The object of this Ph.D. work is to validate stylus profiling techniques for ultra-high precision measurement and positioning in engineering. Stylus methods have been used extensively and successfully in the past in the fields of manufacturing control and components function study, but some problems still exist. Now their role has considerably expanded with the appearance of scanning probe microscopes and the new emphasis on nanotechnology, which shortens the gap between engineering and physics. The profiling technique is interpreted and evaluated in terms of the mechanical aspects of data collection through a stylus surface instrument. This work contains: (a) 3D digital sampling techniques; (b) effects of the finite dimension of stylus and (c) forces contributing to measurement. A new plane sampling model - hexagonal model - has been developed to improve the surface 3D data collection to almost 99% of the continuous case for summit height distribution. The dimension effect has been divided into two aspects: the effects of size and the shape. The cut-off effect caused by the size of the stylus on the surface curvature is not correctable. The analysis of the trace formation suggests that the ‘deconvolution’ of the true profile from the trace is feasible. The simulation using the MAT-LAB computer package confirms this with only computational error. A new method of stylus shape/dimension measurement was proposed based on these principles. Alternatively, a practical method of measuring a stylus shape using a knife-edge was also constructed and further developed. Stylus tips of radii from 1 /μm to 50 / μm can be measured using this rig to an accuracy of only 5% of the movement of the knife-edge. The physical effect of a stylus is discussed theoretically and experimentally in terms of the static and dynamic stylus loading forces. The dynamic variation is only 2.7% of the static one and it is negligible. Through the study, the lateral resolution and the frictional force within stylus-surface contact are found to be the crucial elements to be tackled so that the profiling technique is able to fulfil its requirements. A general discussion of the scanning probe microscopy, with emphasis on these points of view, presents quantitative problems in 3D measurement.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:305194 |
| Date | January 1991 |
| Creators | Li, Man |
| Publisher | University of Warwick |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://wrap.warwick.ac.uk/108847/ |
Page generated in 0.0133 seconds