Functional testing of entirely additively manufactured two-component hydraulic rod seals made of TPU and NBR

The delivery time of expendable items can be quite high despite today’s sophisticated logistics and production systems. In the case of dynamic rod seals for hydraulic applications, this can last weeks or even months. A possible solution to avoid shutdowns can be the fast production of seals using additive manufacturing (AM), at least to use these parts until conventionally produced spare parts arrive. The research question addressed in this study is whether it is possible to produce functional parts in this way to avoid leakage. The paper starts with an introduction to the topic and introduces the materials and equipment used to conduct the study. The main part of this paper includes the documentation of the results of two series of functional tests conducted with five different thermoplastic materials. These tests showed that the research question can be answered in an affirmative way for tested pressures up to 15 MPa and a sliding distance of 320 m. However, the results show different behaviors of conventionally produced seals and those made using AM.