Week 12: Mechanical Design

➡️ View our full group documentation here.

Overview

For this group project, I was responsible for the full mechanical side of the machine. I designed the CAD model, machined the polycarbonate parts on the CNC router, created and assembled the V-wheel carriage, routed GT2 belts, installed the motors, and handled wiring and cable management.

fullCAD

Mechanical System Architecture

I designed a motion system using V-wheels on 20x20mm aluminum extrusion rails and powered it with GT2 belts driven by NEMA 17 stepper motors.

Custom V-Wheel Carriage

I designed a compact carriage that:

The part was 3D printed in PETG for strength and smooth motion.

Custom V-Wheel Carriage

Frame and CNC-Machined Plates

I built the frame from Sigma aluminum profiles and connected them with brackets and T-nuts. I also designed and machined polycarbonate plates on our CNC router, which were used for motor mounting and structural bracing.

Frame Assembly

Motor System and GT2 Transmission

I mounted NEMA 17 stepper motors using slotted 3D-printed brackets and connected them to GT2 pulleys. Idler pulleys were placed at the opposite ends. I clamped the belts directly to my custom carriage design.

Motor and Belt Transmission

Manufacturing

I exported STL files from Fusion 360 for all printed parts and machined toolpaths for polycarbonate using Fusion CAM. All parts were fabricated and post-processed by me.

Assembly and Wiring

I completed the full mechanical assembly, which included:

I also handled all the electrical wiring and cable routing. I used cable channels mounted to the frame and carefully routed motor wires, labeling and organizing them before connecting everything to the control board.

I fixed an issue with uneven belt tension by adjusting the belt clamp design and reprinting the part.

Final Mechanical Assembly

Reflections

Doing all of the mechanical work from CAD to CNC and wiring helped me better understand complete machine design. I enjoyed solving practical issues like belt misalignment and routing clean cable paths. This assignment improved both my design and hands-on assembly skills.