Based on the orthogonal experiments, using micro-diameter tool milling thin-walled parts of hardened steel in high-speed to research the effects of different cutting parameters on the radial cutting force, vibration, and surface roughness which optimize the cutting parameters. Firstly it make the researching goals into a stability characteristic of product quality named SN ratio, then using principal component analysis make the multi-objective quality characteristics into a single objective quality characteristics combined with analysis of variance to optimize the cutting parameters which not only analyze the significant impacts of cutting parameters on comprehensive quality but also obtained more reasonable cutting parameters and it can be a certain guiding significance for milling thin-walled parts of hardened steel with high speed. KEYWORD: hardened steel; thin-walled work piece; Optimization

High-precision and high-sensitivity vibration acceleration sensors have been a research hotspot in engineering technology, which play an important role in engineering structural health monitoring, earthquakes, tsunamis, and geological exploration. A novel, to the best of our knowledge, fiber Bragg grating (FBG) acceleration sensor incorporating a mass block and flexible hinge was proposed against the low sensitivity and poor transverse interference resistance of existing FBG acceleration sensors. The FBG accelerometer with the multi-stage flexible hinge was modeled and theoretically analyzed, the structural parameters of the sensor were optimized and actual sensors were developed, and a sensor performance test experiment was carried out in the end. The result suggested that the sensor’s natural frequency was as high as 1400 Hz, and its response was flat in the frequency range of 50–800 Hz; its sensitivity was 18.4 pm/g, linearity R2 was 0.9983, and transverse interference immunity was below 3.2%. The research findings offered a new way of thinking about high-precision and high-sensitivity vibration measurement in engineering technology.