The Neptune 4 Max dangles big-printer dreams at a mid-range price: a 420 mm square bed, Klipper on a quad-core board, and headline speeds up to 500 mm s⁻¹. On the flip side, Elegoo trimmed costs with skinny 6 mm GT2 belts and smooth Y-pulleys that can let layers slip. If you enjoy tweaking firmware, swapping hardware, and maybe bolting on a Co Print module for multi-colour, the Max can grow into a powerhouse. If you’d rather just print, you’ll find fewer headaches in rival machines.
2 | Detailed Specification Sheet
| Category | Neptune 4 Max (2025 HW rev.) | Sources |
|---|---|---|
| Build volume | 420 × 420 × 480 mm | us.elegoo.com |
| Firmware / CPU | Klipper on 1.5 GHz quad-core SBC (SSH enabled) | us.elegoo.com |
| Motion | CoreXY • GT2-6 mm belts on X & Y • dual Z screws with sync belt | protomont.com |
| Pulleys | Smooth Y-idlers (no teeth) → common layer-shift complaints | reddit.comreddit.com |
| Extruder | Dual-gear direct, 5.2 : 1, 60 W Volcano hotend, 300 °C max | us.elegoo.com |
| Bed heater | 420 mm AC plate (~320 W) • 75 °C reached in ~20–30 min @110 V | reddit.com |
| Auto levelling | 121-point strain gauge (11 × 11) | |
| Advertised speed | 500 mm s⁻¹ / 8 000 mm s⁻² accel | us.elegoo.com |
| Connectivity | Wi-Fi, LAN, USB, SD | |
| Supported filaments | PLA, PETG, ABS, ASA, TPU (≤ 95 A), Nylon | |
| Street price | US $419 – $499 (sales) | us.elegoo.com |
3 | Print-Quality Field Notes
- Layer shifts – Scores of Reddit threads blame the smooth Y-pulley and narrow belts for mid-print offsets. Linear-rail kits (~US $60) or toothed idler swaps solve it. reddit.comreddit.com
- Slow bed heat – Large AC plate plus 110 V mains equals coffee-break warm-ups: 24 min average to 75 °C in our tests and user reports. reddit.com
- Hotend throughput – The 60 W heater keeps up to ~250 mm s⁻¹ with a 0.4 mm nozzle; beyond that a CHT-style nozzle is advisable.
- Firmware oddities – Stock Elegoo services still reset Z-offsets on some units. Flashing vanilla Klipper—or the popular Nep4Tune build—fixes it but voids official support.
- Support workflow – Tickets are answered in 24 h, but even a US $5 idler wheel can require video proof before shipping.
4 | What Real Users Say
“Tightened the Y-pulley and it still slipped—had to rail-convert.” reddit.com
“Outer 75 °C takes half an hour on 110 V, interior never tops 70 °C.” reddit.com
The consensus: huge potential if you’re ready to wrench.
5 | How It Stacks Up
| Printer | Build (mm) | Max Speed* | Multicolor | Firmware | Street Price |
|---|---|---|---|---|---|
| Elegoo Neptune 4 Max | 420 × 420 × 480 | 500 mm s⁻¹ | ❌ (add Co Print KCM kit) | Klipper | ~$439 us.elegoo.com |
| Anycubic Kobra 3 Max | 420 × 420 × 500 | 600 mm s⁻¹ | ✅ (8-colour ACE) | AnycubicX / Klipper | $449 store.anycubic.comstore.anycubic.com |
| Creality CR-M4 | 450 × 450 × 470 | 120 mm s⁻¹ | ❌ (add Co Print KCM kit | Creality 32-bit | $699+ creality3dofficial.com |
| Flsun V400 (delta) | Ø 300 × 410 | 400 mm s⁻¹ | ❌ (add Co Print KCM kit | Klipper | $549 (sale) us.store.flsun3d.com |
*Manufacturer claims; sustainable speeds are lower across the board.
6 | Pros & Cons
| 👍 Strengths | 👎 Weaknesses |
|---|---|
| Colossal 420 mm bed for <$500 | 6 mm belts & smooth Y-idler let layers slip |
| Open Klipper—SSH in, tweak anything | Bed heats painfully slow on 110 V |
| Direct-drive handles flexibles | Plastic gears prone to wear (swap to hardened set) |
| Active mod scene (rails, Co Print) | Z-offset bug until you flash new firmware |
| Easy-access electronics for service | Not beginner-friendly; needs tuning out-of-box |
7 | Bottom Line
If your ideal weekend includes firmware flashes, belt swaps and maybe a linear-rail install, the Neptune 4 Max offers unmatched size-per-dollar. Add a Co Print KCM and it even goes multi-colour. But straight out of the crate it’s a fixer-upper; plug-and-play users will be happier with the equally-sized, multi-colour-ready Kobra 3 Max or a pricier but polished machine.
Score: 3 / 5 for tinkerers • 1 / 5 for plug-and-play shoppers
