Jozef Bílik

Particle Filled Polyethylene Composites Used in the Technology of Rotational Moulding

Particle Filled Polyethylene Composites Used in the Technology of Rotational Moulding The submitted article discusses rotational moulding technology and filled plastics. For testing, linear low density polyethylene filled with talc was used. The materials tested varied way of mixing the filler into the polymer. For the prepared samples were evaluated by tensile, elongation, melt flow index, density, Shore hardness and Vicat softening temperature. Experiments showed that, in principle, it is possible to produce rotational moulding technology filled thermoplastics.

Impact of Viscosity on Filling the Injection Mould Cavity

Abstract The aim of this paper is to look closer at the rheological properties of plastics and their impact on technology in the plastics processing industry. The paper focuses on the influence of viscosity of the material on filling the mould cavity. Four materials were tested with the settings of process parameters with different viscosity. Using simulation software of Moldex3D, we can see the effect of change in viscosity in the material to be filled.

Metal to Composite Plastic Conversion of Mechanically Loaded Part Using Numerical CAE Analyses

The material replacement of component is often used procedure, which helps to reduce production costs, simplify manufacturing, improve functional properties of component and bring another benefits. In the last years, more and more metal parts are converted to plastic, also in the cases of mechanically loaded parts. For these special applications, the fibre reinforced composite plastics are successfully used. However, the mechanical properties of composite plastic are strongly dependent on the fibres orientation and following anisotropic behaviour. Moreover, the orientation of fibres is influenced by the conditions of the part production. Due to the number of these dependencies, the material conversion becomes a complex task which cannot be solved with analytical approach. Especially in case of complicated part geometry. In this study, the connection of two different numerical solvers was used for material conversion of a part from automotive industry. First, the new geometry of analyzed part was designed in order to compensate lower mechanical properties of plastic in comparison to metal. Next, the new part manufacturing was simulated and this way obtained anisotropic properties of composite plastic were described. Finally, the structural analyses of original metal and new composite plastic part with real anisotropic properties were performed to verify achievement of material conversion. The aim of this study is to demonstrate, how numerical analyses can help to predict an unexpected result.

Reduction of Injection Moulded Plastic Part Warpage Using Advanced Gas Assisted Injection Moulding

Dimensional and shape accuracy are the basic quality criteria of almost every injection moulded plastic part, manufactured in the engineering industry. They are dependent on many production conditions as part and moulding tool design, material structure properties and injection parameters. Generally, it is very difficult to achieve high geometrical accuracy during injection moulding, therefore, dimensional tolerances for plastic parts are usually many times larger than in the case of metals. However, according to requirements of the engineering industry, demands for the plastic parts dimensional accuracy keep growing permanently, what also extends to the growing shape complexity of the produced parts. Due to this tendency, engineers must look for more and more advanced solutions to meet market requirements and keep the competitiveness of their product. In consonance with all this, this paper presents a case study where the progressive gas assisted injection moulding is used as a solution for the plastic part warpage reduction while any other conventional methods failed. The study is performed making use of part from the automotive industry, initially produced with unacceptable deformations. In the first step, the real manufacturing state was studied to determine the warp behaviour. Subsequently, the process parameters and cooling conditions were unsuccessfully modified while trying to reduce deformations. Nevertheless, these were effectively eliminated by the only application of internal gas support to the melt injection phase. A numerical modelling based on Finite Volume and Finite Element Method was also used in the case study in order to mathematically represent the fluid, thermal and mechanical processes during the process of injection moulding.

The Influence of the Filler Material on Weld Joints Made of Duplex Stainless Steels

Application of beam welding methods for joining austenitic, duplex and other stainless steels is the right choice which not only lowers weld joint degradation but increases the production efficiency. There are many different demands on butt joints of duplex steels. One of them is equal ratio between austenite and ferrite of weld metal, because it can significantly influence the weld joints performance in real environment. The aim of this paper is to evaluate the influence of filler material on mechanical and technological properties of weld joints made from stainless steel SAF 2507.

Verification CAE System for Plastic Injection

This article is focused on the field of computer simulation and it is subsequent verification in practice. The work highlights the injection process, the simulation software that is specialized in injection molding and the technology process of injection itself. The major subject of the thesis is the use of the computer aided injection molding technology by using the CAE systems. The experimental part of the thesis deals with the production of the 3D model specific plastic parts in two modifications, injection molding simulation in the system Moldex3D and digitization of moldings on the optical 3D scanner. In the thesis we also provide measuring realization on digitized models and comparison of the parts size with the computer model. In conclusion we summarize the results achieved from the comparison. The thesis is carried out in cooperation with the Simulpast s.r.o.

The Description of Precision Forging Technology in Closed Die of Mg Alloy AZ31 Using Computer Simulation

Automotive industry is nowadays constantly strengthening its dominant position. Its primary objective is to reduce weight of automobiles in order to decrease fuel consumption and amount of harmful pollutant emissions. From the viewpoint of further development in the field of automotive industry, very interesting are the issues of die forgings production from light non-ferrous metals. This article describes research of precision die forging technology in closed die with regard to magnesium alloy type AZ 31. Given alloy type Mg-Al-Zn is suitable for bulk forming and is characterized by good formability at hot conditions. Results of this research may be applied to production of forgings with longitudinal shape, e.g. levers and connecting rods. In order to verify the design of forging technology in closed die for lever-shaped forged piece the simulation program MSC.SuperForge was used. Numeric simulation of die forging process confirmed suitable designed shape and dimensions of semi product and also correct material plastic flow in cavity of closed die.

Effect of Drawing Tubes without Interoperation Recrystallization Annealing on the Orientation of Boundaries Grain - Orthogonal Direction

The term cold-drawing of tubes refers to forming when the final material (a tube) is formed in a pipe bell and its vertical cross-section is smaller, the tube wall is thinner or thicker and its length is greater. Steel is most commonly the final material. The forming proceeds in a few draws which depend on the final tube dimension. The selection of relative reduction for particular diameters plays an important role because an unbalanced reduction causes stress, and therefore also deformation or cracks during drawing. The technological parameters are: rolling temperature, de-burring of tube ends, the reduction, which determines the dimensions of the forming tools, the optimal chemical modification, the speed of forming on the drawbenches, and the method of tube drawing.