Modular mechatronics technology for fibre-based manufacturing and biofabrication research : this dissertation is presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Engineering conducted at Massey University, Albany, New Zealand
There exists an opportunity within manufacturing for the development of technology capable of creating
complex fibre-based structures. Additive Manufacturing (AM) has become increasingly relevant due to its ability to generate parts of a higher complexity relative to other traditional techniques. 3D Printing (3DP) technology is a form of AM through which much of this type of complex manufacturing is conducted. Currently this technology allows for the processing of many materials through a range of mechanisms. Whilst 3DP development has predominantly focussed on synthetic polymer and metal production, there is opportunity for this technique within Tissue Engineering (TE). This field is motivated by the shortage of donor organ tissues such as the cornea. AM is a potential methodology for the controlled manipulation of biomaterial/biopolymer as a form of production within TE. It is however critically limited in its ability to process submicron and nanofiber to generate fibre-based constructs such as those found within the cornea (stroma). This limitation yields
restrictions in not only bio-printing based applications but also within attempts to innovate in traditional fibre-reinforcement based industry. There is a manufacturing based opportunity for the research and development of a technology capable of overcoming these limitations. The current restrictions within this field were evaluated through an analysis of relative literature. This led to the identification of electrospinning as a viable technology for both synthetic and biopolymer submicron and nanofiber production. The limitations of this technology were evaluated, leading to the potential for overcoming these utilising traditional methods of 3DP. Further evaluating current literature led to a hypothesized manufacturing technique. Additionally this literature indicated the need for development of a novel technology capable of performing research and development related work within this field. This resulted in much experimentation related to the generation of technology/componentry/mechanisms related to both the testing of the hypothesis as well as capable of facilitating future research. Work related to an
increase in electrospinning productivity via electric field related manipulation was conducted as an attempt to reduce system complexity. This work did not circumvent the requirement for environmental control; as such, a method for the implementation of this to aid in productivity was required. Development of mechanisms yielded a strong requirement for a modular system allowing these components to be varied in accordance with the processing requirements. This ability to manipulate the system was achieved through the creation of both a
function based coding strategy as well as the derivation of a potential modular electronics (PCB-stacking) technique. The derived novel technology’s success was demonstrated through a range of experimentation related to implemented forms of technology within the final machine. Regarding the forming of electrospun material, the direct method of electrospinning-based deposition of material upon molds did not achieve generation of the desired objects as such a method of fibre acquisition was implemented. Regarding collagen electrospinning, no dramatic variation on fibre distribution (alignment) could be derived in comparing the parallel or rotating mandrel-inspired approaches. Functionalisation strategies utilising ultrasonically generated vapour demonstrated promising capability in the bonding of synthetic polymers whilst acting to disrupt the more sensitive biopolymer. The use of corona discharge plasma for crosslinking yielded promising results for synthetic polymer ultimate tensile strength however, the proximity analysis/optimisation of this requires further research if this is to be applied to electrospinning-based AM. Finally, the ability to utilise the developed technology to generate both an automated manufacturing technique for fibre-based additive manufacturing and the creation of associated 3D forms was demonstrated as viable, thus validating this research project.