| Summary: | 碩士 === 國立中興大學 === 機械工程學系所 === 104 === Machine tools are machines mainly for material removing based on cutting, drill-ing and grinding. Cutting precision and stability affect the manufacturing quality of a machine tool. Spindle is a key part of a machine tool. Machining precision, machining productivity and product quality are affected by spindle stiffness. Frequency response function (FRF) is selected to obtain spindle stiffness in this thesis. Excitation force and response are needed to obtain FRFs. Impact hammers, shakers and accelerometers are routinely used for obtaining FRFs. However, contact devices cannot be attached to a rotating spindle. In order to obtain FRFs of rotating spindle, excitation and transducer arranged by non-contact means in this thesis.
A non-contact excitation system is designed and manufactured. Attractive force is generated by the electromagnets of the non-contact excitation system. Force trans-ducers, which act on the same line of action with attractive force, are installed to measure attractive force in real time. The non-contact excitation system is operated on two different test stands by exciting the test piece held by the tool holder. Laser Dop-pler Vibrometer (LDV) is selected to capture the response of rotating spindle. Attrac-tive force is measured by the force transducers installed in the non-contact excitation system. With the readings of the non-contact excitation system and LDV, FRFs of rotating spindle can be obtained experimentally. According to the FRFs, stiffness of rotating spindle is sought in this thesis.
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