First Adventures in 3D Printing

Xebia recently acquired a 3D printer, a Prusa i3 MK2S to be precise. It came as a kit so it required assembly before we could put it into action. Luckily, multiple 3D printing enthusiasts at Xebia had done this before. I wasn’t one of them, so I mostly watched and helped out where I could.

Assembling the printer took several evenings, but eventually, it was done! It needed to calibrate itself afterward, to know the position of its head and nozzle in relation to the bed. Prusa added an automatic setting in its menu to make calibration as painless as possible. The MK2 comes with multiple ready-to-print example models, and over the following weeks, various Xebians (including myself) printed one of the models. Now we have quite an eclectic collection of 3D printed vases, whistles and dinosaur bones laying around the office. 
These models were fun, but I wanted to print something other than an example. I’m a software engineer at Xebia, currently working on a project built in GO.  As some of you may know, the mascot of the Golang programming language is a Gopher. I don’t know why, but for some reason, I got it in my head that I wanted to print a Gopher.

First I needed to acquire a model. I started by looking around at various 3D printing hubs, and after a while, I settled for one I found on GitHub that seemed pretty cool. It consisted of two separate models; one for its body and one for its eyes, which would allow me to print each part in a different color. The first thing I tried was transferring the files to an SD-card and blindly printing them, which didn’t work.  After some research, I discovered that there are multiple, competing formats in the 3D printing world. The most common and universal file format is STL, which was the same for the model I had downloaded. However, after even more research (RTFM), I found that the MK2 only supports GCODE files. So, I needed to find a way to convert these files into the GCODE format.
After some Googling, I found a cloud service that looked very promising. I registered for an account, uploaded and converted my models, then downloaded the results. Again, I transferred these to the SD card and fired-up the printer. This time it recognized the file and immediately started printing – which resulted in a big blob of goo straight away. The next thing I tried was a program called Slic3r, which allowed me to have more control. The first thing I noticed was that the model wasn’t positioned and rotated correctly. Slic3r provided some easy tools to correct this, and after the adjustments, I started up the printer again and hoped for the best. In a minute or so it became clear that it still wasn’t behaving correctly. The mess wasn’t as big as before, but still, no cigar.

Materials

After looking around at the Prusa website, I became aware of a Prusa branded version of Slic3r. The branded version allowed me to choose my printer model, nozzle size, and material type and use that data to make a better conversion. After converting, I again fired up the printer and waited for it to begin printing. Finally, I saw an outline of the gopher feet appear! However, two minutes in, I saw the familiar pile of goo forming again. After trying multiple things, I began reading about different materials. Here’s a break down of the most commonly used materials:

I was trying to print the gopher in ABS because that was the only blue color we had. But after inspecting the roll, I noticed the print temperature range indicated was a lot lower than the print temperature on the printer LCD. I tried multiple things to correct this but had no success, so I finally abandoned the blue ABS in favor of a purple roll of PLA. After slicing the model again using the correct material and firing up the printer, the results were very promising. It printed its feet and was about to start on the body, but failed because the feet came loose from the printer bed.

Success

After some reading on the Prusa forum, I realized that the bed probably was too greasy after all the printing we’d already done. I didn’t have any alcohol or another degreaser at hand, so  I made a mental note to bring some the next time I came to the office. Lucky for me, the next time I came in, someone else in the office had already cleaned the printer bed. So I fired up the printer one more time and selected my model. At last, five hours later, I finally had success!