Lightweight design

How to design lightweight mechanical parts

For a Mechatronics Engineer, there is nothing more exciting than developing a new piece of hardware for our Aerial Scout drone. We’ve asked David Frieling, Mechatronics Engineer at Avular, what it’s like to design lightweight parts for aerial robotic platforms.

The key is to find the optimal balance between material stiffness, extreme fiber distance, manufacturing method, weight and volume in an integrated design. Simplified, that takes three steps.

.1 Concept modeling.

The design process starts with putting our vision on paper and creating a rough 3D model of all of the essential bodies and components. At this stage, we’re focusing on the essential form without details such as final blends and weight optimization. This step requires the most spatial awareness and vision on what the final product will look like. This is also the moment at which we consider what material would be the best for this part. The concept modeling phase requires insight in which shapes are best used to result in a lightweight design, and keeping the chosen material and manufacturing method in mind. The result provides sufficient information about the essential functionalities and dimensions of the part, making it ready for drawing the prototype.

Material choice.

One of the materials we use for our aerial applications is a nylon-type material, namely 3D printed Polyamide 12 (PA12). This material does not only provide an excellent durability but is also very impact resistant, therefore making it perfectly suitable for an aerial robotic platform. 3D printing as a manufacturing method provides extreme design freedom, which allows us to focus on designing the part without the constraints of conventional production methods. Reasons for us to choose for this material are:

  • Impact resistance
  • Surface finish
  • Short lead times
  • Low wall thickness
  • High level of customization

.2 Drawing the first prototype.

The second step is to actually draw the first prototype. The design is subjected to material reduction and reinforcement, such as mounting holes, impact points and load carrying sections. A Finite Element Analysis is performed on all critical parts, to determine stress points and optimize material layout iteratively to ensure good overall performance. Subparts of the design can be tested and optimized separately if they require additional attention to detail. If so, we produce a first (3D printed) version of the subpart and test it accordingly. Multiple design iterations of each subpart are usually necessary to optimize low-weight with proper mechanical properties and manufacturability.

.3 Final design.

At the end of the 3D design process, all the 3D bodies are checked and fused, after which blends are applied to produce a complete, finished part. As a final step, several design iterations should be done on the entire product, to further optimize the product as a whole, which requires additional attention to detail and design.

After the complete design is finished, we export the different parts separately and they’re ready to get printed. Finally, we assemble all the parts in-house.