Metrological aspects of evaluation of diamond abrasive film topography for precise microfinishing

Jednym z ważnych zadań, dotyczących prognozowania cech stereometrycznych powierzchni, po wygładzaniu foliami ściernymi, jest wyznaczenie parametrów charakteryzujących powierzchnię czynną. W publikacji opisano metodykę oraz wyniki badań dotyczących cech stereometrycznych powierzchni na przykładzie diamentowych folii ściernych z ziarnami o nominalnej wielkości pół mikrometra. Narzędzia te stosowane są w różnych zabiegach precyzyjnego wygładzania powierzchni o bardzo wysokiej gładkości i dokładności. Przedstawiono wyniki analizy rozmieszczenia wierzchołków w płaszczyźnie równoległej do powierzchni folii oraz w kierunku do niej prostopadłym. Badając ukształtowanie wierzchołków ziaren i przestrzenie między nimi, można wnioskować o potencjale obróbkowym folii ściernych.One of important tasks related to prognosis of the surface stereometry after microfinishing with abrasive films is delimitation of parameters characterising the active surface. The methodology and investigation results concerned the features of stereometric surfaces on an example of diamond abrasive foils with half-micrometer nominal grain size are described in the paper. These tools are applied to different treatments of microfinishing the surface of very high smoothness and precision. The Nanosurf microscope Atomic Force Microscopy AFM of Mobile S type was applied to investigations of tools of very small grains. There were obtained the topography images of the abrasive film surface of 0.5 micrometer nominal grain size (Fig. 1). In next analyses there were presented the surfaces of grains, formed islands, (Fig. 3) on which there was marked the elevation top and projection on the plane Oxy of the sections binding the grain tops. Using the decomposition of the surface into Voronoi cells, the grains tops were determined with the closest neighbours method. Beginning from the highest top, investigations of abrasive grains and their tops were conducted on various depths h. On the basis of the performed investigations (Figs. 2 and 3), the surface area of the Voronoi cells was determined (Fig. 4) as decomposition of the surface into areas with the central point of the coordinates x, y marking the position of the grain top z(x, y). The results of analysis of the top sizes in the plane parallel to the film surface and in the orthogonal direction are given. From studying the form of the grain tops and spaces between them one can conclude about the processing potential of abrasive films

Basics of the superfinishing results prognostication by the diamond lapping films

Superfinishing with the use of diamond lapping films differs to a significant extent from other machining methods. This is finishing surface machining, one which is realized by a slow rewinding of a microfinishing film, putting it in an oscillating motion and pressing the tool to the surface being machined. The surface being machined moves with a speed which is substantially greater than that of the tool feed. A characteristic feature of the process is a one-time use of the tool, the result being a need of an optimal selection of the machining parameters. Investigations of the topography of the microfinishing film surface were conducted with the use of new parameters that describe the arrangement and the shape of the vertices of active grains. The following were used for the purpose of assessment: coefficients that had been developed that describe the features of the shape of the tool surface, such as the standardized coefficient of the flatness of vertices wNki, the standardized number of vertices in relation to an area unit LNwi and the dissipation coefficient of the height of the location of vertices wNrwi. For the purpose of the assessment of the smoothening ability of diamond lapping films the smoothening potential coefficient wp was developed, which is defined as the geometric mean of the abovementioned indices

Assessment of the technological potential of Diamond Lapping Films to superfinishing using information about the active surface topography

Ocena parametrów charakteryzujących powierzchnię czynną folii ściernych jest podstawą prognozowania cech stereometrycznych powierzchni po wygładzaniu [1]. W artykule przedstawiono wyniki badań i analiz topografii powierzchni czynnej diamentowych folii ściernych. Określone fragmenty folii ściernej jednokrotnie są aktywne, gdyż folia jest w sposób ciągły przewijana w jednym kierunku z rolki podającej na odbierającą. Dobre wykorzystanie potencjału obróbkowego zależy zatem od doboru parametrów zapewniających wypełnienie produktami obróbki przestrzeni między ziarnami [2, 3]. Badając ukształtowanie agregatów diamentowych ziaren ściernych i przestrzenie między nimi można wnioskować o potencjale obróbkowym folii ściernej oraz określać zalecaną prędkość przesuwu folii, zapewniającą maksymalne wykorzystanie tego potencjału.Abrasive films are produced by the American company 3M. 3M™ Diamond Lapping Films are comprised of tightly graded diamond mineral uniformly coated on a polyester film backing enabling long abrasive life with a superior finish throughout the life of the product. Main applications of diamond abrasive tools is fiber optic connector processing, flat lapping, roll superfinishing. Diamond Lapping Films are used for hard finishing of grind materials such as glass, stone, carbide, ceramics, hardened metals, exotic alloys and composites. Parameters of the backing polyester film are: nominal thickness: 1...3 mil (25,4…76,2 žm), actual thickness: 0.92 mil...2.97 mil (23,37…75,44 žm), ultimate tensile strength - 26,500 psi ( 0,18 MPa). Nominal sizes of diamond grainsvary in the range: 0,1…60 žm. Grains are embedded in bonding resin on the backing polyester film [3]. Assessment of the properties of coated abrasives for use in Diamond Lapping Film is a complex problem due to a wide range of superfinishing conditions and nonuniform geometry of aggregates of grains (Fig. 1) [4]. One important task of forecasting the surface stereometric features, after superfinishing with abrasive films, is to define the parameters characterizing the active flank. The paper presents results of research and analysis of the diamond abrasive film surface topography. Studying the shape of aggregates of diamond grains and the spaces between them enables one to conclude about the technological potential of abrasive film (Fig. 5). Investigations of the topography surface of tools for precise finishing were carried out with use of confocal laser scanning microscopy (Fig. 6)

Effect of superfinishing methods kinematic features on the machined surface

The carried out research of the processes for the treatment of superfinishing with the application of microfinishing films of IMFF type with heaping the grain from the alundum with the nominal size of 15 micrometers for the different cinematic system proved that the topography of surface after smoothening depends on the cinematic features of process. It is demonstrated that the machining with oscillation can be substituted and the similar effects can be obtained as a result of the deviation from the parallelism of the directions of object feed and foil feed. This means the possibility to apply the super finisher attachments with a simpler building

Confocal laser scanning microscopy used for assessment of microstructure of milk fouling formed during high-heat milk treatment

W pracy przedstawiono zagadnienia związane z powstawaniem zanieczyszczeń mlekowych pod wpływem wysoko temperaturowej obróbki mleka. Ocenie poddano trzy płytki ze stali nierdzewnej o różnej chropowatości, zanieczyszczone gorącym mlekiem. Do oceny mikrostruktury powstających osadów wykorzystano laserowy mikroskop pomiarowy LEXT OLS4000 firmy Olympus. Analiza uzyskanych danych pomiarowych prowadzona była w środowisku TalyMap Platinum 4.0. Uzyskane wyniki badań pozwoliły określić różnice w ilości i budowie tworzących się osadach mlekowych w zależności od wykończenia powierzchni ze stali nierdzewnej. Na podstawie przeprowadzonych badań stwierdzono, że pomiar techniką LSCM może być z powodzeniem wykorzystany do analiz zanieczyszczeń powstających w procesach przetwórstwa żywności.Formation of fouling during milk heat treatment in dairy industries is still a serious problem both technically and economically. The paper presents the issues related to the formation of milk fouling. Three types of plates of different roughness, contaminated by hot milk were used in the study. The microstructure of impurities was evaluated by the LCSM method, using the laser scanning confocal microscope Olympus LEXT OLS4000. Digital image creation and image analysis were performed using Software TalyMap Platinum 4.0. The results were helpful in determining the quantity and microstructure of milk fouling created on plates depending on the finishing surface. The results showed that the increase in the surface roughness caused the increase in the amount of deposits formed on them. The analyses of the LSCM results also indicate the forming of a few layers of deposits during milk heat treatment. They may be important in the cleaning process. On the basis of the investigation results it can be stated that the measurement technique LSCM is useful for evaluation of impurities built up on surfaces of equipments during food production

Modelling and Analysis of Displacement of Materials Characterized by Different Properties in the Zone of Microcutting

This paper presents the results of numerical studies conducted using Ansys system, the impact of model’s parameters on the workpiece displacement formation. In the simulation, one used the model of real grain. The authors analyzed the influence of material’s properties on the formation of lateral flow in the machining zone. Observation was also made for the material’s stagnation zone, which depends on geometrical characteristics of the blade, shape of its surface and characteristics of the workpiece

A method and new parameters for assessing the active surface topography of diamond abrasive films

This paper describes the methodology and results of research on the tribological characteristics of the surfaces of diamond abrasive films using a stereometric analysis. Abrasive films are used in various finishing processes of surfaces with very high smoothness and accuracy. A morphological analysis of surface vertexes in the plane that is parallel to the film surface and the perpendicular direction allowed an assessment of the distances between particles by means of a decomposition of the surface into Voronoi cells. When studying the formation of the aggregates of diamond particles and the spaces between them, one may infer about the machining potential of the abrasive film and determine the recommended kinematic conditions of the film that ensures the maximum use of this potential. Owing to the investigations related to the morphology of diamond abrasive films, one can observe relevant characteristic abrasive aggregates that vary in term of size and shape depending on particle sizes. Units with elongated shapes have a superior machining ability in relation to spherical-shaped units. One of significant parameters proposed that describe the technological potential of abrasive films is the edge length to width ratio of diamond units. Different operating modes are discussed. A statistical analysis of the dynamics observed of abrasive interfaces allowed a pertinent description of the abrasive process taking into consideration nominal and apparent as well as abrasively efficient morphologies

Evaluation of Micromachining Processes Using Data in the Format and Geometric Characteristics of Micro-Chips

Studies on micro-chips formed in the process of micromachining, including grinding and microfinishing using abrasive films, were conducted. Geometric characteristics of the micro-chips were analyzed and the presence of very long chips compared to their width was observed. One also reported the presence of very high temperatures in the treatment zone despite the applied cooling, which resulted in the formation of spherical chips. The occurrence of two characteristic spherical chip structures was observed followed by evaluation of their chemical composition. Based on the tabular structure of band chips, characteristic micro-discontinuities in the microcutting process were determined

Numerical simulation of shear slitting process of grain oriented silicon steel using sph method

Mechanical cutting allows separating of sheet material at low cost and therefore remains the most popular way to produce laminations for electrical machines and transformers. However, recent investigations revealed the deteriorating effect of cutting on the magnetic properties of the material close to the cut edge. The deformations generate elastic stresses in zones adjacent to the area of plastically deformed and strongly affect the magnetic properties. The knowledge about residual stresses is necessary in designing the process. This paper presents the new apprach of modeling residual stresses induced in shear slitting of grain oriented electrical steel using mesh-free method. The applications of SPH (Smoothed Particle Hydrodynamics) methodology to the simulation and analysis of 3D shear slitting process is presented. In experimental studies, an advanced vision-based technology based on digital image correlation (DIC) for monitoring the cutting process is used

Application of the three-dimensional scanning system to evaluation of the abrasive tool wear

Zużycie narzędzia ściernego jest podstawowym kryterium oceny szlifowalności materiału obrabianego, które ma w konsekwencji decydujący wpływ na okres trwałości narzędzi ściernych. W pracy dokonano oceny zużycia narzędzi ściernych z zastosowaniem skanowania laserowego. Zastosowana metoda skanowania laserowego umożliwiła wyznaczenie cech stereometrycznych narzędzi ściernych. Przedstawiono przykłady zastosowania opracowanej metody do oceny zużycia narzędzi ściernych w procesach szlifowania.Grinding is one of the basic precise machining methods. Abrasive and shape wear, as well as smearing of the tool 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 tool durability and the process results. The applied method of laser scanning enabled determination of the surface coordinates and subsequently of its stereometric features. Using the information on the abrasive tool surface stereometric structure, evaluation of the level of changes in stereometric features of the tool during the machining process is presented. The developed method allowed for evaluation of the level of abrasive tool wear and, subsequently, formed foundations for assessment of the influence of machining parameters on the durability of abrasive tools, evaluation of the influence of the parameters of the process of shaping the abrasive tool active surfaces on their stereometric characteristics and evaluation of the level of correlation between the monitored process parameters and the degree of the abrasive tool wear