Executive Summary : | Ice 3D Printing is the process of producing the objects by depositing water layer-by-layer inside a chamber at sub-zero temperature. The model material will be deionised water (freezing point = 0°C) and the support will be an aqueous solution of dextrose, glycerol, etc. in order to have a lower melting point (freezing point = -10°C). Well established multi-jet print head will dispense both liquids the nozzles divided between them. Shaped ice has several aesthetic and industrial applications. Cold countries have ice museums. Slowly melting water from the ice statues of mermaid or fish is used in parties. However, our focus is industrial. Ice patterns can be used in investment casting instead of wax. The ice pattern can be sublimated from inside the ceramic slurry to obtain the shell. Its anomalous nature reduces the shell cracking tendency apart from its other advantages of environmental friendliness and low cost. Ice can be an ideal support material in 3D printing of photopolymer jetting type. Presently, support removal is cumbersome in these processes apart from the expensive polymer discarded as support. Ice templates can be used for realising microfluidic channels due to the high resolution of the multi-jet technology. Multi-jet water dispensing is the novelty of this project. Dividing the nozzles of the same head between the two liquids is also an innovation resulting in better economy. The model and support are dispensed in the same pass. The chamber of the ice 3D printer will be maintained at less than -20°C. The refrigeration system consists of (a) a rapid cooling system using solid CO2 or liquid N2 and (b) a vapour compression system to sustain it. A unique architecture insulates the electrical (motors, relays, contacts etc.) and electronic (PCBs for motion and print control) systems from low temperatures. There is a heater below the nozzles to avoid the freezing of the liquids. The multi-jet printhead spreads the layer of the liquid selectively on the work platform in a pre-programmed raster pattern. The emerging liquid instantly freezes since the work platform is below its freezing point. The process continues and the 3D object in the frozen state is obtained in a layer-by-layer manner. The support material is dispensed coarsely wherever the object has some overhanging/undercut features. After all layers are completed, the chamber is raised to, say -5°C, and held till the support melts away. Finally, the model is harvested. |