Tuesday, March 11, 2014

Getting Started with 3D Printing

Over the past few weeks I've had the opportunity to work with a Cube 3D Printer. My initial goals were to make sure I can operate the printer and to print a few things that may spark interest in the printer among my Middle School colleagues. Corey Kilbane, one of our Upper School Science teachers, has become a major advocate of the potential of this technology in our school (and has been featured on the Smithsonian Institution's 3D Printing website).  He lent one of his printers to the Middle School so we could start to find out how this technology may be of use to our students and teachers.  At this point, I'm not ready to offer any conclusions about the use of 3D printing in the classroom, but rather I wish to share what I have learned from my first attempts at using the technology.  Here are my lessons learned thus far.

Lesson #1: Watch what you're printing

Corey told me that he usually makes sure his printouts start printing properly and usually feels confident that he can leave the printer after a short time.  I tried this while trying to print a model of Epcot's Spaceship Earth from Walt Disney World.  I returned for find a mess of plastic after a promising start where the base appeared to print properly.  Initially, it was a mystery how this occurred.

I decided to move on to a more constructive print, one that would actually do something. I selected a device that would allow me to mount our new GoPro camera to a tripod and had several failures trying to print this device

Lesson #2 - Level the Printpad

In the course of trying to understand my initial failures I found some suggested leveling the Cube printer printpad before each print. I hadn't given this much thought, as I thought Corey told me the printer was already leveled. However, moving the printer to a new building and the fact that the desk in my office doesn't appear to be 100% level make this a reasonable precaution before each print. It only takes a minute of work, which I'll gladly trade to increase the likelihood of success for prints that make take several hours.

Lesson #3 - The Plastic Can be Brittle

I was pretty exciting when the tripod mount finally printed successfully and eager to try it out. As I started to screw the mount onto a tripod and create the threads in the plastic I grabbed the top of the new printout and quickly broke two of the three loops that were designed to hold the camera in place. Clearly my new tripod mount was not nearly as rugged as the GoPro camera it was designed to support.

The finished GoPro support. My first 3D print that actually does something, though it will likely to relegated to light duty, as I learned how fragile this printed object was.

My next plan was to print something simple, since it wouldn't take long to print. I visited the Thingiverse website and stumbled upon a picture hanger. Since I was in the process of decorating my office, this seemed a good fit for a small print of a photo I wanted to hang on my wall. This printed just fine the first time, with the only problem being that I could only find one self-tapping screw in my office to attach it to the back of the picture frame.

Lesson #4 - Use Enough Glue

Moving on to items that could potentially be used in classes, I decided to try printing a knee joint. I was pretty pleased that this print was progressing very well until I noticed the object move.  I stopped the printing before I got another "birds nest" of plastic filament, but was disappointed the the print did not finish.  The model is still useful, though you can see the top of the leg bone did not finish printing (see image below for an overhead look at the model).

What I learned was not to skimp on glue.  Initially, I tried to be conservative with applying too much glue to the printpad, in part because I didn't want to be wasteful and in part because I wanted to be able to remove the completed printed object without too much trouble.  I discovered that larger objects need to be glued pretty securely to the printpad so that they don't move during longer printings. Fortunately, since the glue is water soluble and the printpad is removable, you can run water across the fused printpad/model or soak those items to dissolve the glue and remove your object.

Lesson #5 - ABS Plastic Warps When it Cools

Before starting printing I was given an introduction to different commonly used plastics (ABS and PLA) for 3D printing. It was also explained that our school's newer and more expensive 3D printer includes a heated bed as a printpad. However, I did not begin to appreciate the importance of these considerations until I began printing objects myself.

A clear example of the effect of a non-heated printpad and using ABS plastic was my attempt to print a map of the United States, with each state sized based on its population density. The object generally printed well, but as the print went on and the plastic around the edges cooled, you can see the warping that occurred. With a heated bed, this cooling would not have taken place until the end of the printing. My understanding is the PLA plastics are also less susceptible to warping, so I'm interested in trying those out with future prints.

I hope these ideas may be of use as others get started with their own 3D printing projects!

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