Research On Photosensitive Resin For Stereolithography Appratus

It has developed more than 30 years since the stereolithography apparatus(SLA) came out. And now it has been used all over the world. The SLA in China begins in the 90 s, but the development is not fast enough. The main problem is that the high-performance resin used for SLA is lacked. The key to promote the development of rapid prototyping in China is to develop high-performance photosensitive resin. Then we can break the foreign monopoly.In this paper, the free radical UV-curing resin system and the hybrid UV-curing resin system were studied. The property like viscosity, shrinkage ratio, mechanical properties, gel content, curing speed and curing thickness were analyzed when the ingredients of UV resin were changed. The studies show that the gel content of the resin changes as the same trend as the curing rate. In free radical resin system, the resin shows the highest curing speed and gel content when the initiator content reaches 4%. For the free radical resin system,907 was thought to be appropriate photo initiator,6118 to be oligomer, and TPGDA to be diluent.In the hybrid resin system, the best ratio of free radical type oligomer to cationic oligomer is 45:25. At this ratio, the hybrid photosensitive resin show a good comprehensive performance. At this point, the content of free radical photoinitiator was determined to be 3%, and cationic initiator was determined to be 2%. Through analysis and experiment, the free radical type oligomer is thought to be 621A-80, and the cationic type oligomer are E-44 and UVR6105. In order to look for the key to the question of bubble, the defoarmer agent 900 from Deko was added to the resin system. By analyzing viscosity, shrinkage ratio, and mechanical properties, etc of the resin which were added with different ratio defoarmer agent, the content of defoarmer agent was thought to be 0.3%.In order to reduce the shrinkage ratio of the resin and improve its mechanical properties, the modified titanium dioxide was applied in the photosensitive resin. Silane coupling agent KH550 was used to modify the titanium dioxide. The result of FTIR, SEM and surface contact angle show that titanium dioxide has been modified successfully. And the surface of titanium dioxide has hydrophobic groups. Study shows that the modified titanium dioxide can reduce shrinkage rate, and increase the mechanical properties. But it can also increase viscosity and decrease curing thickness. The resin show the best mechanical properties when the content of modified titanium dioxide is 0.4%.The curing thickness and gel content of the resin changed when the laser power and scanning speed were changed. Between them, the power of laser have a greater effect on the resin. A hybrid resin system and a free radical resin were conducted on SPS250 stereolithegraphy apparatus. The hybrid resin could be cured on the machine. But the mechanical properties of the hybrid resin need to be enhanced.