Study On The Part Precision Of Rapid Prototyping Of Stereo Lithography Apparatus

Rapid Prototyping (RP) is one of the advanced manufacturing technologies nowadays. It can fabricate the complicated prototype rapidly. The objective of Rapid Product Development can be achieved consequently.Stereo Lithography Apparatus (SLA) is the Rapid Prototyping that developed firstly. Most SLA systems use laser as light source, and its high cost restricts its wide application although it has relatively higher precision. The rapid prototyping system available recently adopts UV as light source instead of laser, thus the cost is reduced, but the forming accuracy is fairly lower. The paper focuses on the forming accuracy of the UV rapid prototyping for CPS (Compact Prototyping System) 350 RP system made in China, and plentiful experimental study was done on the basis of embedded theoretical analysis.The factors affecting the accuracy of SLA process are complicated, which involve many academic disciplines such as mechanical engineering, CAD, optics, material science and automatic control. In the paper, the process principle of SLA is studied theoretically. And the factors that effect the forming accuracy during 3D CAD data analysis and fabrication process is analyzed detailedly.In this paper, the experiment model was designed for the problem of "swelling" in UV rapid prototyping part and the results was analyzed. As for the question of dimension warp and its change trend, through experiment analysis the rule was obtained that how the resin characteristic, scanning length and acceleration and deceleration of the scanning system that affect the part precision. The way that the scanning system adopts varying accelerated motion during accelerating and decelerating phase was brought out.The X-type surface defect is one of the most serious problems affecting the surface quality of SLA Prototyping part, it was also emphasized in the study of this paper. The viewpoint that adds the shading equipment to the scanning system was brought forward.In the view of the influence of the UV rapid prototyping variety of process parameters, making use of the three direction's dimension errors as measuring guideline, the 4-factor and 3-horizontal orthodoxy experiment is designed and processed. Using the measure of the square error, the rules was studied that how the facular compensation, layer thickness, scanning speed and scanning space affect the forming quality, and the optimal process parameters combination of SLA in certain extent was obtained.At last, the measure and method of enhance the part precision is presented, which could be a guidance to the development and application of SLA.