Week 12 - Machine Desin

4-Axis Robotic Arm

Project Overview

For Week 12, our group designed and built a 4-axis robotic arm for performing tasks such as milling and isolation routing, pick-and-place tasks, controlled by Nema 17 stepper motors and firmware. I was part of Group 1, focusing on the design, 3D printing, and assembly of the mechanical structure. Our team was divided into three groups:

• Group 1: Design and Assembly - CAD design, 3D printing, and mechanical assembly (my role).
• Group 2: PCB Design and Manufacturing - Custom electronics for motor control.
• Group 3: Firmware and Interfacing - Firmware and web interface.

The arm was designed to demonstrate coordinated motion and automation, with applications in manufacturing and education.

CAD Design

I used SolidWorks to design the 4-axis robotic arm, creating a modular structure compatible with NEMA 17 stepper motors and a manual gripper. WE reserched the internet for ideas of the already existed projects as we didnt have much time to starct from scratch. We visited the following pages

• Robotic Arm reserach link 1
• Robotic Arm Reserach link 2
• Nema 17 motor link_Dimentions

Nema 17 stepper motor

Nema 17 stepper motor

3D Printing

I 3D printed the arm’s components using PLA on several 3D Printers as the parts were many. Below is a zip file for the Solidworks and STL files

• Components Printed: Base mounts, four arm segments, motor brackets.
• Print Settings: 0.2mm layer height, 25% infill, 50mm/s speed, brim for adhesion.
• Material: PLA, chosen for availability and ease of printing.
• Total Print Time: Approximately 24hours across multiple prints.

I minimized support material by orienting parts carefully and iterated designs to prevent print failures.

3D printed PLA components before assembly.

Assembly

I led the mechanical assembly, ensuring all components were aligned and functional.

1. Mounted the Axis 1 stepper motor with a 3D-printed base segment and bearings.
2. Attached Axis 2 (shoulder) and Axis 3 (elbow) segments, securing motors with M5 bolts.
3. Added the gripper
4. Manually tested each axis for smooth motion and reduced toque on the bolts.

Challenges

I encountered several challenges during the process:

• Print Failures: Warping occurred; resolved with brims and bed temperature adjustments.
• Heavy stepper motors The motors were too heavy forthe joints

Team Dynamics

Our team’s structure leveraged individual strengths:

• Group 1: Designed and built the arm’s structure (our role)
• Group 2: Developed PCBs for motor control.
• Group 3: Created firmware and a web interface.

We coordinated through weekly meetings and WhatsApp. My mechanical work integrated seamlessly with the electronics and software, resulting in a cohesive final presentation.