Automated Design of Snap-Fit Joints for the Additive Manufacturing of Robot Links

The additive manufacturing of robots offers a way to quickly and cost-effectively provide robotic solutions to specialized applications. Individualized robots cannot, however, be produced in a single additive manufacturing step. While the production of monolithic parts is desirable, a certain assembly effort remains. The purpose of this research is to minimize this assembly effort white simultaneously avoiding additional effort required by the manual design of such joints. Snap-fit joints are a good candidate for joining additive manufactured robot parts, as they allow monolithic fabrication of the part and joint features, require little space and provide reliable and reversible joints that are easy to assemble. A library of snap-fit features including lock, locator and compliance features was established. In order to streamline the design process, an automated design algorithm was developed. It analyses given robotic structures, finds the appropriate faces and automatically places the joint features as well as the components for an electric connection while preserving the original kinematics. A 2R demonstrator robot was created, successfully displaying the developed features and a very short assembly time. This work marks an important step towards the completely automated design of robotic solutions for individual tasks.