Development of an open-source bioprinter with multiple print-heads

Over the last decade, the development of 3D printing technology has led to both increased interest and availability of these machines. The steady growth and demand has made 3D printing an affordable and consumer-friendly craft. Due to the shrinking barrier-of-entry, the technology is increasingly integrated into wider areas of science and research, as well as the manufacturing industry in general. The demand for individualized medical solutions is continuously expanding in multiple fields, such as medical training and patientspecific surgical guides—exposing a need for further development of these technologies for mainstream applications. The research areas of material science, life science, biotechnology, and medical applications have greatly benefited from the increasing availability of this technology—especially in regards to 3D printing high viscosity substrates which are biological, biocompatible, or bioresorbable. In this area of research and development, mainly micro-extrusion syringe-based systems are used. However, these extruders are limited to the volume of the utilized syringe. This thesis' primary objective is to develop a multi-material 3D printer capable of processing substrates with a wide variety of viscosities, with a particular focus on biologicalbased substrates. The entire project was developed with an open-source mindset—with the intent of furthering future research possibilities within this space. The hardware is required to be sturdy, reliable, have good maintainability and accessibility, as well as possessing open and customizable firmware. These goals were achieved by constructing a coreXY printer with a print volume of 500x500x500 mm. Furthermore, an automatic tool changing mechanism was implemented for the printer. For material extrusion, different extrusion systems were manufactured and modified to improve their processability for additive manufacturing. The inkjet extruder designed for this thesis enables the ejection of droplets with an acceptable average diameter. The 3D printed peristaltic pump enables the extrusion of hydrogels and thixotropic substrates at a wide range of viscosities. Prototypes were designed and manufactured to be cost-effective and widely available. The files necessary for individual recreation of these prototypes will be available to anyone free of charge via a public GitHub repository.