K. Soeda, H. Suzuki, S. Yokobori, K. Konishi, H. Tamaru, N. Mio, M. Kuwata-Gonokami, J. Yumoto
The University of Tokyo,
Keywords: SLA UV-light resin cylindrical glass window
Summary:Stereolithogaphy (SLA) is one of the most popular 3D printing methods, having a big potential for forming objects with fine structures. Typical SLA 3D printers consist of a building platform and a window substrate. Objects are formed between the platform and the window where the resin is cured by UV laser light modulated by the SLT data passing through the window substrate. However, it is quite difficult for SLA 3D printers to detach the object from the window substrate to form the sequential layers. Some proposed solutions like CLIP (Continuous Liquid Interface Printing), employing an oxygen permeable window, can reduce the forming time dramatically. We propose a novel SLA 3D printer configuration, called RECILS, achieved by combining a plane building platform (BP) and a cylindrical glass window (CW). The BP is deployed above the side wall of the CW with a gap of 0.01 mm to 0.04 mm. The UV laser light with a spot size of about 0.01 mm is linearly scanned by a polygonal mirror along the gap passing through the CW. UV curable resin is supplied into the gap and cured by the UV laser light modulated by the STL data. The gap is adjustable between 0.01 mm to 0.04 mm depending on the required resolution for the object to be formed. The BP is translated in a direction perpendicular to the laser scan direction, synchronized exactly with the laser scan. The operation of the laser scan and the translation of the BP is equivalent to a raster scan and a one-dimensional layer corresponding to the STL data is formed. The subsequent layers are formed below the previous layer by stepping the BP away from the CW in increments of the gap length. In this manner, the object is created layer by layer. RECILS has a laser spot position accuracy of 0.01 mm and a manufacturing resolution of 0.03-0.04 mm. Also, the manufacturing process time is faster than conventional SLA 3D printers because the peeling process and the resin supply process between the object and the CW take place automatically with no additional time required independently for these processes. In summary, RECILS can form objects with fine structures with a high resolution with fairly fast manufacturing time. These characteristics are expected to be especially useful for manufacturing microreactors, radio and electronic components operating at frequencies between microwave and THz. Additionally, a hybrid using resin with metal coatings has superior characteristics to metal 3D printing from the standpoint of machine cost, material cost and energy consumption. RECILS also has the potential of size scalability and it is easy to extend this technique to large scale manufacturing.