Category Archives: 3dprinter

3dprinter

Presentations for Mercy TechTalk

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I’ll be giving to presentations today at Mercy Tech Talk. Here are the links from my presentations:

3D Printing in Education – 11:10 in N-17
Curious about 3D printing? We will walk through the basics of 3D printing and introduce simple programs for creating 3D models suitable for printing. No previous 3D modeling experience is needed. We will also look at some ways 3D printing can be worked into the curriculum and for fundraising.

Flipping with an iPad – 1:00 in Drama Studio
Have you thought about making videos to support your instruction? Maybe even a full flip? With an iPad you can create and distribute videos for your students. We will investigate several apps and accessories you can use to make compelling content for your students without the need for a computer.

3dprinter, physics

Getting Started with 3D Printing – Find a problem to solve

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This week I went high-tech to go low-tech. When I taught physics I taught with a student centered pedagogy called Modeling Physics. In Modeling we have student collect data and then use that data to construct models to explain physics. Basically students do labs, graph the data, find an equation that fits their graph and then they turn that equation into a generic equation that can be used in other situations. Everything works great if you can get the students to collect really clean data and if you can actually convince them to think.

I don’t teach physics anymore, but our new physics teacher, Vance, also uses the Modeling Method. He built some apparatuses last week end to collect really good acceleration data. This is just a wood disk with a golf tee glued to the center of each side. This rolls down a pair of rails and is slow enough to allow students to get some really good data. I’d thought about building these myself in the past, but I knew it would be hard to do and that I’d probably screw it up. So I never constructed any. Vance did a fine job in his construction, but he ended up having all the problems I knew I would have had.

Enter the 3D printer. Looking at Vance’s system I knew I could knock something out on the 3D printer that would work. This is one of the coolest things about owning a 3D printer. You will see problems and begin to envision solutions. Once you start doing this the easier it becomes. The only risk is that you will quickly assume the 3D printer is the best tool for all jobs. As awesome as it is, it is not always the best way to solve every problem.

I spent about 10 minutes in Tinkercad on my design and then it took about an hour and a half to print. Vance tells me it worked great for the lab. I’m already envisioning modifications for future investigations. The design could be easily modified to investigate rotational inertia and energy, but maybe I’ll leave it to students to create these new designs.

Acceleration Paradigm Lab – Teacher Notes

Materials (for each group):

  • 2 bricks with holes or grooved sides
  • 2 five foot sections of electrical conduit
  • 1 wood disk with a golf tee sticking out of the center of each side, or 1 3D printed disk with cones out of each side
  • Dry erase marker
  • A metronome set to 60 peats/minute (or a computer program) – One for the entire class
Basic Procedure:
  • Set the conduit up as a pair of rails spaced appropriately for your rolling disk
  • Let the disk roll down the rails
  • Mark the position of the disk at 1 or 2 second intervals
  • Create a position vs. time graph and find the equation that fits the data (should be a quadratic)
  • Create a velocity vs. time data set and graph from the position data using the secant line created by each pair of points on the position graph. This graph should be linear.
  • Note: If the incline is too steep it will slide rather than roll.
Class discussion:
  • I always have students use the actual variables in their equations, no x’s or y’s. In addition all constants need units.
  • Once students have equations for both their position and velocity graphs I ask them what each constant represents and how they know. This is pretty easy for the velocity graph, but a little harder for the position graph. It leads to some great conversations and ultimately to a pair of generic equations we will use for the rest of the kinematics unit.
My 3D Model:
This is a part 6 of my series on 3D Printers in Education. Go back to earlier parts in the 3D printer series: Part 1, Part 5
3dprinter

Getting Started With 3D Printing – PLA vs. ABS

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There are two main types of plastic used in most FDM printers, polylactic acid (PLA) and acrylonitrile butadiene styrene (ABS). ABS is the same plastic Legos are made from and PLA is a bioplastic typically derived from corn starch. I will not go into a lot of the technical differences, but will instead focus on the practical issues related to each type of plastic.

Each plastic has its own advantages and disadvantages. Most of the newest low cost printers available today will only print with PLA. In order to complete a successful print, the plastic must stick well to the print bed. Sometimes it may be beneficial to heat the print bed to 40-50°C for PLA. However, it is often not necessary and many commercially available printers designed to print with PLA do not have the ability to heat the print bed at all. ABS requires a heated print bed for parts to stick. It is necessary to heat the print bed to 110-130°C when printing with ABS. This is quite hot, remember water boils at 100°C.

There are other practical concerns related to both plastics to consider. ABS shrinks substantially more than PLA while cooling. This can often cause parts to warp. When a part warps the edges or corners lift off the platform. This can lead to a part becoming completely unstuck from the platform or even if it stays in place may be completely unusable. ABS also gives off some fumes while printing. They are not overwhelming, but they are noticeable. One of my colleagues has sever allergies and asthma and reacts to just about any type of smell or fumes in the air. She never had a problem with the ABS fumes in the room.

Since PLA doesn’t shrink as much as it cools it is much less prone to warping and the finished parts are much closer to the intended dimensions. This difference often doesn’t mean much. However, if you are printing something like a phone case it is much easier to design one that fits just right if you print with PLA rather than ABS.

Given the minimal shrinkage, lack of fumes, and no need for a heated bed you might be wondering why I’m even presenting a choice between ABS and PLA. PLA seems to be far superior in almost all respects. One factor to note, however, is it is far more finicky to print with. With PLA, if things are not perfect the printhead can become clogged. This is not a problem I’ve ever had with ABS.

I was so fed up with problems related to ABS that I’ve been printing exclusively with PLA for the last couple of years. For the 9 months, with my first generation Replicator, I have not been able to print something that takes more than an hour and a half before the print head jams. Often it jams much sooner. Newer printers may be more reliable, but I don’t have experience to speak to that. Yesterday I switched back to ABS and was able to do a two hour print of a comet and a five hour print of a fossil skull with no problems. For my printer I may switch over to mostly ABS and just print in PLA when I need something that fits precisely.

While I’m talking about Plastic I should mention that both types should be stored in sealed containers. Over time they will both absorb moisture and this could cause problems while printing. I use a container designed for long term storage of food and I toss in some silica gel to absorb moister. The container I use was less than $15 on Amazon and will hold two spools of plastic. The other bonus with using containers for storage is it will keep your plastic relatively dust free. If dust accumulates on the filament it can cause the print head to become clogged.

Go Back to earlier parts in the series: Part 1, Part 4

3dprinter, tinkercad

Getting Started with 3D Printing – Jazz Hands

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In my last post I walked you through creating a relatively simple cell phone holder in Tinkercad. In this one I want to show you how easy it is to modify an existing design. You can do this with your own models or you can do this with ones you find online in places like the Thingiverse.

We’re going to add a design to our phone case we made in the last post by importing an image in svg format. svg files can be imported, resized and extruded into 3D objects. I’m going to use a public domain image from Pixaby. I like Pixaby because all the images are public domain. They do have svg files available for download, however, I haven’t had any luck importing their svg files into Tinkercad. Instead I find an image (png or jpg) I like and convert it using the Online SVG Image Converter. You’ll want an image that is only black and white (literally black and white, not greyscale). If your image has any grays they will be treated as black when imported into Tinkercad. The image I chose has some grays, but I think it will look fine as black and white.

Basically you just import your svg file, resize it to fit, and the position it where you want it to go. You can either do this as a raised pattern or turn it into a hole and use it as a recessed pattern. You can find full directions in the Google Presentation below.

Go Back to earlier parts in the series: Part 1, Part 3 or go on to Part 5

3dprinter, engineering

Getting Started with 3D Printing – Lets make something

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OK, it’s been a couple of weeks since my last post. I’ve decided to do an instructional post to break things up a little. One of the projects I had my physics students work on last year was an engineering/design problem. I simply asked them to create an accessory for their cell phones. This idea was not original to me, but I honestly can’t remember where I got it from.


In order to actually make their own accessories my students needed some sort of program to create a 3D model. Our school doesn’t currently have drafting or CAD classes, so I was left with only a few options. We have no CAD software and even if we did, my students wouldn’t know how to use it.


I settled on cloud based solution, Tinkercad, for my students. Tinkercad is very simple, which also means it lacks many functions you’d expect in a traditional CAD program. It is also run in the cloud so it can be slow at times, but on the plus side if your computers have Chrome there is also nothing to install. This can be a huge plus in an educational environment. I use Tinkercad at least in part for almost all my 3D printing projects.


The basic idea behind Tinkercad involves building models by joining together simple shapes. Shapes can either be solids or holes. It seems like this would be a difficult way to create anything, but as it turns out you can create some very useful models with this very simple idea.

I originally found this phone stand on Thingiverse. I like it because it holds the phone up a little higher than most of the ones I’ve seen. I’ll show you how easy Tinkercad is to work with by recreating it. We’ll talk about the phone case in a future post.

If you have students create accounts for Tinkercad please steer them away from using their Facebook or Twitter accounts. In the past I’ve had a few students create accounts at home using their Facebook credentials. We block Facebook, so they were unable to access their accounts at school.



Go Back to earlier parts in the series: Part 1, Part 2, or go on to Part 4

3dprinter

Getting Started with 3D Printing – Part 2

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This is part two in my ongoing series of articles on 3D printers for the classroom. Click here for part one.

I don’t know about you, but I have virtually no training in 3D modeling software. How should a classroom teacher start with their new 3D printer? Personally, when my printer arrived I spent a lot of time looking for cool designs online. The main repository I used and still use is the Thingiverse.1

The best way to start with your new printer is to find some models that other people have created and printed successfully and print them your self. There are lots of great ones to choose from. Some of which are simply models for demonstration while others may be tools or puzzles. My printer came with two spools of plastic. I burned through them and called it professional development. I really did learn a lot from this. You should probably do the same thing. Print stuff because you think it might be fun, useful, or you just want to see how it prints. I think the nerd word for this is experiential learning.

The bottom line is, it doesn’t really matter what you print. Print small stuff, big stuff, stuff with lots of small details, stuff with overhangs. Start with the default settings on your machine, then change them to see how it affects the final print. This will begin to give you a sense for what you can print and what you can’t. I also kept a small scale handy so I could determine the mass of my prints and then figure out the material costs. If I buy a 1 kg spool of plastic for $48, then each gram of plastic used is 4.8 cents. So a 20 gram part costs about $1 in materials.

Don’t worry if you’ll never use these early prints in your classes. One of the first things I ever printed was a replacement cup holder for my Ford Focus. While it had nothing to do with teaching it did begin to show me the power of having access to a 3D printer. I also got my first experience with warping2, a problem that plagued a lot of my early 3D printing.

During my learning process I did manage to print a few tools to be used for teaching, including a Macro Extension tube for my camera so I can take extreme closeups without having to buy a $400+ lens, an adapter to hold my iPhone to a telescope, an adapter for my Canon camera that works both with our telescope and our instructor microscope. But mostly I printed random stuff like an iPad sound reflector, games to play with my son, Higgs-Bosons, Pan Tail Duck call, and a bunch of other stuff.

If you feel you must print something useful try these:

  • Triangle “Missing Square” Puzzle: It’s a good critical thinking exercise. Print one and play. You may have to do a little sanding to make it fit perfectly.
  • Wind Puzzle: Not sure if this one is a Bernoulli effect demonstration or some other fluid dynamics principal. Either way it’s fun and my students love it.
  • Microscope Mount for iPhone 5: I modified an iPhone telescope adapter to work with our student microscopes. If it doesn’t fit yours I’ll teach you how to modify it in a future post.
  • One Small Step: Cool desk placard showing the first footstep on the moon on one side and the moon in relief on the reverse.
  • Lincoln Life Mask: The Smithsonian is starting to publish 3D models of their artifacts online. You can see how the presidency aged one of our greatest leaders.
  • Air Powered Rocket Car: This one presents good learning opportunities. It’s the first one I printed that required “supports”3.

Back to Part 1 or Continue to Part 3.

Footnotes:
1. Now I should say that many people have philosophical objections to the Thingiverse. Thingiverse was started by Makerbot. Makerbot had it’s origins in the Open Source Hardware movement. At some point Makerbot moved away from Open Source and was later bought by Stratasys, a large traditional 3D printing company. However you feel about Makerbot’s abandonment of Open Source or their later acquisition, the Thingiverse is a great place to find cool models to make.

2. Warping can happen with larger prints. The corners of the print lift off the build platform. Sometimes the part will still be usable, but more often it will not and sometimes can lead to the whole print coming unstuck resulting in a completely failed print job. I’ll talk about what to do to deal with warping in a future post.

3. FDM printers build from the bottom up. For some prints you will have parts that can not be printed because there is nothing below them to hold them up. Supports are typically a series of thin “walls” added below these areas, designed to be easily broken off the final print.

3dprinter, makerbot

Getting Started with 3D Printing – Part 1

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I’ve had a 3D printer in my classroom for a couple of years now and it is totally awesome. Last year I wrote a blogpost answering a question I received as a tweet. The question was, “What resources or designs do you wish existed for teachers/students when you got your printer?” I’ve decided to do a series of posts from an educator’s point of view to create the resource I wish I’d had when I first got my 3D printer.

There are a lot of emerging technologies that are capturing attention today. Of all of these, I think 3D printing has the most power to inspire students. I managed to get the first generation MakerBot Replicator a couple years ago and every time it’s running in the back of my classroom it acts as a student magnet. Some would just stand and watch a print run from start to finish if I’d let them. I have to say it is pretty awesome to watch an object get made seemingly out of nothingness.

When I got my printer, it cost just under $2,000. Today you can get a pretty respectable machine for under $500 and if you want to go into the $2,000 to $3,000 range you can get a really nice printer. If you’re in the market for one I would highly recommend picking up a copy of Make: Ultimate Guide to 3D Printing. The last two years Make Magazine has done a great rundown on the consumer grade 3D printers that are available. If I was going to buy a new printer, this is where I’d start.

The main thing you need to know, is there are two broad categories of 3D printers you might consider for your classroom, Fused Deposition Modeling (FDM) and Stereolithography (SL). My printer does FDM so that’s what I’m familiar with and able to speak to. I really want to try SL, because it’s totally cool. The most common printers in classrooms today use FDM, but this may change in the future.

In a nutshell, Fused Deposition Modeling printers melt plastic and push it out through a nozzle like a hot glue gun. The nozzle in this case is much smaller and hotter than a glue gun, however. The printer builds the object up one layer at a time.

Stereolithography printers use a liquid resin. The resin solidifies when a light is shined on it. These printers also build an object one layer at a time, but the do so a bit differently. The light source in an SL printer will either be a laser that traces a path similar to an FDM printer or a DLP projector that will simply project an image of the whole layer at one time. Once the layer at the top of the liquid solidifies, the printer lifts the growing object and the next layer is illuminated.

If you’re looking for more resources to get you started I’d recommend:

Continue to Part 2 in the series.

3dprinter, makerbot, openscad, tinkercad

A question about 3D printers in education

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I was recently asked a question about my 3D printer:
This ended up being very thought provoking on multiple levels and as with all thoughts I have like this I thought I’d share them here.
Through serendipity about a year and a half ago I found I had unspent grant money that needed to be spent. As I’d made a few big rounds of purchasing for my classroom lately I felt I pretty well supplied. So I decided to take my largess and spend it on a Makerbot Replicator. I entered into this technology purchase in the worst possible way. Here was a big tech purchase and I really had no specific educational outcomes in mind and yet with a tool with the promise of this one I feel no regrets on that score.
So, back to the question. What resources do I wish I’d had? I wasn’t quite sure what Matt meant and I’ve decided to not ask for clarification on this question, but to answer it a few different ways. A few of these wishes have since been met, I’ll point out the resources where appropriate. I’ll also add in the resources I’m glad I had.
What resources do I wish I had before I purchased my 3D printer? 
I wished I had a good breakdown of all the entry level 3D Printers available on the market created by a third party (that is to say, not marketing material for any one printer). Personally I spent a lot of time on the internet searching before finally settling on Makerbot. Now, of course, there is the Make: Ultimate Guide to 3D Printing and they’re now working on an update to this guide. I’d add that I’d like to see one of these done by educators to see what they’d predict they’d see in a school environment with the different machines. This team should include some dedicated industrial ed teachers as well as core content teachers who might use 3D printed objects in their curricula.
Another thing I would like to see is some sort of article or set of articles that could be used to justify the expense of such a machine in the classroom. These could be used to help sway a school’s administration into investing in such a device. Inspired by the question I will try to create such an article in a future post.
Now, once I had my printer what resources do I wish I had?
First on this list would be easy to use software to run my 3D printer. For those not familiar with 3D printers, you need a piece of software that will take the 3D model file to create the tool paths for the machine to follow. This one has been solved for the Makerbot with Makerware. I’m not sure if Makerware will work with other 3D printers or not. Makerware offers very easy default options, but also gives the more advanced user more control. These advanced features are mostly hidden from novice users which really is a good idea. With the advent of Makerware my Makerbot became much easier to use and more versitile.
Next on this list would be an easy to use CAD program. I teach physics and electronics with micro-controllers. Neither of which have much time built in that could be used to teach CAD (even Sketchup). This problem has also been solved for me in a couple of ways. The first of these is a service called TinkerCad. TinkerCad runs in the cloud and requires no software install (always a bonus in schools). It allows you to easily create 3D models and export them as *.stl files ready for printing. Note, there are actually lots of options now. TinkerCad is my favorite though.
Another option that occurred to me last year was OpenSCAD. OpenSCAD allows you to create 3D models programatically. This is not something I plan to teach to my physics students, however. The power here is that like any program you have variables. So you can create or find a good model and then let students explore how changing variables can change the underlying model. My students were able to investigate how changing the parameters of a wind turbine affected the output voltage while possessing no 3D modeling skills. We created and tested 20 different designs. The designs were all created in only two class periods, one each for my two sections.

I would also have liked more nuts and bolts advice and knowledge on operating my printer and the problems I might encounter. To some degree it really is impossible to put together a resource that covers all the potential pitfalls, but I had to fumble around quite a bit. The biggest issue I had to overcome was the warping of parts. This happens for particularly large parts as they cool. The can pull away from the build platform and distort the part or even come loose ruining the print run. The “Helper Discs” that appeared in the example menu in Makerware have helped me immensely with this problem. While there is some overlap, the needs of a Maker are often much different than the needs of a teacher.
The final thing I wished I had when I got my 3D printer was a good idea of how to leverage the power of this device to enhance my teaching. I know it’s a bit ironic, this is exactly what I said I didn’t have and didn’t really care about when I started this post. What I’m still looking for are really cool design projects I can use with my students to tie together what we’re learning with real world applications and critical thinking. To some degree this has been solved a bit with the Makerbot Curriculum page, but I’m still not satisfied here. Now that I’ve discovered the power of OpenSCAD, a whole range of potential projects has become available as well.

Bottom Line?
Some of the things I wished I had are now available but a few are still lacking and might never really exist:

  • Breakdown of best 3D printer in an educational environment. Ideally created by educators (and their students)
  • Articles to be used to support an educator in the purchase of a 3D printer.
  • Cool design project ideas to be used in conjunction with core content classes.
  • Nuts and Bolts guide for teachers on how to use and trouble shoot problems.
3dprinter, physics

Fun with a 3D Printer – Physics Wind Turbine Project

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Almost a year ago I managed to find money to buy a Makerbot Replicator for my classroom. It really is like magic. Most of the year we’ve really just been playing. Printing out cool stuff from the Thingiverse and a few project enclosures for electronics projects.

I’d been wanting to do a cool design project with my physics students, but never really knew what it should be. 3D design is not a skill in the wheelhouse of virtually any of my students (our CAD program died a few years ago). It turns out there is a cool program that lets you create 3D designs programmatically. It’s called OpenSCAD. The beauty of this is that you can create or find a program that generates the 3D design. Then all you need to do is change some of the variables to get a new design.
I decided to give this a try in my physics classroom. We’re in the time of year after the seniors are gone and now the juniors feel like they should be gone as well. I found a cool Mini-Wind Turbine model on the Thingiverse that was created in OpenSCAD. I played with it a bit to figure out exactly what the variables did and then introduced it to the class. Next year I’ll let them figure out what each of the variables does for themselves.
Each of my two physics classes picked two parameters to vary. We ended up with:
  • Length
  • Width
  • Angle – Which was really twist
  • “Fat Point” – Ratio of top length to bottom length
We created 5 different versions varying our on parameter. I let the students decide what they wanted to set the parameters to as long as the blade was not absurd.
Actually we did end up with an absurd blade when it came to twist, but the group that wanted it were convinced it would be the best. So I went ahead with it.
I asked students to graph and find the relationship for each of our four parameters. Unfortunately none of the parameters gave us very good mathematical relationships. I think we might have needed bigger variation in some and more data points in between in another. Next year I may have students fill in some of the gaps.
Once data were analyzed I asked them to design the perfect wind turbine. Some groups relied on their data and some did not. It should really come as no surprise that the groups that relied on the data did the best. Of these most just picked the one best data point in each and put them together. The very best one extrapolated from their data to predict a better solution. It’s nice when things work out the way the should like that.
The best part for me was how surprising our results were. We all had the image of the big majestic wind turbines in our heads. This, however, was not the shape that we found to be the best. The one we found to be the best looked the least like our pre-conceived notion. It had fat stubby wings rather than long and thin.
Some nuts and bolts details:
  • 3D Pinter costs $2000ish
  • Plastic is fairly cheap. If I had to estimate, I used between $10 and $20 worth of plastic on this project.
  • One full set of 15 blades (3 each of five different states) takes between 3 and 4 hours to print. One set all by itself  40 min to an hour. Time varied depending on the design.