Here are some things I've learned about my Replicator 2 since it arrived. I hadn't had time to work with it since the first day, so I set aside time after school Friday, and invited any of my Calculus students who cared to help explore.
Sticking issues (or, more properly, non-sticking issues)
The day I unpacked my Rep2 (with my 3rd period calculus class) we attempted each of the designs pre-installed on the included SD card. Bracelet -- success. Linked chain -- fail. Mr. Jaws -- success. Comb -- fail. Nut and bolt -- success. The failures were the result of the build becoming unstuck from the build plate mid-process, effectively ruining things.
My hypothesis was that I hadn't fine-tuned the build plate level well enough, so perhaps the extruder nozzle was knocking into builds, causing my issues with comb and chain. Friday I tried the chain once more, and had similar failure. So I went through the utility menus to re-level the build plate. My first time, I had 25 students clustered around me asking questions, so perhaps I got distracted. I was alone Friday, and so could focus well on how much friction there was between my sheet of paper (leveling gauge) and the extruder nozzle.
I tried the chain again, and it worked fine. Leveling seems to have been the issue.
Successes
Students loved watching the build process. It took about 20 minutes each to print the bracelet and Mr. Jaws, and I had some students staring at the motion of the print head for the entire time. Since I had just introduced the concept of a definite integral to them, I was hoping they would make the connection to the notion of accumulating infinitessimally thin layers to build the area under a curve. I had to raffle off the builds (using pseudo-random number generator in my TI-Nspire, tying it to statistics lessons). I had as much male as female interest in the bracelet.
Two students spent considerable time examining the packing materials, and were fascinated to realize some of it had been 3D printed. We talked a bit about recursion.
My last build Friday was the lid to a "bunny box" that I found on thingiverse. Successful, but, man, when I started I didn't realize how long it would take.
File formats
Due to computer issues, I haven't installed makerware on my laptop. It's just too finicky lately, and I don't want to introduce another variable into its operation until I figure out what's wrong. I'll have to install on my home computer to try to explore designing or modifying on my own.
So, I've limited myself to things I can download. I've noticed that most of the designs on thingiverse are in .stl format, whereas my Rep2 only understands .s3g format. Maybe that's a big d'oh to everyone else, but it took some research to understand why I couldn't print the things I was downloading. Now I know the limit my search to the proper file format, until I download and install software to convert for me.
Build time
The display on my Rep2 is friendly enough to tell me what percent of the build is done. But as I was building the box lid (see above) I was dismayed to see that, after almost an hour, it said I was only 20% complete. Yikes!
Less than 30 minutes later the build was done. So now I know that % complete calculation doesn't refer to the build. I'm guessing it refers to the final build height.
Odor
I opened the door to my room while building, and had windows open, but there was still a distinct aroma of melting plastic and I was coughing. I wonder about the health effects of volatiles from melting PLA.
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