Optimization of a Fuze MEMS Setback Arming Device Based on the EDM Process

This paper introduces the working principle of a MEMS safety and arming (S&A) device and measures and tests a setback arming device. To solve the problem of large fabrication errors in the UV-LIGA process, a MEMS S&A fuze device fabricated by low-speed wire electrical discharge machining (EDM) is proposed. Microsprings are susceptible to flexural deformation and secondary deformation in the EDM process, which is solved by setting the auxiliary support beam, using multiple cuts and destress annealing. The linewidth, thickness and elastic coefficient of the microspring fabricated using the EDM process are closer to the designed values than those fabricated using the UV-LIGA process under the same conditions. When comparing the MEMS S&A devices fabricated by the two processes, it is found that the EDM process has a the higher machining accuracy. In view of the plastic deformation of the upper end of the microspring, the structure of the microspring is optimized to incorporate a gradient linewidth, and the optimized setback arming device is tested. The results show that the device can ensure service process safety and launch reliability. The maximum overload that can be withstood in service processing is 17000 g, and the minimum overload for insurance release during launch is 1500 g.