Traditional bike saddles are usually made of three structures: a plastic support, a middle layer filled with PU or EVA material, and an outer layer made of leather or fabric. However, traditional saddles have limitations: limited breathability, lower comfort, and limited design freedom.

Our customer, a bike maker, wanted to use a simpler structure and a more effective manufacturing method — 3D printing technology — to improve these problems. They contacted us and provided their original design. They wanted to use FDM technology and TPU material to manufacture the saddle. However, after reviewing the design and considering our industrial engineering experience, we found that FDM was not a suitable solution and would be difficult to achieve successfully.

FDM is a widely used 3D printing technology, and TPU materials are also popular among engineers, especially for making simple designs and small parts such as standard shells and seals. However, in this project, the lattice size, structural details, and overall design complexity were beyond what FDM could achieve smoothly and stably. The reasons are as follows:

1. The lattice structure is too complicated for FDM to produce stably because of its printing process, which is similar to spinning a thread.
2. When TPU meets FDM, it is difficult to achieve effective support or simply recover the design because of TPU’s soft properties.
3. FDM-printed parts are usually not good enough to meet products that focus on appearance because of the rough surface finish and obvious layer lines.

Why still use TPU?

TPU has better flexibility and fatigue resistance compared with many other materials. It is already widely used in applications such as shoe soles and motorcycle seals, where repeated deformation is required.

In this project, we used Shore 60A TPU. Its properties can fully meet the requirements of a bike saddle, which needs both support and comfort. It can maintain a good balance between flexibility and support.

Why use DLP instead of FDM

You can find the reasons one by one in the table below.

The customer's original CAD file was designed based on FDM printing logic, which means there were many enclosed areas inside the structure.

If we used the original design directly for DLP printing, uncured resin would remain trapped inside these areas and could not be removed. It would also create many internal supports that would be difficult to remove after printing.

Therefore, we needed to perform DfAM (Design for Additive Manufacturing) optimization to help the customer achieve the original design concept while also meeting the requirements of DLP printing.

The following are the four main steps we performed:

1. Refine the internal structure to improve the resin flow and drainage by redesigning the internal connection way of the lattice.
2. Refine the lattice connection points to improve structural reliability by adjusting the direction to better suit the DLP’s printing process.
3. Refine wall thickness distribution to improve the load distribution by adjusting the part and detailed design.
4. Refine the printing orientation and support strategy to improve printing success and reduce the difficulty of post-processing.

After printing, the saddle part showed a semi-transparent black appearance. However, we can apply additional coloring treatment to the surface to achieve a more uniform and high-quality black appearance. This process can further improve the overall quality and style of the part. It helps transform the saddle from only a prototype into a real ready-to-use product. It also allows customization with different colors based on different customer preferences.

In the end, we successfully created a one-piece TPU lattice bike saddle using DLP technology.

We successfully achieved the customer's requirements:

• Not using traditional materials and manufacturing methods, but instead using one-piece 3D printing with a lattice structure and TPU material.
• Improving the appearance and breathability of the saddle.
• Supporting personalized colors and a high-quality appearance.
• Turning the customer's idea into reality with an excellent manufacturing solution.

See the whole process about DLP printing on YouTube:

See the full case study video on IG:

Do you have a great idea or creative design? Just contact us, and we can help you make it a reality.

You can send your files or project details to sales@in3dtec.com. We will support you from the beginning to the end.