CEL Robox review – a 3D printer for the masses?

Price when reviewed

Personal 3D printing is very much an emerging technology: although its potential is exciting, the devices we’ve seen so far have felt more like clunky industrial prototypes than slick consumer products. Now, the CEL Robox printer – originally funded through Kickstarter, but now general sale – aims to address its predecessors’ shortcomings.

CEL Robox - front

This begins with the stylish, self-contained physical design, which immediately makes the Robox a more attractive desktop companion than the bare scaffolds we’re used to seeing at this price. It’s practical, too: the pungent fumes associated with 3D printing are sealed beneath the Robox’s plastic lid, and the enclosed atmosphere also helps to keep temperature consistent, so your plastic is more likely to cool and set evenly. There’s even a safety benefit: the lid automatically locks down while the printer is in operation, which is a sensible precaution since the working print head heats up to more than 200°C.

The precise temperature will depend on the type of plastic you’re using: acrylonitrile butadiene styrene (ABS), polylactic acid (PLA) and nylon filament are supported. That’s par for the course for a device such as this, but the Robox makes it easier than usual to switch materials by embedding a chip into each spool of filament that identifies it to the printer. It’s an approach we’ve seen before with the Cube 3D printer, but CEL’s chipped spools are more reasonably priced at around £25 per 240m spool – and, unlike the Cube, the Robox happily lets you use an unchipped third-party spool if you prefer, entering the appropriate settings by hand in CEL’s AutoMaker printing host software.

CEL Robox - side view

That software accepts models in STL and OBJ format, and although its cryptic, text-free buttons aren’t immediately welcoming, a quick glance over the manual is all that’s needed to get the hang of its linear workflow. Sliders let you choose print quality, fill density and so forth, and once you kick off your print job, a graph at the bottom left of the window lets you check operating temperatures at a glance. A progress bar and a series of pop-up notifications also detail what’s going on as the printer heats up and your model is sliced and processed.

After a few minutes, your model starts printing. The Robox uses twin nozzles – a 0.3mm one for detail and a 0.8mm one for filling in – both equipped with internal shut-off valves, which according to CEL prevent the oozing of extraneous plastic from the nozzles while printing. The print base is factory-fixed in place, so there’s no need to calibrate its height, and the polyetherimide (PEI) coating cools rapidly when printing is complete, helping your model to easily detach from the bed – so there’s no need to break out the wallpaper scraper to prise your model off its base.

CEL Robox - side

The proof is in the printing

Although the Robox package is a solidly engineered piece of hardware, the core business of squirting molten plastic out of a moving nozzle remains an inexact science. That’s especially true if you’re using ABS, which can behave unpredictably as it cools. Even within the Robox’s closed microclimate, we found ABS base layers occasionally failed to adhere to the print bed, instead being dragged around by the extruder head and either deforming or totally ruining the lower portion of the model.

Even when things did go to plan, print quality still wasn’t as great as we’d hoped. The Robox boasts a 20µm vertical resolution, which coupled with a 0.3mm nozzle sounds like it ought to be capable of producing some very fine designs. Unfortunately, thermoplastics are gooey substances that don’t naturally form neat corners and points, so rough edges and irregular gaps between layers are a fact of life. Despite CEL’s valved nozzles, our models also tended to came out with odd bobbles and bits of stringy detritus dangling off them, which had to be trimmed away – as did the inevitable support material used to hold up overhanging elements.

CEL Robox - 3D printed skull in ABS

Frustratingly, the current version of AutoMaker gives you no control over where this material is placed – your only options are Off and Auto – and left to its own devices, it doesn’t always position it very intelligently. When we tried printing a chess pawn with a protruding collar, AutoMaker wrapped support material around the entire central section of the model, making it impossible to trim away cleanly. Overall, the output from the Robox is a step up from the coarse models that were par for the course only a year ago, but you still can’t be confident of clean, fuss-free results.

Lastly, we need to talk about print speeds. CEL states that one of its goals for the Robox was to achieve better print speeds than existing printers, and we can’t argue with the intention: even small objects can take hours to emerge from a modern 3D printer. The Robox’s dual nozzle is a clever innovation in this direction, but even so, printing a single Lego-type brick took us 31 minutes at default quality, and a model skull standing 3in high took more than seven hours. The Robox isn’t exactly noisy, but that’s a long time to endure the insistent whirring of its twin motors.

CEL Robox - 3D skull print

Looking forward to twins

As offered, the Robox is a work in progress. A twin filament-feeder mechanism anticipates an (as yet unavailable) second spool that will allow the printer to combine two colours – or two materials – in a single print job. Software upgrades promise the ability to control the printer from a mobile device, the ability to edit and manipulate 3D models, and pause and restart capabilities that can save your bacon if you run out of filament halfway through a job. What’s more, both the print head and base are designed for modular replacement, so with future upgrades the Robox could be turned to jobs as diverse as icing cakes or machine-tooling designs in metal.

If you’re considering investing, however, it’s best to focus on what your £849 gets you today. That is, a printer that remedies many of the failings of last-generation 3D printers, but – we’re sad to say – can’t entirely tame the inherent challenges of layer-based thermoplastic printing. For enthusiasts, it’s the best device of its type we’ve encountered; it’s easy to see why the original Kickstarter project raised more than double its funding target in pre-orders. If you’re waiting for a fuss-free, consumer-friendly personal 3D printer, however, a few further steps forward are needed before this technology is truly ready for the mainstream.

Print technologyDual extruder head
Resolution20µm vertical, 300µm horizontal
Supported filament typesPLA, ABS, nylon, PC and PVA
ConnectionsUSB 2, microSD card slot
Build volume (WDH)210 x 150 x 100mm
Size370 x 340 x 240mm
Buying information
Warranty2yr C&R
Price£849 inc VAT

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