Junior Engineer Workshop Update #2!

3D Printed STEM Catapult

Good news! The prototype catapult components are finished and they look great! We are excited to put it together and play with it... I mean test it... ;)

In the picture below you can see all of the 3D printed components. These were printed using white PLA on our Ultimaker S5 machine. On the left side of each frame you can see the hooks that will be the attachment point for the rubber band. The rubber band will then extend over the adjustable tension rod and connect to eye bolt on the pivot arm. For safety, the basket has been designed specifically to hold a soft, Nerf style ball.

3D Printed STEM Catapult

One constraint with using Extrusion 3D printing technology is that it cannot print features with overhang angles greater than 45 degrees from vertical without support. If you print overhangs greater than 45 degrees, you need additional support material to ensure that the feature prints correctly. This support material is then removed after the printing is completed.

As an example, assume that the picture below is a hole that will be 3D printed. The bottom of the picture will represent the plate that the part will be printed on. The layers will start at the bottom of the picture and each consecutive layer will be printed on top of that. When the part is completed you will end up with a hole on the side of the part. A section of this hole will require support material to avoid deformation or sagging. This area is represented by the highlighted red section.

FDM Overhang Constraint

The pivot arm of the catapult was designed with features that would allow us to avoid this condition. As an example, take a look at the diamond shaped holes below. These are the mounting hole locations for the basket and the eye bolt. If we made these features circular like typical CNC machined clearance holes, there would be overhangs inside greater than 45 degrees. This would require support material inside the holes and it would be difficult to remove after printing. We avoided this problem by designing these features as diamonds with angles equal to 45 degrees.

3D Printed STEM Catapult

Contact us and let us know your thoughts about this project! Stay tuned for more project information. We will continue to announce more updates about the Junior Engineer program as we approach the release date. ​Interested parents and kids can keep an eye on our website or sign up for our newsletter to receive more announcements about opportunities to sign up for our first classes.

At Nexus3, we partner with businesses to bring their innovations to life. If you have an engineering challenge that needs solving or if you need parts fabricated using AM technology, contact us. We will help you solve your toughest problems.

Nexus3 is your innovation partner. Let us help you realize what is possible.

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