Well, our Learning Commons has had our 3D printer for just over two months now. I will have to put up a gallery of photos of objects that we’ve made, but this morning I thought that I’d share some things that I’ve learned and some observations that I’ve made since my last post on the topic.
The first major road block that I ran into was with an extruder jam. If you think of a 3D printer as a complex hot glue gun, where you are building layers of glue to build objects rather than sticking things together, the extruder is the hot part that the material passes through to melt before it gets printed on to the build plate. I left work one night with a bust of Shakespeare busily printing away knowing that the build would finish about the same time I returned to work in the morning. Given that the extruder is the only truly hot part of the machine and everything around it is well cooled, I was and am comfortable leaving it on over night. While I don’t need to do this with every print job, the size of the bust was such that it would take longer than a full school day to print so it would have to be left on to complete the job. I returned to find the printer “air-printing.” Air-printing refers to when the print mechanism is going through all the motions of printing, but no filament is being added to the object being printed.
It took me a couple of days to figure out what had gone wrong and how to fix it. The extruder itself had become jammed. That meant that there was cold filament in the extruder mechanism that was not melting. I found a number of tutorials on how to remove this filament. Most involved over-heating the extruder as much as 20 degrees hotter than normal and pushing new filament into the softening filament with the hope that it would get stuck and then I could use the attached filament to pull out the stuck material. None of that worked for me and after discussing my issue with two very helpful support folks at Makerbot, we determined that we needed to replace the extruder. They shipped me the new part (free this time, but it is normally a $100 part that I will have to pay for if this happens again) and I rebuilt the motor to install the new extruder. This wasn’t a terribly complicated process, but it did involve detaching and reattaching wiring and getting into the guts of the electronics of the machine. I’m not an engineering whiz or even much of a home repair guy, but I didn’t have too much trouble with this. If you find yourself fearful of this kind of work, perhaps getting a shop or electronics teacher in to help might be advisable.
What I did realize through the process of learning about the jam, was that I’d been missing the signs that the extruder was becoming clogged and I could have prevented it’s complete seizure had I been able to recognize those signs. I was seeing filament spiralling as it came out of the extruder rather than coming out as a full stream. I was also seeing more loose threads on my print jobs itself, particularly when the print went from one part of the object to another. Now, when I see this kind of stuff, I take the motor off and make sure that there is nothing clogging up the works.
I’ve also been playing with different replicator/maker software to generate the actual print files. As I think I wrote about in my last 3D printing post, there is a piece of software from Makerbot that you can use to print your objects. It is called Makerware and it’s sole purpose is to take whatever design that you feed it and build a file that will give the printer the instructions to build it. It tells the printer what temperature to heat the filament to, how much infill (how solid or hollow) to use, how many layers of outer shell and such things. Makerware is pretty straight ahead and easy to use. I also use an open source piece of software called ReplicatorG. It does the same thing but seems to allow you much more control than Makerware does. This can be a good or bad thing. I think that Makerware probably would prevent you from doing anything too strange that might damage your printer, where as ReplicatorG would give you full control regardless (although I have gotten warnings in my print settings about the potential for damage.) As I play with both, I realize that Makerware allows greater control than I initially thought and I haven’t settled on one being necessarily better for my uses than the other.
What is more interesting from a software angle is the design software. There is much more variety when it comes to finding software that allows you to capture an idea for a 3D image and get it ready to be printed. One way of getting ideas into digital form is to scan existing objects. We have the Makerbot Digital Scanner that I’ve yet to have great success with. The best object that I’ve scanned is the commemorative pop cup top of Gandalf from the second Hobbit movie. I put Gandalf on the turntable of the scanner, and in 9 minutes I had a digital image. I have the option of scanning the same object multiple times from multiple angles to gain clarity and resolution. I’ve had mixed results with that. I also have found an app for my phone called 123DCatch by Autodesk. It allows me to use my phone’s camera as a 3D scanner by walking around an object and taking multiple pictures. I’ve yet to get good at separating the background from the object in order to get a printable file, but I love the idea.
Of course, one can always use CAD programs like AutoCad, and SketchUp to design objects from scratch. Students in my area all have a math unit in Grade 8 where they use SketchUp to explore geometry. It makes sense to use that same software to design objects but I’m finding that my skills are somewhat lacking there and I need to play around with SketchUp more to be able to make effective use of it. Whatever program one uses, one needs to be aware of what programs work with which file formats. Makerware can open .obj, .stl, and .thing files. ReplicatorG can open GCode, .stl, .obj, and .dae files. You need to make sure that you can save your designs in a format that your printing software can open.
The most interesting possibility in 3D design that I’ve been playing with is that of designing objects in Minecraft. So many of my students live in the Minecraft world. They have great skills already in building things there. They can use those skills to build objects for printing. There is a server (a Minecraft world that one can log on to) called Printcraft that you can claim a plot of land that you can build on. Once the plot is claimed, you can have it for a day or a week and build your object. Once the object is done, you can push a button on a control panel to print your object. This process gives you a link to a file that you can either download or send to a commercial printer who will print and ship your object to you (for a fee). If you know Minecraft, you know that objects are built in blocks, somewhat akin to lego. This would mean that you can’t print super high resolution or smooth objects, but for buildings or other boxier objects, it is perfect.
The most interesting observation that I’ve made thus far is that the boys (I do teach at an all-boys school), are fascinated with the 3D printing technology. I have students who will come to the Learning Commons first to see what’s printing, and then go to their lockers to get settled in for the day at school. But very few of them have presented me with designs to print. I purposely have not advertised that they can print on it, thinking that word of mouth would overload my print cue, but that has not been the case. I wonder how much is that the students haven’t found good uses for it or don’t want to put the time into designing objects on their own. I do have one student prototyping a design for a product that he is working on in a business class. I also have art students asking me to print objects that they have found online to incorporate into their art pieces. I had one student ask to have a model of the Taj Mahal for his display on Indo-Canadian immigration. I’m encouraging a student who has done fashion design work to design a wearable item based on some of the clothes that we’ve looked at in Thingiverse. But I would have expected much, much more. I’m thinking that I might run a Minecraft design contest to get interest and awareness up.
As always, any thoughts, questions or responses are greatly encouraged!!!!