The development of colour 3D food printing system : a thesis presented in partial fulfilment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University, Palmerston North, New Zealand

Comprehensive appendices are on the disk with the vault copy.Foods are becoming more customised and consumers want food that tastes great, looks great and is healthy. Food printing, a method of distributing food in a personalised manner, is one way to satisfy this demand. The overarching goal of this research is to develop the ability to print coloured images with food, but this thesis focuses on a subsection of that research. It aims to establish a broad base for future research in the area of food printing, present the design and development of mixing techniques applicable to food printing and finally use image processing to examine the distribution of colour in images likely to be printed. By developing and testing various components and systems of the existing food printer and by performing a broad review of relevant literature, future researchers will be able to progress topics identified as essential in this field. Photographs of samples mixed using selected mixing techniques were analysed in order to produce qualitative and quantitative results. Six sample images were processed in such a way that colour distribution values were able to be used to estimate the average distances a food printing machine head would have to move between successive deposited volume elements while using discontinuous flow. The results show each mixing technique tested has advantages and disadvantages, which make them more or less useful for different applications. Testing with static mixers and our oscillating mixer shows they are very capable of achieving complete mixing. However, the static mixing system used would be unable to achieve sufficient contrast between successive volume elements and the oscillating mixer needs development of operating mechanisms before it could be implemented. Mixing with our conical surface mixer showed it was unable to achieve complete mixing, but the novel technique has potential as a mixing technique if additions to the process are made. Results from processing the sample images showed the average distance was 3.26 pixels, which equates to 16.3mm with a 5x5x5mm volume element. For research to continue, an appropriate mixing technique will need to be selected with regard to the goals and application of the food printing system. The distance between volume elements was deemed acceptable so the oscillating mixer or conical surface mixer would be most appropriate for discontinuous flow while static mixers should be used if a continuous flow is required