Problems of Selecting the Wavelet Transform Parameters in the Aspect of Surface Texture Analysis

This paper discusses one of the most important problems related to analysis of surface texture using wavelet analysis - the problem of selection of mother wavelet and decomposition level. The literature related to wavelet transform does not explicitly determine which mother wavelet is most suitable for surface profile analysis and at which level of decomposition this analysis should be performed. The paper describes the criteria of selection of the mother wavelet from the aspect of analysis of two-dimensional surface texture. Details of the algorithms are also included. The calculations were performed on the 3D roughness profiles. The evaluation was based on five selection criteria: autocorrelation test, Pearson correlation, evaluation of 3D roughness parameters, Hotelling test and entropy-based method. The calculations were performed in authorial computer procedures coded in MATLAB software

Multiscale assessment of additively manufactured free-form surfaces

The article reviews the results of experimental tests assessing the impact of process parameters of additive manufacturing technologies on the geometric structure of free-form surfaces. The tests covered surfaces manufactured with the Selective Laser Melting additive technology, using titanium-powder-based material (Ti6Al4V) and Selective Laser Sintering from polyamide PA2200. The evaluation of the resulting surfaces was conducted employing modern multiscale analysis, i.e., wavelet transformation. Comparative studies using selected forms of the mother wavelet enabled determining the character of irregularities, size of morphological features and the indications of manufacturing process errors. The tests provide guidelines and allow to better understand the potential in manufacturing elements with complex, irregular shapes

Dimensional and Shape Accuracy of Foundry Patterns Fabricated Through Photo-Curing

This paper deals with the potential use of the PolyJet Matrix (PJM) technology and digital materials to fabricate foundry patterns. The primary purpose of the study was to assess the dimensional and shape accuracy of additively manufactured objects by determining the draft angle as well as the roundness, waviness and roughness parameters. The experiments were conducted for cylindrical samples printed using VeroWhite liquid polymer resin. The analysis focused on the relationship between the build direction and the geometry and surface finish of prints. Three different orientations, i.e. 0º, 45º and 90º, were considered. The surface texture analysis involved comparing the statistical, graphical and numerical data, including calculation results obtained with the wavelet transform method. The findings confirm that the build direction has a significant effect on the dimensional and shape accuracy of prints and that the PJM technology can be used to fabricate precise foundry patterns, especially in investment (lost-wax) casting

Quality of surface texture and mechanical properties of PLA and PA-based material reinforced with carbon fibers manufactured by FDM and CFF 3D printing technologies.

The paper presents the results of mechanical tests of models manufactured with two 3D printing technologies, FDM and CFF. Both technologies use PLA or PA-based materials reinforced with carbon fibers. The work includes both uniaxial tensile tests of the tested materials and metrological measurements of surfaces produced with two 3D printing technologies. The test results showed a significant influence of the type of technology on the strength of the models built and on the quality of the technological surface layer. After the analysis of the parameters of the primary profile, roughness and waviness, it can be clearly stated that the quality of the technological surface layer is much better for the models made with the CFF technology compared to the FDM technology. Furthermore, the tensile strength of the models manufactured of carbon fiber-enriched material is much higher for samples made with CFF technology compared to FDM

Tribological Properties of Medical Material (MED610) Used in 3D Printing PJM Technology

The development of modern manufacturing technologies related to the ongoing industrial revolution Industry 4.0, is largely related to the dynamic development of materials chemistry. This means that currently 3D printing technologies allow the production of physical models using newer materials with better properties and application in new industrial sectors. The article presents the results of tribological tests of the bio-medical material under the trade name MED610, which shows biocompatibility for medical and dental purposes. The paper presents the results of measurements of tribological models of samples designed and manufactured in the shape of rings. Using the variable friction parameters, the wear process was described in the pressure-rotational speed (P-V) system. Moreover, the friction coefficient and wear measured by using the linear method were analyzed. The paper also presents a metrological analysis carried out with the application of an optical profilometer on the surface of the samples after pressing at the contact point of the surface during the test. The preliminary review of the test results showed that the MED610 material exhibited relatively good abrasion resistance. However, it cannot be employed for heavily loaded friction nodes, and in the PV diagram even at a relatively small value, the sample models were destroyed

Quality of surface texture and mechanical properties of PLA and PA-based material reinforced with carbon fibers manufactured by FDM and CFF 3D printing technologies

The paper presents the results of mechanical tests of models manufactured with two 3D printing technologies, FDM and CFF. Both technologies use PLA or PA-based materials reinforced with carbon fibers. The work includes both uniaxial tensile tests of the tested materials and metrological measurements of surfaces produced with two 3D printing technologies. The test results showed a significant influence of the type of technology on the strength of the models built and on the quality of the technological surface layer. After the analysis of the parameters of the primary profile, roughness and waviness, it can be clearly stated that the quality of the technological surface layer is much better for the models made with the CFF technology compared to the FDM technology. Furthermore, the tensile strength of the models manufactured of carbon fiber-enriched material is much higher for samples made with CFF technology compared to FDM.Web of Science1311art. no. 167

Methods of comparison of surface texture based on fractal dimension and Hotelling’s T2 test

Comparative analysis of the surface texture of machine parts can be successfully carried out using statistical tests. The paper presents a methodology of method used to compare the surface texture by applying Hotelling’s T2 test as well as a method used to evaluate surface topography by applying fractal dimension. The tests were carried out on samples produced with the use of face milling process for four types of materials. The following types of steel were used: 40HM, C45, NC6 and WCL. For each type of material, four areas were machined with the same machining parameters. Based on these results a decision was made whether the surfaces, despite the same machining conditions, were significantly different from each other. Furthermore, the analysis indicated that the fractal dimension enabled to characterise signal irregularities in quantitative and qualitative way

Multiscale Data Treatment in Additive Manufacturing

The article assesses the impact of data treatment on the possibility of assessing the morphological features of additively manufactured spherical surfaces. Tests were carried out on specimens manufactured by PBF-LB/M additive technology, using titanium-powder-based material (Ti6Al4V). The surface topography was assessed using one of the multiscale methods—wavelet transformation. The tests carried out on a wide spectrum of mother wavelet forms emphasized the occurrence of characteristic morphological features on the surface of the tested specimens. Moreover, the significance of the impact of specific metrology operations, measurement data processing and its parameters on the filtration result were noted. Comprehensive assessment of additively manufactured spherical surfaces with simultaneous analysis of the impact of measurement data processing is a novelty and fills a research gap relating to comprehensive surface diagnostics. The research contributes to the development of modern diagnostic systems allowing for a fast and comprehensive assessment of surface topography, taking into account the various stages of data analysis

The Effect of Non-Measured Points on the Accuracy of the Surface Topography Assessment of Elements 3D Printed Using Selected Additive Technologies

The paper presents the results of research aimed at evaluating the surface topography including the analysis of the number of unmeasured points of the samples 3D printed using four additive technologies (i.e., PolyJet Matrix, fused deposition modeling, selective laser sintering, and selective laser melting). The samples were made in three variants of location on the printing platform of 3D printers. Measurements of the samples’ surface topography were carried out using a Talysurf CCI Lite optical profilometer and a Talysurf PGI 1230 contact profilometer. The percentage of non-measured points for each sample and the parameters of the surface topography were determined. Then, the non-measured points were complemented and the topography parameters for the corrected surface were recalculated. In addition, to perform comparative measurements, each surface was measured using a contact profilometer Talysurf PGI 1230. Preliminary results of the research showed that the measurement of the surface topography of the samples made using selective laser sintering technology with the Taysurf CCI optical measuring system is very unreliable, as the number of non-measured points for the analyzed samples was higher than 98%. The highest accuracy of optical measurement was obtained for PJM technology and three variants of location on the printing platform of the 3D printer

An assessment of applicability of the two-dimensional wavelet transform to assess the minimum chip thickness determination accuracy

The objective of the study was to assess the potential use of optical measuring instruments to determine the minimum chip thickness in face milling. Images of scanned surfaces were analyzed using mother wavelets. Filtration of optical signals helped identify the characteristic zones observed on the workpiece surface at the beginning of the cutting process. The measurement data were analyzed statistically. The results were then used to estimate how accurate each measuring system was to determine the minimum uncut chip thickness. Also, experimental verification was carried out for each mother wavelet to assess their suitability for analyzing surface images