平面微弹簧的模拟、加工制备和力学性能表征研究

Simulation,fabrication and characterization of planar microsprings

微弹簧是一种重要的MEMS器件 ,可为微传感器和微执行器提供弹性力。我们设计并用UV LIGA技术制备了数种不同形状的平面微弹簧 ,并用ANSYS对其力学性能如刚度、断裂强度等进行了模拟。由于制备出的平面微弹簧体积很小 ,无法用常规的测试仪器进行测试 ,我们为此设计并制备了一台平面微弹簧力学性能测试仪 ,其位移分辨率为 1μm ,力分辨率为 1mN。模拟得出的结果与测量结果一致性较好 ,与闭环平面微弹簧相比 ,S型平面微弹簧具有较大的位移和较小的刚度 ,弹簧的刚度随着弹簧厚度的增加而增加。铜微弹簧的屈服强度和屈服位移仅为镍平面微弹簧的 5 % 7%。

Microspring is an important MEMS device, which can provide elastic force for the microactuators and microsensors. UV LIGA technology was used to fabricate several forms of nickel and copper planar microsprings. Its mechanical properties were simulated using ANSYS program. Due to small volume of fabricated planar microsprings, it is difficult to measure the mechanical properties using conventional testing equipment. We designed and fabricated a new measurement system to characterize the mechanical properties of the microsprings. Our ANSYS simulation results of mechanical properties of microsprings are tally with the measurement results. In contrast with closed form microsprings, S form microspring has larger elongation and smaller stiffness. Its stiffness enhanced with increased spring thickness. The yield load and yield elongation of Cu microspring has only 5%～7% than nickel microspring.