A desktop 3D printer that’s affordable, user-friendly, and capable of top quality prints? Read our review of the formidable CEL RoboxDual.
3D printing technology continues to advance with the latest generation of machines making huge leaps forward in design, reliability, and quality. CEL is one manufacturer leading the charge; their latest model, the RoboxDual (RBX02) is a dual extrusion 3D printer.
The CEL RoboxDual follows the company’s previous single extrusion Robox (RBX01), a small and compact 3D printer that arguably packed in more innovations and features than any other 3D printer on the market at the time.
And although it bucked many trends, it swiftly became one of the top ten printers on 3D Hubs, swatting aside bigger name brands like Ultimaker and Makerbot.
All of which means the CEL RoboxDual has a lot to live up to. With CEL’s first release being such a big hit, the industry is closely watching this new arrival — one of the first affordable dual extrusion 3D printers that’s widely available.
Mainstream dual extrusion printers are only just coming to the forefront. Until recently, the setup and configuration of these complex machines could be a real pain.
The CEL RoboxDual, BCN3D Sigma and Ultimaker 3 have all recently come to market, and each strives to prove that dual extrusion doesn’t have to be difficult.
But whereas the BCN3D Sigma and Ultimaker 3 have their roots firmly in the maker community, the CEL RoboxDual aims to bring quality dual printing to the mainstream.
The machine’s size, price and quality make this an ideal option for smaller spaces, and the innovative modular design means that the printer has plenty of scope for future upgrades.
In use everything about the printer is aimed at simplicity with auto-loading filament, auto-leveling bed, and easy to use AutoMaker software. The SmartReels enable you to keep tabs of the filament use and cost as well as print progress.
Quality-wise, single extrusion prints are as good as you can get from a fused filament fabrication (FFF) printer, and ABS print quality is almost identical to that of the Ultimaker 3. Dual extrusion prints are equally impressive, mixing materials and colors well.
If you’re looking for a quality desktop 3D printer for the home, office or classroom, then there’s little not to love about the formidable CEL RoboxDual.
Before we start let’s take a quick rundown of the features. It’s of course of the dual extrusion type — whether it’s two color or two material the choice is yours — and these two extruders act independently so the temperatures can be adjusted as needed.
Print platforms are always a good place to start and the CEL RoboxDual is 210 x 150 x 100mm. This is pretty small, but for the vast majority of prints at home, this is more than adequate. That print platform size also means that the printer itself has a relatively small footprint of just 370 x 340 x 240 mm.
Filament wise it takes 1.75mm and it’s fully compatible with any standard PLA and ABS, together with a huge list of specialist materials. The hot-ends can reach a volcanic 280ºC, and each extruder uses a unique needle valve to adjust the filament flow for better accuracy.
The filament is supplied on SmartReels which contain all the filament data, cost, length, etc. Manufacturers supporting SmartReel technology are ColorFabb and PolyMaker. The connection with these brands is instantly reassuring, showing some high-end interest for this machine.
Filament from any manufacturer can be fed into RoboxDual, either directly from the source reel or wound onto a SmartReel with a custom profile written to the EEPROM memory on the reel. This gets around the initial worry that you’ll be locked to high priced filaments and any limitations of range.
As required by most modern materials, there’s a heated print platform with a max temperature of 150ºC. This ThermoSurface doesn’t require glue or adhesive. The surface is also quickly removable and flexible so prints can be easily popped off if needed.
The RoboxDual is a closed environment when printing, with a top down door locking warmth inside and fingers out. The RoboxDual bed heats from 20°C to 60°C in 1 minute 15 seconds, and to the ABS bed temperature of 125°C in ~4 mins (in comparison to UM3 which quotes <4mins from 20°C to 60°C) .
The dual extruder head is part of the ‘HeadLocks’ ecosystem, an innovative design that enables the head to be removed and replaced for one of several different head options. These additional heads include different nozzle sizes for greater accuracy or speed, along with other possible future cross-grades.
Filament is pushed to the head along bowden tubes using two SmartExtruders. These make the process of loading and unloading easy (bar the filament tangle) and uses dual pinch wheels to minimize any slip.
The list of features and innovations are impressive and, as you flick through the supporting literature, it’s plain to see that most of these innovations are trademarked and unique to the Robox printers.
Unlike many competitors such as Lulzbot and Ultimaker, CEL have from the outset aimed to create a printer that could be used by anyone safely and without the need to tinker. The Lulzbots and Ultimakers are fantastic class-leading machines, but the RoboxDual offers something a little more refined.
Another big departure from the foundation of modern 3D printing is that CEL is a completely commercial enterprise. The printer itself isn’t part of the open hardware community, although the company is actively involved in open source with their other products.
For this reason, the CEL RoboxDual is a very different machine from others in its class, as it utilizes custom electronics, extruders, and hot-ends. These components aren’t designed to be tinkered with, which makes that CEL RoboxDual one of the few 3D printers out there that really should find wide appeal in workplaces and schools rather than just the maker community.
The CEL RoboxDual has also been designed to be future-proof with a variety of modular components such as the HeadLock system. Indeed, the single extrusion Robox can be easily upgraded to the RoboxDual (RBX02) by simply fitting the upgrade kit (RBX01-DMKIT):
This kit includes the new head, second reel holder, and a few other additions to bring the older Robox bang up to date.
Ultimaker, Lulzbot and Makerbot might be better-known brands, and there’s no doubting their abilities and quality when it comes to printing. But the RoboxDual and Robox have both been designed as a usable mainstream 3D printer, much in the same way as any 2D printer of old.
You might be fooled into thinking that the new RoboxDual is just the Robox with a different head. Which to a certain degree it is.
The housing for the new RoboxDual is identical to the single extrusion machine, there is no real difference in the shape, form or color. The differences come in the head unit inside. This means that if you do have one of the older machines or want to start off with the single extruder, then it is possible to upgrade at a later date.
The upgrade will set you back around £290, and the head takes a couple of minutes to change once the filaments have been extracted.
From the outset, everything about the CEL RoboxDual shows that this is the work of engineers rather than hobbyists, with a set of design and development features that are not slapdash but carefully considered.
The size and shape of the printer, for example, is roughly that of a traditional 2D A4 printer. That means that it’s the ideal size to have sat on your desk. The other design feature that really sets it apart from the majority of other printers is that almost everything is contained, there’s no feeder tubes — just the two reels sticking out of the side.
Connection-wise, there’s just the power and USB cable. There’s also a covered slot for a MicroSD card on the back, but this is used for internal flash storage and diagnostic use, so should be left well alone. This flash storage is used to store the model file once downloaded from the AutoMaker software.
The CEL RoboxDual connects to your computer through USB. At first, this makes you think that it’s a tethered system, but far from it. The wired connection enables you to fully interface with the machine, and those intelligent SmartReels have a great deal to say along with the printer itself. Once you’ve connected and sent the model to print, the USB can then be disconnected leaving the printer to get on with it.
This way of working has quickly caught on, and although the RoboxDual is the first printer we have seen that uses this workflow, the Ultimaker 3 uses a very similar system. But of course, the Ultimaker 3 has the Wifi connectivity as well.
(Editor’s Note: ALL3DP is currently testing the UM3 for a review, full details on print speeds and quality will be available soon.)
For future innovations, CEL already have the wheels in motion with a successful KickStarter campaign. The campaign has already met its target, which is unsurprising as the demo we saw of the new product at TCT in 2016 was impressive.
The product is a network print system, stand and app called the Root, Tree and Mote. The network part being based on the Raspberry Pi. This means that if you really want must indulge in some tinkering then you’ll soon be able to get the plans and build the network tree yourself.
This innovation is an interesting development and will enable the connection of multiple printers through a network system. This will enable the control of multiple prints from one base station. The root and tree network system makes sense in a commercial or education environment where you can split the prints across multiple printers.
At home, this system will enable you to use the printer without first having to connect through USB, and all files can be sent to the printer from the app. If you want to go retro you can always print from an SD card.
This way you can network and print larger projects across multiple printers, enabling you to minimize any downtime if something does go wrong. Why block up one large printer when you can print on multiple? The downside is of course the cost; more printers means a greater outlay, but then the Ultimaker 3 is more than double the price.
Out of the box, the the CEL RoboxDual takes around five minutes to set-up, download software and get running. A small plastic clamp that has been printed by your printer during the final stages of manufacture holds the print head in place, and this needs to be removed prior to priming.
Although simple, this clamp shows the quality of print that is possible with the RoboxDual. This quality is no surprise when you take a look through the specifications and see that the CEL RoboxDual has an Ultimaker 2 matching layer resolution of 20 microns.
Once the clamp is removed and the printer is attached to your computer via AutoMaker (CEL’s custom 3D print software) the printer is ready to load with filament.
This process is where the first of the real engineering features come to light. Unlike other 3D printers that require a little fiddling to load filament into extruders, the CEL RoboxDual incorporates two feed slots on the side. Simply stick the end of the filament into one of the slots and the machine automatically grabs it and feeds it through the system.
The filament loading process is one of the easiest of any 3D printer we’ve used, and swapping the materials out for replacements is equally straightforward using the AutoMaker software.
Each of the two spools is then loaded onto the side, with a small spindle extender needing to be clicked into place to seat the second reel. These reels feature a hub with SmartReel technology. This is a small circuit that details the filament type and weight and is basically along the same lines as a UFID (Universal Filament Identification) system.
As you use the filament, this data is constantly updated so the machine and software know exactly how much filament you have and whether there’s enough to complete a print.
Other companies such as XYZ Printing offer a similar proprietary filament system, which might put some people off. However, the filament is no more expensive than standard quality filament reels.
The filament is also provided by some of the best-known filament providers in the world, including ColorFabb and PolyMaker, and there’s a good selection available. If you want to use your own filament then you can, either by feeding it in and telling the software which filament profile to use or by loading it onto an empty SmartReel and updating the circuit info through the AutoMaker software. The system is open and easy to experiment with.
CEL includes their own software in the package, Automaker, with Cura used as the foundation of the slicing engine. But don’t expect to find any similarity between the look and style of the two programs.
When setting up the software, you need to run through the settings prior to plugging in the USB cable. The installation and setup process for the software only takes a couple of minutes. With AutoMaker set you can then plug in the printer and start installing the filament.
Looking at the left of the interface, the printer and filament details are listed. This is where the SmartReels really come into play. Information about the reel size, material and color is all passed to the software along with pricing info, so you can keep up with the cost and quantity of the materials.
This is especially handy if you’re about to start a large print, as you’ll get direct feedback about whether or not there’s enough filament to finish the job. An issue we seem to frequently have!
The rest of the interface is tuned in a similar fashion with plenty of information about the status of the machine and materials.
There’s also a good range of maintenance features that enable you to purge materials as they’re swapped, to ensure that there’s no contamination during the initial print. The purge process is quite lengthy at around five minutes but well worth it (and you can skip if you really want).
Automaker has three basic zones; Status, Settings and Layout.
Status gives you a good overall impression of the 3D printer, showing the materials, hot end and heated bed temperatures along with any jobs that are currently running. At the bottom of the interface are a series of additional options that enable you to calibrate the 3D printer, return the head to home, eject filament and remove head etc.
Auto base leveling is a feature but as with many other aspects of the RoboxDual, it’s completely different to anything else we’ve seen. Prior to a print, the head shoots across the base and presses down into the print platform at several points, the effect of doing this tilts back the head slightly registering the print platforms level at different points. This data is then used for the calibration.
This system seemed to work well, although the slightly mechanical nature of the setup may in time see wear and tear, but the company prides itself on customer service. Feedback around the site and on forums seems to back this up.
The eject filament option nicely rounds off the ease of filament loading; simply click and a list of the two filaments appear, enabling you to either remove one or both.
Another feature to highlight is the “Remove Head” option, this simply retracts the filament so that the RoboxDual head can be removed and replaced with another unit. Soon there will be two other head options, including larger and smaller nozzle sizes, with more in the pipeline from CEL.
Moving on to the Layout screen shows the usual virtual display of the print area. At the bottom of the screen there’s the option to Add Model; if you’re loading a dual material model then the two STL files can be selected and loaded into AutoMaker, which will then automatically align the two sections.
The final section shows the settings; the majority of this is handled by the printer with the SmartReels supplying the filament data so you don’t need to worry.
By default there are three print settings which can be quickly selected; these aren’t named, just highlighted with a self-explanatory icon. Under these base options is the Custom quality settings that enable you to get creative.
The next set of settings is the raft and support structure, and this section really starts to show how although it looks seemingly simple, AutoMaker is really an incredibly sophisticated piece of software, enabling easy control over complex aspects of your print.
If you’re printing a support structure with a material such as the PolyMaker PolySupport, then the support section enables you to allocate the material to the correct STL.
We were impressed by both the ease of use of the AutoMaker software and the actual filament with the support it gave and how easy it was to remove from the final model.
The CEL RoboxDual is packed with innovative features that make the setup and use of this 3D printer feel more like a mainstream commercial product than any other 3D printer we’ve used. Only the XYZ Printing machines come close to a home and classroom friendly design.
Initial setup went without a hitch, and when loading filaments it’s a good idea to place the reel flat on the work surface prior to feeding the end into one of the two feeder tubes. The 1.75mm filament can get a little tricky to handle without tangling, especially on a full reel.
Once the filament is fed into the system, then the reel can be clicked onto the spool. After several weeks of prints and material swaps we did have a couple of occasions where the filament refused to load.
In these cases, despite the filament end being seeming clean, a sharp cut through the filament with a pair of scissors and then reloaded seemed to do the job, along with a little jiggling of the filament back and forth until the machine gripped.
The size of the printer was definitely welcome, and the RoboxDual sat comfortably without dominating the workspace. The completely enclosed design along with the safety catch is also great, as it stops inquisitive fingers and paws from getting too close.
The security lock on the door is also an important feature that will widely appeal to the education sector. A quick release version of this would be a good idea, but the old credit card trick seemed to work. Alternatively, you can switch the safety features such as the lock off in the settings.
AutoMaker is exceptionally well thought out and tries to make things as easy as possible for the novice printer. If you do want a little more, then switching on the advanced settings enables you to check out a G-Code Console as well as open a series of Diagnostic options.
Selecting size, quality and the materials you want to use for the print (either for a mono or dual material print) is also straightforward.
When it comes to the print times for single material prints, the times are directly comparable with the Ultimaker 2 and Lulzbot Mini.
The process of printing a two material rather than single material print is far more straightforward than expected. Although modeling the prints is quite a bit more tricky.
Simply select the STL files that make up your model and then click to assign the print material in AutoMaker. The rest is handled by the printer. There is no complexity to the actual print process; single or dual material prints are equally easy, the only real difference is the time involved for the actual print.
Dual prints do take longer, but side-by-side printing the same model on the Ultimaker 3 you can expect the RoboxDual to be complete in considerably less time.
Noise is always an issue with any 3D printer and whilst the RoboxDual isn’t hugely noisy, it’s also not the quietest we’ve used. The majority of the noise is generated by the steppers and fans, but really there’s no way around this.
In a busy design technology classroom, the noise from the CEL RoboxDual at full print speed is unnoticeable, and even when printing in the office the noise is perfectly bearable.
Print extraction from the platform is the fight that folks least enjoy about 3D printing, whether that’s trying to extract a model from the perforated base of the Zortrax M200, lever a print from the glass base of the Ultimaker 2, or dunk a resin-coated masterpiece from a Form 2. With the RoboxDual (RBX02), however, is a print platform that we can learn to get along with.
A small lever releases the front and then a quick pull and the print surface can be removed. Then just flex and the print pops off. It’s sensible, easy and avoids any injured fingers or impaling.
However innovative and slick the design of a 3D printer, when it comes down to it all we really want to know is this; how good are the prints?
The quick answer is excellent. But obviously because this is a dual filament 3D printer, we have both the single and dual material experience to evaluate.
The single print experience is as good as it gets, the AutoMaker software makes selecting print quality and material easy, and the fact that you have two materials preloaded means that much of the usual faff of swapping reels isn’t required.
Print quality at all three presets is good, and we used the standard 3D Benchy model to check out how the printer performed.
Quality varied between PLA and ABS, with ABS producing far better results. When printing PLA, the door needed to remain open to help the PLA set quickly.
On the first run printing PLA with the door closed, we found that the low and high-quality prints both suffered from some bubbling of filament.
However, once the door was open for PLA printing and closed for ABS, the print quality was superb and directly comparable with the Ultimaker 2.
Overall the print quality using the default profiles was excellent. The accuracy was spot on and for the most part produced good clean prints with few of the common printing issues.
There was a slight issue with the cleanness of the print around the anchor eyelets, and some very fine stringing on the high-quality print, but these were the only details slightly out of place. On the finest print quality there was sign of some slight fine stringing but ultimately a very good print.
The CEL RoboxDual may divide opinion, especially among those who are ardent supporters of the open hardware and software communities. The RoboxDual is a closed system; it uses proprietary filament reels, specially designed extruders, and heads that are swappable but only for CEL’s own.
The software is also of CEL’s own design, although Cura is used as the slicing engine. When it comes to customizing settings it is possible, but those options are limited in comparison to normal Cura or Simplify3D.
There’s also the issue of the print bed size at just 210 x 150 x 100mm, which makes it one of the smaller 3D printers on the market.
But then if you just looked at the specifications and moved one, you’d be completely overlooking one of the most innovative printers on the market.
It’s been designed by engineers as a tool, something to be used on a daily basis without issue. In those terms we would say that this is the first 3D printer that truly mimics the ideology of a standard paper printer. It sits there in the corner of the room and prints without any fiddling or calibration, it just gets on with it.
When it comes to reliability there really was no issues with the printing. A purge feature within the software means that there’s no cross-contamination of the filaments as they’re changed.
And the HeadLock system that enables you to swap out the standard dual head for the QuickFill (and further releases as they become available) is where this 3D printer really starts to get interesting. Although it isn’t Open Hardware, there’s plenty of options to cross grade, swap and change components as you need.
The SmartReels are really smart, and unlike other systems that are locked to the filament that is shipped on the reel, CEL have devised a system that enables you to update the reel data, so if you want to load your own filament then you can.
When it comes to quality, the three standard quality settings all produce decent 3D prints. The extruders use a different system to the standard retraction material method, instead using needles that cut off the material dead. This enables faster swapping between materials, but with our 3D prints some very fine hair width lengths of filament could be seen dotted around the surface of the print. However, this hair is easy to brush off.
The low-quality mono prints were produced relatively quickly at 1h 30, medium quality at 2h 17 and high quality at 5h 18. Compare with the Ultimaker and the same model: Fast Print 1h 9, Normal 2h 38, high 4h 22 and Ulti 6h 33. Comparing the quality of the mono prints between the two printers and there’s very little in it at the high end.
When printing Dual materials, the print times are almost double, but so far early comparisons against the UM3 show that the RoboxDual’s dual extrusion system is far quicker.
The CEL RoboxDual is a solid performer; it might be compact but it turns out decent prints and has the reliability and quality to be more than enough of a machine for the hardcore 3D enthusiast.
Feedback about prints, time, cost and filament used in AutoMaker is all useful information that helps you to better understand the costings of your 3D printing habit.
As innovations go, the CEL RoboxDual 3D printer is packed with features that constantly reveal themselves the more you delve into settings and options. Features such as the GoPro time-lapse connection and future product launches such as the Root, Tree and Mote make it a very exciting product.
Dual extrusion 3D printers are becoming more prevalent, and the market in this sector is rapidly expanding. At this point in time, the RoboxDual offers a printer that is cost-effective, reliable and offers great quality beyond any other dual extrusion printer on the market at this price.
Factor in the pricing, innovation and future modular expandability, and it’s difficult not to recommend the CEL RoboxDual.
License: The text of "CEL RoboxDual 3D Printer Review: Dual Extrusion Redefined" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.
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