Applied Mechanics and Materials Vol. 693

Abstract: The technology of part manufacturing by means of 3D printing is currently the essential tool in fast production of prototypes and significantly participates in shortening the development an innovation time of the product. In manufacturing by means of a 3D printer as well as in any other manufacturing technology, the precision of the end product is affected by a variety of factors and effects that shall be familiarised with in order to provide high dimensional and shape precision.The research specified in this post is focused on dimensional and shape precision analysis of part manufacturing using the Selective Laser Melting method (SLM). This technology manufactures a prototype by selectively melting metallic powder layer by layer by means of a laser. A CAD model of a specific shape was designed for the purpose of the analysis. An orientation of this part was designed by means of SLM 280HL workspace with regard to minimisation of the internal stress. The part itself was made of AlSi12 material and printed on this machine. The part was afterwards digitised by means of Atos II 3D optical scanner. The data obtained by digitising were compared to the nominal CAD model. The comparison was a basis for the evaluation of the resulting dimensional and shape precision of a prototype manufactured by means of this technology.

Abstract: Paper deals with use of methods of Reverse Engineering and 3D printing for the fashion shoe design. It contains an example of a procedure for implementation of fashionable footwear collection "Instant Shoe 2" designed by designer Pavla Podsedníková for the purpose of presentation in a fashion show. The paper also contains a described process of digitising a shoe model and solving problems related to it. The next step is the printing of physical shoe models using 3D printers. Two types of 3D printers were used. The article concludes with a presentation of results presented at a fashion show.

Abstract: The research activities of the Department of Manufacturing Systems at TU of Liberec are related to projecting, designing and construction of prototype CNC machines for laser cutting. The result is a prototype device assembled of standard aluminium profiles using the motion control linear actuator with ball screw.The paper presents the design and construction of the prototype machine. The components and their assembly are described below. The implementation of technical parameters and other options outlined the continued development and application of the equipment is also listed below.

Abstract: The efficient decision-making process is the key criteria for evaluation of the managers and their future career in the enterprises. In the frame of operation research and operation analysis it is possible to use number of methods and techniques. However considering the up-to-date situation in the enterprises, linear programming is one of the most efficient techniques. It can be used by managers to solve problems considering any manufacturing or logistical problems. Application of the linear programming generally enables the managers to maximize the profit and minimize the costs on the other hand. This contribution presents the results of pilot research focused on the use of operations research methods in business. For this purpose we have contacted 10 companies which deal with the issue of operations research methods. The authors of the contribution primarily took into consideration the linear programming, particularly application and results achieved by this method. The analysis of software tools that can be used in the context of linear programming is also included in the contribution. In the next chapter of the contribution selected example of application of linear programming in a company is presented.

Abstract: This paper deals with mechanical properties research of innovative polymer multiphase composite materials consisting of matrix and isotropic or anisotropic oriented deterministic fractal shapes made by 3D printing. Standard polymer composite materials consisting for example of polypropylene matrix and glass fibres have mechanical properties which depend mainly on matrix-fibre interface strength, fibre length, fibre strength and fibres orientation. [1] In case of under critical fibre length is fibres orientation stochastic in for example injection moulded composites. So is possible to say that mechanical properties of these (standard) composites with short fibres are isotropic and thus all direction limited. However by creating of reinforcing internal structure consisting of deterministic fractal connected shapes is possible to gain unlimited mechanical properties directing. These fractal shapes – placed in multiphase system matrix – are significantly influencing whole material system mechanical properties mainly in case of stress on the limit of strength, proportional elongation on the limit of strength or tensile/ flexural modulus. Fractal shapes are also possible to properly locate, orient or shape modify according to potential material using with goal to gain maximal efficiency of fractal shapes occurrence. Producing of this multiphase system is realized by the help of two component 3D printing technology. So is possible to create any fractal shapes placed in polymer matrix which are by another technology unmanufacturable. Mechanical properties analyse is performed with respect to fractal shape type, fractal dimension, fractal shape orientation and shear and tensile strength of matrix.

Abstract: This paper deals with research in area 3D digitalization of large objects. Application of 3D scanners for transportation is not common. Digitalized area is a final placement for new machines. Final location and transport way for machines is in very a low ceiling room. Using the 3D data we can determine an optimal way for transport. In next step we define optimal final placement for CNC machine tools. If we have 3D model from 3D scanner we can measure the height between the floor and ceiling.

Abstract: Computer simulation becomes an essential tool improving the efficiency of business processes, due its ability to mimic the behavior of the simulated processes. However, Its use is not trivial. Simulation is not “only” about model design. Planning and implementation of simulation experiments are equally important. Manufacturers of the simulation software are aware of that and they provide support also in this area such as integrated heuristics algorithms. There are other options how to improve process of experimentations and one of them is methodology of DOE (Design of experiments).This article is focusing on mentioned area of planning of the simulation experiments using DOE and it shows gained experiences on particular example. This article describes design of the experiment, how to select main factors (their influence and influence of their interaction) and experimentation itself using SW Minitab. Further there are presented experiment results given by simulation models. There are briefly discussed benefits and disadvantages of this approach.

Abstract: The paper deals with multi-axis machining of complex shapes of freeform surfaces. Machining of such surfaces is very difficult and the critical operation is the optimal setting of tilt and lead angle which, along with other parameters, must ensure collision-free machining. This paper describes the possible dividing of solved freeform surface areas into partial elements with similar properties from CAD data using Matlab software instruments. The partition is solved by algorithms calculated according to the curvature of the surface using both methods the maximum and the Gaussian curvature. These partial elements can be machined separately which allows employment of tools with optimal dimensions for individual elements. This process enables significant reduction of tool-path necessary for machining these shapes which also leads to reduction of the working time. Furthermore, there are practical examples including a comparison of standard method and the use of machining process optimized by the algorithm in this article.

Abstract: The paper deals with evaluation of selected mechanical properties of tensile test specimens which were made from AlSi12 material by Direct Selective Laser Melting (DSLM) technology. Specimens were built in three various set-ups such as different angles towards building platform and various types of supporting structures in order to prove the influence of these parameters to mechanical properties of resulting product. The specimens were also subjected to material tests to reveal its inner structure, quality of a grain and chemical composition of the material. As a conclusion, the selection of the most suitable supporting structure and alignment of a model towards building platform are discussed. Mechanical parameters evaluated from tensile tests such as Young’s modulus (E), 0.2% proof stress (Re_0,2) and tensile strength (Rm) are compared with values typical for the selected material AlSi12.

Abstract: The aim of this applied research is to focus on real-life application of multiple attribute decision making (MADM) methods and their adaptation in a way which can be acceptable for business practice. The study will apply the group decision making methods on a Balanced Scorecard (BSC) as a type of performance measurement and strategic decision making. The study is mainly concerned with multiple criteria decomposition method of analytic network process (ANP) method, WINGS technique and entropy. This group of methods had been already applied in several business domains. However, majority of the implementation was only presented as an example how it could work in practice, but they were not investigated from the perspective of how much information they could provide to the management. In this paper, proposed methods will be used to determine which criteria are most important for the company within the Balanced Scorecard and results of all methods will be compared. The aim of this study is, by utilizing group MADM approach, to discover the areas of the BSC which must be improved so that a total performance increases.