In-process gage frequency response measurement

Abstract

This paper describes a method for determining the frequency response characteristics of in-process measurement systems. Determination of the frequency response extends the usefulness of such mechanical systems by allowing proper detection and interpretation of out-of-roundness information on the surface of a workpiece. The excitation and analysis methodology using established signal processing techniques is presented in detail with appropriate references. The experimental setup is discussed in detail including a brief introduction to the piezoelectric system used for excitation and the signal processing hardware and software used for analysis. Results are shown for both internal and external LVDT based in-process gages used primarily by manufacturers to improve the precision of the internal and external grinding process. The discussion includes analysis of both the frequency domain and with respect to the maximum number of undulations per revolution that the gage is expected to detect. The work presented introduces a commercially available technique that can be adopted by industry for the purpose of gathering additional information from existing in-process measurement systems during a process.