Forum Medical, Dental & Orthopaedic Technology

• Presentation of the current status of Additive Manufacturing at Daimler Buses
• Presentation of our 3D printing parts which have already been installed in our premium buses
• Change of the current supply chain due to the 3D printing technology
• AM Big Picture - Daimler Buses

Ralf Anderhofstadt and Janis Kretz

3D printing in medicine is experiencing stable growth even in pandemic times. Irrespective of the crisis, the industrial production of implants and instruments is being continuously optimized. Thanks to industrial FDM technology, the additive manufacturing of patient-specific polymer cranial implants has a disruptive character, as investment and material costs can be significantly reduced compared to conventional manufacturing techniques and alternative materials. Individualized polymer cranial plates today are predominantly made of PEEK, a high-performance polymer that is widely used and accepted in medical manufacturing. Currently, the implants are mostly milled. This means low resource efficiency, as only 10% or less of the processed material is used for the implant. In addition, the investment in hardware and maintenance is much higher compared to an industrial FDM printer. Here, the waste of an implant is around 10% of its own weight, primarily due to the support structures that are necessary in FDM printing.In addition to PEEK as an established material for cranial implants, titanium implants are also manufactured additively.  Again, significantly higher investment costs and maintenance costs for the printer contrast with the comparatively low investment in an industrial FDM printer.  In summary, industrial FDM printing of implants is an economically attractive solution for MedTech companies compared to titanium printing or polymer milling.

Practical experiences show possibilities, limits and an exemplary learning curve in dealing with additive manufacturing. On the basis of concrete application examples, solutions are presented whose implementation without 3D printing would be very difficult or impossible.
Introduction
Digital manufacturing has been finding its way into OT for some time now and will manifest itself even more strongly. Besides the daily process acceleration, which is aspired in many places, the innovation potential is a decisive factor to adopt this technology and to increase the quality of supply.
Methodology
Due to the lack of specifications and characteristic values in always individual areas of application, the procedure is strongly determined by personal experience, trial and error as well as test series. Wall thicknesses, surface structures, material selection as well as printing processes offer a multitude of factors which seem to increase the possibilities of application. New technologies, surface structures as well as finishing techniques have therefore always been used in consultation with patients, in consultation with manufacturers and service providers. Current developments in manufacturing technology as well as a lively exchange with technicians as well as manufacturers and producers is a way to success in correctly assessing the potentials.
Conclusion
The use of printed aids goes far beyond cosmetic coverings and mere process optimisation. First and foremost, orthopaedic technicians are given the opportunity to define new fitting standards and to integrate new functions with the help of manufacturing precision that was previously difficult to achieve. In this way, the quality of the aids can be increased not only functionally but also aesthetically.

Orthoses are produced patient individually by the orthopedic technicians. But therefore the traditional way of orthoses manufacturing with manual work of modelling and deep drawing is very time-consuming, wasteful of material and needs a high-precision work by the technicians. Also the finished orthoses are not reproducible. Thereby these facts are going hand in hand. Consequently, it is necessary to rethink, optimize and digitize the whole traditional process-chain.
First step is digital patient-data-acquirement (mechanic, anatomic parameters, metadata, body part scans) for construction analytics. This is needed by input of construction parameters for shaping CAD-initial-models of orthoses elements. Therefore, our selected example is a new designed joint of a specific ankle foot orthoses. In step two, patient parameters need to be implemented in CAD for controlling joint configurations. With assistance by neuronal networks, it is possible to automate generation of perfect joint specifications and time-saving adaptation of its CAD-model. Step three is printing the joined ankle foot orthosis with additive manufac-turing (AM). AM enables a precise, fast result and there is no need to rework the orthosis or to repeat the process due to flawed manufacturing. There is no waste of material. All in all, the process is more efficient and sustainable.

Dipl.-Ing. Lydia Mika

Over the years, Additive Manufacturing with the powder bed process has established itself in medical technology, especially in orthopedics and implant manufacturing. Titanium and titanium alloys are primarily used for these applications due to their high biocompatibility and excellent mechanical properties. Nevertheless, some applications place higher demands on the material behavior which cannot be completely addressed by titanium. Amorphous metals offer a promising alternative with not just good compatibility in the human body but also increased elastic behavior. This represents a great potential for Additive Manufacturing of implants subjected to high dynamic loads such as rib arches.

Since beginning of 2019 Laura Kastenmayer is the Industry Manager for Medical Technology at TRUMPF Additive Manufacturing. Starting her career as an application engineer for TRUMPF Additive Manufacturing in 2017, she had to deal with all questions related to process and parameter set-up as well as freedom and restrictions in design and material. These topics have been no news to her since she already got involved with powder bed fusion AM during her studies of Medical Technology at Friedrich-Alexander-University in Erlangen-Nuremberg.