A study on the recoating thickness of high-resolution stereo-lithography system

The recoating performance is a key factor influencing the fabricating accuracy and resolution of the stereo-lithography system. In order to obtain thinner resin layer, a piston recoating system is adopted in the high-resolution stereo-lithography system. To improve the recoating performance of the piston recoating system, the influences of the parameters of recoating system on the coating thickness are studied, and a mathematic model of resin layer thickness is established. Experimental results show that the thickness of the resin layer increases with the gap between blade and object and the resin volume added into the vat during recoating. The experimental results also indicate that the thickness of resin layer decreases with the increase of blade speed and blade thickness. A phenomenon is found that the thickness of resin layer increases with the increase of the height of the coated object in high-resolution stereo-lithography system. To solve this problem, a novel methodology is proposed. First, the experiential model describing the relationship between the thickness of recoating layer and the height of the coated object and the blade speed is established, and then based on the mathematical model, the blade speed according the object height during building process is dynamically optimized, and uniform resin layer can be obtained.