Jorge Cuautle-Cortés

Bio: Jorge Cuautle-Cortés is an academic researcher from Benemérita Universidad Autónoma de Puebla. The author has contributed to research in topics: Electronic circuit & Polishing. The author has an hindex of 5, co-authored 6 publications receiving 95 citations.

Edge effects with the Preston equation for a circular tool and workpiece

Abstract: In a polishing process the wear is greater at the edge when the tool extends beyond the border of the workpiece. To explain this effect, we propose a new model in which the pressure is higher at the edge. This model is applied to the case of a circular tool that polishes a circular workpiece. Our model correctly predicts that a greater amount of material is removed from the edge of the workpiece.

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.

Experimental results and wear predictions of petal tools that freely rotate

Abstract: It is difficult to calculate the wear produced by free-pinned tools because their angular movement is not entirely predictable. We analyze the wear produced with free-pinned ring tools, using both simulations and experiments. We conclude that the wear of an incomplete ring is directly proportional to the ring’s angular size, independently of the mean radius of the ring. We present an algorithm for calculation of the wear produced by free-pinned petal tools, as they can be considered a linear combination of incomplete free-pinned ring tools. Finally, we apply this result to the enhancement of a defective flat surface and to making a concave spheric surface.

Improved Ronchi tester

Abstract: We used a LED in a Ronchi tester to obtain two main improvements: (i) We can choose one of two wavelength bands to illuminate and record the ronchigram, and (ii) we can change the irradiance of the illumination source according to the optical system under test and the detector array. This can be done by use of an adequate electronic circuit.

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

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.

Modification of tool influence function of bonnet polishing based on interfacial friction coefficient

Abstract: Aimed to improve the modeling accuracy of tool influence function (TIF) of bonnet polishing, a theoretical and experimental study is presented. This paper starts with the affecting mechanism of key parameters on the material removal of workpiece. It is indicated that the interfacial friction coefficient between tool and workpiece is changed with the variety of the tool rotational speed, which impacts the TIF but has not been taken into account in most current TIF models. Consequently, modification of TIF model based on the interfacial friction coefficient is proposed and then experimentally validated. The results show that, for the experimental groups in which the spot size is 15 mm, the difference between the maximum removal depth of the TIF predicted with the pre-modified model and that of the experimental TIF is −0.204 to 1.244λ (λ = 632.8 nm), which is obviously larger than that between the TIF predicted with the modified model and the experimental TIF −0.187 to 0.168λ. Moreover, for the experimental groups in which the spot size is 20 mm, the difference between the maximum removal depth of the TIF predicted with the pre-modified model and that of the experimental TIF is −0.135 to 2.235λ, while that between the TIF predicted with the modified model and the experimental TIF is −0.046 to 0.571λ. The experimental results indicated that the TIF predicted by the modified model is much closer to the experimental TIF, which proves the effectiveness and correctness of the modification.

Edge control in CNC polishing, paper 2: simulation and validation of tool influence functions on edges

Abstract: Edge mis-figure is regarded as one of the most difficult technical issues for manufacturing the segments of extremely large telescopes, which can dominate key aspects of performance. A novel edge-control technique has been developed, based on ‘Precessions’ polishing technique and for which accurate and stable edge tool influence functions (TIFs) are crucial. In the first paper in this series [D. Walker Opt. Express 20, 19787–19798 (2012)], multiple parameters were experimentally optimized using an extended set of experiments. The first purpose of this new work is to ‘short circuit’ this procedure through modeling. This also gives the prospect of optimizing local (as distinct from global) polishing for edge mis-figure, now under separate development. This paper presents a model that can predict edge TIFs based on surface-speed profiles and pressure distributions over the polishing spot at the edge of the part, the latter calculated by finite element analysis and verified by direct force measurement. This paper also presents a hybrid-measurement method for edge TIFs to verify the simulation results. Experimental and simulation results show good agreement.

Computer Controlled Optical Surfacing With Orbital Tool Motion

Abstract: Asymmetric aspheric optical surfaces are very difficult to fabricate using classical techniques and laps the same size as the workpiece. Opticians can produce such surfaces by grinding and polishing, using small laps with orbital tool motion. However, hand correction is a time consuming process unsuitable for large optical elements. Itek has developed Computer Controlled Optical Surfacing (CCOS) for fabricating such aspheric optics. Automated equipment moves a nonrotating orbiting tool slowly over the workpiece surface. The process corrects low frequency surface errors by figuring. The velocity of the tool assembly over the workpiece surface is purposely varied. Since the amount of material removal is proportional to the polishing or grinding time, accurate control over material removal is achieved. The removal of middle and high frequency surface errors is accomplished by pad smoothing. For a soft pad material, the pad will compress to fit the workpiece surface producing greater pressure and more removal at the surface high areas. A harder pad will ride on only the high regions resulting in removal only for those locations.