At our company, we place a special focus on developing ergonomic products that are 3D printed, allowing for complete customization in terms of size, fit, color, and materials.
While there are already several comparable ergonomic solutions on the market, most are made using standard manufacturing technologies. This typically involves conventional materials such as silicone, foam, or rubber. In contrast, our approach is based on the use of cellular structures, which ensures superior biomechanical performance, enhanced comfort, and a fully personalized fit for each user. Additionally, our solution is significantly more environmentally friendly, contributing to greater sustainability overall.
In close collaboration with the IPD CAD Lab FS MB (Laboratory for Integrated Product Development and CAD Faculty of Mechanical Engineering in Maribor) we developed the first ergonomic armrest featuring a cellular structure. The geometry of the armrest was designed with the following key criteria in mind:
• Optimal fit to the user’s arm through a dual-curvature profile.
• Variable radius along the contact edge for a softer and more comfortable support.
• Symmetrical cushion shape in both longitudinal and transverse directions, enabling versatile use.
The cellular structure itself ensures breathability, comfort, and a lightweight design.
Following the testing of the first 3D-printed prototypes, we made initial topological and geometrical adjustments to the armrest design. This allowed us to define the structural framework of both the cushion and its base.
Development of a biomechanical numerical model of the arm to improve the properties of the cellular armrest.
The basic geometry of the arm was created based on a CT scan that captured both soft tissues and the bones of the radius and ulna. In the numerical simulation, all soft tissues were combined into a single part, which simplified the model and optimized computational processing.
Since the palm did not come into contact with the armrest in the simulation and was treated as a rigid body, the hand bones were not included in the geometric model of the arm. The position of the arm and bones was adjusted to reflect the use of the cellular armrest during work with a desktop computer mouse.
Transparent views of the arm model illustrate the position of the radius and ulna bones within the soft tissue and their relationship to the armrest. The bones were anthropometrically adjusted to a position that corresponds to the use of a computer mouse. Ensuring the correct positioning is crucial, as the thickness of the soft tissue layer between the bone and the armrest significantly affects the distribution and magnitude of contact pressure.
In the analysis of biomechanical systems, such as the simulation of interaction between the arm and the armrest, two key parameters are commonly used: contact pressure and displacement. These were carefully considered during the product development process. Contact pressure is directly related to comfort, as excessive pressure values or high concentrations can lead to discomfort or even soft tissue damage.
On the other hand, displacement is used to evaluate the stability of the analyzed component. The maximum contact pressure and its distribution were analyzed at the interface between the cushion and the arm. Vertical displacement of the cushion is presented in cross-section.
For the purpose of mechanical testing, the geometry was defined according to ISO 3386-1:1996, using open and closed cylindrical samples with a diameter of 60 mm and a thickness of 15 mm. In total, more than 40 different samples were tested throughout the project, featuring various ligament thicknesses, cell diameters, and open or closed structures.
The thickness of the samples was primarily based on the proposed cushion thickness, as increasing the thickness also increases the number of base cells along the height, which in turn affects the mechanical response of the structure.
Based on all conducted analyses and experimental tests, we developed the final cushion geometry that fully meets the initial project requirements. A key factor was the implementation of functional gradation in cell size, which enabled an optimal balance between mechanical response, stability, and user comfort.
A softer response was achieved in the central part of the cushion to provide greater comfort, while the stiffer outer regions ensured the necessary support.
Why don’t we use standard manufacturing methods (e.g. rubber injection molding)?
Application-specific customization:
3D printing allows us to create complex cellular structures optimized for specific properties such as exceptional comfort, elasticity, strength, durability, and energy absorption — features that cannot be achieved with conventional materials.
Product complexity:
This technology enables the production of geometries that were previously impossible to manufacture using traditional methods, allowing us to closely match the individual needs of the user.
Weight reduction:
Cellular structures make it possible to drastically reduce product weight — by up to 80% — while maintaining mechanical properties such as strength, flexibility, and appropriate mechanical response. This is a major advantage in applications where weight reduction is critical, such as in the automotive and aerospace industries — or in our case, in an ergonomic product that users can easily take with them when traveling by plane.
Waste reduction in production:
3D printing technology enables almost 100% material utilization (support-free printing, with excess powder being reusable). This significantly lowers material costs and makes the entire process highly sustainable.