Elegoo Neptune 4 Max Review — Big, Cheap, Fast… with Caveats

Quick Specs

• Build Volume: 420 × 420 × 480 mm

• Advertised Speed: up to 500 mm/s (real-world varies)

• Hotend Temp: up to 300 °C

• Materials: PLA, PETG recommended; ABS/ASA/Nylon possible but not in open air (fume risk)

• Features: Klipper, auto bed leveling (with manual knobs), Wi-Fi/LAN printing, filament runout sensor, LED bar, smooth + textured PEI sheet

Setup & First Impressions

The Neptune 4 Max is quick to assemble—about 10 minutes to build, then run the first leveling sequence. Wi-Fi printing works through Elegoo’s slicer (an Orca/Bambu-style fork). You can send jobs, monitor progress, and skip the USB shuffle. The LED bar actually helps with first-layer visibility.

Noise is the first reality check: fans are loud. And the printer is open air, so expect heat bleed into the room and fumes with certain materials. For PLA/PETG, that’s manageable; for ABS/ASA/Nylon, plan an enclosure and ventilation.

Real-World Speed vs. “500 mm/s”

The “500 mm/s” figure is a peak under ideal conditions. Real jobs—especially big ones—should be tuned for reliability, not bragging rights. Pushing speed on tall, heavy prints increases wobble, adhesion issues, and the chance of a Y-axis layer shift as the bed slings more mass over time.

Bottom line: the machine is fast enough when tuned, but huge prints should be slowed down to finish cleanly.

Adhesion: Textured vs. Smooth PEI (What Actually Worked)

You’ll likely see two different behaviors:

• Textured PEI: Can release mid-print on some PLAs (especially long jobs).

• Smooth PEI + glue stick + 65–70 °C bed (PLA): Reliable. This combo rescued multi-hour jobs.

Routine: Clean the surface with IPA, add a fresh glue layer when switching filaments, and don’t be afraid to bump bed temps within reason.

The Y-Belt & Heavy Prints

On multi-day, >1 kg parts, a late layer shift can happen as the Y belt loosens under load. The bed is moving a heavy print back and forth for hours—eventually you build enough inertia for the belt to skip teeth.

Prevention checklist:

• Retension the Y belt before long runs, and recheck mid-project on multi-day prints.

• Reduce speed/acceleration for tall or heavy parts.

• Add brims/mouse ears for tall shells; align the longest dimension with Y for stability.

• Keep Z-hop on and accelerations conservative.

Noise, Fumes, and Open-Air Reality

• Noise: This is not a quiet printer, especially at speed.

• Heat: Large heated bed + long runs will warm the room.

• Fumes: For ABS/ASA/Nylon, use an enclosure and ventilation/filters.

What Prints Look Like

• Everyday test models (Buddha/Benchy/tools) came out fine using stock profiles.

• Flexi dinos at max size printed cleanly; filament swap resume worked so well you couldn’t feel the seam.

• Cosplay shells (e.g., Nova/helmet backs) are totally doable in one shot if you slow down, use the right surface (smooth PEI + glue), and keep supports sane.

Expect more visible ringing/lines near the top of tall prints if you run aggressive speeds. Slowing outer walls and dialing in accelerations improves finish.

The Good

• Price-to-size ratio is outstanding.

• Klipper + Wi-Fi on a budget machine.

• Setup is quick; first layer is easy to see with the LED bar.

• Resume after filament swap worked flawlessly in testing.

The Not-So-Good

• Loud, open-air machine (noise, heat, fumes).

• Auto-level + manual knobs feels dated; you’ll still tweak the bed.

• Klipper boots slowly; rare hiccups after quick power cycling.

• Textured PEI can let go mid-print on some PLAs.

• Y-belt can loosen on heavy, multi-day jobs, causing layer shifts late in the print.

My Large-Print Profile (PLA/PETG starting point)

• Layer Height: 0.20–0.24 mm

• Walls: 3 perimeters

• Top/Bottom: 5–6 layers

• Speed (big parts):

  • Perimeters 45–80 mm/s

  • Infill 100–150 mm/s

  • Travel 150–200 mm/s

• Accel/Jerk: Conservative; keep ringing down (start around 2000–3000 mm/s², adjust after input-shaper tuning)

• Bed Surface: Smooth PEI + glue

• Bed Temp: 65–70 °C (PLA)

• Adhesion: 8–12 mm brim on tall/thin shells

• Cooling: Full fan for PLA after layer 3; reduce if small cross-sections are curling

• Checks: Re-tension Y belt before and midway through multi-day prints

Should You Buy It?

Yes—if you need huge volume for cheap and you’re comfortable with a little hands-on tuning.
**No—**if you want whisper-quiet, enclosed, fire-and-forget reliability out of the box.

This machine is what 3D printing looked like a couple years ago: big value, some tinkering required. If you set expectations and follow the guardrails above, it delivers.

Alternatives to Consider

• Ender-5 Max (~$799, 400³, CoreXY): sturdier motion system, smaller volume, almost double the price.

• Anycubic Kobra 3 Max (~$550, 420×420×500): slightly taller; user experience varies by preference.

Final Verdict

The Elegoo Neptune 4 Max is a “bells, no whistles” big-bed workhorse. It’s not quiet, it’s not enclosed, and you’ll want to baby the Y belt on marathon jobs—but the amount of printable volume per dollar is undeniable. For prop shops, cosplay makers, and anyone scaling up on a budget, it’s a smart buy with the right expectations.