Engineering news
German researchers have developed a highly flexible, multi-material additive manufacturing method that allows them to produce bone implants, dentures, surgical tools, or microreactors 'in almost any conceivable design'.
The Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden has used the printing technique to create a small pharmaceutical implant no bigger than a one pound coin. With wires and channels that are just a few hundred micrometers wide, it constantly mixes various drugs – painkillers, blood thinners, and antibiotics – and fine-tunes them to the patient’s current health condition.
The researchers from Dresden are focusing on suspension-based additive manufacturing methods and combinations of them with other manufacturing tecniques. The ceramic or metallic suspensions rely on a thermoplastic binder that becomes liquid at temperatures of around 80 °C. This is a crucial point in additive manufacturing: it means the suspensions can quickly cool down and one layer after another can be deposited in sequence.
In this binder, they disperse powder particles of metal, glass, or ceramics. ”Our mixtures are very homogenous and we precisely set the optimum level of viscosity,” said Moritz. “Only then can the printer put out the droplet size suitable for the particular component contour. Our mixtures can’t be too liquid or thick. To achieve this, we have to master the preparation technique.”
The electrically generated temperature in the printer melts the suspension. After deposition, the droplets immediately harden as a result of the quick cooling process. The workpiece is then built up point by point on a flat platform. This allows different materials to be deposited at the same time via multiple application units.
The scientists have already successfully made components out of high-performance ceramics and hard metals. Moritz hopes the technique will open up new options for microreaction technology based on ceramic components, which have mostly been held back by production methods.
Mortiz said: “To date, ceramic microreactors have mostly been milled out of plates. Internal and external sealing have always been a technological challenge for this. And there has been the problem of making connections that fit. Now we can just print them onto the ceramic component during manufacturing in whatever form.” This benefits not only doctors, but also pharmacists and chemists who will often be processing very expensive or hazardous substances. ”It is more affordable and safer to first work with minimal quantities in a microreactor,” said Moritz.
The researchers said that the multi-material approach could also have big implications for surgery: endoscopes frequently employ an instrument to first cut open tissue, and then quickly close the blood vessels back up again using electric current. To prevent electricity from shocking the patient, the instrument needs not only high-grade steel but also insulated ceramic components. ”Ceramic substances are often well-suited for medical devices and components. Ceramics are sturdy and can be cleaned thoroughly,” said Moritz.
Researchers from the Fraunhofer institute will present their findings at the Medtec medical technology tradeshow in Stuttgart. They are now looking for partners to put their technology to real-world use.