Alberto Cordero-Dávila

Bio: Alberto Cordero-Dávila is an academic researcher from Benemérita Universidad Autónoma de Puebla. The author has contributed to research in topics: Ronchi test & Conic section. The author has an hindex of 11, co-authored 52 publications receiving 401 citations.

Cylindrical lenses: testing and radius of curvature measurement.

Abstract: Using a technique that was previously developed for measuring the radius of curvature of spherical surfaces, an alternative method for testing cylindrical as well as toric lenses is presented. The basic equipment required is a nodal bench and a low power He–Ne laser.

Correction of the Preston equation for low speeds

Abstract: According to Preston [J. Soc. Glass Technol. 11, 214 (1927)], the wear on a glass point in the polishing process is proportional to the work given by frictional force between glass and tool. He supposed that the frictional coefficient is a constant value. To verify this hypothesis, we measured the dragging forces applied to a tool as a function of the relative speed between a rotating glass and the tool center. To reproduce these experimental results, it was necessary to propose a new model, for which the frictional coefficient has a Gaussian dependence with relative speed. Therefore the wearing Preston equation has to be modified in order to include the frictional coefficient as a function of the relative speed.

Profile measurement of a conic surface, using a He–Ne laser and a nodal bench

Abstract: A method of measuring the profile along one diameter of a conic surface is presented. Using some well-known formulas for the conic sections, useful mathematical relations are derived that, together with a simple experimental setup can be used for comparing theoretical and real values of the sagitta of the surface.

Polynomial fitting of interferograms with Gaussian errors on fringe coordinates. I: Computer simulations.

Abstract: A series of simulations were made for an ideal Twyman–Green interferogram of equally spaced straight fringes having tilt only about x. It was found that fitting polynomials to the interferometric data resulted in biased estimates of some of the fitting coefficients to the optical path difference. The acceptance of the Seidel aberrations grows with the noise level and diminishes when the number of fringes is increased.

Algorithm for the simulation of ronchigrams of arbitrary optical systems and Ronchi grids in generalized coordinates.

Abstract: We present a simple algorithm that makes possible the simulation of ronchigrams for any optical system in which it is possible to make an exact ray tracing. We report the simulations for the following grids: the Ronchi classical, square, circular, radial, circular-radial, biparabolic, elliptic-hyperbolic, bipolar, and bielliptic ones.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Abstract: A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Abrasive fine-finishing technology

Abstract: Abrasive fine-finishing technology is often applied as a final finishing process, and the selection of the right technology is crucial to obtaining the desired performance of functions such as fatigue life. This paper begins with classifications of the technology along with fundamentals and brief histories of the individual methods. The material removal mechanisms, specific energies, and finishing characteristics of the various technologies are summarized giving assessments of the surfaces created by them. Guidelines developed for selecting the appropriate methods, and case studies illustrate the effectiveness of various methods. This paper ends with a discussion of the future prospects of the technology. (C) 2016

Null-screen testing of fast convex aspheric surfaces.

Abstract: A method for null-testing fast convex aspheric optical surfaces is presented The method consists of using a cylindrical screen with a set of lines drawn on it in such a way that its image, which is formed by reflection on a perfect surface, yields a perfect square grid Departures from this geometry are due to imperfections of the surface, allowing one to know if the surface is close to the design shape Tests conducted with a full hemisphere and with the parabolic surface of a lens show the feasibility of the method Numerical simulations show that it is possible to detect surface departures as small as 5 microm

Parametric modeling of edge effects for polishing tool influence functions.

Abstract: Computer controlled polishing requires accurate knowledge of the tool influence function (TIF) for the polishing tool (i.e. lap). While a linear Preston's model for material removal allows the TIF to be determined for most cases, nonlinear removal behavior as the tool runs over the edge of the part introduces a difficulty in modeling the edge TIF. We provide a new parametric model that fits 5 parameters to measured data to accurately predict the edge TIF for cases of a polishing tool that is either spinning or orbiting over the edge of the workpiece.