Adaptive Grinding Process—Prevention of Thermal Damage Using OPC-UA Technique and In Situ Metrology

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Matthias Steffan ◽  
Franz Haas ◽  
Alexander Pierer ◽  
Gentzen Jens
Keyword(s):  
Thermal Damage ◽  
Control Variable ◽  
Safety Margin ◽  
Value Added ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Production Chain ◽  
Process Step ◽  
Edge Zone ◽  
Control Concept

The production process grinding deals with finishing of hardened workpieces and is one of the last stages of the value-added production chain. Up to this process step, considerable costs and energy have been spent on the workpieces. In order to avoid production rejects, significant safety reserves are calculated according to the present state of the art. The authors introduce two approaches to minimize the safety margin, thus optimizing the process’ economic efficiency. Both control concepts use the feed rate override of the machining operation as regulating variable to eliminate thermal damage of the edge zone. The first control concept is developed to avoid thermal damage in cylindrical plunge grinding by controlling the cutting forces. Therefore, the industrial standard Open Platform Communications Unified Architecture (OPC-UA) is used for the communication between a proportional–integral–derivative (PID) controller and the SINUMERIK grinding machine tool control system. For noncircular workpieces, grinding conditions change over the circumference. Therefore, thermal damage cannot be ruled out at any time during the grinding process. The authors introduce a second novel control approach, which uses a micromagnetic measure that correlates with thermal damage as the main control variable. Hence, the cutting ability of the grinding wheel and thermal damage to the workpiece edge zone is quantified in the process. The result is a control concept for grinding of noncircular workpieces, which opens up fields for major efficiency enhancement. With these two approaches, grinding processes are raised on higher economic level, independently of circular and noncircular workpiece geometries.

Modeling of the Grinding Wheel Topography Depending on the Recipe-Dependent Volumetric Composition

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Sebastian Barth ◽  
Michael Rom ◽  
Christian Wrobel ◽  
Fritz Klocke
Keyword(s):  
Research Work ◽  
Distribution Functions ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Edge Zone ◽  
Application Behavior ◽  
Wheel Topography ◽  
Grinding Wheel Topography ◽  
Grinding Tool

The prediction of the grinding process result, such as the workpiece surface quality or the state of the edge zone depending on the used grinding wheel is still a great challenge for today's manufacturers and users of grinding tools. This is mainly caused by an inadequate predictability of force and temperature affecting the process. The force and the temperature strongly depend on the topography of the grinding wheel, which comes into contact with the workpiece during the grinding process. The topography of a grinding wheel mainly depends on the structure of the grinding wheel, which is determined by the recipe-dependent volumetric composition of the tool. So, the structure of a grinding tool determines its application behavior strongly. As result, the knowledge-based prediction of the grinding wheel topography and its influence on the machining behavior will only be possible if the recipe-dependent grinding wheel structure is known. This paper presents an innovative approach for modeling the grinding wheel structure and the resultant grinding wheel topography. The overall objective of the underlying research work was to create a mathematical-generic grinding tool model in which the spatial arrangement of the components, grains, bond, and pores, is simulated in a realistic manner starting from the recipe-dependent volumetric composition of a grinding wheel. This model enables the user to determine the resulting grinding wheel structure and the grinding wheel topography of vitrified and synthetic resin-bonded cubic boron nitride (CBN) grinding wheels depending on their specification and thus to predict their application behavior. The originality of the present research results is a generic approach for the modeling of grinding tools, which takes into account the entire grinding wheel structure to build up the topography. Therefore, original mathematical methods are used. The components of grinding wheels are analyzed, and distribution functions of the component's positions in the tools are determined. Thus, the statistical character of the grinding wheel structure is taken into account in the developed model. In future, the presented model opens new perspectives in order to optimize and to increase the productivity of grinding processes.

scholarly journals Análise de Sinais de Emissao Acústica e Estatística Counts na Detecção da Alteração Microestrutural na Retificação de Aço 1045

2018 ◽  
Vol 3 (1) ◽  
pp. 414
Author(s):  
Felipe Aparecido Alexandre ◽  
Martin Antonio Aulestia Viera ◽  
Pedro Oliveira Conceição Junior ◽  
Leonardo Simões ◽  
Wenderson Nascimento Lopes ◽  
...  
Keyword(s):  
Acoustic Emission ◽  
Value Added ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Frequency Bands ◽  
Finishing Process ◽  
Grinding Conditions ◽  
Grinding Machine ◽  
1045 Steel ◽  
Selection Of

Grinding is a high-precision, high-value-added finishing process as it is usually the last stage of the manufacturing chain. However, unsatisfactory results may occur, mainly due to changes in the microstructure of the ground workpiece. Such changes are caused by the high temperatures involved in the process due to the grinding conditions in which the part was subjected. In this way, the main objective of this work is the monitoring of the grinding process in order to detect changes in the signal and to relate them with damage occurred in the ground workpiece. The tests were carried out on a surface grinding machine, aluminum oxide grinding wheel and ABNT 1045 steel parts. Metallography was performed on the parts for a more further analysis of their microstructure. The recording of signals was obtained at a sample rate of 2 MHz through an acoustic emission sensor (AE). A frequency study for the selection of the best frequency bands that characterize damage occurred in the ground workpiece. The event counts statistic was applied to the filtered signal in the chosen frequency bands. The results of this work show that the grinding conditions influence the signal and, therefore, its frequency spectrum.Keywords: Manufacturing process; automation, monitoring; grinding process; acoustic emission, damage detection

scholarly journals Surface microgeometry treated with a precast textured grinding wheel

2020 ◽  
Vol 329 ◽  
pp. 03019
Author(s):  
Vladimir Gusev
Keyword(s):  
Surface Layer ◽  
Thermal Damage ◽  
Transverse Plane ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Geometric Errors ◽  
Time Process ◽  
Cutting Surface ◽  
Surface Microgeometry ◽  
Textured Grinding Wheel

The article considers the formation of the geometry of internal cylindrical surfaces when grinding with a precast textured wheel, which is under the influence of the unbalances main vector and a variable cutting force caused by the discreteness of the cutting surface (texture). Under the influence of these factors, each point of the axis of the textured tool makes vibrations in the transverse plane in the form of a wavelike sinusoid consisting of two sinusoids. The Space-time process of forming the processed surface is mathematically described. It is in applying wavelike sinusoids to the workpiece, taking into account their phase shift at each revolution of the workpiece. To ensure minimal geometric errors at the maximum possible productivity of the grinding process, phase shifts φf = (0.07–0.12)π and φf = (0.88–0.93)π are recommended. The results of the study are recommended for use in the production of high-precision details, primarily from materials that are prone to thermal damage to the surface layer under the influence of high temperature in the grinding zone.

scholarly journals Automatic detection of thermal damage in grinding process by artificial neural network

2003 ◽  
Vol 56 (4) ◽  
pp. 295-300 ◽  
Author(s):  
Fábio Romano Lofrano Dotto ◽  
Paulo Roberto de Aguiar ◽  
Eduardo Carlos Bianchi ◽  
Rogério Andrade Flauzino ◽  
Gustavo de Oliveira Castelhano ◽  
...  
Keyword(s):  
Neural Network ◽  
Thermal Damage ◽  
Intelligent System ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Output Variable ◽  
The Neural Network ◽  
Wheel Drive ◽  
Drive Motor ◽  
Grinding Conditions

This work aims to develop an intelligent system for detecting the workpiece burn in the surface grinding process by utilizing a multi-perceptron neural network trained to generalize the process and, in turn, obtnaing the burning threshold. In general, the burning occurrence in grinding process can be detected by the DPO and FKS parameters. However, these ones were not efficient at the grinding conditions used in this work. Acoustic emission and electric power of the grinding wheel drive motor are the input variable and the output variable is the burning occurrence to the neural network. In the experimental work was employed one type of steel (ABNT-1045 annealed) and one type of grinding wheel referred to as TARGA model ART 3TG80.3 NVHB.

Modeling of the Grinding Wheel Topography Depending on the Recipe-Dependent Volumetric Composition

2017 ◽  
Author(s):  
Fritz Klocke ◽  
Sebastian Barth ◽  
Michael Rom ◽  
Christian Wrobel
Keyword(s):  
Spatial Arrangement ◽  
Distribution Functions ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Wheels ◽  
Mathematical Methods ◽  
Edge Zone ◽  
Application Behavior ◽  
Wheel Topography ◽  
Grinding Wheel Topography

The prediction of the grinding process result, such as the workpiece surface quality or the state of the edge zone depending on the used grinding wheel is a great challenge for todays manufacturers and users of grinding tools. This is mainly caused by inadequate predictability of the forces and temperatures acting in the process, which depend on the topography of the grinding wheel coming into contact with the workpiece during the grinding process. The topography of a grinding wheel depends, beside the dressing process, on the structure of the grinding wheel, which is determined by its recipe-dependent volumetric composition. The structure of a grinding tool therefore determines its application behavior strongly. As a result, the knowledge-based prediction of the grinding wheel topography and its influence on the machining behavior is only possible if the recipe-dependent grinding wheel structure is known. In this paper, an innovative approach for modeling the grinding wheel structure and the resultant grinding wheel topography is discussed. The overall objective of the underlying research project was to create a mathematical-generic grinding wheel model in which the spatial arrangement of the components grains, bond and pores is simulated in a realistic manner starting from the recipe-dependent volumetric composition of a grinding wheel. With this model it is possible to determine the resulting grinding wheel structure and the grinding wheel topography of vitrified and synthetic resin-bonded CBN grinding wheels and thus to predict their application behavior. The originality of the present research results is a generic approach for the modeling of grinding wheels, taking into account the entire grinding wheel structure and build up the topography based on it. Using original mathematical methods, the components of grinding wheels were analyzed and distribution functions of the components were determined. Thus the statistical character of the grinding wheel structure was taken into account. In future, the presented model opens new perspectives in order to optimize and to increase the productivity of grinding processes.

RPM-Synchronous Grinding: Control Concepts to Improve Surface Qualities for a Highly Efficient Non-Circular Grinding Approach

2017 ◽  
Author(s):  
Matthias Steffan ◽  
Franz Haas ◽  
Thomas Spenger
Keyword(s):  
Grain Size ◽  
Fixed Ratio ◽  
Basic Research ◽  
Force Sensor ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Wheel Wear ◽  
Process Step ◽  
Fine Grain ◽  
Grinding Machine

The RPM-Synchronous Grinding process offers new possibilities to generate defined macro- and micro-geometries on workpieces. With present technology, various macroscopic non-circular geometries must be grinded subsequently in an oscillating process where the X-axis is coupled with the rotary workpiece-spindle axis. Such workpieces can be machined in an ordinary plunge grinding process by implementing the approach of RPM-Synchronous Non-Circular Grinding. Therefore, the workpiece and the grinding wheel rotational rates are in a fixed ratio. A non-circular grinding wheel is used to transfer its geometry onto the workpiece. The authors use a unique machine tool for basic research and control concept development for RPM-Synchronous Grinding (RSG). The machine was especially designed for this RSG technology. Highest revolution rates on the workpiece spindle are mandatory for its success. The grinding approach is performed in a two-step process. For roughing, a highly porous vitrified bonded grinding wheel with medium grain size is used. It ensures high specific material removal rates for producing the non-circular geometry on the workpiece efficiently. A control algorithm adapts this process step, which uses acquired data from a piezoelectric three-component force sensor fixed at the tailstock-side of the grinding machine. For finishing, a grinding wheel with fine grain size is suited. This process step is tuned by a digital process adaption strategy. Roughing and finishing are performed consecutively among the same clamping of the workpiece with two locally separated grinding spindles. With the presented control and adaption concepts for RPM-Synchronous Grinding, a significant increase in surface quality on the workpiece is attained. The minimization of grinding wheel wear results concurrently. Especially the automotive industry shows big interest in RPM-Synchronous Non-Circular Grinding. This emerging trend in finishing machining opens up various fields of application.

Study on Edge Contact Area and Surface Integrity of Workpiece in Point Grinding Process

2009 ◽  
Vol 407-408 ◽  
pp. 577-581
Author(s):  
Shi Chao Xiu ◽  
Zhi Jie Geng ◽  
Guang Qi Cai
Keyword(s):  
Surface Integrity ◽  
Contact Area ◽  
High Speed ◽  
Ground Surface ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Edge Contact ◽  
Cylindrical Grinding ◽  
Theoretic Foundations

During cylindrical grinding process, the geometric configuration and size of the edge contact area between the grinding wheel and workpiece have the heavy effects on the workpiece surface integrity. In consideration of the differences between the point grinding and the conventional high speed cylindrical grinding, the geometric and mathematic models of the edge contact area in point grinding were established. Based on the models, the numerical simulation for the edge contact area was performed. By means of the point grinding experiment, the effect mechanism of the edge contact area on the ground surface integrity was investigated. These will offer the applied theoretic foundations for optimizing the point grinding angles, depth of cut, wheel and workpiece speed, geometrical configuration and size of CBN wheel and some other grinding parameters in point grinding process.

scholarly journals Tentative Investigations on Reducing the Edge Effects in Pre-Polishing the Optics

2020 ◽  
Vol 10 (15) ◽  
pp. 5286
Author(s):  
Xiaolong Ke ◽  
Lei Qiu ◽  
Chunjin Wang ◽  
Zhenzhong Wang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Edge Effect ◽  
Edge Effects ◽  
Material Removal ◽  
Processing Time ◽  
Grinding Process ◽  
Element Analysis ◽  
Edge Zone ◽  
The Finite Element Analysis

The material removal depth in the pre-polishing stage of the precision optics is usually tens of microns to remove the subsurface damage and grinding marks left by the previous grinding process. This processing of the upstand edge takes a large part of the time at this stage. The purpose of this paper is to develop a method that can reduce the edge effect and largely shorten the processing time of the pre-polishing stage adopting the semirigid (SR) bonnet. The generation of the edge effect is presented based on the finite element analysis of the contact pressure at the edge zone firstly. Then, some experimentations on the edge effect are conducted, and the results proved that the SR bonnet tool can overhang the workpiece edge in the pre-polishing stage to reduce the width and height of the upstand edge to largely shorten the subsequent processing time of it. In addition, there exists a perfect overhang ratio, which generates the upstand edge with the smallest width and height, with no damage to the bonnet tool in the meantime. In addition, one combination of the pre-polishing parameters is concluded according to this method, which can be safely adopted in practical process.

scholarly journals Study on the Effect of Grinding Pressure on Material Removal Behavior Performed on a Self-Designed Passive Grinding Simulator

2021 ◽  
Vol 11 (9) ◽  
pp. 4128
Author(s):  
Peng-Zhan Liu ◽  
Wen-Jun Zou ◽  
Jin Peng ◽  
Xu-Dong Song ◽  
Fu-Ren Xiao
Keyword(s):  
Residual Stress ◽  
Surface Roughness ◽  
Service Life ◽  
Material Removal ◽  
Removal Rate ◽  
Grinding Force ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Grinding Temperature ◽  
Grinding Efficiency

Passive grinding is a new rail grinding strategy. In this work, the influence of grinding pressure on the removal behaviors of rail material in passive grinding was investigated by using a self-designed passive grinding simulator. Meanwhile, the surface morphology of the rail and grinding wheel were observed, and the grinding force and temperature were measured during the experiment. Results show that the increase of grinding pressure leads to the rise of rail removal rate, i.e., grinding efficiency, surface roughness, residual stress, grinding force and grinding temperature. Inversely, the enhancement of grinding pressure and grinding force will reduce the grinding ratio, which indicates that service life of grinding wheel decreases. The debris presents dissimilar morphology under different grinding pressure, which reflects the distinction in grinding process. Therefore, for rail passive grinding, the appropriate grinding pressure should be selected to balance the grinding quality and the use of grinding wheel.

Calculation of Effective Ground Depth of Cut by Means of Grinding Process Model

2011 ◽  
Vol 496 ◽  
pp. 7-12 ◽  
Author(s):  
Takazo Yamada ◽  
Michael N. Morgan ◽  
Hwa Soo Lee ◽  
Kohichi Miura
Keyword(s):  
Process Model ◽  
Ground Surface ◽  
Depth Of Cut ◽  
Grinding Wheel ◽  
Grinding Process ◽  
Wheel Wear ◽  
Elastic Deformations ◽  
Proposed Model ◽  
Effective Depth ◽  
Grinding Machine

In order to obtain the effective depth of cut on the ground surface, a new grinding process model taking into account thermal expansions of the grinding wheel and the workpiece, elastic deformations of the grinding machine, the grinding wheel and the workpiece and the wheel wear was proposed. Using proposed model, the effective depth of cut was calculated using measured results of the applied depth of cut and the normal grinding force.

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