Simulation And Manufacture Of Self-Closing Micro Mechanical Structure

The micro clamping system is a sort of important tools for manipulating objects with dimensions at the micro/nano level to change their shape and spatial position,enabling humans to further accurately revamp the micro world.Currently,micro clamping systems have more or less requirements for operating objects due to their clamping principles.The contact mechanical clamping structure has been widely studied and applied due to their universality,but it is limited by the driving method and always unable to achieve 6 degrees of freedom in all directions in space.In order to solve this technical bottleneck,it is necessary to design and fabricate micro devices that drive themselves to the closed state.This article is based on this purpose.Traditional three-dimensional microstructure fabrication strategies cannot meet the requirements of self-closing.Thin self-closing technology has been developed in combination with the art of "origami",using regional deformations generated on planar structures to build three-dimensional devices.Inspired by this,this paper designed and successfully fabricated a self-closing micromechanical structure.Firstly,a self-crimping model of the initial strain released from the bilayer membrane is derived from the perspective of minimizing the elastic strain energy of the system.The derived results indicate that the degree of crimping is closely related to the material,initial strain value,and film thickness.This model was established in the Comsol Multiphysics multi-physical field simulation software,where its accuracy was verified at the simulation level from the perspective of the above three parameters.After that,this model was applied to practical experiments to obtain the initial strain value of Pt/Au bilayer films grown by the magnetron sputtering process used in this article.Combined with XRD testing of the microstructure of materials,the idea of introducing initial strain through lattice mismatch was proved to be successful.Secondly,a two-dimensional structure was designed in Comsol software,and a regional initial strain was applied to it.Through the design of the film thickness,initial strain,and its own size,the folding angle was successfully adjusted to achieve a selfclosing state.After that,using simulation design parameters,a mask was drawn,and selfclosing micromechanical devices were prepared through magnetron sputtering,photolithography,and etching sacrificial layers.Experimental results showed that the film thickness can adjust its self-folding degree.It is also shown that the self-closing micro mechanical structure capture microbeads with diameter less than 50 μm during the release self-closing process.Then,under the guidance of existing microfluidic theory,the simulation study was conducted to investigate the changes in the magnitude of viscous force and position trajectory of the micro self-closing mechanical structure prepared in this paper when it performs non reciprocal motions in liquid.Provide a theoretical model for controlling the position of this closed structure in incompressible liquid.Finally,in order to enrich its functions,a magnetic thin film with out of plane magnetic anisotropy is added to the prepared structure to maintain its advantages of remote control.It is expected to use magnetic fields to regulate the self-losing structure to achieve switching between closed and open state.