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Zur Herstellung von langfristig stabilen Metall-Kautschuk-Verbunden sind chemische Haftvermittler notwendig. Nach Auftrag dieser wird Kautschuk mittels Gummispritzgießen auf die metallischen Grundkörper aufgebracht. In Klein- und Kleinstserien kann der Haftvermittler in präzisen Volumina händisch mit Hilfe eines Fluid-Dispensers aufgetragen werden. Allerdings verhindert dies eine Homogenität und Gleichheit der Schichtdicke, wodurch die Zuverlässigkeit und Stärke der Haftung variieren können. Als technische Lösung wurde ein Pipettierroboter avisiert. Mit Hilfe mehrerer mechanischer und elektrischer Adaptionen – so auch einer neuen Steuerungstechnik – wurden verschiedene Fluid-Dispenser auf 3-Achs-Portalfräsen integriert. Somit konnte die volle Funktionsfähigkeit erreicht werden.
3 dimensional (3D) printing evolved during the last decade to a consumer friendly and affordable craft. Furthermore, implementations of this techniques in the field of biotechnological research and development within laboratories is a very expansive process. Bio-printers’ prices cover a wide spectrum and most basic models are available for around 5000€. On the other end, high-end printer machines with a vast variety of features are available for several hundreds of thousands of euros. Thus, due to the immense potential in the field of Biotechnology the availability of this technology for research purpose should be enhanced. A developed ecological syringe extruder prototype for processing of biological based gels has been further improved. The original prototype was capable to processing multiple layers of agar with concentrations of 1% and 2.5%. Based on these results the prototype was revised regarding printing process parameter, which include among others applied forces to the substrate, air-ventilation, and heating of the substrate. The process behavior will be simulated with computational fluid dynamics for the processing of biological based substrate. After a concluding validation these results are intended to be implemented into a new design for improved processing of a variety of bioinks.
The current state of technology for 3D printing with biomaterials is based on the extrusion of viscous materials. Mostly, extrusion heads utilize pneumatic pressure systems or stepper motors to force the substrate onto a surface. These methods are well developed for high viscouse materials. However, processing low viscous liquids may cause leakages in the system. This could be solved by applying continuous extrusion. Additionally, in order to process gelable substrates, such as gelatine and agar, tempered print heads in combination with a multi stage tempering system are required to prevent the system from clogging. The ongoing work presented in this paper focuses on the development of an extrusion system, which should be able to process multiple viscosities of gelatine sequentially. In order to achieve this, several measurements to examine the properties, as well as the material parameters of different biomaterials are performed. In this process gel point, force resistance and elasticity are the factors of particularly interest. Due to their ability to gel and their availability, the most relevant biomaterials are gelatine and agar. Using this data, an extrusion system involving a peristaltic pump, a heated tube and a nozzle, has been developed. The next step envisaged is to calibrate the extruder based on the obtained data and finally to validate the printing process by printing simple geometric structures. Assuming that a positive evaluation is obtained, the printing system will be tested for printing first organic test structures from patient data using the examined biomaterials.
Processing biological materials with 3-dimensional (3D) printers has attracted increasing interest in several research areas. At the same time, off-the-shelf solutions are increasingly available in a wider variety to meet the current market demand. However, most of the available bioprinters are closed source, thus, modifications are quite challenging or require an avoidable consultation process with the manufacturer. Furthermore, the entry prices for basic machines amount to several thousands of euros. Whereas, high-end 3D bio printers with a vast array of features are available for several hundred thousand euros. Due to the immense potential of this tool in the field of biotechnology it is important to extend the availability of this technology for research purposes in terms of adaptability and price. This ongoing work focuses on open-source 3D printer heads with the ability to extrude biological materials. The print heads include several techniques to process low as well as high viscose biomaterials such as agar and gelatin. Additionally, obstacles such as continuous substrate tempering or integration into existing 3D printers are addressed. The work presented is open source and thus freely adaptable to any user’s specific needs. Our goal is to process a diverse range of biomaterials with different print techniques.
The novel approach of an individualized medicine affects nowadays various areas of therapeutic treatment. Primarily, these include the application of pharmaceuticals, private point-of-care solutions, surgical procedures as well as steps of rehabilitation. However, beside these existing strategies the development of patient specific models for the training of clinical personal is currently insufficient. Such models are essential to prepare a personalized approach of medical care. One possible solution to address this problem could be the adaption of the established 3d printing technology for the processing of suitable biopolymers. The presented work is focused on the development of a printing system utilizing collagen. Therefore, it is intended to design multiple extrusion heads in accordance with the material parameters. In order to achieve the aspired physiological properties of the final model, a first set of experiments will be performed with several compositions of collagen to validate the fundamental mechanical characteristics. Hereby, the elasticity, thermal stability, force resistance as well as the haptic behaviour are of most interest. Afterwards, these obtained experimental results should be used to simulate the extrusion process and to validate the extruder concepts. In case of a positive evaluation these concepts are realized by using rapid prototyping technologies. Finally, this novel 3d printer will be used to print first organic test structures with collagen.
Das Ziel dieses Projektes war es eine automatisierte Lösung für das Auftragen von Haftvermittlern auf metallische Grundkörper im Nanoliterbereich zu ermöglichen. Für die automatisierte Auftragung von Haftvermittler wurde eine neue Steuerungseinheit auf Grundlage eines Mainboards für die Ansteuerung von 3D-Druckern verwendet, als Firmware diente Marlin. Notwendig waren Anpassungen im Bereich der Motorströme, Geschwindigkeiten, Beschleunigung, Sensitivität, Druckbettgröße und Auswahl von Mainboard und Display. Für die Verfahrwege wurde G-Code mittels eines Programms in Python generiert. Für eine homogene und gleichmäßige Benetzung werden die einzelnen zu benetzenden Objekte angefahren und der Pipettiervorgang gesteuert. Es war möglich die vollständige Funktionsfähigkeit herzustellen.