Can a 3D printer be open source AND offer a stress-free experience? In his BQ Hephestos 2 review, Thomas Sanladerer reckons this machine comes pretty close.
Note: This review originally appeared on Thomas Sanladerer’s YouTube Channel and is subject to copyright. Text and images have been reproduced with the author’s permission.
So just to point it out again — as my full time job, I work for BQ in their educational department in Germany, but this YouTube channel is mine and everything I say is my own personal opinion (even if I’m sure BQ’s marketing department would sleep easier if they could pre-approve my videos).
Now, the Hephestos 2 is the second version of BQ’s DIY kit 3D printer. The Hephestos 1 still carried the Prusa i3 name proudly and it was a relatively vanilla i3. Combined with €499 price tag, it was a surprisingly successful entry into the 3D printer market for BQ.
Now, the Hephestos 2 is very clearly still based around the Prusa i3, but has seen a redesign of almost every single part. And one of the first things, as a user, that you are going to notice is just how efficient the entire Hephestos 2 feels, and that starts with the packaging and the assembly.
Assembling the BQ Hephestos 2 Takes Less than 3 Hours
I did an entire video on the pre-release assembly, and that experience stayed mostly the same, with a few tweaks here and there, like the improved bed clamping, wires that are now pre-labeled and some changes to the packaging design, which now includes labels for the individual parts in the cardboard trays, and an actual, physical manual.
And that manual is about as good as it’s going to get — if you can assemble an IKEA table, you can assemble this printer. I built the first beta unit and had my padawan Luke assemble the two retail ones, and we always ended up between two and three hours, which I consider, at the very least, quite fast for a full-size machine.
So full-size, this case means the typical roughly 210 x 300 x 220 millimeter build space, up from the 200 millimeter squared a typical i3 offers. The Y-axis (alias the bed) rides on encased LM8UU bearings, while the X and Z axes use Hiwin linear rails as a smooth, reliable and stiff linear guide.
Where’s the Heated Print Bed?
The extruder is a Bondtech-inspired two-sided drive mechanism with a spring-loaded idler drive gear — so both sides contribute to driving the filament, and that works so well that they decided there was no need for easy accessibility of the drive gears — all you get is a tension adjustment screw in the back. And personally, I fully agree with that decision, this thing is an absolute workhorse and possibly one of the best features of the Hephestos 2.
And as a bonus, since the filament is so well constrained after the drive mechanism, this extruder eats flexible filament for breakfast, and I’m totally on the same page as RichRap, it’s probably one of the best printers out there if you’re planning on printing with flexible filaments.
The hotend is another custom design in an almost-all-metal-hybrid fashion. It’s still got a piece of harder-than usual PTFE going almost all the way down into the melt zone, but it’s also got a stainless steel heat break, kinda like what the E3D Lite6 is doing, but using the extruder body as a heat sink. For this particular machine, it’s okay for the hotend to top out at 250-ish degrees Celsius. Why?
Well, let’s jump straight to my personal least favorite part of the Hephestos 2, and that’s the print bed, or more precisely, the lack of a heated one. It’s simply a piece of glass bonded to a sheet of steel, and while the design allows for a quick-release of the build surface, it is not heated, at all. Which means the hotter plastics like ABS are just not going to happen on this printer unless you find some way to not only make it stick to the bed, but also to keep the layers from cracking due to the cooler ambient temperature.
Even PLA would have profited from a heated platform, but is becoming more and more reliably printable with the application-specific adhesion improving surfaces becoming available like the Coropad or Buildtak, 3D EEz, or the favorite of most folks at BQ, 3DLac, a hairspray-like single-use coating material.
Inductive Sensor is a Neat Feature
Now, the steel layer of the bed enables the custom-made inductive sensor to work — BQ’s argument against using the off-the-shelf industrial sensors is a) having full control over the quality of the sensors; b) having a sensor that is actually made for sensing a set distance precisely; and c) being able to tweak things like temperature compensation (which, to be honest, I haven’t specifically noticed to be a problem with other sensors, but then again, I haven’t really put any research into that specific topic, either).
The point is, the sensor works, and I trust it enough to completely ignore the option to manually tram the bed on the included adjustment points. For those of you who still like to manually adjust your beds and turn off the auto-tramming, the option is still there and well-implemented, but I’d rather have the extra stiffness you get from completely tightening down the bed and just relying on the sensor.
There is a tiny little hiccup there, though, and it ties into the next thing I want to point out. The sensor is obviously also used to adjust the nozzle offset from the bed and set your starting height, but since it actually has an offset in the Y direction from the nozzle, it can throw your offset off if you end up ever so slightly tilting the printer frame by, for example, just picking it up and setting it down.
Thankfully, adjusting the offset it rather simply to do through the LCD, but it’s certainly not a printer you should be constantly moving around. And if you look at the frame, it’s clear it’s not intended for that use at all. There is no bracing that supports the main frame plate staying upright, it all relies on the 8mm rods holding it together. And that does make for a rather wobbly frame, at least in this direction. Some i3 designs or the Mendel90 have specifically added struts to make the frame stiffer, but not the Hephestos 2.
Ease of Use and Performance
Now, what seems to be the predominant theme with this machine is ease of use and reliability. Don’t get me wrong, this is still a very well-performing, open-source machine (I like to think I had a part in the all-out open-source decision), but the Hephestos 2 is definitely not catering towards the power users.
Instead, the choice of components, features and even how they are implemented, seem to be catering towards users that might not precisely have a clue about what they are doing. The build with the pre-assembled extruder and drag chains, the bulletproof extruder design, and (one of my favorite features) the LCD screen all point towards that.
The LCD is a nice-looking white graphical screen with the usual clickwheel and SD reader, but the interface is completely custom-built on top of a modified version of the Marlin firmware. Gone are the cryptic abbreviations and text-only menus, and they are instead replaced with assistants that guide you through the first setup as well as simple things like removing and inserting filament.
Yes, it does seem weird that the printer will always home all axis before it lets you change the filament or, the other way around, heats up the nozzle when you only want to adjust the offset. Reason behind that being “well, the user might try to swap filament with the nozzle right up against the bed or try to adjust the offset with a booger stuck on the nozzle”. So while some of the scripts might feel like they’re doing everything else first and then, finally, the one thing you actually intended to do, they are set up like that for a reason and make using the printer just so much easier.
And, on a short note, the electronics board used here is a custom-made Atmega-based unit equivalent of something like a four-axis RAMBo without the heated bed part. There are talks about possibly an expansion set with all the extra hardware for a heated bed, but nothing too specific at the moment.
Final Verdict and Pricing
Now, all that comes together to a machine that is really not going to wow anyone on first sight, and it took me a while as well to warm up to the Hephestos 2. But it’s a machine that just does its thing, and reliably, and that’s what everyone I’ve heard from who’s also using a Hephestos 2 seems to confirm. And its print quality can certainly keep up with any other FDM printer on the market.
So the moment when I personally paused was when I heard the price of the retail version: €850 (including tax). It’s quite a step up from the original Hephestos’ €500, and on paper, you’re only getting a slightly larger build space. Also compared to the PrusaResearch Prusa i3, which comes with a heated bed and E3D all-metal hotend at €655, it seems like a rather bad deal.
But here’s the thing: If you know you need a heated bed and don’t care much about the assembly time, looks (because, let’s face it, the Hephestos 2 is pretty darn sexy), or about no-fuss components like the Hiwin rails, comfortable LCD screen, bed sensor, or the fault-proof extruder, then by all means get the PrusaResearch machine, that’s also a great option. But it’s practically the same hardware and experience we had three years ago.
The Hephestos 2, only the other hand, takes a lot of tiny baby steps in a direction that feels like it’s the right way forward for consumer 3D printers. There are a few sacrifices in the Hephestos’ features, but those features that are there are really well implemented. With the exception of a few teething pains, that is. One single instance of the units I assembled came with stripped threads in the main frame, wonky tolerances on some of powder-coated through-holes, and pulleys that were a bit too tight to mount. And all of the machines come with overly loud stepper whine at 15 kHz that I can personally not take for more than a few seconds without popping on some hearing protection.
But these are things that, as of mid-February 2016, which is when this video was shot, I’ve already whined to BQ’s engineers about. I fully expect these issues to get fixed with better quality control in manufacturing and a firmware update that should fix the stepper whine for all printers, even those that are already out there.
So in the end, it’s up to you to decide what level of involvement you’re going for. But if you’re part of the 99% and just want a stress-free printing experience, then the Hephestos 2 is definitely one of the better options for you.