Tailoring the Curing Kinetics of NBR-Based Rubber Compounds for Additive Manufacturing of Rod Seals

Sundermann, Lion; Leineweber, Sebastian; Klie, Benjamin; Wittek, Heike; Ebel, Thomas; Reitz, Birger; Ottink, Kathrin; Graf, Matthias; Lankenau, Tobias; Overmeyer, Ludger; Giese, Ulrich

doi:10.1155/2023/7343194

Cited by 3 publications

(1 citation statement)

References 35 publications

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“…Recent studies have investigated the ability of AM technologies to generate seals with acceptable sealing properties that ensure machine operation, until an original spare part is available. It emerged that fused filament fabrication (FFF, also named fused deposition modelling (FDM)) is a suitable technology here [1,2]. FFF uses a thermoplastic polyurethan (TPU)-based filament, which is extruded in a heated nozzle.…”

Section: Brief State Of the Artmentioning

confidence: 99%

Fluid–structure interaction of a dynamic seal with a 3D‐printed surface

Graf,

Lankenau,

Ottink

et al. 2023

Proc Appl Math and Mech

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Additive manufacturing (AM) methods are finding more and more applications in the manufacturing of machine parts. One consequence of this method is that generated surface qualities are typically lower than in other processes. This becomes especially relevant when the surface quality is critical for the mechanical function: This is the case in dynamic sealing technologies, for example, in seals between a moving rod and a hydraulic cylinder. Between the seal lip and the polished rod, a thin lubrication film is established with the goal of minimal leakage. How well this goal is reached depends on the surface quality of the seal. For spare part production of seals, we investigate AM methods, which have a surface defined by layers from fused filament fabrication (FFF). We apply a coupled model for fluid–structure interaction of the elastic seal and the film flow. This model provides information on flow field and pressure distribution. Results change when the ‘ideal’ seal lip is replaced by the seal lip geometry from FFF. The continuous loss of solid body contact is replaced by a stepwise loss of contact for the FFF surface.

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Section: Brief State Of the Artmentioning

confidence: 99%

Fluid–structure interaction of a dynamic seal with a 3D‐printed surface

Graf,

Lankenau,

Ottink

et al. 2023

Proc Appl Math and Mech

Self Cite

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An approach simulating interacting solid, liquid, and gas domains for dynamic seal applications

Graf,

Lankenau,

Ottink

et al. 2024

Proc Appl Math and Mech

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In seal applications a solid elastic body (the seal) ensures the separation of a liquid (e.g., hydraulic oil in one chamber) from a gas (e.g., air in another chamber). In the case of a dynamic seal, the rod is moving and transports a thin liquid film from the liquid chamber into the air chamber. The seal gap consists of a converging gap, a minimum distance between seal and rod and a diverging gap, where transported liquid detaches from the seal. Between the three states of matter (gas, liquid, gas) appear the following contact conditions: liquid‐to‐solid, gas‐to‐liquid, and gas‐to‐solid. A classical fluid‐structure‐interaction is technically possible with limited effort, but is not sufficient to distinguish between the liquid and the gas. A solution can make use of the fact, that the liquid has significant dimensions only in the liquid chamber and is pressurized only there. There is a thin liquid film on the rod in the air chamber, but it has dimensions clearly lower than the air chamber and has the same pressure as the air. Therefore a simulation is possible with the “variable viscosity approach”: Liquid and gas are modeled in one single fluid domain. Differences between liquid and gas are included by pressure‐dependent fluid parameters, especially viscosity and density. The resulting violation of the mass balance is very small as the low mass flow through the seal lip is low. The presented approach allows to apply a fluid‐structure simulation with special fluid properties to model a system with three states of matter. Advantages are a less complex model with less complex contact conditions and a reduced simulation time.

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

Ebel,

Lankenau,

Sundermann

et al. 2024

Discov Mechanical Engineering

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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.

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Tailoring the Curing Kinetics of NBR-Based Rubber Compounds for Additive Manufacturing of Rod Seals

Cited by 3 publications

References 35 publications

Fluid–structure interaction of a dynamic seal with a 3D‐printed surface

Fluid–structure interaction of a dynamic seal with a 3D‐printed surface

An approach simulating interacting solid, liquid, and gas domains for dynamic seal applications

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

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