Micro-assembly precise coaxial alignment methodology based on surface roughness and reflectiveness matching

Purpose – The purpose of this paper is to propose a novel method of coaxial optical precision alignment based on surface roughness and reflectiveness matching. Design/methodology/approach – The micro-assembly experiment system set-up was constructed according to the principle of the coaxial optical alignment. The coaxial optical alignment error is theoretically analyzed and calculated. When the prism orthogonal alignment mechanism produces the error of 0.001°, the theoretical deviation was less than 0.87 μm and the actual experimental micro-assembly platform assembly accuracy exceeded 3 μm. A peg-in-hole precise assembly of punching pin micro-assembly experiment was done in order to validate feasibility of this method. Findings – The results indicate that coaxial optical precision alignment could be used for the assembly of complex micro-heterogeneous system which is integrated by similar devices, such as 3D complex micro-structures, silicon micro-electro-mechanical system (MEMS) devices and non-silicon MEMS devices with flat structure. Originality/value – The paper provides certain methodological guidelines for MEMS for high precision automatic assembly of complex 3D micro-structures.