scholarly journals Suppression of Surface Waviness Error of Fresnel Micro-Structured Mold by Using Non-Integer Rotation Speed Ratio in Parallel Grinding Process

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 652 ◽  
Author(s):  
Yongcheng Pan ◽  
Qingliang Zhao ◽  
Bing Guo ◽  
Bing Chen ◽  
Jinhu Wang
Keyword(s):  
Large Scale ◽  
Rotation Speed ◽  
Simulation Models ◽  
Speed Ratio ◽  
Grinding Process ◽  
Surface Waviness ◽  
Experiment Research ◽  
Grinding Kinematics ◽  
Parallel Grinding ◽  
Proper Wave

Fresnel micro-structured lenses are widely used in the field of modern optoelectronic technology. High-precision Fresnel micro-structured mold is the key technology to achieve its large-scale replication production. Focusing on the surface waviness error of Fresnel micro-structured mold machined by parallel grinding process, this paper conducted theoretical modeling and experiment research. Based on the grinding kinematics theory, the simulation models of the surface waviness topography and the circular waviness profiles of the ground Fresnel micro-structured mold were developed, considering the combined influence of the non-integer rotation speed ratio and other grinding parameters. A series of grinding experiments were carried out to verify the proposed simulation models. The influence of a non-integer rotation speed ratio and a wave-shift value upon the surface waviness error of the ground Fresnel micro-structured molds were analyzed. Both the simulation and experimental results proved that choosing the non-integer rotation speed ratio and a proper wave-shift value could greatly reduce the surface waviness error and improve the surface quality and uniformity.

An investigation of the surface waviness features of ground surface in parallel grinding process

2020 ◽  
Vol 170 ◽  
pp. 105351 ◽  
Author(s):  
Yongcheng Pan ◽  
Qingliang Zhao ◽  
Bing Guo ◽  
Bing Chen ◽  
Jinhu Wang ◽  
...  
Keyword(s):  
Ground Surface ◽  
Grinding Process ◽  
Surface Waviness ◽  
Parallel Grinding

scholarly journals Experimental Analysis of Process Parameter Effects on Vibrations in the High-Speed Grinding of a Camshaft

2020 ◽  
Vol 66 (3) ◽  
pp. 175-183 ◽  
Author(s):  
Tao Liu ◽  
Zhaohui Deng ◽  
Lishu Lv ◽  
Shuailong She ◽  
Wei Liu ◽  
...  
Keyword(s):  
Process Parameters ◽  
High Speed ◽  
Survey Methods ◽  
Process Condition ◽  
Speed Ratio ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Surface Waviness ◽  
High Speed Grinding ◽  
Grinding Machine

The capacity to minimize vibrations in grinding by the selection of appropriate process parameters is a significant benefit in the process optimization of cam grinding. This paper presents survey methods to characterize and quantify the vibrations and waviness in a camshaft grinding application. First, a modal analysis was conducted to study the dynamic characteristic of a camshaft grinding machine. Then, developed methods were applied to study the influences of various parameters on vibrations in the high-speed grinding of a camshaft. Furthermore, the influence of each grinding process condition on surface waviness in high-speed camshaft grinding was studied. The results show that the vibrations and the surface waviness change with the increase of grinding depth, and an appropriate grinding wheel speed combined with a workpiece speed has, for most grinding conditions, a reducing effect on vibration magnitudes and waviness. Finally, the specific indications about the optimal grinding process parameters in terms of dynamic characteristics of the grinding machine were given, and the speed ratio=1.2 is a novel choice.

scholarly journals Surface Quality Improvement by Using a Novel Driving System Design in Single-Side Planetary Abrasive Lapping

Materials ◽  
2021 ◽  
Vol 14 (7) ◽  
pp. 1691 ◽  
Author(s):  
Zhenzhen Chen ◽  
Donghui Wen ◽  
Jianfei Lu ◽  
Jie Yang ◽  
Huan Qi
Keyword(s):  
System Design ◽  
Surface Quality ◽  
Material Removal ◽  
Rotation Speed ◽  
Target Surface ◽  
Speed Ratio ◽  
The Novel ◽  
Particle Trajectories ◽  
Driving System ◽  
Single Side

For the traditional single-side planetary abrasive lapping process particle trajectories passing over the target surface are found to be periodically superposed due to the rational rotation speed ratio of the lapping plate to workpiece that could affect the material removal uniformity and hence its surface quality. This paper reports on a novel driving system design with combination of the tapered roller and contact roller to realize the irrational rotation speed ratio of the lapping plate to workpiece in the single-side planetary abrasive lapping process for the improvement of surface quality. Both of the numerical and experimental investigations have been conducted to evaluate the abrasive lapping performance of the novel driving system. It has been found from the numerical simulation that particle trajectories would theoretically cover the whole target surface if the lapping time is long enough due to their non-periodic characteristics, which can guarantee the uniformity of material removal from the surface of workpiece with relatively high surface quality. The encouraging experimental results underline the potential of the novel driving system design in the application of the single-side planetary abrasive lapping for the improvement of the surface quality in terms of surface roughness and material removal uniformity.

scholarly journals Synthesizing published knowledge of boreal forest cover change for large-scale landscape dynamics modelling

2003 ◽  
Vol 79 (1) ◽  
pp. 132-146 ◽  
Author(s):  
Dennis Yemshanov ◽  
Ajith H Perera
Keyword(s):  
Boreal Forest ◽  
Large Scale ◽  
Forest Canopy ◽  
Forest Cover ◽  
Forest Succession ◽  
Simulation Models ◽  
Limiting Factors ◽  
Sources Of Information ◽  
Forest Cover Change ◽  
Discrete State

We reviewed the published knowledge on forest succession in the North American boreal biome for its applicability in modelling forest cover change over large extents. At broader scales, forest succession can be viewed as forest cover change over time. Quantitative case studies of forest succession in peer-reviewed literature are reliable sources of information about changes in forest canopy composition. We reviewed the following aspects of forest succession in literature: disturbances; pathways of post-disturbance forest cover change; timing of successional steps; probabilities of post-disturbance forest cover change, and effects of geographic location and ecological site conditions on forest cover change. The results from studies in the literature, which were mostly based on sample plot observations, appeared to be sufficient to describe boreal forest cover change as a generalized discrete-state transition process, with the discrete states denoted by tree species dominance. In this paper, we outline an approach for incorporating published knowledge on forest succession into stochastic simulation models of boreal forest cover change in a standardized manner. We found that the lack of details in the literature on long-term forest succession, particularly on the influence of pre-disturbance forest cover composition, may be limiting factors in parameterizing simulation models. We suggest that the simulation models based on published information can provide a good foundation as null models, which can be further calibrated as detailed quantitative information on forest cover change becomes available. Key words: probabilistic model, transition matrix, boreal biome, landscape ecology

Large-Scale Simulation Models in Population and Development: A Reply

1977 ◽  
Vol 3 (1/2) ◽  
pp. 126
Author(s):  
W. Brian Arthur ◽  
Geoffrey McNicoll
Keyword(s):  
Large Scale ◽  
Simulation Models ◽  
Large Scale Simulation

Experiment on Surface Roughness and Acoustic Emission Signal in Infeed Period of Cylindrical Plunge Grinding

2013 ◽  
Vol 690-693 ◽  
pp. 2442-2445 ◽  
Author(s):  
Hao Lin Li ◽  
Hao Yang Cao ◽  
Chen Jiang
Keyword(s):  
Surface Roughness ◽  
Acoustic Emission ◽  
Acoustic Emission Signal ◽  
Feed Rate ◽  
Grinding Process ◽  
Experiment Research ◽  
Plunge Grinding ◽  
Emission Signal ◽  
Ae Signal ◽  
Ae Signals

This work presents an experiment research on Acoustic emission (AE) signal and the surface roughness of cylindrical plunge grinding with the different infeed time. The changed infeed time of grinding process is researched as an important parameter to compare AE signals and surface roughnesses with the different infeed time in the grinding process. The experiment results show the AE signal is increased by the increased feed rate. In the infeed period of the grinding process, the surface roughness is increased at first, and then is decreased.

scholarly journals Grinding of AISI 4340 steel with interrupted cutting by aluminum oxide grinding wheel

2015 ◽  
Vol 68 (2) ◽  
pp. 229-238
Author(s):  
Hamilton Jose de Mello ◽  
Diego Rafael de Mello ◽  
Eduardo Carlos Bianchi ◽  
Paulo Roberto de Aguiar ◽  
Doriana M. D'Addona
Keyword(s):  
Aluminum Oxide ◽  
Rotation Speed ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Wheel Wear ◽  
Machined Surface ◽  
Aisi 4340 Steel ◽  
4340 Steel ◽  
Grinding Machine ◽  
Aisi 4340

AbstractThere has been a great advance in the grinding process by the development of dressing, lubri-refrigeration and other methods. Nevertheless, all of these advances were gained only for continuous cutting; in other words, the ground workpiece profile remains unchanged. Hence, it becomes necessary to study grinding process using intermittent cutting (grooved workpiece – discontinuous cutting), as little or no knowledge and studies have been developed for this purpose, since there is nothing found in formal literature, except for grooved grinding wheels. During the grinding process, heat generated in the cutting zone is extremely high. Therefore, plenty of cutting fluids are essential to cool not only the workpiece but also the grinding wheel, improving the grinding process. In this paper, grinding trials were performed using a conventional aluminum oxide grinding wheel, testing samples made of AISI 4340 steel quenched and tempered with 2, 6, and 12 grooves. The cylindrical plunge grinding was performed by rotating the workpiece on the grinding wheel. This plunge movement was made at three different speeds. From the obtained results, it can be observed that roughness tended to increase for testing sample with the same number of grooves, as rotation speed increased. Roundness error also tended to increase as the speed rotation process got higher for testing the sample with the same number of grooves. Grinding wheel wear enhanced as rotation speed and number of grooves increased. Power consumed by the grinding machine was inversely proportional to the number of grooves. Subsuperficial microhardness had no significant change. Micrographs reveal an optimal machining operation as there was no significant damage on the machined surface.

scholarly journals High Dimensional Electromagnetic Interference Signal Clustering Based On SOM Neural Network

2016 ◽  
Vol 20 (1) ◽  
pp. 27
Author(s):  
Hongyi Li ◽  
Di Zhao ◽  
Shaofeng Xu ◽  
Pidong Wang ◽  
Jiaxin Chen
Keyword(s):  
Neural Network ◽  
Electromagnetic Interference ◽  
Large Scale ◽  
Spectral Characteristics ◽  
Simulation Models ◽  
Integrated System ◽  
Interference Signal ◽  
Global Features ◽  
Strongly Nonlinear ◽  
Emc Design

In this paper, we study the spectral characteristics and global representations of strongly nonlinear, non-stationary electromagnetic interferences (EMI), which is of great significance in analysing the mathematical modelling of electromagnetic capability (EMC) for a large scale integrated system. We firstly propose to use Self-Organizing Feature Map Neural Network (SOM) to cluster EMI signals. To tackle with the high dimensionality of EMI signals, we combine the dimension reduction and clustering approaches, and find out the global features of different interference factors, in order to finally provide precise mathematical simulation models for EMC design, analysis, forecasting and evaluation. Experimental results have demonstrated the validity and effectiveness of the proposed method.

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