Freudenberg Sealing Technologies
Sealing System Evaluation

Global Simmerring® Engineering

All-Round Service for Your Optimal Sealing System

With its services tailored specifically to Simmerrings®, sealing expert Freudenberg Sealing Technologies offers its customers added value that goes far beyond a comprehensive selection of high-quality sealing components.

To find the optimal sealing solution for each specific application, the experts take a holistic view of the sealing system and examine the interaction of all the components involved.

A radial shaft sealing system is a complex tribological system whose function and service life are influenced by various factors. These include the interactions between the individual system components (radial shaft seal, shaft and lubricant) and the various operating conditions of the respective application.

Our Simmerring® Engineering experts rely on extensive analysis and characterization methods of the system components as well as specific inspection and test procedures of the tribological system to find answers to the questions:

  • What is the optimal design of the sealing system for this particular application?
  • What led to a failure or leakage in this specific case?

Detective Flair and State-of-the-Art Analysis Methods

Only if all the components involved, i.e. the radial shaft seal, the shaft and the lubricant, are optimally matched to each other will the sealing system deliver maximum performance over a long service life. For this reason, the comprehensive analysis of the entire tribological system is the focus of the investigations. Using state-of-the-art testing and measuring technology, detailed statements can be made about the condition of all components of the sealing system by means of standardized or newly developed analysis and evaluation procedures. From the results of the various analyses, the experts derive a hypothesis of the possible causes of failure and then verify this by performing either the respective tests or simulations. The results are profound findings that lead to concrete recommendations for action to optimize the system – for an improved sealing function and a significantly longer service life of the sealing system.

We Are There For You When You Need Us

In total, our customers have access to extensive testing and validation capacities for customized tests, also on demand, at the world’s largest test facility for dynamic seals in Weinheim and the test center in Ashland, New Hampshire (USA), with more than 300 test heads.

All Services of Our Service Package at a Glance

examination of a blue Simmerring®.

Characterization of the Radial Shaft Seal

A detailed examination of the seal provides information on its condition. For this purpose, optical, chemical as well as micro- and macromechanical changes (e.g. wear, hardening, etc.) are determined and evaluated. The goal is to obtain information on possible damage mechanisms and their causes by analyzing the condition of the seal.

Investigation methods:

  • Microscopic assessment of the seal condition
  • Measurements of dimensions and sealing characteristics
  • Measurement of the International Rubber Hardness Degree (IRHD) according to DIN EN ISO 48
  • Mechanical µ-characteristic (microindentor)
  • Scanning Electron Microscopy & Energy Dispersive X-ray Spectroscopy (SEM-EDX)
  • Nano computed tomography (Nano CT)
  • Gas chromatography-mass spectrometry (GC-MS)
  • Infrared spectroscopy (IR)
microscope pointed at metallic shaft

Characterization of the Shaft

The reliable function of a radial shaft sealing system depends to a large extent on the seal counter surface – the shaft. In addition to the appropriate shaft diameter, roundness and hardness of the shaft surface, the microscopic properties of the topography of the seal counter surface are of particular importance.

Investigation methods:

  • Tactile and optical measurement of surface parameters of waviness and roughness, according to DIN EN ISO 4287 and DIN EN ISO 25178 as well as VDA, for example
  • Qualitative and quantitative macro- and micro lead analysis according to MBN 31 007-7 and IMA Micro Lead®.
  • Wear investigation
  • Evaluation and suitability assessment of the seal counter surface
  • Chemical analysis of deposits on the shaft surface
two blue rotary shaft seals with CFW engraving

Characterization of the Fluid

The lubricant plays an important role in the optimal functioning of a radial shaft sealing system. The interactions between the sealing material and the respective lubricant in a specific application must be closely examined. Analysis of the condition with regard to appearance, viscosity, aging, and its chemical composition provides important information on possible interaction mechanisms.

Investigation methods:

  • Physical and chemical characterization
  • Infrared spectroscopy (identity, additive degradation, oxidation, tramp oils, opacification).
  • Analysis of additives in ppm (Ba, Ca, Mg, Cl, Sb, P, Zn, S, Na, Si, K)
  • Analysis of abrasion elements in ppm (Al, Cr, Cu, Fe, Pb, Sn, Mo, Ni, Ti, Ag, Mn, V)
  • Checking the wetting behavior
test rig for rotary shaft seals

Application-Oriented Answers Through Functional Tests and Simulation

The greatest possible insight into the performance of a sealing system is gained through functional testing under the most realistic possible application conditions. Freudenberg Sealing Technologies’ Engineering Service Centers have state-of-the-art dynamic test benches at their disposal to simulate operating conditions as close to reality as possible by means of a wide range of test cycles that can be customized. This allows the entire range of complex tests and validations to be carried out efficiently for all areas of application of radial shaft seals. Furthermore, standardized test procedures allow for reliable assessment of lubricant-elastomer compatibility. Thanks to the use of various simulation methods, the possible behavior of the sealing system in the intended application can be evaluated. For example, FEA (finite element analysis) simulation is used to predict the mechanical behavior of the seal. In addition, specifically developed calculation and simulation methods provide answers to questions concerning functionally relevant parameters of the radial shaft seal.

Functional tests:

  • Design and customer validation according to DIN, ISO, RMA or customer specification
  • Lubricant-elastomer compatibility according to FLENDER and SEW or customer specification
  • Component comparison
  • Friction torque measurement
  • Assembly force measurement

Testing according to specification

Custom testing and design validation with

  • high speeds up to 36,000 rpm
  • high pressure up to 15 bar
  • high and low angle reciprocating shaft movements (robotics) ±720° with 0.1 ... 5Hz (±720° @ max. 2Hz)
  • low temperature up to -50 °C
  • contamination by dust and muddy water
  • hydraulic motors


  • FEA deformation, contact stress, load and voltage peaks
  • EHL simulation
  • Contact temperature determination
  • Lift-off speed analysis
Blue background

Do You Have Questions About Sealing Systems?

Our experts will be happy to advise you on the right choice of sealing systems. Contact us.

Your sealing system request

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