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A kind of cutting force sensor based on semi-conductive strain gauge is proposed in this paper in order to optimize the contradiction between sensitivity and natural frequency of strain-gauge type sensors. A new sensing element of two mutual-perpendicular octagonal rings 1 1 TMPOR: two mutual-perpendicular octagonal rings. (TMPOR) is developed to improve natural frequency; and semi-conductive strain gauge that fabricated by MEMS (micro-electro-mechanical system) technique is used to enhance sensitivity of the sensor due to its higher gauge factor (GF). Static calibration experiment results show that semi-conductive strain gauge has improved the sensitivity by 16 times than traditional metal foil strain gauge, which proves the feasibility of settling the contradiction aforementioned by using MEMS technique. Modal impact test indicates that the natural frequency of the fabricated sensor is 771 Hz in primary direction, which fulfills its most application in high speed machining process. During dynamic cutting force measurement test, the developed sensor exhibits satisfying ability in dynamic cutting force signal detection. Generally, the MEMS technique based sensor shows great potential in solving technical defect between sensitivity and natural frequency in current cutting force sensor research. [ABSTRACT FROM AUTHOR]

• Silicon carbide (SiC) high temperature pressure sensor is widely needed. • Common methods face great difficulty in SiC deep etching for sensitive diaphragm. • Femtosecond laser micromachining is promising for SiC deep etching. • High machining accuracy (size error 0.38 %) and low surface roughness (320 nm). • Small sidewall inclination (1.7°), shape deviation and over etching need improve. Pressure sensors that can work over 500 ℃ are widely needed in aerospace and petrochemical fields, while silicon based high temperature pressure sensors are difficult to survive such high temperature. Silicon carbide (SiC) shows better mechanical and electrical properties than silicon, which is a feasible candidate to replace silicon for manufacturing high temperature pressure sensor that can work over 500 ℃. However, because of the ultra-high hardness and excellent chemical inertness of SiC, it is difficult to pattern structures on SiC wafer by common etching methods, especially deep etching. Femtosecond laser (fs-laser) is a practicable tool for SiC micromachining as reported in many literatures, but few of them concerns on SiC deep etching in fabricating high temperature pressure sensor's sensitive diaphragm. In this paper, blind holes with diameter of 1200 μm and depth of 270 μm were fabricated on a 350 μm-thick 4H-SiC wafer by fs-laser, which forms an 80 μm-thick membrane as sensitive diaphragm for pressure sensor. Experiments were conducted to study shape deviation, machining accuracy, edge morphology, sidewall steepness as well as surface roughness of the machined structure. Testing results show that the size errors of machined blind holes are 2.02 % in diameter and 0.38 % in depth, the sidewall steepness is good with an inclination angle of 1.7°, and surface of the sensitive diaphragm is smooth with an average roughness of 320 nm. However, elliptical shape and over etching happens to the fabricated sensitive diaphragm because of inappropriate laser scanning mode, uneven energy distribution and laser irradiation delay. Generally, research shows that fs-laser micromachining is a feasible method for SiC deep etching in fabricating sensitive diaphragm of high temperature pressure sensor. [ABSTRACT FROM AUTHOR]

The design, fabrication and test of a novel MEMS fuze are presented in this paper. It is a multilayer stacked device: the bottom layer is the MEMS detonator, which can generate a high speed slapper (4088 m/s) when initiated by 2500 V surge voltage. The middle layer is the SA (safety and arming) device. With proper driven voltages, the SA device can generate 508.98 μm output displacement and realize changing safety mode to arming mode in 16 ms. The top layer is the MEMS encapsulation, which is integrated with the position limiting structure and energetic grain. 3D printing process and laser process are introduced during the whole fabrication process, and the total size of the device can be minimized into 15 mm × 17 mm ×5 mm successfully. [ABSTRACT FROM AUTHOR]

This paper describes a micro resonance accelerometer working in air with differential configuration using silicon spring-mass and quartz double ended tuning fork (Q-DETF) resonator. When acceleration is applied in sensing direction, the inertial force of proof mass will apply axial force on Q-DETFs, which shifts the resonance frequency of Q-DETFs. Dual Q-DETFs, working in differential condition, are bonded in the same plane at the middle of proof mass thickness along the diagonal line of square proof mass. The configuration has the advantage that the inertial force of proof mass is mostly applied along the axis of Q-DETF tines when acceleration is applied in sensing direction, and the bending of DETF induced by acceleration in sensing direction is very small so that it can be neglected, which can improve sensor nonlinearity. The highly symmetrical configuration of the sensor can better eliminate most of common-mode disturbance, especially temperature and residual stress. Theoretical analysis on sensitivity is conducted and the result matches well with experimental data. The sensor is fabricated and characterized in air using rotary experiment in earth gravitational field. In the experimental range of ±1g, the tested sensitivity, nonlinearity and hysteresis are 6.317 Hz/g, 0.26% and 0.09%, respectively. The sensor stability in 12 h is also tested in air under the influence of temperature turbulence and residual stress and the drifting of sensor output is less than 0.5 Hz. [ABSTRACT FROM AUTHOR]