I recently got a RepRap Prusa i3 Hephestos 3D printer kit, from bq and this is some notes about assembling it, and getting starting using it.
First a disclaimer: I am by no means an “electronics” guy. I do have minimal solder knowledge, and access to most ordinary hand tools (inclusive a bench vice), but I have never done much electronics, nor 3D printing before I got this kit. I have not followed reprap.org, or anything like that. I did have a 3 hours “hands on course” in using a 3D printer (Ultimaker), about a week before I got this printer, but nothing else. I got the kit, because I wanted to 3D print, and needed a kit that was easy to assemble, and easy to set up. Not because I wanted to actually build/customize a 3D printer (that quickly followed though, but that is another story).
First impressions: everything extremely neat packaged, in high quality boxes, with clear indications. Everything seemed like very high quality. Very, very nice and very comforting. (I have later learned that one does pay somewhat more for this kit than if one sourced by oneself, but I would buy the kit again in an instant, if I needed another 3D printer of the same type).
The package came with a Spanish set of assembly guides. Beeing somewhat challenged by Spanish, I located the english guides and additionally I did consult once or twice with the assembly video. (Bq frequently updates the assembly video, at least, so make sure to check out if a newer exist!).
In general the assembly guides are very good, and assembly was very straightforward. I would rate assembly difficulty a good step above IKEA furniture, and somewhat on par with the most complicated LEGO Technic sets. You should not be unfamilar with normal hand tools, or scared by soldering though. Timewise, I was able to go from scratch to first print in a single (sun)day, and assembling was very rewarding and even fun! (And I learned some valuable techniques, actually).
A few steps in the assembly were unclear:
- One should probably mount the Z endstop before mounting the smooth rod.
- It is a good idea to check that the X belt tensioner can move freely, before assembling the X axis completely.
- When putting the cables for the extruder and X axis engine into the flexible joined “thingy”, it is quite unclear which end goes where: what is the “start” of a cable. I managed, but I think it was by luck more than by anything else. I believe the part with 27 joins in the manual should only have 25 joins, and vice versa.
- The mount for the fan to cool the electronics (RAMPS) has difficult to reach allan screws, when the Z axis has been mounted. I shortened an 2.5 mm allan key and used that.
- The holes for mounting the bed are tigth! I used a 3 mm screw from the other side, and even tapped some of the holes.
- Don’t overtighten the Y endstop mount screw – it does not go all the way in!
All in all, I was very happy with the kit, and the assembly, and compared to some of the horror stories on reprap.org (for cheap kits), it was a very happy experience. Complicated at times, but the good folks at bq has done a lot to make it easy.
However, they failed a bit in one aspect: When assembly is done, there are no more manuals. I was sure I needed to do some calibration, but this is not mentioned in the manual. And, there was no indication on how to use e.g. the printers physical interface. Luckily, I found some information on reprap.org. The next section is about this.
Final calibration & getting started
The physical interface on the printer is called a “smart controller”, and is very much like this from RepRapDiscount. Basically you control the printer by turning “the knob”, and pressing it to select menu entries. The small button in the lower right corner is a “panic button”, I think: It stops whatever the printer is doing, and you need to powercycle it to get it going again, or use one of the reset buttons: there are two, one on each electronics board (Arduino and RAMPS) and they are both placed facing left, near the place where the power lines goes into the RAMPS, and are easily pressed when facing the front of the printer.
The firmware used is called “Marlin”. I have not really seen any documentation for using it, but its like navigating a menu on an old-style HP printer or similar. You will figure it out quickly.
To calibrate the printer after assembly, you need a couple of steps more
- Adjusting the two z axis rods: basically measure from the surface that the X axis is level. Rotate each Z axis rod (while the machine is off) until it is level.
- Levelling the bed: Use the autolevel feature of the printer – you should adjust the bed to allow a piece of paper to slide beneath the extruder and the bed.
There are more information about final calibrating at reprap.org. Note also the point about cleaning the extruder – you may need that. (Why this information is not printed, I do not know).
The last issue I had, was feeding the filament into the extruder. You should of course use the “Control|Filament|Load” option on the interface, but you should also press the button on the extruder to insert the filament. Now, that button is really hard to spot! Its actually the top of a spring loaded lever, that keeps a roller tight agains the motorshaft that feeds the filament. On this image, it is the “low” part of the top of the extruder. Its near the frame, between the frame and the filament feed hole.
BQ provides cura profiles at the download page, bottom under “Perfil_Extrusion_Cura.zip“. With this, you can easily download a thing from thingiverse or a similar site, run it through cura, write the gcode to a suitable SD card, insert it into the printer, and get printing.