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Robox 3D printer review: Fast, innovative and frustrating

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MSRP: $1,499.00

The Good The Robox 3D printer has an innovative nozzle design, and can print very quickly. The printer uses proprietary smart filament spools, but also works with third-party materials.

The Bad This expensive printer can't print directly from an SD card or thumbdrive, and it requires an unintuitive manual calibration. Its print quality is marginal with a high failure rate on its print jobs, and using third-party filament with it will void the warranty.

The Bottom Line The Robox 3D printer's very fast print speed isn't quite worth its lengthy, problematic setup and disappointing print quality.

Visit for details.

5.7 Overall
  • Setup 6
  • Feature 6
  • Support 6
  • Performance 5

Review Sections

The new Robox 3D printer from Cel is a great idea only half realized. Between its fast printing speed and uncommon features, there's a lot to like about it. Getting in the way, though, are poor print quality and an overcomplicated calibration process. That's why in the end, it can wind up being very frustrating.

The Robox is the first 3D printer I've tested that uses two nozzles for a single source of filament, which lets it print much faster than other machines. Unfortunately, to get the best results, you have to manually calibrate it through a difficult and lengthy process. But even worse, the speed didn't matter much in the end as the Robox's print quality was disappointing and failed prints occurred more often than I'd like to see.

Depending on your skills and level of patience, the Robox can be a good experience or a terrible one. I just found mine closer to the latter. Keep this in mind before spending $1,499 to buy one. (In the UK, it's £999.90, and in Australia it's currently on sale for AU$1,495.)

For something that's easier to use with more consistent print quality, I'd recommend the XYZPrinting Da Vinci 1.0 AiO, the Cube 3 from 3D Systems or the Be3D DeeGreen.

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The Robox is a nice-looking compact 3D printer. Josh Miller/CNET

Advanced print-head, no PC-less printing support

With its two print nozzles, the Robox looks like a regular dual-extruder 3D printer when you first take it out of the box. Look closer, though, and you'll see something unusual: while other dual-extruder machines need a filament spool for each nozzle, the Robox uses only one (Cel prefers to call the spools "reels," but the only difference is in the terminology).

How does it work? It's simple: the single reel feeds both nozzles, with one nozzle dedicated to printing fine details and the other to filling in larger areas of a job. It's a brilliant idea that worked well in my testing, making the Robox by far the fastest 3D printer I've seen. I'll talk more about the quality in the Performance section below.

That's why it seemed odd that the Robox has a second, but unused, filament intake. Cel said the reason was that in the future, the printer can be updated with another printhead that feeds from two reels. If that happens, though, there's no space to add another reel holder. And as I see it, a second reel would just add bulk to the Robox's pleasantly compact size of 14.5x13.4x9.4 inches (370x340x240mm).

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There are two filament intakes but there's only one place to hold a filament reel. Josh Miller/CNET

Robox's active print platform shares the same mechanism design as the Cube 3. That means that during a print job the platform moves backward and forward while the printhead moves sideways and up and down. I like that for such a small printer, the Robox has a large print platform: it can build objects measuring up to 8.3x5.9x3.9 inches (210x150x100mm).

Cel Robox 3D printer specs

Extruder Dual-extruder (single filament source)
Plate Removable plate
Print technology Fused Filament Fabrication (FFF)
Build volume 8.3x5.9x3.9 inches (210x150x100mm)
Nozzle diameter 0.012" and 0.031" (0.3mm and 0.8mm)
Resolution 20 microns
Printer control Via software
Printable materials PLA, ABS, HIPS, Nylon, PC, PVA
Power source 230 V / 120 W
External dimensions 14.5x13.4x9.4 inches (370x340x240mm).
Inputs USB
Software Robox AutoMaker
Operating system supported Windows 7 or later, Mac OS 10.8 or later

The printer has a removable print bed, which is the top part of the print platform. That makes it easy to remove and clean, a necessary step in the calibration process.

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The machine's two extruders are designed to work with one source of filament for faster print speed. Josh Miller/CNET

The Robox connects to computer via a USB port on the back. The printer doesn't have an SD card slot, a touchscreen or any control button located on the unit itself, other than the on/off switch. As a result, you can't use it without a computer. Everything needs to be done via the downloadable AutoMaker software, which is available for Windows, Mac and Linux platforms.

On the whole, the software worked well in my trials -- despite some random errors and freezes -- and has a high level of customization. You can change any settings, including the openings of the printing nozzles themselves. Most importantly, the software also guides you through the calibration process.

Tricky calibration procedure

The Robox can automatically level the print bed, which it does before each print. Yet, you also need to manually calibrate it, especially the Nozzle Opening and Nozzle Height, both of which require a lot of work. The former determines the amount of material output for each nozzle and the latter makes sure the nozzles are at a perfect distance from the print bed below.

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"Flowing" is a vague term to determine the exact material output level. Screenshot by Dong Ngo/CNET

Manually calibrating a 3D printer is always tricky and time-consuming, but the Robox's process is worse than usual, thanks to the vague wording of the instructions.

For example, when adjusting the nozzles' openings, the instructions tell you to gradually use the software to open them bit by bit until you see the material "flowing" out. What exactly is meant by "flowing," isn't defined, however, and it's hard to know when the nozzle is properly opened. After talking to Cel, I learned that you need to merely open the nozzle until the material appears at the tip. Opening it further would be too much. That kind of detail is useful, but you won't find it in the included instructions.

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