FIRST®
I. Innovation of 3D Printed Part
Our robot, #StraightFlexin’, includes several essential 3D printed parts that we designed, programmed, and built, but we are submitting our most innovative part for consideration for the 3D Printing Award. It is the continuous wheel used in our ball feeder.
We believe we are the only team to invent and incorporate this innovative approach to ball-feeding. It was essential to our selection as the 2014 Quality Award winner and in making the play-offs at the Inland Empire Regional Competition. The part’s effectiveness and efficiency was critical to our high success in gaining control of the ball and passing it to alliance team members. And the judges also appreciated the design aesthetics of the part.
The continuous wheel ball feeder was designed using Autodesk Inventor and then converting it into an STL file for use with our MakerBot Replicator 2X. We were able to design the parts from scratch without using model libraries because our school’s required curriculum includes four years of Project Lead The Way, beginning with Introduction to Engineering Design in 9th grade. In this class, the students, including all who are on the robotics team, learn how to use Autodesk Inventor to design and model their projects.
II. 3DP Design Rules & Knowledge Base Enhancement
II-I. 3DP Design Rules Used By Your Team
The design rules most critical to this part were making sure it was a closed structure, with the structural strength and tolerance to be used with the hex shaft that created the rotational motion for the feeder. We designed the structure to maximize functionality and to be lightweight. The most difficult part of the design was the tolerance of the hex shaft inside the feeder wheel. Even with accurate measurements and understanding of the tolerances within our 3D printer, several sample parts were first printed to ensure the shaft can fit easily inside the wheel and lock in place when rotating. The design criteria used to create the hex shaft hole were then used when our team needed to print hex spacers for wheels and other components.
lightweight. The most difficult part of the design was the tolerance of the hex shaft inside the feeder wheel. Even with accurate measurements and understanding of the tolerances within our 3D printer, several sample parts were first printed to ensure the shaft can fit easily inside the wheel and lock in place when rotating. The design criteria used to create the hex shaft hole were then used when our team needed to print hex spacers for wheels and other components.
The other design considerations focused on the ball’s dimensions. The arc specifications of the continuous wheel feeder had to mirror almost exactly the curve of the ball in order to maximize friction and contact. We determined the proper