Development of a Acrylonitrile Butadiene Styrene toner for an electrophotography based additive manufacturing process
Research in to utilising electrophotography for Additive Manufacturing has been under investigation for over a decade. However, the research has been primarily focused on resolving the height limitations caused by charge accumulation and also the development of toners from tough engineering polymers. The aim of this study is to develop a suitable negatively charging engineering polymer for the Selective Laser Printing process and a more efficient method of generating toners with a suitable particle range and to assess the mechanical properties of parts produced using the toner developed through this route. The study is comprised for two parts; Chemical and Mechanical toner production. The chemical production method utilises a process, Evaporative Limited Coalescence, to produce an engineering toner in the desired 20-50μm range. It was found that during the chemical production process the negatively charging polymer was converted to charge positive. Analytical assessment of the toner was carried out to explain the change in polarity. Mechanical milling trials were also conducted under both ambient and cryogenic conditions, as well as a novel method to reduce the feed-stock material to the desired particle size range. The results suggest a significant increase in efficiency compared to prior research. Printing trials were conducted using the mechanically milled toner to assess the mechanical properties for different heating, pressure and stand-off distance conditions. It was found that, due to insufficient heating and applied pressure the final samples suffered from high porosity and poor tensile strength.
- PhD