3D Printing: Trial and Error

So, tonight, I thought I’d take a departure from my norm. I’m not going to waste time telling you about the delicious rack of lamb I made that took 3 times as long to cook as the website indicated, or the quiche I made that’s still making my mouth water.


Instead, tonight, I’m going to talk about 3D printing. My boyfriend has had his first 3D printer for about 18 months now. He knows the ins and outs of it, and from photos of someone’s print or a look at the gcode can generally make a fairly good determination at what’s gone wrong and how to help put it to rights. I think it’s really cool, but I have to admit, I’m more likely to spend my evening writing fan fiction or reading a new fantasy novel (Robin Hobb is my latest favorite) than trying to teach myself something. I find it a little strange since, over all, I do enjoy making things with my hands–I crochet, cross-stitch, sew, and draw when the mood to create takes me.

I’ve made some attempts this week at learning a digital sculpting program called Zbrush, but I keep finding myself distracted by those Robin Hobb books. Seriously, dragons, ships, and an evil uncle? The books have everything, and even at 800 pages they’re hard to put down.

Thus, my attempts at 3D printing have been rather limited. A few weeks ago, I made this, a tripod adapter for my phone to make it easier for me to film my cooking videos. Suffice it to say, it took me several tries and some long distance tech support from him, but in the end, I was pleased with the result. If you want to hear a little more about that, you can check out this video.   Last weekend, I printed a TARDIS someone had made on Thingiverse. I didn’t make any modifications to it, and I didn’t really have a clear idea what I was doing. It could have turned out better, it could have turned out worse.

Tonight, he suggested I make a fan guard for our new addition to the household, the Revolution Qu-Bd printer. There are a number of programs I could have used. Zbrush is intended for organic shapes–things with curves, and a lot of freehand involved. There’s a good chance you’ve seen Zbrush’s work–the ghost King of the Dead in The Return of the King was made using it. I had experimented a little with Viacad a few months ago, which does a decent job with standard shapes, but is very finicky in my experience.

Another program, OpenScad, takes an entirely different approach. Objects are created in OpenScad programatically using mathematical formulas to define the shapes. You define the parameters of what you want to make, and it makes it. This is one of the most impressive things I’ve seen come out of OpenScad. It has 14 moving parts that all print a a single piece. I think it’s stunning.

I went to Thingiverse tonight and found the design someone had made for a generic fan guard. We’ve already had to replace the fan on the Qu-Bd printer once because something got caught in the blades. The file on Thingiverse was an OpenScad file, so, I took a deep breath and downloaded OpenScad and sized up the code in front of me rather warily. My experience attempting to write any sort of code is extremely limited. Fortunately since someone else had already written this, all I had to do was measure our fan with a set of calipers and replace the generic numbers with the specific ones I needed.

It took me 3 tries for my print to turn out right. Fortunately, I had some guidance with the troubleshooting.

For the record, here is a picture of the part I was trying to print.


It doesn’t look that complicated, right?

My first print managed to have lines in one direction for the beehive, but no crossing lines. I had taken a guess at what the “mesh string thickness” for the beehives ought to be, and I went with 120 mm. I think the default had been 98 mm; I think I changed it because the sides of my fan were bigger than the default sides in the code.

3D objects are designed in any number of programs: Zbrush, OpenScad, Viacad, Maya Autodesk, you name it. To 3D print an object, it needs to be changed into a .stl file and exported to a slicing program. A slicing program is what tells the printer how each of the thousands of thin layers that make up an object should be printed. I exported my OpenScad file to Cura, a slicing program I have, and I decided to just use the same settings I’d used on my tripod adapter and TARDIS. I prepared the bed of the printer by putting down blue painter’s tape and swabbing it with rubbing alcohol, to help the print stick to the bed.

This is how my first print turned out.


I was unaware that Cura has a nifty feature that lets you look at the layers that it’s planning to print. When I was looking at my first print in dismay and trying to figure out where the other half of my lines went, I was shown this function. Lo and behold, Cura had decided that those lines weren’t thick enough to print, and left them off of the model. For my second attempt, I adjusted the mesh “string thickness” to 110 mm. Since the whole print was only 40 mm x 40 mm x 1 mm, I’m still not sure where this number fits in.

The blue painter’s tape I mentioned is really good for any sort of print with a significant amount to height to it. It will stick the print to the bed really well. If you’re working on a thin print, for example, butterfly wings, or Christmas cards you can print on Kapton tape. It’s a lot smoother than the blue tape, and has the benefit of being reusable. One side of our printer bed has Kapton tape on it, the other side we keep the painter’s tape on. Since this is a thin print (only a millimeter high), I decided to try printing it on the Kapton tape. However, when you’re working with layers that are .12 of a millimeter thick, every .1 of a millimeter really counts.

My second print failed to stick properly to the bed, and warped at the corners. Why didn’t it stick? Well, Kapton tape is thinner than painter’s tape, so suddenly, the bed wasn’t at the right height when I flipped it over. Here’s my second print. You can see the corner curling up slightly, but the missing lines have been resolved at least.


Third time pays for all, right? Using a screw driver, I adjusted the bed height just slightly. I made no other changes. This print turned out just right.


After that, it was a quick matter of peeling the print off the bed and using a scalpel to clean up the honeycomb shapes just a bit. Then I screwed the fan guard to the printer. Hopefully, this will be the last fan that printer needs.


I think this was a really good experience. I acknowledge that a degree of reading the book and understanding the programs is important–I think I’m going to have to pick up the Zbrush book again and get through it, because I really want to make cool things. At the same time, I know that I learn really well by doing. I explored Thingiverse and our Ultimaker printer and learned a lot more about them. I found out about features in Cura I wasn’t aware of by making mistakes tonight. I even found out that I can make changes to the code in an OpenScad project and turn out something decent. I made some mistakes tonight with my prints, but I gained a lot of knowledge and a finished product that was exactly what I needed. I may even be ready to set down the novel I’m reading and get back to some Zbrush studying. Then again…it’d be a shame to stop 50 pages from the end. Maybe I need to find out what happens to the dragons first, then study.

And by the way, if you want a laugh, here’s a couple of pictures of what I made when I started exploring Zbrush. I thought about trying to print the Franken-Fish, but it turns out, I didn’t successfully manage to connect the fins to the body.



I’ll be back again soon, probably with more scallions. I haven’t tried scallion pancakes again since my post recently, but I have started putting them in my breakfast quesadillas. It was an excellent idea.


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