Bicycles are amazing machines—simple yet complex, a perfect paradigm of form following function. For over a century, that beauty has drawn the attention of designers and engineers looking to leave their mark on the bicycle’s legacy.
I happen to be a designer and full-blown bicycle enthusiast, so I set out to design my own custom bike saddle. This design sprint was an excellent example of how to go from idea to sketch to CAD, to 3D printing, all in a weekend. The exercise shows an interesting contrast between the design methods used in the early ages of bike design and the modern tools available to designers today.
Research Bike Saddles
I started by gathering and organizing saddle designs as well as other environmental influences on ergonomics. Designers today have the internet to use as a research tool, which is a real advantage over turn-of-the-century craftsmen. My goal was to get to the essence of the design features required by a bike saddle.
- Does it fit on the bike properly?
- Can it support a rider?
- Does it look as good as it functions?
For my design, I was inspired by the forms of early supersonic jets and organic cellular structures.
Sketching out bike seat designs.
Sketching on paper is a critical step in the iterative design process. Creating thorough sketches beforehand gave me a strong plan to refer to once I moved over to CAD. This isn’t to say that I would only model what I had sketched—3D modeling allowed me to further experiment and learn more about the form as a three-dimensional shape. Exploring the shape in a 3D space helped me learn more about proportions, dimensional accuracy, and design for manufacturing or 3D printing.
Create CAD Models from Sketches
Although plenty of great CAD tools are out there, I felt Rhino was the best tool for this particular project. Rhino is a NURBS (Non-Uniform Rational B-Splines) 3D modeling tool with a high degree of flexibility and accuracy. The tool is good for designing a bike seat because it allows for uninhibited form exploration, unlike many other parametric modeling programs.
In Rhino, I created multiple iterations of my original seat design by cloning the base model and altering features of each iteration. The features ranged from hole patterns to the saddle profile, and everything in between. Once I was satisfied with one of these iterations, I dragged and dropped the 3DM CAD file directly into MakerBot Print (which converts it automatically to a .STL) to prepare it for fast, high-quality printing.
Prepare CAD Model for 3D Printing
Although 3D printing has come a long way from the days of build-it-yourself kits, it is still requires a good degree of skill and offers a wide scope of optimization. For this design, the two most important things to consider were the print settings and the model’s orientation. The first print did not need to be especially durable because it would not be a working product. Therefore, I was free to use faster, more minimal settings, less internal support material (3%-5% infill), and bigger layers (0.3mm-0.4mm layer height).
Getting a good feel for print orientation takes practice, but one trick worth knowing is that MakerBot Print will automatically generate supports for any angle more dramatic than 68 degrees. With the seat oriented vertically, none of the curves exceeded that limit, and the slice preview confirmed that the saddle would print cleanly with no supports.
Test Bike Saddle Prototype
With a physical part in hand, I could interpret my design within a real-world context. At this stage, I could mount the saddle to a bike and fine-tune dimensional accuracy and compare the design to existing bike saddles. Once I had a better idea of the changes I needed to make, I used a marker to make notes directly on the part.
3D printing lets designers make faster iterations, which means they are more likely to catch flaws before presenting a final product. This greatly improves the end product’s value.
Having access to a 3D printer directly on my desk allowed me to treat the printer like a sketchbook, and each 3D print like a sketch. Because I didn’t outsource for the prints and spend a few weeks or a few hundred dollars to get them, they did not need to be treated like precious items. I could tinker with, write on, or even break the prints knowing that I was not derailing the process, all the while getting a deeper physical understanding of the saddle.
Print, Test, Revise, Repeat
With the additional notes from my real-world testing, I could now go back into Rhino and make some final design adjustments. Being able to print my idea and bring it into the physical world gave me a great deal of additional information to work with. At the same time, my project gained focus and definition. Iterative printing, testing, and polishing my ideas enabled me to inch closer to my final design.
Adding a texture to the saddle, coring out material to make it lighter, and improving the aerodynamic profile were just a few of the ideas that I was able to test along the way as I iterated. With a personal printer at my disposal, I was able to immediately test my ideas.
Final Design Print
With the final design changes made to my CAD model, I could easily send the revised design file back to MakerBot Print and print my final model. Testing a wide range of options gave me a solid starting point for the manufacturing steps that would follow.
More importantly, I was able to physically test my ideas. Not having them limited to a flat sheet of paper or computer screen enabled me to get an in-depth understanding of the real-world implications of my design decisions.
As this project shows, a 3D printer is more than a rapid prototyping tool: It can serve as a sketchbook, research tool, and second set of hands, all of which represents a paradigm shift. By placing a 3D printer seamlessly in your design process, you can explore more broadly and deeper, and ultimately design faster than ever before.
Felipe Castañeda is MakerBot UX and industrial designer.