The single most impactful upgrade you can make to a budget 3D printer — Ender 3, Elegoo Neptune, Sovol SV06 — is the part cooling fan. Stock 4010 axial fans push roughly 4-5 CFM of air. A 5015 blower pushes 7-9 CFM. That difference is the gap between overhangs that curl up into the nozzle and overhangs that print clean at 70 degrees. I’ve done this upgrade on four printers and the overhang improvement is immediate and measurable. Here’s the complete guide.
Why Stock Cooling Fails
Part cooling does one job: it solidifies freshly extruded plastic before the next layer goes down. When the previous layer is still soft, the nozzle drags through it, creating rough top surfaces and curling overhangs.
Stock 4010 axial fans have two problems:
1. Low static pressure: Axial fans move air but can’t push it through a duct. The airflow drops to near zero by the time it reaches the nozzle.
2. Wrong airflow pattern: Axial fans blow air in a wide cone. Only a fraction of it hits the melt zone where it matters.
A 5015 blower fan solves both. It’s a centrifugal (radial) fan — it builds pressure and directs air through a focused nozzle. The stream hits exactly the tip of the nozzle where plastic is being deposited.
5015 Blower Upgrade: Parts and Installation
Parts List
- 5015 blower fan: 24V for most printers, 12V if your board runs 12V. Winsinn and Sunon make reliable units for $8-12 each.
- Printed duct: Choose based on your printer model and hotend. See duct recommendations below.
- JST connector: Most 5015 fans come bare-wire. Crimp or solder a JST-XH 2-pin connector to match your board.
- M3 bolts: Two M3x12mm or M3x16mm to mount the fan to the duct.
Installation Steps
- Remove the stock fan and shroud: Two or three screws. Save the screws — you’ll reuse them.
- Mount the 5015 to your printed duct: Use M3 bolts through the fan flange into the duct. Don’t overtighten — PETG cracks, PLA creeps.
- Connect wiring: Red to positive, black to negative. If the fan runs backwards (blowing out instead of in), swap the wires.
- Mount the duct assembly to the hotend carriage: Reuse the stock screws. Make sure the nozzle tip sits in the airflow stream, not above or below it.
Verify: Power on the printer, set fan to 100%, and hold a tissue near the nozzle. The tissue should flutter vigorously. If airflow feels weak, the duct has internal restrictions — try a different design.
Duct Design Comparison
The duct is as important as the fan. Here’s what works:
| Duct Design | Printer Compatibility | Cooling Performance | Print Difficulty | Notes |
|---|---|---|---|---|
| Hero Me Gen 7 | Universal (modular) | Excellent — dual 5015 | Medium (many parts) | Best all-around; modular for most hotends |
| Petsfang Bullseye | Ender 3, CR-10 | Very good — single 5015 | Easy | Simple, reliable, single fan |
| Satsana | Ender 3 series | Good — single 5015 | Very easy | One-piece print, stock BLTouch mount |
| Mini-Me V4 | Voron Stealthburner | Excellent — dual 5015 | Complex | Purpose-built for Voron toolheads |
| Stock duct (for comparison) | Any | Poor | Already installed | Don’t bother with a 5015 on the stock duct |
Material choice matters: Print ducts in PETG minimum. PLA ducts will soften and deform within a few hours of printing, especially with an enclosure or when printing PETG/ABS. If you print ABS/ASA at 250°C+, use ABS or ASA for the duct — PETG can still soften near the hotend. As covered in our PLA vs PETG comparison, PETG handles up to about 80°C ambient before deforming.
Fan Settings That Actually Improve Overhangs
After the hardware upgrade, your slicer settings need adjustment:
Fan Speed by Material
- PLA: 100% after layer 2. PLA loves cooling — the more the better. Leave fan off for first layer for bed adhesion.
- PETG: 30-50% constant. Too much cooling makes PETG brittle and reduces layer adhesion. 50% on a 5015 is still more airflow than 100% on a 4010.
- TPU: 20-40%. Minimal cooling preserves layer adhesion. Some TPU prints well with zero fan.
- ABS/ASA: 0-20%. Too much cooling causes warping and layer splits. In an enclosure, run 10-15% to help bridges without cooling the part.
Bridging Settings
Enable “Bridge settings” in your slicer. Set bridge fan speed to 100%, bridge flow ratio to 0.95, and bridge speed to 25-30mm/s. The combination of full cooling and slightly reduced flow prevents sagging bridges.
Overhang Speed
Reduce speed on overhangs above 45 degrees. In Cura, set “Overhang Wall Speed” to 50% of normal at 45-75 degrees and 25% above 75 degrees. The slower speed gives the filament time to cool and solidify against the previous layer.
What Most Makers Get Wrong About Cooling Upgrades
Mistake 1: Running the 5015 at 100% for all materials
More cooling isn’t always better. PETG cooled too aggressively loses layer adhesion and becomes brittle. ABS cooled at high speeds warps off the bed. Match fan speed to material — the 5015 gives you headroom, not a mandate to max it out.
Mistake 2: Printing the duct in PLA
A PLA duct sitting next to a 250°C hotend softens, sags, and eventually contacts the heater block. Best case: warped prints from inconsistent cooling. Worst case: melted plastic on your hotend. PETG minimum, ABS/ASA preferred. Our ABS/ASA printing guide covers the enclosure and safety setup needed to print these materials.
Mistake 3: Installing a dual 5015 setup without reducing fan speed
Two 5015s at 100% push 16+ CFM — enough to cool the hotend below printing temperature and cause thermal runaway errors. Run dual 5015s at 50-70% maximum. A single 5015 at 100% already outperforms stock by 2x.
Mistake 4: Ignoring hotend cooling during the upgrade
The stock fan shroud often cools both the part AND the hotend heatsink. When you remove it, make sure the hotend cooling fan still has unrestricted airflow to the heatsink. A separate 4010 axial fan on the heatsink is non-negotiable. Without it, heat creeps up the heat break and causes clogs — our nozzle clog clearing guide walks through diagnosing heat creep clogs.
⚠️ Safety Notice: 3D printer modifications involving electrical wiring should be performed with the printer powered off and unplugged. Verify fan voltage compatibility before installation — connecting a 12V fan to a 24V circuit will destroy the fan immediately and may damage the mainboard. All wiring connections should be properly insulated. When printing ducts for use near hot components, use materials rated for the expected operating temperature. Ensure all modifications comply with your printer manufacturer’s warranty terms and local electrical safety regulations.
Product Recommendation
The Winsinn 5015 24V dual ball bearing blower fan ($9 for a 2-pack) has outlasted every other budget 5015 I’ve tried. The dual ball bearings don’t develop the whine that sleeve bearing fans do after 200+ hours. For a duct upgrade that pairs perfectly with these fans, the Hero Me Gen 7 platform at uavmodel.com includes the modular mounts needed for most popular hotend configurations.