Medical engineering

A detailed understanding of the biological model is the basis for needs-oriented design in the field of implant development and is obtained through biomechanical characterization and the acquisition of technical parameters. Experimental investigations can be used to verify computational and parametric models. For the determination of biomechanical characteristic values, we can draw on a wide range of testing machines and methods. In addition to classical tensile, compression, and torsion testing machines, optical testing methods are also available. A 3D laser vibrometer measures the dynamic properties of the test object, enabling the verification of numerical models.

To date, a human hip bone has served as the test object. Using a motion analysis system, the relative displacement of multiple components with respect to one another can also be investigated. This provides, among other things, crucial insights into the restoration of the original range of motion and into the development of motion models.

The transfer of the developed component into a clinical setting first requires evidence of its efficacy. As an initial step, this can be provided through demonstrator testing. This testing is closely linked to the determination of biomechanical parameters and forms an iterative optimisation loop.

By combining experimental and numerical investigations, the target parameters can be fine‑tuned to support integration into the clinical environment. In doing so, usability for the surgeon must also be taken into account. Given the increasing complexity of medical technologies, surgical planning and navigation, for example, are valuable tools that support surgeons during procedures.

Conceptual design is a crucial step in the development process and should take holistic and interdisciplinary factors into account.

Engineering design represents the stage preceding manufacturing. Unlike conceptual design, it is strictly dependent on feasibility and the available technologies. The integration of active materials enables the development of new, complex systems with novel functionalities.

Simulation is essential for the goal‑oriented and resource‑efficient implementation of the developed concepts. The finite element method (FEM) for simulating object properties and processes has also become well established for modeling biomechanical phenomena. The use of numerical models is regarded as a valuable tool for design optimization in both medical research and clinical practice (e.g., surgical planning). Our expertise lies in the field of numerical modeling and the associated experimental verification. In addition, we have extensive experience in the numerical investigation of active materials such as shape memory alloys and their integration into implants and textiles.

The technical implementation of the developed innovative concepts often places high demands on manufacturing. It is frequently a limiting factor in the design freedom of novel medical technologies and products, as well as in their technical realization. However, ongoing advances in conventional manufacturing processes and the use of novel technologies continue to open up new possibilities:

• Additive manufacturing processes enable the production of topology‑optimized as well as patient‑specific implants.
• Technological developments in machining, material‑removal, and forming processes for precision and micro‑manufacturing allow implant production down to the micrometer scale.
• Bone‑like structures are manufactured using cellular structures, for example from metal foams or by means of additive manufacturing processes.
• Bulk forming processes make it possible to improve material properties while reducing material usage.

Active materials

Active materials such as shape memory materials and piezoceramics offer a wide range of application possibilities in medical device technology and prosthetics. They can be used as alternative actuation elements, while also enabling the development of new, complex systems with novel functionalities. Depending on the application, they can function as sensors or act as active components, for example, to influence the force interaction at the bone-implant interface and thus - from a long‑term perspective - help prevent implant loosening.

Additive manufacturing of implants

We use additive manufacturing technologies, specifically powder bed fusion, to produce implants from biocompatible metallic materials such as titanium, cobalt–chromium alloys, and stainless steel. This enables the realization of implants with highly complex and freely designable geometries. To optimally adapt mechanical properties to the surrounding bone, implants can be equipped with complex and, if required, variable geometric structures -either throughout the entire volume or selectively on the surface. This allows targeted adjustment of strength and stiffness and supports improved osseointegration. Functional channels and internal cavities can also be integrated into the implant design. These structures enable, for example, the postoperative delivery of medication directly at the bone-implant interface. In addition, implant geometries can be customized for individual patients. Patient‑specific designs are typically based on computed tomography (CT) data, allowing the precise adaptation of the implant to the patient’s anatomy.

Precision and micro manufacturing

We develop technologies and manufacturing systems for the production of miniaturized and micro‑structured components, for example, for applications in medical technology, and implement them across various application levels. Our research focuses include, among others, the machining and forming‑based manufacturing of miniature prostheses as well as the development of manufacturing technologies for medical components and devices.

In the field of medical diagnostics, microfluidic lab‑on‑a‑chip sensors are used to detect a wide range of blood and urine parameters. These complex microfluidic systems often require functionalized surfaces to control fluid flow within the microchannels. The goal of manufacturing process optimization is the reproducible and reliable transfer of microstructures in a single embossing step using sub‑structured tools, as well as the reduction of process times for the production of fluidic components.

Metal foams

The use of metal foams as base materials for implants offers a wide range of advantages. For example, their rough surface structure provides optimal conditions for bone cell ingrowth, while both the elastic modulus and weight can be adjusted to match the surrounding bone by varying the material density. Compared to solid implants, the reduced stiffness of metal foams - and the associated adaptation of the elastic modulus to that of bone - actively counteracts implant loosening caused by bone resorption (osteoporosis). This mechanical compatibility supports long‑term implant stability and contributes to improved clinical outcomes.

Bulk metal forming

The high requirements for strength and safety, particularly for dynamically loaded components, are excellently and reliably met in medical technology by closed‑die forged components. As with almost all forming processes, a long and structurally complex final geometry cannot be produced in a single forming step during closed‑die forging. The initial geometry is therefore often a billet with a constant cross‑section.

To reduce material waste, a precise distribution of the initial volume along the billet axis in accordance with the final geometry is advantageous. The manufacturing process of cross‑wedge rolling provides the basis for the application of near‑flashless closed‑die forging by enabling the economical production of intermediate preforms with precisely defined mass distribution.

In addition to hot bulk metal forming, load‑bearing implants are also manufactured using cold extrusion. This process is particularly well-suited for the production of small‑scale implants.