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3D Printing: Bringing the Past to the Present

Fab Lab Houston may not have a permanent space yet, but that hasn’t stopped us from bringing digital fabrication equipment to the community. Monday we were at Shotwell Middle School in the Aldine Independent School District using the 3D printer to help with a History Fair project.

3D printers can be used for a variety of projects, this time to print a small model of Little Boy, the atomic bomb dropped on the Japanese city of Hiroshima on 6 August 1945 during World War II by the Boeing B-29 Enola Gay.

Basically anything that can go from liquid to solid or solid to liquid to solid again can be used with a 3D printer. You may have seen videos online of people using them to make pancakes that are elaborate pictures. We prefer to use ABS. It is versatile, and once printed is a hard plastic, like a Lego brick. Even though the finished product is hard, the plastic printing process can best be compared to how a hot glue gun works.  The glue stick goes in at the top, in a wide and long form. It is then heated up, and comes out of the nozzle as a thin string, warmed up so it is pliable.

When you are plotting points on a piece of paper, you are operating on an X-Y axis. The process of 3D printing also adds a Z axis, which is what goes ‘up’ and makes an object 3D.  There is a variety of free online software that can be used to help you get started on your first project. If you go to www.thingiverse.com you will encounter a variety of searchable projects. Their projects range in difficulty and practicality, from small model cars, to modifications for drones, to detailed models. Once you have your project downloaded, you can go to www.tinkercad.com where you will upload the project from a CAD (computer aided design) format to a CAM (computer assisted machining) format. The change in format makes the project able to be printed on the 3D printer.  If you have a project in mind that cannot be found on Thingiverse, you can design your own using Tinkercad.  While in Tinkercad you can customize the thickness of the model, the amount of fill used, and many other variables.  Sometimes the projects may be too large to print, Thingiverse sometimes has them split into printable sections for you. Other times you may need to break them up yourself in Tinkercad.

Once you have set the variables in Tinkercad, you will save your project to an SD card for easy transfer to your printer. The process of printing in 3D can best be compared to stacking pieces of paper. Each layer that is printed is so thin, if they were next to each other they would be inconsequential.  However, when you start to stack up pieces of paper, one on top of the other, you can see the thickness increase.  This is the same with 3D printing. It adds layer upon layer of thin melted plastic, building up slowly, with projects sometimes taking hours to print. If you have split your project into 2 or more sections, you will need to glue them together once done.

It was wonderful being at Shotwell Middle and seeing the students get excited about the technology being used for their projects.  Without the Fab Lab Houston and the machines it has available, these students would not have had the opportunity to bring history to life in such a futuristic way.  Good Luck to the teams from Shotwell Middle School as they travel to Austin, TX this weekend for the History Fair State Finals!

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