Good Morning from my Robotics Lab! This is Shadow_8472 and today I am continuing to work with my 3D printer. I’m covering a lot of ground this week, so let’s get started!
.Gcode Flavor
I left off last week wondering what was with my printer cooling its head when I had already preheated it through firmware. I reached out to various help channels until I randomly speculated that my printer was speaking a slightly different dialect than what PrusaSlic3r was feeding it. A helpful user suggested I switch my .gcode flavor to Marlin (listed as Marlin (legacy) in Slic3r).
I compared outputs from the two flavors after slicing the same object. The two files were similar, but legacy machines like mine –it would seem– do best with some additional information before any custom .gcode a user might want.
In retrospect, I probably should have learned to make my own temperature tower. Running .gcode meant for a larger printer can cause any one from a number of problems. At the same time, I’m glad I printed the tower with raw .gcode or else I might have easily given up.
Calibration Park
Armed with an optimal or near-optimal printing temperature, I set about printing a calibration multi-test [1]. I came back part way through the print and found that a PVC pipe I use to extend the filament holder had fallen off and both the X and Y had been gotten way off (I’m just glad it wasn’t on a more serious print). Additionally, the base was warped something awful. The test was still stuck to the printbed, but it was almost trivial to remove. I figured my bed was too low, which it was, but it took me until I noticed my heated bed turning off after the first layer that I had a setting wrong in Slic3r.
I was able to save my second serious attempt at the test by manually adjusting the temperature from my printer’s touchscreen. It turned out pretty well after that. The scratch in the middle of the bed was obvious, and a lot of the fine details in the lettering describing each test were lost. Otherwise, everything appeared to do OK at the very least. The overhang test was technically still together at the 80 degree inclination, but artifacts were beginning to show up by around 45 degrees. Most importantly: the large artifacts I had when unknowingly printing with wet filament were fixed.
Planning a Complex Print
To date, the most complex print I’ve successfully probably pulled off would have to be my Blinkie Pie case, where I modified a PacMan ghost case so a camera could see out one eye. Aside from a little impossible bridging that quickly evened itself out, that wasn’t a difficult print. But the world of 3D printing is much more diverse than variations on simple shapes.
I decided to try printing a model of unicorn Twilight Sparkle — both for her (percieved) relative simple geometry compared to her friends and so I wouldn’t have to risk her potentially breakable wings as seen across most of the show. I found a model on Thingverse after looking at several different places that wouldn’t let me download without creating an account — free or otherwise [2].
I went back and forth with it between Slic3r and Blender a time or two to refine Twilight’s model. While skimming through the planned layers, I noticed she had a sizable oral cavity. Her tongue and teeth were simple enough to delete, but it took a bit more patience to remove the rest of her mouth and stitch it back together. Somewhere in there I got rid of her eye lashes, which were also separate meshes from her main model as I was sure they would be hardly there to begin with and likely would be damaged while removing support material.
Speaking of support material, I knew from the beginning that I wasn’t getting away without a bunch of it. Twilight’s mane has a number of spots that hang down from layers printed later – let alone her tail as it arches up, backwards, and not quite to the ground. I messed with the automatic settings until I had what looked like a minimal amount of support, but after seeing the results of the overhang test, I put the settings back up. I also ordered up a raft three layers thick to cover up the scratch in the middle of my build plate.
Another concern I had was what Twilight’s center of mass was going to look like. At one point, Slic3r had her tail slotted for mostly solid infill with her head at 15% honeycomb infill. While I was able to find a solution involving analyzing the sliced figure with a Blender plugin, I ended up scaling Twilight up to about four inches as opposed to about three/three and a half – big enough so her tail was also rendered as a shell with infill, but small enough that her legs were solid.
A closer inspection of some supports gave me the distinct impression that Slic3r was being silly. The most complicated part of Twilight’s geometry is her mane, and there were more than a few tiny “overhangs” I figured would be fine being bridged instead of supported. I found some support blocker cubes I could move and scale, but it was clunky and there’s a better system for painting on supports I’ll be looking into next week. I wasn’t the happiest with the results I had, but I printed it anyway.
Cleanup and Repair
Between six and seven hours later, I had a pony standing on my build plate rendered in my recovered red filament. Cleanup started quickly as I cut away large sections where I knew there wasn’t anything, but as I got closer in, needle nose pliers and cutters were getting to be a little too awkward. My father arranged for a poker fashioned from some construction grade tie wire often used for holding re-bar in place while pouring concrete structures. Even then, it was a bit thick to fit in all the needed places. My mother offered a sewing straight pin which was versatile, but bowed more easily.
I quickly became jealous of dual+ head printers that can possibly use a soluble filament for easy support removal. It was a major morale boost when I was finally able to free Twilight’s face. Other tough spots included the arch of her tail, The tight spots between her legs and up across her belly, several tight spots in her mane, and the raft stuck to her hooves. I am very glad I scaled her up as much as I did.
There were a few moments when I wasn’t as careful as I should have been. I broke Twilight’s right back leg below her hock (the ankle-like joint most of the way up her leg) about half way through, and snapped her mane a few times in a couple places. Sections across her belly had to be cut away.
Despite the missing leg, there remains a piece just behind Twilight’s front legs. I had a feeling from the beginning that the supports between her forehead and bangs wouldn’t be coming out and they haven’t. At this point, I’d need to melt a handle to the remaining support material and carefully yank. The toughest holdout is physically trapped between her neck and the bit of her mane hanging to the side. I’ve already chipped the tip of her mane there trying to get it out.
I had already decided that I’d be reslicing and reprinting – I just haven’t yet. However, it doesn’t feel right to leave this Twilight without at least reattaching her leg and doing what we can with her mane. My father and I worked on the remaining bits of raft with a razor stuck to her hooves and used some superglue. The first repair on her mane didn’t go the best, so we’re using some painter’s tape to hold it in place. The leg was more promising, so at least she can stand while she waits. Maybe I’ll come back to her when I have more skill, but for now, this model has served as a learning experience so my next print should go better.
Side Project
I accidentally closed my main FireFox window. Normally that’s annoying, but since there was an update cued, I managed to destroy it completely in my attempts to recover it. I checked around online and learned a little about how Firefox stores saved sessions and I found a backup from not quite two weeks ago. It’s not perfect, but I’ll take 96% restoration over nothing!
Takeaway
3D printing is an art form, even if you’re printing other people’s .stl files. There are many factors to adjust to keep your printer in top condition. Slicing programs require knowledge about your printer’s tolerances to use effectively. Even if it prints correctly, you may want to sand, prime, and paint it.
Final Question
Have you ever set aside a work-in-progress for when you’re better equipped to finish it?
Works Cited
[1] majda 107, “*MINI* All In One 3D printer test,” Thingverse.com, Feb. 25, 2018. [Online]. Available: https://www.thingiverse.com/thing:2806295. [Accessed Jan. 3, 2022].
[2] dragonator, “Mane 6 models MLP:FIM,” Thingverse.com, April 09, 2012. [Online]. https://www.thingiverse.com/thing:21076. [Accessed Jan. 3, 2022].
[2*] David, “Mane 6 models MLP:FIM – Fixed,” Thingverse.com, June 19, 2012. [Online]. Available: https://www.thingiverse.com/thing:25282. [Accessed Jan. 3, 2022].
* The second [2] hosts the same models but “fixed” variants. I don’t know for sure which version I used, but I’m slightly more sure than not that I used the 21076 models.