Case Study: Optimization of a Generatively Designed Drone Frame Using Multi Jet Fusion 3D Printing

Introduction

This case study walks through the step-by-step development of a generatively designed drone frame, with a focus on cutting down weight and improving structural performance. Using the high-precision HP Multi Jet Fusion 5200 printer, we refined our first prototype to strike a better balance between weight, strength, and airflow.

Background

The original frame was built in Autodesk Fusion 360 using its Generative Design tool, with the goal of making the chassis as strong as possible while taking advantage of the geometric flexibility that Multi Jet Fusion (MJF) 3D printing offers. While the first design turned out to be solid and stiff, it missed the mark when it came to weight savings. So, for version two, the goal shifted to dialing in meaningful weight reduction while still keeping the frame strong enough for reliable flight.

Key Objectives

• Reduce overall frame weight without compromising strength.

• Distribute loads more effectively to keep flex behaviour predictable.

• Clean up the aerodynamics by cutting out material that messes with airflow.

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Analysis of Version 1.0 What Worked:

• Dimensional Accuracy: All the mounting points and holes were exactly where they needed to be.

• Battery Holder Design: Fit in seamlessly without causing any weird bending forces.

• Structural Reinforcement: The spars connecting the arms to the battery holder helped a lot with crash protection.

• Aesthetic Appeal: The frame looked good and had a clean, purposeful design.

  
  

What Didn't:

• Too Heavy: Despite using generative design, the frame ended up heavier than we wanted.

• Overbuilt Sections: Some areas were reinforced more than needed, adding bulk without much benefit.

• Rear Arm Flexing: In flight, the rear arms twisted a bit, messing with motor alignment and reducing efficiency.

• Blocked Airflow: Some front structural parts were in the way of the propellers, hurting performance.

  
  

Root Cause Analysis Here’s what led to the issues:

• Generative Design Settings: Using the "Minimize Mass" setting led to more material being added to fight flex, which backfired on the weight-saving goal.

• Estimated Forces: We based simulations on rough guesses rather than actual flight data, so we ended up over-reinforcing the frame.

• Post-Processing Edits: Some manual tweaks in Blender introduced weak spots we didn’t intend.

  
  

Revised Approach for Version 2.0 To fix those issues, we made a few key changes:

• Updated Design Objective: Switched to "Maximize Stiffness with a Target Weight" to better balance strength and weight.

• Set a Clear Weight Goal: Targeted a final weight of 12 grams, based on comparisons with other FDM-printed frames and what we learned from v1.0.

• Better Force Estimates: We used more accurate force estimates that better matched real flight conditions.

  
  

Implementation With those updates, we created a new generative design in Fusion 360. Here’s what came out of it:

• Hit the Weight Target: The frame now weighs 12 grams—right on target.

• Rear Arm Improvements: Flexing is now predictable and controlled, which helps keep flights stable.

• Better Aerodynamics: Front structures were trimmed down, improving airflow around the propellers.

• Print-Ready Design: The frame was optimized for Multi Jet Fusion printing, making use of the process’s ability to handle intricate details.

  
  

Results and Key Findings

• Nailed the Weight: The final weight came in exactly at 12 grams.

• Good Strength-to-Weight Ratio: The frame kept its strength while shedding unnecessary material.

• Improved Flight Performance: Controlled arm flexing led to better motor alignment and more efficient thrust.

• Clean Airflow: By reducing material in the wrong spots, we boosted aerodynamic performance.

  
  

Conclusion and What’s Next

This project shows how refining a design through iterations—and combining that with powerful tools like generative design and Multi Jet Fusion 3D printing—can result in a highly efficient, lightweight drone frame. For the next version, we plan to use real-world flight data to make our load simulations even more accurate and explore ways to make the frame more aerodynamic and crash-resistant.