Mechanical Engineering

Grinding is one of the basic precise material removal methods. Abrasive and shape wear, as well as smearing of the tools' active surface handicap the processing results. The loss of cutting capacity in abrasive tools or alteration of their shape influences the surface quality and precision of the workpiece dimensions and its shape. Evaluation of the abrasive tool surface is the basic criterion of forecasting the tools' durability and the process results. The applied method of laser scanning made determination of the surface coordinates and subsequently of its geometric features with micrometric accuracy possible. Using the information on the abrasive tool surface geometric structure, a methodology of evaluation of the level of changes in geometric features of the tool during the grinding process was developed. Criteria for evaluation of the level of abrasive grains attritious wear, the degree of smearing of the abrasive tool surface and evaluation of the cutting capability of the abrasive tools were determined. The developed method allowed for evaluation of the level of abrasive tools' wear, and subsequently formed foundations for assessment of the influence of the grinding parameters on the durability of abrasive tools, evaluation of the influence of the parameters of the process of shaping the abrasive tools' active surfaces on their geometric characteristics and evaluation of the level of correlation between the monitored process parameters and the degree of the abrasive tools' wear. SCANNING 36: 53-63, 2014.

Szlifowanie jest jednym z najczęściej stosowanych procesów obróbki dokładnej. Proces usuwania materiału następuje w wyniku oddziaływań wielu ziaren ściernych o zróżnicowanym rozmiarze i kształcie. Parametry kinematyczne oraz cechy geometryczne kontaktu ziarna i materiału obrabianego wpływają na efektywność oraz cechy energetyczne procesu [10]. W typowych procesach szlifowania głębokość skrawania pojedynczym ostrzem nie przekracza kilku mikrometrów. Ze względu na stochastyczny charakter budowy narzędzi ściernych, rozmiaru ziaren i losowy rozkład cech geometrycznych naroży, modelowanie ich cech stale są trudnym zadaniem. W wielu ośrodkach badawczych podejmowane są próby modelowania powierzchni ziaren ściernych [11], całych powierzchni czynnych ściernic [3-4] jaki i procesów szlifowania [1-2,6-9]. W pracy przedstawiono metodykę modelowania geometrii naroży ziaren ściernych z wykorzystaniem wyników badań ziaren rzeczywistych z elektrokorundu szlachetnego 99A o rozmiarze 320. Przedstawio...

The increase in requirements for accuracy and properties of elements, minimisation of the wear of materials, mass and dimensions of elements, the increase in load capacity and endurance, and also the development of manufacturing technology, lead to the development of many measurement methods and equipment to carry them out as well as to increase the number of parameters for use in evaluation of the surface stereometry features. Taking into account new requirements, a new system for evaluation of the surface stereometry features was developed. The system consists of a collectionof evaluation methods and applications to complex analysis and surface evaluation. In this paper a methodology for selecting parameters for complex evaluation of the surface topography features is presented. Analysis of the classification ability of parameters was performed. It was proved that when selecting parameters for the classification of a collection one should consider: classification ability, technolo...

The article presents a comprehensive system to modeling and evaluation of technical surfaces topography allowing for cheap and full assessment of the geometric structure of the surface. The system consists of a large number (over 200) scripts, functions and applications, also with the graphical user interface (GUI). The system was developed using Matlab computing system, which is the most commonly used system for scientific and engineering calculations.

Analysis of the geometric features and determination of the condition of the surfaces machined during an abrasive process is of crucial importance for evaluation of their wear properties. Numerous parameters can be used for assessing topography of technical surfaces. Many of them contain information that is general or poorly correlated with the wear features. The group of parameters used for such purpose should include those that do not cause information redundancy and provide distinct information. Evaluation of the surface geometric structure after precision machining is a difficult process due to the limited scope of unevenness heights that fit within the range of a few micrometers to a few nanometers. In this paper the synthetic indexes of the evaluation of extra smooth surfaces were created, taking into consideration numerous elementary parameters. The value of the synthetic index was determined as the geometric average of the partial indexes which, when compared to the arithmet...

The article presents the scientific problems and development trends of abrasive micromachining. The research problems were characterized and the results of the analysis of research directions based on programs of implemented projects in the world's scientific centers were presented. The most important features of the abrasive micromachining were described. The importance of phenomena important in micromachining were emphasized, such as discontinuity of material removal processes, the importance of friction in the treatment zone and topography of the tool. Scientific problems requiring solutions, important for increasing the efficiency of processes micromachining were indicated. New methods of the micro grinding and criteria for modeling and simulation of grinding processes were presented. Proposals for directions for further research and industrial applications of new processes and tools for abrasive micromachining were developed.

In the paper a methodology of neural modelling of grinding process using process simulation data was presented. Grinding process simulation parameters were chosen based on the results of the experiment. The experiment consisted of an analysis of the influence of processing parameters (allowance ae, table feed speed vft and table axial feed fa) on the roughness parameter Sa of the grinded surface. Accuracy of fitting the results of numerical simulation results and the accuracy of the neural network model was determined.

One of the most important procedures in modern surface metrology is digital filtering. It is realized by many filters which are complicated mathematical tools for analysis of a wide variety of surface characteristics. In practice, filters are used among others for denoising, correcting the data obtained from measuring tools and displaying important characteristics of surfaces. The ISO committee is continuing works to develop the standards of the ISO 16610 group, concerning the digital filters. This group contains description of various filters, namely: linear profile filters (basic concepts – ISO/DIS 16610-20, spline filters - ISO/DIS 16610-22, spline wavelets – ISO/DIS 16610-29), morphological profile filters (basic concepts – ISO/DIS 16610-40, disk and horizontal line-segment – ISO/DIS 16610-41, scale space techniques – ISO/DIS 16610-49), robust areal filters (Gaussian regression filters – ISO/DIS 16610-71) and areal morphological filters (segmentation – ISO/DIS 16610-85). The pap...

The application of the theory of fuzzy sets lets on the qualitative evaluation of the surface on the basis of parameters of the geometrical structure of surface. Enlarges this the communicability of the evaluation of the structure of the geometrical surface which is not described exclusively by the series often confounding of many parameters. This paper is introduced to evaluation the guild of surface stereometry on the example of amplitude parameters. The using of fuzzy logic methods makes possible the creation of the linguistic model which contains influence of each parameters describing the surface stereometry on the correct classification.

Residual stresses influence, among other parameters, on the performance characteristics of the machine, such as deformation, static and dynamic strength, material usage, or the strength of the contact. Extensional stresses as a result of abrasive machining reduce the fatigue strength for the dynamically loaded machine parts. It is preferred when the surface layer of the compressive stress is obtained. Therefore, it is recommended to reduce or remove most of the tensile stresses in the elements of the machine, for example, by reducing the value of technological parameters (feed-in). Note also that the type of occurring stresses depends also on the characteristics of the used grinding wheel, where the importance has the type of selected abrasive material. Grinding, eg. grinding wheel with aloxite grain is almost always the occurrence of tensile stresses, in contrast to CBN, which causes the formation of an compressive stresses in the surface layer. The article presents the issues rela...