Development of instrumentation systems for macro- to micro-scale dimensional metrology

This dissertation presents three major developments. The first describes the development of a real-time, contact-based high-frequency response profilometer employed as a roundness gage for rapidly (less than a second) measuring circular form error for a 100% part inspection on the shop floor with an accuracy of better than 0.5 mum. The second discusses the development of a high-aspect-ratio, micro-scale probe for measurement of micro-scale features. An investigation of a 700:1 high-aspect-ratio probe with a 7 mum contact diameter attached at one end to an oscillator is presented. The third describes the development of an ultra-precision instrumentation spindle with an application to metrology. The spindle is designed with less than a 10 nm asynchronous error motion and up to a 2 mum synchronous error motion.; The profiler comprises a gage head consisting of a contact force probe that is rigidly attached to a high-bandwidth linear translator. During operation, the translator is used to maintain contact between the probe tip and specimen surface using a servo control system. The gage head assembly is, in turn, attached to a precision spindle. The objective of the complete tool is to contact the sidewall of the circular feature, rotate the gage head assembly, and simultaneously translate the probe tip radially to maintain a defined contact force, thereby following surface deviations. The gage head assembly (including probe and servo drive) has a fundamental natural frequency of 330 Hz while scanning the workpiece with a constant contact force, typically less than 100 mN. Form error (deviation from a nominal circle) is measured using a capacitance-based displacement sensor measuring the relative radial displacement of the probe with the spindle rotating at a constant rotation speed. This dissertation discusses the design and characterization of this metrology tool.; To enable a micro-scale high-aspect ratio feature measurement, the above measuring machine would have to be equipped with a micro-scale probe tip. To address this need, a probe having a 700:1 high-aspect ratio and a 7 mum diameter shank was fabricated and attached at one end to an oscillator. The oscillator produces a standing wave in the oscillating probe shank as opposed to conventional probes that use a microscale sphere on the end of a comparatively rigid shank. As a result of the standing wave formed in steady state vibration, the free end of the shank generates an amplitude of oscillation greater than the probe shank diameter. Thus, the probe does not require a spherical ball to serve as the contact point and simply uses the free end of the vibrating shank as the contact tip. This methodology is referred to as a virtual probe tip. Experiments in this dissertation indicate the ability to repeatedly resolve surface features of less than 5 mum height while maintaining bandwidths greater than 1 kHz. Furthermore, the effects of adhesive forces, which have often been problematic with micro-scale probes, are significantly attenuated. (Abstract shortened by UMI.)...