32,123 research outputs found
Similarity measures for mid-surface quality evaluation
Mid-surface models are widely used in engineering analysis to simplify the analysis of thin-walled parts, but it can be difficult to ensure that the mid-surface model is representative of the solid part from which it was generated. This paper proposes two similarity measures that can be used to evaluate the quality of a mid-surface model by comparing it to a solid model of the same part. Two similarity measures are proposed; firstly a geometric similarity evaluation technique based on the Hausdorff distance and secondly a topological similarity evaluation method which uses geometry graph attributes as the basis for comparison. Both measures are able to provide local and global similarity evaluation for the models. The proposed methods have been implemented in a software demonstrator and tested on a selection of representative models. They have been found to be effective for identifying geometric and topological errors in mid-surface models and are applicable to a wide range of practical thin-walled designs
Optimization of cut surface quality during CNC Plasma Arc Cutting process
Optimization of cut surface quality during CNC
plasma-arc cutting (PAC) of mild steel plates is presented. Using
design of experiments (DOE) the optimum process parameters are
estimated. The process parameters tested include cutting speed,
cutting height and arc voltage. Analysis of means (ANOM) and
analysis of variances (ANOVA) were used in order for the effect of
each parameter on the surface quality to be assessed
Tool wear monitoring and hole surface quality during CFRP drilling
The present investigation focuses on the evaluation of tool wear and surface integrity in the context of CFRP cutting. Series of drilling experiments were performed on CFRP plates using cemented carbide solid drills with the aim to investigate correlations between tool damage, cutting forces, temperature and hole surface quality. In particular, a new methodology has been developed to measure the drilling temperature and to assess the quality of the hole surfaces where occurred uncut fibers. As the surface roughness criterion is not relevant for such work materials, a discussion on the definition of the surface topography is proposed for CFRP work material
Characterisation of the fused silica surface quality with a β-source
A method to characterise the quality of a fused silica surface using a β-source is presented. Two fused silica bars (5×10×400mm3) were fabricated for the Cherenkov detector for proton Flux Measurement installed at vacuum chamber of the Super Proton Synchrotron at CERN. The resolution of such device is defined by the collection efficiency of the Cherenkov light, which is produced by relativistic charged particles in the fused silica. Thus, the surface quality of the radiator should be as good as possible to avoid light losses. The method is based on the scanning of the radiator surface with a90Sr radioactive source and measurements of the Cherenkov light rate, detected by a PMT attached to the quartz bars. The data have been compared with a Monte-Carlo simulation, providing an estimation of the radiator's probability of the total internal reflection and inefficient area at the edges of the bars
Surface Quality of a Work Material Influence on Vibrations in a Cutting Process
The problem of stability in the machining processes is an important task. It
is strictly connected with the final quality of a product. In this paper we
consider vibrations of a tool-workpiece system in a straight turning process
induced by random disturbances and their effect on a product surface. Basing on
experimentally obtained system parameters we have done the simulations using
one degree of freedom model. The noise has been introduced to the model by the
Langevin equation. We have also analyzed the product surface shape and its
dependence on the level of noise.Comment: 12 pages, PDF of figures can be obtained from
http://archimedes.pol.lublin.pl/~raf/graf/fpic.pd
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Modelling and simulation of the dynamic cutting process and surface topography generation in nano/micro cutting
In nano/micro cutting process, the surface quality is heavily dependent on all the dynamic factors in machining including those from the material, tooling, cutting parameters, servo accuracy, mechanical structure deformation, and non-linear factors as well. The machined surfaces are generated based on the tool profile and the real tool path combining with the various external and internal disturbances. To bridge the gap between the machining conditions and the surface quality, the integrated simulation system presented involves the dynamic cutting process, control/drive system and surface generation module. It takes account all the intricate aspects of the cutting process, such as material heterogeneity, regenerative chatter, built-up edge (BUE), spindle run-out, environmental vibration, and tool interference, etc. The frequency ratio method is used to interpret the surface topography and texture formation. The proposed systematic modelling approach is verified by the cutting experiment
Improved surface quality of anisotropically etched silicon {111} planes for mm-scale integrated optics
We have studied the surface quality of millimeter-scale optical mirrors
produced by etching CZ and FZ silicon wafers in potassium hydroxide to expose
the planes. We find that the FZ surfaces have four times lower noise
power at spatial frequencies up to . We conclude that mirrors
made using FZ wafers have higher optical quality
Multi-parameter surface-quality analysis
Recent years have been rich in the research in the field of metrology. Firstly, the research focused on contact gauges, especially on contact profilometers. Consequently, with the investigation and development of materials, it was revealed that contact profilers were not sufficient and it was necessary to focus on 3D non-contact optical profilometers and surveyors. This article describes a new method of the surface control. It is a method of surface printing using the SILOFLEX© dental silicone and the subsequent evaluation. The surface-quality control is carried out using profile geometries that are divided into two basic groups. The first group consists of contact devices and the second group consists of non-contact devices. Both of these groups can use 2D- and 3D-measurement options. Subsequently, the surface quality is assessed using the amplitude parameters specified in the standards. These parameters have to be evaluated complexly using the multi-parameter analysis. This analysis is used today by more and more companies and has become an essential part of the control. It is utilized for all the material types from the engineering industry to medicine. The article deals with a non-contact measurement method. It also shows possibilities of an evaluation using the multi-parameter analysis.TBU in Zlin [IGA/FT/2017/002]; [IGA/FT/2017/010
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