Research On The Key Techniques Of UV-curing Three Dimensional Printing

With the economic globalization, the market's competition will be more and more ruthless and time-to-market of the products is a key success factor of the corporations. As a result, the enterprise will need more and more Rapid Prototyping (RP) equipments, which can increase the successful ratio of developing a new product, decrease the time and cost required for a new product development. Compared with other RP technology, Three Dimensional Printing (3DP) has advantages in many aspects such as processing velocity, variety of processing materials, price of equipment, cost of running and maintenance of equipment. Consequently, 3DP has better developing potentialities and expansive applying foreground, and represents the developing direction of RP technologies. According to the developing trending of 3DP and the need of corporations in China, the UV-curing 3DP was researched in this paper, and the object was to develop 3DP system with our own knowledge right. The main content of research in the paper is as following:The spreading and reconsolidating of jetting droplets on the processing surface were studied in theory. It was calculated that the minimum resolution factor of printing in X-Y surface should be 300dpi in the developed the rapid prototyping system of UV-curing 3DP, and the minimum processing thickness of Z axle was 0.011mm. The solidified process of materials of photosensitive resin in UV-curing 3DP was studied in theory, the function of the maximum solidified depth with the moving velocity of the UV-lamp and the required relationship of slicing thickness with the moving velocity of printhead along X axis were educedBased on the idea of decreasing the cost of the hardware when the using performance was ensured, the project and structure of the mechanical system, controlling hardware system and controlling software system in the original UV-curing 3DP equipment were designed. It was established the groundwork of the first UV-curing 3DP equipment with our own knowledge right to be developed.According the number of controlling states needed in the single layer's processing of UV-curing 3DP, two pieces of bitmap of black and white were adopted to express the layered data, one expressing the solid bitmap and the other expressing the support bitmap. The scanning beam way was used to creating the bitmap data. Combined with the character of the layered contour of slicing the CAD model in rapid prototyping system, a new algorithm of creating bitmap based on the contour edge was proposed. The new algorithm could dispose expediently all the odd points, especially the odd points produced when the horizontal contour edge was on the scanning beam, which were difficult to be distinguished and disposed by the classical algorithms. Based on the new algorithm, the algorithm of creating layered solid bitmap in UV-curing 3DP system and the algorithm of fast seeking the layered support bitmap were achieved.According the character of the layered bitmap in the UV-curing 3DP and the shortage of the lossless compressing methods of bitmap data in common use, one new compressing method of bitmap data based on byte was designed. The compressing way made the best of the character of bitmap data in UV-curing 3DP, the compressing rate of the method is high. It was showed that the minimum compressing rate was 12.1:1 and the maximum compressing rate was 53.9:1 when many CAD models' bitmap data were compressed compared with the noncompressed bitmap data. The compressing way did not need complicated computing in the compressing and decompressing process, its compressing and decompressing velocity was fast, which did not form bottleneck of the condition of having thousands pieces of bitmap data to be disposed and which was well suitable for the data compressing in the UV-curing 3DP systemThe shortages of the classical multi-objective optimizating algorithm (MOGA) of NSGA II were analyzed and the improving methods were put forward. One new MOGA named nondominated sorting uniformly generic algorithm (NSUGA) was proposed, which was better in the precision of seeking pareto solutions, the efficiency of computing and the avoidance of gaining local optimal solutions than the MOGA of NSGA II.The effect of part building orientation on the part's surface quality, supporting area and building time were studied in UV-curing 3DP. One new idea of optimizating part building orientation using multi-objective optimizating way based on the pareto optimal principle was proposed. Using NSUGA to optimize the part building orientation, not only the better solutions were found than the single-objective optimizating way, but also many pareto optimal solutions could be gained once.