Robox review: This 3D printer is great for beginners but lacks in print quality

I’ve spent the past two years waiting for a 3D printer that a beginner can unbox and just start using. The CEL Robox wins the award for the first printer I’ve used that actually does that.

It does so with smart features like an auto-leveling print head and print bed that requires no extra help to keep prints firmly stuck to its surface. It’s relatively fast and friendly, and for $1,499 it’s competitive with the cheaper printers on the market.

Unfortunately, it has some disappointing flaws when it comes to print quality. Here’s a look at how the printer performed over a month of tests:

My best print. The layers are so fine you can hardly tell it came off a 3D printer.

My best print. The layers are so fine you can hardly tell it came off a 3D printer.


The Robox has the fastest setup of any printer I have ever encountered. It’s ready to print out of the box; all you need to do is download software and install the filament spool.

The spool is proprietary. That’s generally irritating because it makes it difficult to use inexpensive, generic-brand plastic. CEL’s filament is extremely expensive — $59 for 1.54 pounds, compared to the $30 you pay for 2.2 pounds of cheap plastic.

However, CEL doesn’t take any measures to prevent you from winding your own off-brand of filament around the spool. It’s annoying to have to rewind filament, but potentially worth it for the benefits CEL’s system brings.

The Robox's spool sits flush with its side. It contains a chip so it can be recognized by the printer.

The Robox’s spool sits flush with its side. It contains a chip so it can be recognized by the printer.

The spool sits snugly in the side of the Robox, where there are also two holes for feeding filament into the machine. You insert the filament into the hole and the Robox pulls it the rest of the way in. It’s easy.

And that’s it. You are ready to print.

The software

CEL’s software, Automaker, is not exceptionally well-designed or smart. But it gets you through what you need to do relatively intuitively.

The program’s home screen displays the printer. Its parts are interactive: You can tell the printer to move its bed forward or backward or even change the color of the light illuminating the print head.

The home screen also displays the temperature of different parts of the printer. A pullout screen has advanced features such as nozzle calibration.

New print jobs are opened in tabs. You can have multiple tabs at once, which I found very useful for deciding between different prints and saving models for the near future. When you open a tab, you are presented with a rotating view of your model. You can scale it, duplicate it and move it around with easy-to-understand buttons.

Prepping to print.

Prepping to print.

My main gripe with the software was it gave no warning of errors. It wasn’t capable of recognizing the steep overhangs that can cause a print to fail. It couldn’t fix the models downloaded from Thingiverse that might contain errors.

Twice, I didn’t realize the filament was not fed all the way into the machine. There was no indication until suddenly the “print” button didn’t exist, for which no reason was given. At one point, the print bed was also homing itself at the wrong location, causing it to jam into the front and back of the printer and calibrate the print head incorrectly. The software never noted anything was wrong.

The machine

The Robox's cover lifts up to reveal the bed.

The Robox’s cover lifts up to reveal the bed.

Let’s start with the aesthetics. The Robox looks great. As I noted in my coverage of Robox’s $450,000 crowdfunding campaign, it feels a bit like the Apple iMac G3 — it’s candy-colored and fun. It’s also small and sleek, and has a profile shaped like an iMessage chat bubble.

The front of the machine has a transparent cover that slides up to give access to the print bed. The bed sits very low to the printer’s floor and is capable of moving forward and backward. The print chamber is separate from the machine’s electronics, allowing the chamber to be heated to a higher temperature and prints to cool more evenly. A few of my prints did end up with curled corners, which indicates that they cooled unevenly, but most turned out fine.

Bulbasaur and Charmander fresh off the Robox's unusual PEI print bed.

Bulbasaur and Charmander fresh off the Robox’s unusual PEI print bed

The Robox has an unusual print bed made from polyetherimide, a plastic that becomes sticky when it is hot. Most 3D printer beds need to be covered in painter’s tape, glue, hairspray or another type of gunky material in order for a print to stick nicely to them. Not the Robox’s bed. Stuff sticks great.

Once the bed cools down and loses its special heated properties, items are supposed to pop off easily. That was the case most of the time. But whenever I printed something flat, like a coaster or a keychain, it became a game of strength and will to get it off. So be warned.

The Robox uses two nozzles to get the job done.

The Robox uses two nozzles to get the job done. This print’s corners curled.

The Robox’s biggest advancement is its print head. It has two nozzles, one of which is dedicated to printing fine details and the other to infill. The infill nozzle puts out far more filament, which allows the printer to work faster. Considering I sometimes ran the printer for several days straight on a large print (which it handled with ease), it was a great option to be able to shave some time off printing the unimportant inside of an object. Every printer should have this feature.

Oh, and when CEL says its printer is auto-leveling, it really means it. Before every print the print head touches itself to the print bed several times to ensure both of the nozzles are at the right height. It’s a confidence-boosting display that the printer is in working order, and it always got the calibration right.

I actually worked with two separate Robox printers. The first printer worked well until it randomly would not turn on one day. CEL was stumped on the issue, and eventually the printer just resumed working.

My worst and best prints on the Robox. The Bulbasaur on the left is a victim of the oozing nozzle.

My worst and best prints on the Robox. The Bulbasaur on the left is a victim of the oozing nozzle.

The second printer arrived with two problems. The bed homed itself in the wrong location, causing the print head to calibrate incorrectly. It turned out there was filament wedged in the bed’s path. The larger nozzle also oozed small dabs of filament intermittently, which led to some terrible-looking prints. This was likely caused by a faulty spring in the print head, which only a CEL technician could fix.

The prints

Unfortunately, the quality of the prints that came off the Robox was inconsistent. They tended to have at least one error, if not more. The printer sometimes struggled with fine details.

Charmanders printed at low, medium and high quality.

Charmanders printed at low, medium and high quality.

The Robox is actually capable of printing very fine layers — down to .02 millimeters in height. That’s unusual for a fused deposition modeling-style 3D printer. I was able to print some really fantastic-looking pieces with the Robox set at its highest quality setting. The layers are so fine that you almost can’t tell the item came off a 3D printer.

The takeaway

There is quite a bit to love about the CEL Robox. It’s built to be nearly maintenance-free, making it perfect for anyone more interested in making things than tinkering with a machine.

But it also had slip-ups, little errors here and there that marred an otherwise perfect print. For anyone who needs consistently good-looking prints, the Robox is not your printer.

Two prints with curled corners and inconsistent details.

Two prints with curled corners and inconsistent details.

Overall, the Robox almost makes my list of printers I would not mind owning. I loved the auto-leveling print head and confidence that every print would adhere to the bed. And it looks great sitting on any home desk. But the number of times prints came out with obvious errors was a deal breaker for me. That’s a shame because CEL gets everything else just right.