Ultimaker’s newest model, the Ultimaker2 was launched at the New York Maker Faire in late September 2013, and began shipping towards the end of October. I was lucky enough to be part of Ultimaker’s team for the launch weekend, so I got to spend a couple of days watching it print as I talked with the crowds of folks that surrounded Ultimaker’s stands. My initial impressions were very favorable – it’s a visually stunning printer, that looks amazing with the built-in white LED lighting, and it prints very quietly and cleanly. The new direct drive extruder system seems to offer very precise extrusion control; in particular, retraction seems to work especially well. That first weekend I was seeing some great results printing parts such as Emmett’s Gear Bearing and Barspin’s Printable Wrench which require good retraction control to ensure that the various moving parts do not get stuck together. I was excited as I waited for my printer to be delivered, so I could put it through its paces.
In fact, I’ve had mine for about a month now, and once I got to grips with it, I’ve been even more impressed than I expected to be.
It wasn’t all plain sailing though. Some of the early shipments – including mine – had some assembly and quality control issues, which meant it took me about a week to get my printer working properly. I had to replace some of the fan wiring going to the print head, and tighten up one of the pulleys. It wasn’t anything major, but it meant that the first week of ownership was more frustrating than it should have been. I know though, from their public pronouncements, and conversations I’ve had with them in my semi-privileged position as a moderator on their forums, that Ultimaker has been working hard to identify and resolve the issues so that the experience for future users can be as simple and trouble-free as possible. They’ve also been inundated with much higher demand than they expected, so that has put additional strain on their support and customer service staff, as well as the logistics and manufacturing teams. Shipment lead times got pushed out a few weeks, from the initial one or two weeks lead times. They’re still a lot better than many other 3D printer companies are doing; Form Labs has been shipping since the time of the San Mateo Maker Faire back in May, and is still running a 3-month lead time on new orders. And don’t get me started on the operational, technical, communication and support growing pains that I’ve witnessed in dealing with QU-BD and their RXL printer.
Finding Your Way
The user experience with the Ultimaker2 is also quite different from the Original model, and it takes a little bit of getting used to. It’s a much less ‘hands-on’ printer than its predecessor. At first it feels a lot like the printer is locked in a glass box, and you can see it, but not really get in and tweak things. There’s no giant extruder gear wheel to grab and turn. The start and ending gcode sequences are now all internal to the firmware, so you can’t tweak the behavior to suit your expectations or workflow. In the current early versions of the firmware, the configuration and control options in the user interface panel can be hard to find or, indeed, totally missing – at least compared to the excellent UltiController interface on the older model of printer. At first, I was quite frustrated; now I’ve gotten used to it – and while there’s still quite a bit of work to do to make the user interface as good as it could be, the total Ultimaker² package is already good enough to give some fabulous results.
Pushing the Envelope
Once I had the printer working correctly, and had gotten comfortable with the workflow and user interface, I wanted to see just how good it was, and how far I could build on the initial sense I’d gotten back at Maker Faire that the Ultimaker² could deliver great quality through its improved extruder drive control, and especially what seemed to be very precise retraction capability.
And so I started looking for some prints that would give me a sense of what the printer could do. So far, I’ve tried three different, challenging prints, and they all came out really well. All of them were prepared for printing using Cura 13.11.2.
Joint Stars, by Dizingof
I scaled this tangled ball of interlocking starfish to 10cm high for printing, and then had to add a lot of additional support, since there are many places where the arms loop down and the attached body actually starts to build up from a totally unsupported overhang. Rather than using Cura’s built-in support capability, I wanted something a bit more intelligent, that I could hope to remove without damaging the print surface as much as Cura’s broad-area support material was likely to. I find Cura’s support is great for large areas, or simple geometry, but I feared that a shape this complicated was likely to become a solid ball of un-removable, interlocked support and print if I didn’t find a more targeted approach.
I thought about adding custom support manually, but in the end, I decided to use MeshMixer 2.0’s support generation capabilities. It’s an interesting tool, and it certainly gave some good results in this case. I’ll add another post in a few days about my experience using that.
I printed it in Ultimaker Blue filament, with 0.1mm layers at 30mm/s. The support pillars and 20 loops of brim kept the print well-anchored to the bed, and the total print time was about 21.5 hours. Afterwards, the pillars of added support broke away very cleanly. The undersides of the lowest, near-horizontal, overhangs were just a little rough, but they sanded down quite nicely, and all the easily visible surfaces printed beautifully.
Leaf Lamp 2, by Gergely
This was another 30mm/s, 0.1mm layer print. A fairly simple but elegant design, from Thingiverse, the artichoke-like structure is made up of rings of interlaced, ribbed leaves, that curve in three dimensions. The challenges of this print are both the numerous independent, small, thin, overhanging structures, and the fine edges and pointed tops that they have. Retraction needs to to be spot on to avoid stringing between the individual elements, and to avoid any blobbing on the surfaces of the leaves. Positional accuracy and precisely controlled extrusion is needed to recreate the pointed leaf tips without blobs or drooping.
I printed it using Faberdashery Greenery Green filament, and was delighted with the finished print. The sides of the leaves were smooth and unblemished, and the tips of the leaves all held their points nicely. Only on the very topmost leaves did I get even the faintest hint of stringing between the separate ‘islands’ of the printed layers, and that was mostly due to Cura’s idiosyncratic insistence on reversing the print order on alternate layers, so that as it finishes one layer, it immediately starts the next layer on the same part of the print. This causes it to lay down two layers in the same place, with no delay between them, so that the plastic doesn’t have time to cool. But the only ill effect was a few stray wisps of plastic that easily cleaned away when the print was done.
The total print time for this one was 15 hours.
Cells Bowl, by Dizingof
I’m a sucker for Dizingof’s wonderful Math Art creations, and I had printed his Cells Bowl about a year ago, when it was available for free on Thingiverse. It’s a dual-walled bowl consisting of Voronoi cells delineated by thin tubular walls, and standing 13cm high. These days, as with the Joint Stars ball, the STL is only available from his ponoko.com store. But’s it’s a great looking design, and while it had turned out ok on the Original Ultimaker, I wasn’t really pushing the envelope in terms of print quality, and it wasn’t going to win any awards as a great print. This time, I really wanted to see exactly what the Ultimaker2 could do with it.
Again I printed it at 30mm/s, 0.1mm layers, and with all the retractions the total print time was about 44 hours. But the result was absolutely stunning. Again, I used Faberdashery filament for this one – Bling Bling Gold, this time. There wasn’t even a hint of stringing in the cells, and just the slightest droop in the top of some of the cells as the first layer of bridging was laid down to close the cells up. A couple of minutes work with a scalpel quickly cleaned all of those up. Look at the photo gallery below for some close-ups of the cells texture to see just how smooth and shiny it turned out. It looks more like vapor polished ABS, but it’s PLA, printed – like all of these pieces – at 225°C.
I was delighted how all three of these prints turned out, even though they represent the three longest prints I’ve ever done, up to this point. All of them had the same basic settings: 30mm/s, 0.1mm layers, 0.8mm skin thickness (i.e., 2 loops of 0.4mm) and zero infill. They also featured no slicer-provided support; as already noted, the Joint Stars print included a framework of support bars added in Meshmixer, in order to ensure the structural integrity of the print. The other two were printed as-is, with no added support at all.
Perhaps the most challenging part of all these prints though was the detailed structure made up of multiple independent islands of printing on each layer. The print head has to jump back and forth between them, and there’s always a risk of oozing or stringing as a result. Filament retraction is the standard way to minimize that, but Bowden-tube printers like the Ultimakers are supposedly notorious for performing more poorly than head-mounted extruders, because of the hysteresis introduced in the filament travel due to space in the tube (and the tendency for thermal creep to cause extrusion problems as hot filament repeatedly gets dragged back and forth out of the hot zone in the print head). But, in practice, the Ultimaker 2 was flawless in how it handled all the retractions – and these prints were insanely hard on the extruder drives in terms of all the retractions. The Joint Stars print required over 65,400 retractions; the Leaves print took about 46,200 retractions, and the Cells Bowl required a massive 147,000 retraction cycles during the print. For each of the prints, it averages out to about 1 retraction and de-retraction cycle per second, for the entire time of the print – hours and hours of rock-solid reliability. Looked at another way, the Cells Bowl required about 18 meters of 3mm filament to print; but once all of the back-and-forth retraction cycles were factored in, the extruder motor actually moved over 1.6km of filament.
Since I was printing fairly slow, and aiming for the best possible finish quality, I was quite aggressive with my retraction settings. On the printer, I set the retraction distance to 5.5mm at 35mm/s, as I found that the default settings (4.5mm at 25mm/s) were sometimes not quite strong enough to avoid oozing on longer travel moves. I also upped the travel speed to 250mm/s, to keep non printing moves as brief as possible, and then in Cura I disabled the ‘Combing’ feature (which is supposed to keep travel moves within the print volume wherever possible, and avoid crossing edges unnecessarily, but seems a bit buggy at present, and doesn’t retract as much as I think it should to give the best possible print quality). I also set the minimum travel distance at just 1mm, and the minimum extrusion amount between retractions to zero) – so that pretty much any move much further than between adjacent lines of infill was going to trigger a retraction. And the Ultimaker2 handled them all, wonderfully.
While I’m at it, a hat-tip too, to Faberdashery. Not only do they have a great selection of colors, but their filaments print really nicely too. The Ultimaker Blue filament is a nice color, and definitely printed well – but I did feel that the Faberdashery filaments in the second and third prints behaved even better, and gave a beautiful surface finish – they will definitely be my go-to filament for demanding prints in future.