| Summary: | 碩士 === 國立中興大學 === 機械工程學系所 === 103 === The purpose of this study is to develop a compact and add-on ultrasonic tooling system which can be easily retrofitted into a conventional CNC machining center which can be used for machining the difficult-cutting aerospace materials, ceramic materials and composite materials by exploiting the ultrasonic machining principle. To fit this purpose, we adapt a side-coupling non-contact electric power transmission technology. The advantages of the side-coupling non-contact power transmission technology include easy set-up, low-cost, and compact compared with the previous work. In order develop a high efficient, stable and reliable non-contact power transmission ultrasonic cutting system, we have finished the following tasks:
1. The non-contact electric-magnetic inductive coupling has been design, simulate and analysis by the MAXWELL 3D software, experimental results have confirms the coupling coefficients between the 20kHz~50kHz of the simulation and experiment are matched very well. The difference is less than5%.
2. The ultrasonic boosters have been designed and evaluated by using the ANASYS in the frequency range between 20kHz~50kHz. We have proposed a new type booster which reduce the total length from previous 175mm to 132mm. Experimental results of the resonance frequency and vibration amplitude are also matched well with the simulation result, less than 10% error.
3. A auto-scan and phase-lock resonance tracking technology has been developed to secure the vibration amplitude stability for the long term operation and changing tools. The resonance tracking is based on the impedance analysis and phase lock principle. Experimental results have proved that the auto-scan and auto-lock of the resonance frequency can be less than 10 sec. (from 20kHz~50kHz). After the resonance frequency has been locked, the response bandwidth for the tracking resonance frequency is better than 100Hz.
4. Experimental results show that the 25 m vibration amplitude has been achieved with less than 15W power supply. The variation of vibration amplitude in the static state (i.e spindle is non-rotating) and dynamic state (spindle is rotated in 6000rpm) is less than 5%, based on an experiment that the vibration amplitude level is controlled at the 16 m.
5. A long term continuous running test extended for 72 hours has been conducted to evaluate the stability of this ultrasonic cutting system. Experimental results show that the amplitude variation is less than 5% when the vibration is controlled at the 18.3m level.
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