May 4, 2016

3D Printed Piggy Bank - a Journey in Problem Solving

This is a guest post from Bethany Jones, who currently teaches a 7th grade science elective called Engineering Design in Mason, Ohio. Bethany is the mother of two tiny humans and one very energetic dog. She is a tinkerer, lover of learning and recent 3D printing enthusiast.

“If at first you don’t succeed, call it version 1.0”
This has become my motto as I have leapt headfirst into the world of 3D printing with my 7th graders. One thing I have tried to share with my students is that it’s not all about the end product, but the journey you take along the way. There is often more learning that takes place through failing than if you get it right the first time around.  

Ever since our 3D printer arrived a month ago, I have been adamant that it not just be a toy, but an avenue for creation.  I am encouraging my students to try designing something on their own that has a purpose or that solves a problem. In an attempt to show them that I was in this crazy new adventure with them, (as well as wanting to test the print size limits of the printer) I decided to make a piggy bank.

I kid you not, about an hour into the print, a group of students are hovering over the printer watching in awe and one says, “how are you going to get the money out Mrs. Jones?” Face-palm. I had forgotten to put a hole in the bottom to get the money out! 

I told my kids that we’d just have to break it open. It ended up not mattering, as this version printed with a giant mystery hole in the back. But I quickly went back to the computer and edited my model to include a money-retrieval hole in the bottom. Great teachable moment about learning from your mistakes right? 

My students and I had fun analyzing the possible causes for the other print issues and we decided to try and make the walls thicker for more support and hopefully close the mysterious hole.

The second time around, I think something went awry with the printer as everything went well until the very end. The slot on the top printed crooked and the ears  were hanging on by a thread about halfway up. Since I couldn’t find any explanation for this, I printed the same model with no edits and it worked! Third time's the charm!

I am loving the iterative process of designing, printing, redesigning and reprinting until I get something right. It is a wonderful lesson that my students are learning as well. I am finding that in a world where they may have been afraid to fail before, they are energized by the possibility that they can analyze the problem and attempt to fix it! Beyond making something cool to look at, it is something to be proud of when you can create something on your computer screen and make it come to life as a tangible object to enjoy and share with others.

*Addendum: Fast forward one day past writing this post and the poor perfect piggy version 3.0 took a flying leap off my desk and met his demise as a clean break ripped through his body, splitting him in twine. I almost cried real tears in front of my students. But looking on the bright side, as one must do to remain sane, we can now analyze broken piggy from the inside out.


  1. Fantastic!
    I love how you've got the link to the TInkercad plans and described the process. One thing that we're going to do is print this out in New Zealand as my students would love to do this. Thinking about any changes that could be made but obviously you could put the students name into the Piggy Bank and personalise them by using lettering - we might just try it out and see how it goes.
    Great post, brilliant idea and I am sure the kids were super pleased to see this.
    Mr Webb, Auroa Primary School, New Zealand

  2. I think you mean "Twain", not twine. The word "twain" is an archaic form meaning "two". But on the serious side, I'm told standard super glue should fix that.