Applied Mechanics and Materials Vol. 693

Abstract: Nowadays, manufacturers and users of parts made of polymeric materials make increasing demands on surface quality of these parts. In order to fulfill these claims, it is necessary to use not only the quality measurement systems for surface quality inspection, but also suitable products that allow to set up the inspected polymeric component properly set up to the measuring system scanner. However, it is not sufficient. Due to the requirements of the customers or the production it is often necessary to repeat the surface quality measurement, which is more and more often done in 3D; that might be quite difficult. Except for special cases there should not be any marks done by the inspection workplace which might lower the inspected surface quality. Therefore it is not suitable to make mechanical marks such as scratch, ridge, etc. On the other hand, other types of marks done by non-invasive method, such as sticking paper marks, measuring cross, etc. is also not admissible as there might result in surface damage due to adhesive forces as well by mechanical or chemical processes. Thus it is necessary to take into account the fact that parts made of polymeric material can be so small that none of the above mentioned methods that are widely used nowadays cannot be applied just because of the dimensional reason.

Abstract: The article focuses on the field of PMMA laser micromachining at change of the technological parameters. The aim was to evaluate machined surface roughness at different setting of DPI definition (number of dots – paths on square inch). The aim is application of the Theory of Hypothesis testing for evaluation changing of final surface during imputing variable technological parameters.

Abstract: One of the most important characteristics of a cosmetic product is maintain or improving the condition and characteristics of the skin surface. In dermatological, respectively cosmetic practice, there is very often a problem of an objective assessment of the obtained data, which corresponds to visual changes in skin relief. With technical advancements has it been proposed many approaches of solution: mechanical needle devices, optical interference devices, and microscopic, holographic, laser and photometers ones. Each of them has its advantages and negative qualities. The newest devices allow not only two-dimensional assessment (2D), but also spatial one (3D). Scientific literature such as Measuring the Skin recommends for these cases scanning the surface in 3D, using the contact scanners for made imprints. Here, however, errors that may be caused by mechanical method of scanning skin relief are not taken into consideration and there is also not clearly described the material suitable for the production of custom impression. The following article focuses precisely on this issue, specifically on the implementation of the biological surface relief imprint using a silicone impression material, its 3D scanning without contact and forming an enlarged replica by rapid prototyping technology.

Abstract: The paper presents the research on the quality of thirteen-component granular mixture. The changes in the quality of the mixture after reduction the mixing time from a standard time of 30 minutes to: 25 minutes, 20 minutes and 15 minutes have been analyzed. The research has been conducted in industrial conditions where a vertical mixer with worm agitator with the charge of two tons was used. Research results were presented graphically as changes in concentration of components shares in the mixing time of 30, 25, 20 and 15 minutes and the obtained results were compared. Quality assessment of a thirteen-component mixture with the use of residual sum of squares for four mixing times was carried out.

Abstract: The article presents industrial conditions of manufacturing multi-component heterogeneous mixtures of granular materials. The study analyzed the production technology and devices used for production such as storage siloes, an impact screen, a cyclone separator, a shaving and dust extractor, a screw mixer, a tensometric weigh, a bucket conveyor. A division and the successive stages of manufacturing process has been presented: unloading, receipt and storage of raw materials, quality control of components, technology cleaning and sorting of raw materials, dosage and mixing of feed material, bagging, storage, extraction processes and evaluation of homogeneity in a fodder mixing plant. Moreover the methods of assessing the homogeneity of the multi-component heterogeneous mixtures has been presented. The research was conducted in industrial conditions.

Abstract: This paper presents a method of finite element modeling and analysis used in the process of development of laminating tools of automotive interior parts. In this research, the automotive interior part considered for analysis is a center console part covered with leather. This part is subjected to concentrated loading and the stress variation within the complete assembly is determined. Also, due to the fact that the leather is stretched and glued to the plastic part using heat transfer between two molds, a thermal assessment is necessary. The results, in the form of deformations and tensions, and conclusions of both analyses will demonstrate the need to use this method in the development of laminating tools of automotive interior parts.

Abstract: This paper describes the benefit obtained from implementing a cutting tool management system. Also, a state of the art on tool management systems available on the market is presented. By analysing the drawbacks generated by the implementation of such a system, we are providing a cheap and practical solution: an Augmented Reality aided machining and tool management system. Using augmented reality we managed to improve the tool management systems by providing, at the scene of action, all the necessary tool information in a much more user friendly way.

Abstract: This paper presents the stages taken to remanufacture a damaged part, for which no documentation is available, using the SLM additive technologies. A damaged part is scanned using the COMET L3D scanner and the points cloud is used to redesign and reconstruct the part as a 3D CAD model. Using the generated 3D CAD model the build job for the SLM is created by designing and adding the construction supports, the material type and the type of hatching strategy for each slice. The slices are used by the SLM250HL equipment and the new metallic part is manufactured. The manufactured part was scanned with the same 3D scanner and the data from the original part was compared with the new reading. The results can be used to reconstruct more complex parts, to redesign the broken parts and to improve the manufacturing process.

Abstract: Dynamic behavior of mechanical structures results from complex interactions between applied forces and the stiffness properties of the structure. Currently, many problems of structural dynamic analysis are solved using Finite Element Method (FEM). However, in recent years, the implementation of the Fast Fourier Transform (FFT) in low cost computer-based signal analyzers has provided a powerful tool for acquisition and analysis of vibration data. This article discusses combination of two approaches to structural dynamics testing; the experimental part which is referred to as Experimental Modal Analysis (EMA), respectively the analytical part, which is realized by Finite Element Analysis (FEA). Main goal of the paper is calculation of material properties from experimentally determined modal frequencies.

Abstract: The paper deals with problems of computer modelling of heat treatment processes. The effect of the choice of the coefficient of heat transfer between the coolant and components was quantified. The oil Isorapid HM 277 was chosen as the coolant. Two cases of application of the convective boundary condition were studied through numerical experiment. In the first of the cases, a real functional dependence of the heat transfer coefficient (HTC) was applied on the surface temperature. In the second case, it was used constant and temperature independent values of HTC on the surface temperature. Cooling curves were obtained through numerical experiment. Derived variables such as cooling rate, the density of the thermal flows are shown in the paper. Code ANSYS was used as interpretative tool of the numerical experiment.