Implants today are mostly made of steel or titanium. Titanium in particular is considered to be a well-tolerated material in medical technology, and so far hardly any allergies have been proven. However, titanium also has a number of disadvantages: On the one hand, a growing number of patients show metal sensitivity with conventional titanium implants. In addition, the implants can only be removed again in a complex operation.
In order to avoid stressful follow-up operations, scientists have been working for several years on the development of biologically resorbable implants. These can be broken down by the body when the appropriate tissue is formed and offer the patient temporary support - the subsequent operation is not necessary. Magnesium, for example, a biologically resorbable alloy that can be used for cardiovascular and orthopaedic applications, is considered promising.
Currently, resorbable implants are mainly used as screws and pins for fixing bone and tissue. But larger and more complex applications are also possible. If resorbable magnesium implants are manufactured, for example by means of additive manufacturing, it is possible to quickly and individually produce even complexly shaped implants that do not have to be removed again.
The goal of the AdPro joint project is to design and develop a manufacturing process chain for biologically resorbable magnesium implants using the example of a cranial implant. The process chain consists of the additive manufacturing of the implant by means of binder jetting and the subsequent finishing by milling. A team of researchers at the Fraunhofer IPT is designing the processes for milling and finishing the additive-manufactured magnesium implants. The team pays particular attention to the necessary clamping and referencing strategies.
For the additive manufacturing of the cranial implants, a binder-jetting system for the layered structure of the workpiece is designed and built in the first step. In the next step, the magnesium powder is qualified and the necessary binder is developed. After successful additive build-up of the component, the sintering process for the cranial implants is finally designed.
For automated post-processing by milling, the research team plans the automated and adaptive tool path and designs the milling process for machining the magnesium implants. For tool path planning, they implement a CAM plug-in that plans the tool path automatically and independently of the geometry of the implant. For the milling of magnesium implants, they basically design the tools and processes and develop a special clamping and referencing system. Finally, the scientists summarize the results obtained in order to demonstrate the developed manufacturing process chain holistically.
This project is funded by the Federal Ministry of Education and Research (BMBF).
German Aerospace Center (DLR)