When designing the exoskeleton of lower limbs, due to the complex geometry of several key elements, it was decided to made their with the use of 3D printing technology. This approach allows to skip the multi-stage manufacturing process and reduce production costs. Despite the positive results obtained from the numerical analyses, after performing tests on the constructed physical object, it turned out that some of the components transmitting torque in the joint were damaged. Therefore, strength tests of the material used to additive manufacturing were carried out. Studies taking into account the preparation of test pieces in three printing directions, and it was also checked whether the samples subjected to heating would improve their strength properties. The obtained experimental data were implemented in the FEM computation model and the necessary optimizations were made of elements exposed to high torques. The modified elements were verified on a real object, controlling the engines in such a way as to reproduce the extreme operating conditions of the system, obtaining positive results.