Dynamic 2-Component Parts created using Additive Manufacturing

• Applicants: Dr.-Ing. Benjamin Klie; Professorin Dr.-Ing. Kathrin Ottink
• Subject Area: Engineering Design, Machine Elements, Product Development ; Plastics Engineering
• Term: from 2020 to 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 447009134

• Final Report Year: 2025

Final Report Abstract

The aim of this project was the additive production of 2-component parts (2K parts) and the qualification of these parts for general applications in frictional contact. Typically, for friction applications thermoplastics with good frictional properties are used. In order to generate the necessary contact pressure in frictional contact, a preload force must be applied. In sealing technology, which places particularly high demands on the materials used, this contact pressure is often achieved by a second component, an O-ring made of an elastomer. Such 2K components are conventionally manufactured either in such a way that both components are produced separately (separating, primary forming) and then combined in the application or in a 2K injection moulding process, for which, however, complex mould construction is required. The additive manufacturing of both components of such a 2-component part without prior mould construction is the innovative matter of this research project. After starting with the determination of processes and possible materials to be used for the additive manufacturing of the thermoplastic component, the second step to print prototypes of these seals. They were then investigated concerning dynamic sealing mechanism, form stability and size accuracy. In functional tests these prototypes were qualified as rod seals in typical applications with pressures up to 15 MPa. Moreover, the functional tests were used for FEM model validation. The developed simulation model showed interesting details concerning pressure rate when comparing the printed and the conventional manufactured seal under high pressures. Prior to additively manufacturing the second seal component, the o-ring, a natural rubber mixture needed to be developed and characterized. For the manufacturing itself a modified 3D printer – originally used for printing thermoplastic materials – was used. This allows a prototype manufacturing of a two component seal in a single process. Functional tests on these prototypes have shown good performance for the NBR/TPU combination up to sliding distances of 5.32 km. The sealing function was given for pressures up to 15 MPa. The developed manufacturing processes can be applied for different application in many technical fields. One is the spare parts production of seals in outlying areas in the world.

Link to the final report

https://doi.org/10.34657/24798

Publications

• Additive Manufacturing of 2-Component Rod Seals Based on Nitrile Butadiene Rubber (NBR) and Thermoplastic Polyurethanes (TPU). 14th Fall Rubber Colloquium, Hanover, Germany.
  Sundermann, L.
  
• Additive Manufacturing of 2-Component Rod Seals Based on Nitrile Butadiene Rubber (NBR) and Thermoplastic Polyurethanes (TPU). Global Summit on 3D Printing & Additive Manufacturing, Copenhagen, Denmark.
  Sundermann, L.
  
• Towards additively manufactured dynamic rod seals. 21st International Sealing Conference 2022. VDMA Fluidtechnik.
  Graf, Matthias; Ebel, Thomas; Lankenau, Tobias & Ottink, Kathrin
  
• Additive Manufacturing of 2-Component Rod Seals Based on Nitrile Butadiene Rubber (NBR) and Thermoplastic Polyurethanes (TPU). ACS Rubber Division ACS Spring Technical Meeting, Cleveland (OH), USA.
  Sundermann, L.
  
• Fluid–structure interaction of a dynamic seal with a 3D‐printed surface. PAMM, 23(2).
  Graf, Matthias; Lankenau, Tobias; Ottink, Kathrin & Ebel, Thomas
  
• Simulation Strategy for Fluid‐Structure Interaction of a Pre‐tensioned Dynamic Seal. PAMM, 22(1).
  Lankenau, Tobias; Graf, Matthias; Ottink, Kathrin & Ebel, Thomas
  
• Tailoring the Curing Kinetics of NBR-Based Rubber Compounds for Additive Manufacturing of Rod Seals. Advances in Polymer Technology, 2023, 1-16.
  Sundermann, Lion; Leineweber, Sebastian; Klie, Benjamin; Wittek, Heike; Ebel, Thomas; Reitz, Birger; Ottink, Kathrin; Graf, Matthias; Lankenau, Tobias; Overmeyer, Ludger & Giese, Ulrich
  
• An approach simulating interacting solid, liquid, and gas domains for dynamic seal applications. PAMM, 24(2).
  Graf, Matthias; Lankenau, Tobias; Ottink, Kathrin & Ebel, Thomas
  
• Compound and Process Development of Carbon Black Reinforced Rubber-Based Elastomers for Additive Manufacturing. PhD Thesis, Gottfried Wilhelm Leibniz Universität Hannover
  Sundermann, L.
  
• Eignung von additiven Fertigungsverfahren für die Herstellung dynamischer Dichtungen. Dissertation, Gottfried Wilhelm Leibniz Universität, Hannover
  Ebel, T.
  
• Functional testing of additively manufactured hydraulic rod seals. 22nd International Sealing Conference 2024. VDMA Fluidtechnik.
  Ebel, Thomas; Ottink, Kathrin; Graf, Matthias & Lankenau, Tobias
  
• Functional testing of entirely additively manufactured two-component hydraulic rod seals made of TPU and NBR. Discover Mechanical Engineering, 3(1).
  Ebel, Thomas; Lankenau, Tobias; Sundermann, Lion; Ottink, Kathrin; Graf, Matthias; Klie, Benjamin & Giese, Ulrich
  
• INFLUENCE OF THE MIXTURE VISCOSITY ON MECHANICAL ANISOTROPY AND PROCESSABILITY OF AN NBR-BASED RUBBER MIXTURE FOR ADDITIVE MANUFACTURING. Rubber Chemistry and Technology, 97(1), 24-43.
  Sundermann, Lion; Klie, Benjamin; Wittek, Heike; Ebel, Thomas; Ottink, Kathrin & Giese, Ulrich
  
• Leakage flow simulation in dynamic seals from 3D-printing. 22nd International Sealing Conference 2024. VDMA Fluidtechnik.
  Graf, Matthias; Lankenau, Tobias; Ottink, Kathrin & Ebel, Thomas
  
• RELAXATION BEHAVIOR OF 3D PRINTED NBR-BASED RUBBER O-RINGS AS THE INNER PART OF ROD SEALS. Rubber Chemistry and Technology, 97(3), 244-258.
  Sundermann, Lion; Klie, Benjamin & Giese, Ulrich