500 mm Louvered AC Condenser Air Deflector — Support-Free, Prints in 4 Parts

I created this model with the support of AI, based on images of deflectors I saw online.

Print Settings

• Printer brand / model: Bambu Lab P2S (any printer with a 256 x 256 mm or larger bed)

• Rafts: No

• Supports: No

• Resolution / layer height: 0.2 mm

• Infill: 15%

• Filament: ASA (PETG acceptable in shaded installations)

What it is

A 500 mm diameter louvered deflector that mounts over an AC condenser fan outlet and redirects the hot exhaust air at 45 degrees, away from a balcony, a neighbour's window, plants, or anything else you'd rather not blast with hot air. Modelled after commercial sheet-metal louver discs, redesigned from scratch for FDM printing.

Key features

• 100% support-free. Every louver blade sits at 45 degrees, and all 100+ stiffening ribs are full triangles whose bottom edge starts on the build plate. Slice it and check: zero support material.

• Prints on a 256 mm bed. The disc splits into four 249.9 x 249.9 mm quadrants. The top pair mirrors the bottom pair, because the louvers all face one direction, so print each of the four files exactly once.

• Zip-tie assembly. 16 tie points (5.5 mm hole pairs) along the two seams. No glue needed, tolerates thermal expansion, and it's field-serviceable.

• Engineered louvers. Each blade is anchored on all four sides: a horizontal flange behind the hinge, triangular struts across the opening at 35 mm pitch, end caps fused into the slot walls, and rear gussets on the wide blades. The blades don't flex.

• 54% open area (38.5% effective aperture at 45 degrees), maximised within the structural constraints. The slots run to within 8 mm of the rim, with solid pad islands preserved around the twelve M6 mounting holes.

• Fully parametric. The included Python script (trimesh + manifold3d) regenerates every STL from around 30 named parameters: diameter, blade angle, slot sizes, hole circle, strut density, and more.

Specs

• Outer diameter 500 mm, plate 3 mm, overall height about 42 mm

• 16 louver blades at 45 degrees, 2.4 mm thick

• 12 x M6 clearance holes (6.5 mm) on a 480 mm circle, arranged in 6 pairs

• Material: roughly 830 cm3, about 890 g of ASA total (around 220 g per quadrant)

Bill of materials

• 4 printed quadrants (Q1 to Q4)

• 16 cable ties, 4.8 mm wide, about 100 mm long. Use black UV-stabilised (PA66W) or stainless ties, standard white nylon goes brittle outdoors within a season or two.

• Up to 12 M6 bolts plus washers (or more zip ties) to mount to the condenser frame. Use washers; the plate is 3 mm.

Assembly

1. Print all four quadrants flat side down. No supports. No brim needed if your ASA adhesion is good, glue stick on textured PEI with a 100 C bed works well.

2. Lay the quadrants out matching the file names (Q1 top right through Q4 bottom right). The 0.2 mm seam clearance is intentional.

3. Thread a zip tie down through one hole of each pair, under the plate, and back up through its partner. Cinch it on the bottom face so the head sits underneath. Snug, not crushing.

4. Work from the centre outward, alternating between the two seams, checking flatness as you go.

5. Mount to the condenser through the rim holes. If you can, stand the deflector 5 to 10 cm off the condenser face using spacers or standoffs, it reduces back-pressure on the fan significantly.

Airflow note

Effective aperture is about 755 cm2, which is 38.5% of the disc area. Against a typical 400 mm or larger condenser fan that's a real constriction, and the standoff mounting described above is the recommended mitigation. If your condenser runs long cycles in peak summer, keep an eye on it after installation.

Customisation

Everything is driven by the included deflector_v11.py script. Install trimesh and manifold3d, edit the parameter block at the top, diameter, BLADE_ANGLE, HOLE_R to match your condenser's bolt pattern, STRUT_PITCH, and so on, then run it. It regenerates the full model plus all four quadrants. Note that the strut geometry assumes the 45 degree blade angle; if you change it, re-check printability before committing to a print.

Remixes welcome. The parametric script is the intended remix path.