For years my goto CAD solution for designing parts to be 3D printed has been Tinkercad. It really is the fastest way to get students designing their own 3D parts. The basics of Tinkercad can be taught with less than five minutes of instruction. Best of all, it is totally free and you don’t need admin rights to install any software..
The basic idea is that you create objects by combining primitives and then using other primitives to create holes or take away materials. The other thing to know is that once a shape has been added you can stretch or squish it in the x, y, or z dimension or rotate it around the x, y, or z axis.
Using this very simple paradigm you really can create some very complex objects. Creation of these objects often involves a lot of critical thinking and problem solving for students to figure out the best way to get to their desired final part.
You can easily modify my version to suit what ever cup you might have. It currently will accommodate a standard coffee cup. To play with my design goto: https://tinkercad.com/things/i02pOyl5X81 and click on “Tinker this” (you must be signed in to Tinkercad first). Then click on Ungroup to reveal the underlying shapes. You might need to do this multiple times to see all the shapes. The order in which you group things has a huge effect on your final design.
The Centripetal Force Demonstrator was created from:
A “Cylinder” (orange) as the base with a squished “Torus thin” (red) to make a lip to keep something from sliding off.
A “Torus” (green) to swing it by. This was placed above the center of the base floating in space. It is important that this be centered above the base at the desired height. Then group it with the base so it will stay centered.
A “Torus Thin” (blue) was stretched and then rotated slightly to attach the base to the ring. “Box” holes were used to remove the un-needed bits.
A stretched “Half Sphere” was tacked on to the flat surface of the half torus in order to make the ring attachment more attractive. This is can’t be seen in the picture below.
Just over a year ago I made a physics apparatus to help students develop a good mathematical model of acceleration. The idea wasn’t original to me, I just made it easy to make via 3d printing. My design works really well, but I wasn’t really satisfied with it. It consisted of a ring with two cones glued to the center of both sides. The side of the disk facing down always needed some clean-up prior to gluing. I let redesign ideas percolate in my brain to see if I could come up with something better. Then a couple months ago I saw a cool spinning top on the Thingiverse.
The two halves screw together and are sized perfectly to fit a CD. The instant I saw this I immediately knew I could do the same thing for my acceleration apparatus. All I needed to do was combine my idea with the nut-bolt bits from the top.
For me the ability to easily share, iterate, and re-mix existing designs is where the power of 3D printing really hits its stride. I don’t have the CAD skills to make working screw threads and even if I did I wouldn’t have hit on using a CD as the disk. Since Gwo-Shyong Yan shared his design on the Thingiverse with a Creative Commons License I was able to not only find inspiration, but I could also build directly on his work.
After the inspiration came the iteration. Overall, I printed at least seven different versions before I was satisfied. I was trying to balance printability, usability, and overall appearance. When I was done I was pretty happy with the final design.
Of course, since I completed my original design more than a year ago I’ve already printed a full set of my old apparatus for the physics teacher in my school, so I really have no need of a new design. So, why did I spend several hours on this project?
There are really multiple reasons that all play into why I spent a Saturday working on this. I wanted to create a thing that other teachers could use with their students. I also wanted to add back to the community of Makers so that someone else might find inspiration to create something cool. But really I did this just to see if I could. I did it for the sheer joy of making a thing. That others might find this useful or interesting was really secondary. This makes me wonder, how do we engage our students to embark on things like this? How do we get them interested enough in doing a thing that they are forced to learn the bits they need to get it done? If you have any insights into this, or really any thing else please share them with me in the comments or via twitter (@falconphysics).
If you’re interested, you can find my final design on Thingiverse. You can also find links to my Tinkercad projects there in case you want to modify my designs.
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.
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.
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