation and Layer Strength
3D prints are a lot like wood: they’re strong with the grain but weak across it. Layer lines act as natural break points, so how you orient your part makes a huge difference.
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Align your part so the layers resist the forces it will face.
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Avoid designs where stress pulls directly across layers.
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Certain infill patterns (like gyroid or cubic) distribute loads better than basic grids.
Materials Matter
Not all filaments are created equal:
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PLA – stiff, easy to print, but warps in heat (like a hot car).
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PETG – flexible, durable, great for outdoor use.
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ABS / ASA – handle heat well, but need an enclosure.
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Nylon – very strong, but absorbs moisture.
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Polycarbonate (PC) – one of the strongest, requires high temps and a capable printer.
Choosing the right material for your project often matters more than tweaking print settings.
Print Settings That Boost Strength
Here are the big ones to keep in mind:
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Walls: 4–6 walls for most parts.
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Line Width: 120–140% of nozzle size for stronger passes.
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Layer Height: 60–75% of nozzle diameter.
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Temperature: Print at the high end of your filament’s range.
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Cooling: Keep fan speeds low or off for better bonding.
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Nozzle Size: Larger nozzles (0.6–0.8 mm) lay down stronger layers.
Two walls with high infill = aluminum can stuffed with bubble wrap.
Six walls with low infill = solid brick.
Design for Strength
Good print settings only get you so far—design matters too.
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Ribs add support to walls.
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Fillets (rounded corners) reduce stress concentrations.
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Gussets spread out loads.
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Bosses & heat-set inserts make stronger fastener points than screwing directly into plastic.
These small tweaks can massively improve real-world durability.
The Quick Guide
Here’s the cheat sheet for stronger 3D prints:
Download the Guide for Free: https://makerbuildit.com/products/make-a-print-strong-guide
The truth behind the infill lie is simple: more infill doesn’t always mean more strength. Stronger parts come from walls, bonding, orientation, and material choices, not just stuffing your print with plastic.
So next time you’re tempted to crank infill to 100%, remember—smart design and print settings will save you time, filament, and frustration.