Michał Wieczorowski

Surface roughness analysis of hardened steel after high-speed milling.

The work refers to analysis of various factors affecting surface roughness after end milling of hardened steel in high-speed milling (HSM) conditions. Investigations of milling parameters (cutting speed v(c) , axial depth of cut a(p) ) and the process dynamics that influence machined surface roughness were presented, and a surface roughness model, including cutter displacements, was elaborated. The work also involved analysis of surface profile charts from the point of view of vibrations and cutting force components. The research showed that theoretic surface roughness resulting from the kinematic-geometric projection of cutting edge in the workpiece is significantly different from the reality. The dominant factor in the research was not feed per tooth f(z) (according to the theoretical model) but dynamical phenomena and feed per revolution f.

Calculation of plasticity index of two-process surfaces

This paper presents the method of plasticity index calculation of isotropic two-process surfaces on the basis of index developed by Greenwood and Williamson for random surfaces of Gaussian ordinate distribution. This method was applied to computer generated isotropic two-process textures. The proposed plasticity index of two-process surface was compared with that of plateau surface and of the whole surface calculated by traditional manner. It was shown that plasticity index and generally the contact properties of two-process surfaces depended not only on plateau but also in a smaller degree on valley roughness. The method of estimation of summit radius of plateau surface from the analysis of two-process surface was presented too.

The effect of selected parameters of the honing process on cylinder liner surface topography

Many truck cylinder liners made from gray cast iron were machined. Ceramic and diamond honing stones were used in the last stages of operation: coarse honing and plateau honing. The effect of honing parameters on the cylinder liner surface topography was studied. Selected surface topography parameters were response variables. It was found that parameters from the Sq group were sensitive to honing parameter change. When plateau honing time varied, the Smq parameter increased, while the other parameters, Spq and Svq, were stable.

The analysis of directionality of honed cylinder liners surfaces

Various methods describing the directionality of honed cylinder liner surface topography are compared. The procedure of deep valleys recognition and determination of angular spectra on the basis of ratio of valleys widths in perpendicular directions is described in detail. The applications of deep valleys analysis, power spectral density, and cross-correlation functions for measured plateau-honed cylinder surface topographies were studied. It was found that method based on the deep valleys study assured correct values of honing angle estimation. Procedure of sampling interval selection for this method application was developed. Usefulness of deep valleys analysis for obtaining parameters characterizing other features specific for cylinder liner surfaces is described.

Experimental Investigation of a Hemisphere Contact with a Hard Flat

In this paper experimental investigation is presented to study the contact of a deformable hemisphere with a hard flat. Hemispheres were made from steel and copper, but flat from silicon carbide. During contact, deformation of hemisphere was measured. After experiment, plastic contact area of hemisphere was estimated on the basis of surface topography measurement by white light interferometer. The experimental results were compared with the theoretical models, showing good agreement.

Ensuring the Reliability of the Car Body Controls by Controlling the Current Inspection of Measuring Machines

Coordinate measuring machines are one of the most often used measurement devices in modern industry. Keeping high level of their accuracy parameters becomes then a critical issue. In the paper, some aspects regarding CMM reverification in production conditions and periodical check were discussed. A method of periodical check was elaborated in order to obtain regular information about changes in accuracy parameters. Possible risks and consequences of lack of knowledge regarding current CMM accuracy status were indicated. The results of current research conducted on 6 CMMs with single and double column construction were shown. One common measurement program for all machines working in CNC mode was developed for repeatability. During 6 months, 106 studies were performed and 7326 points were collected. The paper presents also some extreme results of the check together with the discussion. The presented method was adapted to production conditions. Its use is associated with a small 15 min break in a working time of a coordinate measuring machine.

Measurement of Surface Topography Using Computed Tomography

Computed tomography is a new field of coordinate measuring metrology. For this reason, many areas of its application are not yet completely known. The paper presents reproduction possibilities of geometrical structure of a surface by computer tomography. Results are combined with data from a classical tactile profilometer to measure surface topography. Comparison of the obtained values makes it possible to confirm the usefulness of computer tomography to reconstruct the surface geometry. This is especially important when indoor surfaces are indispensable. Such measurement with any other device than computer tomograph is not possible or requires damage of the element being measured. As a result of the measurement by means of a computer tomograph, from the same measurement data we obtain not only information about the surface and shape of the element, but also—as an additional advantage—ability to evaluate internal structure of material, for example its porosity or fibre distribution in case of composites.

Acceptance and Reverification of CMM in Industrial Conditions

Nowadays, coordinate measuring machines (CMM) are featured by a great degree of complexity and high accuracy of manufacturing. During use of a machine, usually after periodical maintenance it is highly recommended to perform a verification test according to the same procedures as a standard verification test, including a difference that performance conformity is checked with user’s declaration. Periodical verification should be performed as often as it comes from a user’s experience and after every interference influencing mechanical and electronic systems of a CMM that could potentially cause a change in its accuracy parameters. The best solution is employing for that purpose an independent accredited laboratory that is featured by high competence and experience. In the paper rules of acceptance and periodical verifications are described, sources of measurement errors resulting from CMM imperfections are presented as well as examples of results for specific measurement devices installed in industry were shown.

Analysis of 3D printing parameters of gears for hybrid manufacturing

The paper deals with analysis and selection of parameters of rapid prototyping of gears by selective sintering of metal powders. Presented results show wide spectrum of application of RP systems in manufacturing processes of machine elements, basing on analysis of market in term of application of additive manufacturing technology in different sectors of industry. Considerable growth of these methods over the past years can be observed. The characteristic errors of printed model with respect to ideal one for each technique were pointed out. Special attention was paid to the method of preparation of numerical data CAD/STL/RP. Moreover the analysis of manufacturing processes of gear type elements was presented. The tested gears were modeled with different allowances for final machining and made by DMLS. Metallographic analysis and strength tests on prepared specimens were performed. The above mentioned analysis and tests were used to compare the real properties of material with the nominal ones. To improve the quality of surface after sintering the gears were subjected to final machining. The analysis of geometry of gears after hybrid manufacturing method was performed (fig.1). The manufacturing process was defined in a traditional way as well as with the aid of modern manufacturing techniques. Methodology and obtained results can be used for other machine elements than gears and constitutes the general theory of production processes in rapid prototyping methods as well as in designing and implementation of production.The paper deals with analysis and selection of parameters of rapid prototyping of gears by selective sintering of metal powders. Presented results show wide spectrum of application of RP systems in manufacturing processes of machine elements, basing on analysis of market in term of application of additive manufacturing technology in different sectors of industry. Considerable growth of these methods over the past years can be observed. The characteristic errors of printed model with respect to ideal one for each technique were pointed out. Special attention was paid to the method of preparation of numerical data CAD/STL/RP. Moreover the analysis of manufacturing processes of gear type elements was presented. The tested gears were modeled with different allowances for final machining and made by DMLS. Metallographic analysis and strength tests on prepared specimens were performed. The above mentioned analysis and tests were used to compare the real properties of material with the nominal ones. To improve t...

The assumptions to credibility assessment of surface topography measurements in various scales

W referacie przedstawiono podstawowe zało żenia projektu „Badania i ocena wiarygodno ści nowoczesnych metod pomiaru topografii powierzchni w skali mikro i nano”. Celem realizacji projektu jest oszacowani e różnic w wynikach pomiarów topografii powierzchni w grupac h przyrządów stykowych i bezstykowych oraz mi ędzy grupami. Pozwoli to okre ślić wiarygodność pomiarów wykonywanych ró żnymi przyrządami zarówno w praktyce przemysłowej jak i w badaniach naukowych oraz ws kazać optymalny dobór metod do ró żnych zastosowa ń. Odpowiedni poziom wiarygodno ści uzyskiwany podczas pomiarów struktury geometrycz nej powierzchni jest niezbędny podczas bada ń naukowych oraz w przemy śle do podejmowania decyzji dotycz ących sterowania jakością wyrobów.