Every beloved gadget must have a name. I’ve experimented with a few different alternatives but the one that has stuck was suggested by a friend. He had recently attended a conference where an eminent professor had described 3D printers as “glorified icing bags” and therefore though Squirty would be an apt moniker. I think it is both endearing and accurate, so Squirty it is.
The same friend also caught the 3D printing bug and decided to order his own Huxley. This event gave me the perfect opportunity to see if Squirty could move to its next life stage and spawn a set of new plastic parts to be used in the construction of another Huxley.
Squirty had been showing signs that it had been ready to reproduce for some time. When it first arrived in the world it had to be taught to do the most basic tasks, like bed-levelling. After it mastered that it moved to a kind of moody adolescence where it wouldn’t print anything properly, but once it discovered hair products¹ it became much more stable and could be left unsupervised. Finally Squirty experienced a dramatic change “down there” when I switched out its small, brass 0.5 mm nozzle for a one-piece 0.3 mm stainless steel version. With the greater resolution of a 0.3 mm nozzle it became a responsible and productive adult member of society.
Tortured puberty analogies aside, I was quite excited at the idea of trying to print a copy for Squirty. However I had no idea whether I would have enough time to get the parts ready before next seeing my friend. In the end I managed to squeeze the printing into 1.5 weekends just before Christmas. The timing was fortunate because at least during the day I could try to minimize wifely irritation at the printing noise by playing Christmas carols. At night I tried to move the printer as far as possible from the bedroom, which was a bad idea because at one point while trying to move it I managed to pull the power cable 16 hours into a print. Fortunately the print could be recovered with the right blend of googling and panic (see below). I do need to find a way to make Squirty quieter so I can leave it on overnight and still be able to sleep.
The parts were downloaded from the Reprap github. They come as individual .stl files which I plated using Slic3r (which is included with the precompiled version of Pronterface I got from RepRapPro). The parts are already quite different from the ones I received December 2012 when I made my Huxley. There are a few optional parts I hadn’t seen before, like the fan mount, and the main extruder cog now has the teeth on the inside of the circumference rather than the outside.
The kitchen sponges underneath the printer feet cut down on the noise from the printer. They make a big difference because they stop the whole table acting as one big sounding board. The big black PC fan strapped to the side of the X gantry is something I added to help with printing small parts, but I very rarely use it.
Since it was almost Christmas at the time I decided to go with the holiday mood and go for a Christmassy green and red colour scheme. I made the extruder red and everything else green. In the first plate of green parts above you can see the optional fan mount that was included in the github repository. It looks like it funnels air from a fan into a narrow slot to cool the plastic as it is laid down – I’d be interested in seeing how this works in practice.
The plate above had a lot of parts but didn’t take too long to print as most of them are not that tall.
I looked around for some suggested settings for printing the parts at but couldn’t find any hard and fast recommendations. I went for standard settings but with 35% infill (usually I’d print at 20%). You can see the infill pattern in the image above.
The fourth plate gave me a couple of issues. Firstly I think my x endstop offset is a little bit off because it printed some of the parts overhanging the edge of the plate (the feet on the left). One of these parts then came partially unstuck but thankfully did not wreck the whole plate. I reprinted that foot on the next plate.
The more serious issue when I went to bed. The plate had been printing since the morning so it was about 16 hours in but still had ~10% to go. I had an early flight in the morning for work so went to bed around 11pm, but realized I could still hear the printer working in the next room. I ingeniously decided to move it to the other end of the dining table so it would be a bit quieter, but forgot to hold the power cable in while I moved it. Damn.
The progress of the print is stored in the printer itself, so I couldn’t just plug it back in and tell it to restart. Fortunately it does tell pronterface which byte of the gcode it has got to, so I was able to check the last byte printed and then edit the gcode for that plate so it started at the same byte. I had to add some gcode at the start to get it to the right height too. I then told it to print the modified gcode and it immediately screwed up because one of the parts stopped it from homing properly. Cue frantic scramble to turn it off before it started spraying plastic randomly over the partially finished parts.
Luckily the part stopping it from homing was complete, so I could snap it off and try again. Fortunately it worked and the parts seemed normal once completed.
The last plate was trouble free and finished just in time to be packed into a beautiful custom-made Christmas stocking my wife made.
I forgot to take a picture of all the parts together, but fortunately my friend did and also arranged them rather artistically.
Now we play the waiting game and see if the parts actually work! I’ve got three questions I hoping to get answers to soon:
- Are the tolerances on the parts OK?
- Are they strong enough to print with (pretty confident on this one as long as the parts on plate four weren’t weakened by the interrupted print)?
- Did I remember to print them all? (this is a question of basic organization, which is why I am most worried about this point)
1. L’Oreal Elnett Satin Super Hold hairspray is the ultimate secret to good bed adhesion