Previously Published Newsletter

Medical products, food and other products are often sealed for air-tight packaging. There are various standardized tests available to verify the quality and leak tightness of the seals or the whole packaging.

Calcium phosphate ceramics are widely used for the repair of bone defects and as coatings for orthopaedic implants. In order to match the growth rate of new bone, the resorption properties of these materials must be carefully controlled. In particular, the resorption rate may be affected by foreign crystalline or amorphous phases or chemical contamination. In vitro testing of the dissolution kinetics as well as the (equilibrium) solubility of calcium phosphates provides an indication of the stability of the material in the human body. Therefore, dissolution testing is required in ASTM F1926 and the determination of the solubility product is recommended in ISO 13779-6.

RMS Foundation has been active in the research of calcium phosphate bioceramics for more than 35 years. During this time, our experts have developed materials with outstanding physical and chemical properties. As a testing, research, and consulting institute, we offer our expertise to partners from academia and industry. Our services include transfer and implementation of specialized manufacturing processes to the clients’ facilities, consulting to improve existing processes, and supply of raw materials and samples for research projects.

Do you know the behaviour of your products under impact loading? How does the individual component, the assembly or the hardened material behave? What is the failure mode after what number of impacts?

If you want to clarify such ques-tions, RMS with its know-how offers an ideal possibility to measure these properties.

The cleanliness of medical devices (MD) is a critical factor and is addressed in ISO 19227, for example. Due to the manufacturing process, packaging and sterilization, substances hazardous to health may remain on the end product. The same applies to MDs that are reprocessed after use. In both cases, the products go through a validated cleaning process which must also be checked and verified. With the TOC/TIC/TN analyzer, RMS now has the possibility to offer its customers another accredited service in the field of cleanliness analysis. The possibility to collectively quantify organic contaminants and proteins via their C and N content, makes this method simple, fast and therefore cost-effective.

Would you like to know the properties of your products under torsion?

What is the failure pattern and is there room for improvement? The Zwick torsion testing machine at the RMS Foundation is the ideal testing machine for determining properties such as torsional stiffness or torque at failure.

Read our Newsletter 35 to find out how we can support you with our equipment and many years of experience in testing a wide variety of products.

Many medical devices consist of several components and are exposed to cyclic loads during their use. This can result in micro-movements between the individual parts, which can produce wear particles. If the medical device is implanted in a patient, particles are released into the body over the period of use.
In order to prove the safety of a product, many medical device manufacturers determine the type, quantity and size of the abrasion particles, which are formed in a simulated mechanical stress situation. Such tests are also increasingly required by the regulatory authorities.

Do you know the cutting properties of your drill bits?
Do you want to compare the wear behavior of different cutting edge geometries?
With the test rig from the RMS, such properties can be measured quantitatively. This will help you to qualify your drill bits on the basis of objective measurement data and statistical evaluations.

The quality and safety requirements for medical devices are becoming increasingly stringent. For this reason, the cleanliness of medical devices is being examined more closely. With its many years of experience in analytical chemistry and certification of medical devices, RMS Foundation offers its customers the planning, execution, and documentation of cleanliness determination.

Calcium phosphate ceramics such as β tricalcium phosphate (β-TCP) and hydroxyapatite (HA) are among the best-known synthetic materials used surgically for filling of large bone defects. In order to ensure patient safety and provide optimum support for bone healing, the products must meet high requirements in terms of chemical purity, phase composition, microstructure and mechanical properties. At RMS Foundation we offer complete analyses of CaP bone substitutes according to ISO 13175-3 as an attractive bundle.

In recent years, additive manufacturing (AM) has developed into a promising manufacturing technology with revolutionary possibilities such as «complexity for free». In contrast, the physical properties of these inhomogeneous or layered components are often neither known nor assessable. This entails new risks and challenges with regard to the quality and reliability of such products, especially for applications in medical technology. The RMS Foundation (RMS) has been pursuing this technology for years in its own projects with a focus on product safety. As a result, a number of AM-specific in-house analyses from investigations of the raw material to the final component, supporting the step from the laboratory to series production have been established.

The technical cleanliness test (residual dirt analysis) examines particle impurities resulting from the manufacturing process. Even the smallest particles can cause nozzles or filters to clog, valves to jam, bearings to block or circuit boards to short-circuit, leading to component and system failures.

Inorganic chemical analysis plays an important role in guaranteeing the safety and performance of countless materials and products. In particular, medical devices in contact with the human body must comply with strict maximum limits of potentially harmful elements such as heavy metals. ICP-MS is an extremely sensitive technique that allows simultaneous quantification of 70 elements down to trace levels in the µg/L or sub-µg/L range, and can therefore handle a large variety of analytical challenges.

This test method is used to determine the mechanical seal strength when separating the entire cover (lid / membrane) from a container (blister).
The continuous forces required to separate the lid will be evaluated as well as the maximum seal strength and the work. Furthermore, the mean value can be determined over the entire graph or e.g. from the «valley to valley» area. The lid is separated at a constant angle of 45° over the entire test period. This is implemented with an additional horizontal movement of the blister.

By means of CGHE analysis, carbon, sulfur, hydrogen, nitrogen, oxygen and argon can be quantitatively determined in metallic and non-metallic materials. The samples are melted under a gas atmosphere suitable for each element (carrier gas). The analysis is then carried out by means of selective infrared detection (O, C, S), via the change in the thermal conductivity (H, N) or by means of a mass spectrometer (Ar).

The crystal structure of ceramics, metals, and polymers drastically affects their physical, chemical, and biological properties. Even materials with the same chemical composition but different structures can be substantially different in many aspects. Powder X-ray diffraction analysis (XRD) identifies crystalline phases by the geometric arrangement of the atoms in the crystal structure.

Failure analysis covers the elucidation of the causes of failure, and the prevention of future damage. The knowledge gained can be used for overall risk assessment as part of a technical documentation and can help to document implants to a high quality.

The RMS Foundation has an FTIR microscope for the characterization and identification of organic materials. It enables the study of small particles and fibers (down to 30 microns), and their identification based on a spectral library with more than 25,000 reference spectra.

The surface structure and its roughness are decisive for many applications. Thus a quick and accurate measurement of these properties is essential.

In component or material testing, displacement and acceleration sensors are often employed to gain detailed information on specific points. With the aid of a dynamic optical measurement system, such data can be obtained in a contactless manner with relative ease.

Previously, separate circuit boards were installed in electronic devices. Today, the trend is in the direction of the three-dimensional, injection molded interconnect devices (MID). These devices not only replace the conventional circuit boards, but at the same time provide many additional features. For developers and manufacturers of MIDs and electronic components, the RMS Foundation offers a number of useful laboratory services.

Particles play an important role in many applications. Therefore, information about their size, number and shape are of major concern. For example wear particles of artificial joints are considered the main cause of bone resorption and prosthesis loosening. Similarly, strong ceramics rely on a good control of the particle size distribution of the raw material. Laser diffraction has become the leading principle in particle analysis during the last years. Benefits are short analysis times, good reproducibility and ease of calibration.

Materials that deform plastically at low loading rate and hereby absorb much deformation energy may become brittle at high loading rate, especially under impact or notched conditions. Products and materials with low impact toughness will break brittle and after low plastic deformation. The Charpy notched impact test is an ideal tool to assess the effect of loading under striking conditions on the failure mode of materials.

Processing of ceramic powders and solids puts high demands on raw materials and production processes in order to obtain optimum product properties. The RMS Foundation offers services and consulting in the field of ceramic and powder engineering. In addition to established analytical methods, the RMS staff has extensive experience in production and in research and development of ceramic materials, which allows to find customer-specific solutions for product-specific questions.

The RMS Foundation was commissoned to analyze forceps, which discoloured to dark grey in the daily use during cleaning and conditioning with the thermodesinfector. The goal of the study was to figure out the reason of the colour change and how it can be avoided in the future.

A surface can be quickly characterised by measuring the contact angle: is it hydrophilic or hydrophobic? Is a sample contaminated? Did a coating process work?

There are continuous developments of new implant materials and new implant designs, which have to be submitted to realistic preclinical tests. The wear test with a simulator is an important one for artificial joints.  

Testing every single design of a product is generally highly time consuming and cost intensive: specimens first need to be manufactured then tested with an appropriate set-up. Furthermore, samples are often destroyed during testing. Short-cutting these steps is possibly leading to a substantial reduction of the time to market and to enhanced cost control: numerical simulations and more particularly structural finite element analysis (FEA) allow the evaluation of, among other, the structural performance of single element or complex multi-component products.

A prior newsletter dealt with both function and use of the scanning electron microscopy. Now this issue provides further examples for the successful use of the scanning electron microscope (SEM) in material research and testing.

In the material research and testing, the SEM is a multipurpose and indispensable instrument for the analysis and depiction of surfaces and structures. The field of application of the electron microscope begins where the classic light microscope reaches the limits of the resolution or of the depth of focus. In the RMS Foundation a modern SEM with an EDX analysis unit (Energy Dispersive spectroscopy by X-rays) is available for customer mandates. It is specifically used for material as well as surface examinations.  

Would you like to reduce the failure risk of your products, components or parts? – Do you need materials that have to comply with specific mechanical requirements? – Would you like to examine whether your raw material meets your specifications?
If your answer to such questions is «Yes», a mechanical test with a load that is in step with actual practice is required. Static and quasi-static investigations are optimally suited to test and evaluate raw materials and/or the structural characteristics of components even at a very early stage of development and of production.

What are those stains on the product? How clean is the surface? Why does the coating come off again and again? Was the plasma treatment effective? X-ray photoelectron spectroscopy helps to answer such questions. This analytical method allows for the determination of the chemical composition in the top 5-10 nm of the surface.

Corrosion (from the Latin corrodere, «gnaw away») generally designates the gradual destruction of a material by the influence of other materials from its environment. The economic damage caused by corrosion adds up to many billion francs per year. Several tons of steel corrode per minute all over the world. The pipelines in the chemical big industry, the drinking water installations, the automobiles and the ships, the electronic products but the medical ones as well have to be manufactured in such a way that they can be used for many years without corrosion.

The components, component parts and products are developed and produced for very specific uses. It is frequently the fatigue strength that is decisive for the operational reliability, on which the design, the choice of materials, but also the surface design have quite a substantial influence. The static strength can be assessed by simpler means. A confirmation of the operating safety by assessing the fatigue strength is much more elaborate and generally calls for a dynamic functional test.