Box Tube Extension

A modular aluminum extension system that allows for smooth, lightweight, and rigid linear motion for robot mechanisms while maintaining precise alignment and a compact design

Updated: 10-05-2025 Status: Completed

Overview

This project was a proof of concept made for my high school robotics team in the season of 2025. I used mostly the material that our makerspace already had such as the extrusion tube and square tube, which was the parameter everything else was designed around. Although some inserts would ideally be machined from metal for durability, I 3D printed them for simplicity and rapid prototyping, which slightly reduced rigidity but allowed for faster iteration.

I wanted to make this because I have seen many other teams implementing it in their robot and wanted to increase the rigidity of our lift mechanism, which still had noticeable flex even with dual drawer slides. This design focuses on rigidity, simplicity and easy implementation, so our team could easily implement it in their robot in the future.

Key features:
Modular aluminum frame design for scalable and lightweight structural extensions
Lightweight pocketed square tube to reduce mass while maintaining structural integrity.
3D-printed components for easier integration of more lift stages.
Low-cost design achieved through reusing existing parts and 3D printing majority of the components.
Tools: Placeholder

V1 — 05-08-2025

Download CAD Open in Fusion 360

What changed in this version

I cut the extrusion bar and square tube down to a workable length. Then I modeled them in fusion, and designed the inserts around size of the extrusion bar and square tube. To use the parts that we already had, I used the bearing we already had in the design. Althoough for the inner inserts, other team used smaller bearing like the ones used on the outer inserts, I decided to use larger bearing for more rigidity.

Once the CAD model was done, I 3D printed the parts, and becuase not all the bearings had came in. I first 3D printed them as a temporary soultion. And replaced them with the metal bearing once they came in.

Notes / Issues / Next Step

Since this was a proof of concept, and I was tight on time, I did not end up pocketing the square tube. Due to the inserts being entirely 3d printed, the outer insert's bearing mount was very fragile, and the problem would be alleviate by making that part out of metal.

Physical Prototype

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CAD / Render

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Downloads

Box_Tube.step CAD · 454 KB Inner_Tube.step CAD · 54 KB Outer_Tube.step CAD · 16 KB

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