Elegoo Neptune 4 Max: 420 mm on a Bedslinger, Assessed
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The Neptune 4 Max is a 420 × 420 × 480 mm open bedslinger with a 300 °C hotend, an 85 °C bed, Klipper, 121-point levelling and a rated 500 mm/s that large parts never reach. It is one of the cheapest routes to a 400 mm class bed and is a PLA and PETG machine. The 85 °C bed and moving 420 mm platform rule out ABS at size. Based on manufacturer data and owner reports.
Where to buy
Specifications
| Item | Value | Note |
|---|---|---|
| Build volume | 420 × 420 × 480 mm | 85 litres |
| Frame | Bedslinger | The 420 mm bed moves in Y |
| Max nozzle temperature | 300 °C | Extended hotend, 60 W heater |
| Max bed temperature | 85 °C | At 25 °C ambient; lower than most |
| Speed / acceleration | 500 mm/s / 8000 mm/s² | Default 250 mm/s; realistic 100 to 150 mm/s on big parts |
| Levelling | Auto, 121 points | Manual Z-offset |
| Firmware | Klipper | Input shaping with X and Y accelerometers |
| Weight | 18.1 kg |
What it is for
Helmets, cosplay armour, large planters and one-piece props in PLA or PETG. At this size the bed mass sets the speed, not the spec sheet; owners run 100 to 150 mm/s for clean walls. The 121-point mesh is essential on a 420 mm bed and is the reason the machine works at all; see mesh levelling.
Limits
- 85 °C bed. Enough for PLA and PETG; marginal for ABS even with an enclosure. See warping.
- Bedslinger at 420 mm. Tall, heavy prints show ringing unless slowed.
- No enclosure available from Elegoo; third-party tents at this size are large. See Neptune 4 Max upgrades.
Alternatives
The Creality Ender-5 Max is a 400 mm cube frame at 700 mm/s rated with a 100 °C bed and an optional enclosure; it costs more and prints large parts faster. The Anycubic Kobra 3 Max Combo is a 420 × 420 × 500 mm bedslinger with ACE Pro multi-colour. See Ender-5 Max for the cube-frame comparison.
The units in the box
Neptune 4 Max listings on Amazon US come and go. Shown are the Kobra 3 Max, the Ender-5 Max and the Neptune 3 Pro as Elegoo’s smaller option.
FAQ
Can it print ABS? Not reliably at size; the 85 °C bed and open frame are against it.
What nozzle for big prints? 0.6 or 0.8 mm; a 0.4 mm nozzle makes 400 mm parts take days.
LayerWalker
Print defect diagnosis, calibration procedures and parts that actually fit. Corrections welcome through the contact page.
