Techniques to minimise stair-stepping effect in micro-stereolithography process: A Review

Recently, micro-stereolithography (MSL) has emerged as a promising fabrication process to develop three-dimensional (3D) micro-structures by photocuring 2D layers and stacking the same on the previous one as per the order of curing. Successful fabrications of 3D micro-structures are demonstrated by variants of the MSL. However, stair-stepping effect along the build direction is commonly observed in all the variants of the process due to the inherent characteristics of layer-by-layer fabrication. Various techniques are proposed to minimise stair-stepping effects inherently developed on the lateral surface (surface formed due to stacking of layers) of 3D micro-structures. This paper presents an exhaustive review of all reported techniques on minimisation of stair-stepping effect. The developed techniques are applicable for various types of micro-structures and variants of micro-stereolithography. This review lays the basic guidelines for the development of a process plan based on the micro-structures to be developed and the type of micro-stereolithography process to be deployed.