Materials Science Forum Vol. 952

Abstract: Surface properties are important aspect for correct function of construction (technical) parts. By improving mechanical properties of surface, an increase of abrasion resistance and wear resistance is reached. Longevity and economical aspect have an important role in final useful properties of product. Measurement of surface properties was done by ultra-nanoindentation technique (UNHT³), this is the best tool available right now, this technique is based on instrumented testing. Surface properties were modified by ionized radiation, that caused the creation of crosslinked structure in polyethylene. During radiation a three dimensional network is created, that improves final properties of product such as: hardness, elasticity modulus, thermal stability, etc. During ionized radiation there are two actions that take place at the same time, crosslinking and degradation. Goal of this paper is to consider how radiation intensity affects surface properties (indentation hardness, indentation modulus, deformation work, etc.) Another goal of this paper is to find out the optimal dose of radiation, that will cause more three dimensional crosslinking and less degradation as degradation causes decrease in mechanical properties.

Abstract: Modification of polymers by fillers is one of the most used material alterations to improve its required properties. This article is about modification of polymer matrix by fillers with layered particles. Linear low density polyethylene (LLDPE) was used as matrix and it was mixed with different kinds of fillers. Fillers used were: CaPhP – Calcium Phenylphosphonate, double layered hydroxides (ZnAl-DDS, ZnAl-lac and ZnAl-CO3) and natural Talc. Individual fillers were mixed into the matrix by kneading machine with the use of several velocities. The article focuses on influence of the individual filler on mechanical properties measured by tensile strength test. This paper also investigates the problem of process parameters’ influence on final mechanical properties and later confirms positive impact of all fillers that were used, although the size of them differs.

Abstract: The process of manufacturing polymeric material products includes the entire processing system; from their properties and the technical level of the manufacturing device, through its control and regulation system, and the manufacturing tools. This article deals with the study of aluminium alloy materials used in the manufacture of moulds - with different coatings, in order to reduce the surface contamination of the cavity moulds. The reason for choosing this topic is to discover a way as to how to understand the contamination process. The method chosen for eliminating such contamination is then, dependent on the degree of knowledge regarding the state and cause of the problem in the production process under investigation.

Abstract: Injection molding is one of the most extended plastic processing technologies. Delivery of polymer melts into the mold cavity is the most important stage of the injection molding process. This paper shows the influence of mold cavity surface roughness and technological parameters on the flow length of thermoplastic elastomers and rubber into mold cavity. The fluidity of polymers is affected by many parameters (mold design, melt temperature, injection rate and pressures) and by the flow properties of polymers. Evaluation of the data obtained by experiments where the testing conditions were widely changed shows that quality of the cavity surface does not affect the length of flow.

Abstract: Plastics are the world's most widely used materials, largely due to their wide-spectrum use and relatively cheap manufacturing of complex shapes. Due to its properties, the use of plastics is possible in all manufacturing sectors. Important aspect of plastic moulding is that the heat passed to granulate is sufficient to properly heat up the plastic mixture. Another important factor is that the plastic mixture is blended as evenly as possible. Heterogeneities could lead to the formation of non-conformances with incorrect colour shades, unevenness of the mass or others. One of the factors that greatly affects the homogeneity of the mixture is the surface treatment of the guides that are designed to transport the granulate and it is important to take care of those lines.

Abstract: This paper presents the technology of production of synthetic fibrous materials from PET-raw by vertical blowing method. The formation of fibers from the melt of thermoplastics by vertical blowing method is accompanied by complex and specific phenomena, so creation of new progressive technologies, high-performance machines and units for producing such materials is impossible without process modeling, which can significantly reduce the number of natural tests, cost and development time and choose optimal operating modes. The motion of the molten material in the melting unit of the hydrostatic type is determined from the Poiseuille formula. Also in the article proved that the greatest impact on process productivity is made by the melting unit, exactly by outlet radius and the pressure change of compressed air, acting on the molten material surface. The increase in the height of the molten material column in the main cylindrical chamber of melting unit also leads to increase of process productivity.

Abstract: At present, biomaterials are used in several sectors of medicine such as implant manufacturing, tissue engineering, orthopedic and prosthetic aids, drug delivery systems and many others. The use of biomaterials is increasingly related to the additive manufacturing (AM) of various medical devices and aids. Biomaterials and their use in medicine are important not only in terms of their biocompatibility and direct effect on the human organism, but also in terms of their biodegradability, processability and non-toxicity to the environment either during their production or during their processing after use. Bioplastics of the type Polylactic acid (PLA) appears to be a suitable biomaterials for use in a variety of medical applications in conjunction with an AM process. For this reason, this article discusses 1) description and use of biomaterials in medical applications 2) AM and biomaterials 3) key properties and uses of PLA bioplastics in medicine and 4) the specific AM of an orthopedic corset made of PLA and its benefits.

Abstract: The technology of cold die drawing of tubes is used for processing of metals and alloys with good or worse formability, while the tube production itself is affected by various process parameters, i. e. mostly die geometry, strain degree and strain rate, force conditions, conditions of friction, method of lubrication and type of used lubricant. The paper is concerned with an evaluation of influence of the selected process parameters, i. e. drawing tool geometry and strain rate on plastic flow and energy intensity of the process of cold die drawing of tubes. The FEM analysis of the drawing process was an important aid for this research. The computer simulation resulted in interesting graphs illustrating the influence of the shape of the drawing tool reduction cone on the size of the drawing force at various strain rates.

Abstract: This paper deals with an FEM simulation of a multi-purpose tyre. It is focused on the tyre tread pattern lateral stiffness under static conditions. Its behaviour under given radial and lateral loads and its stiffening using connecting bridges are simulated. A tyre is a complex composite composed of different rubber materials and textile or steel reinforcements. Rubber materials are described using hyperelastic models in the analyses. FEM software MSC Marc/Mentat is employed as a calculation tool and its various functionalities are utilized for a description of the tyre models. In the last step, calculated stiffnesses of all the tread patterns were evaluated and compared to each other.

Abstract: The aim of the paper is to evaluate numerical analysis of the fluid flow during the outflow from vessel orifices at various locations. The problems of the outflow velocities and pressure fields were well-chosen for the given purposes. The selected fluid flow problems were solved by numerical simulation using FEM in ANSYS. For numerical simulation, we used the basic steps to design an abstract model in the ANSYS virtual environment. Numerical simulation requires a geometric model complemented by physical properties of flowing fluids as well as both the initial and boundary conditions. It is then possible to calculate the velocity and pressure fields by numerical simulation for a particular fluid type. The results obtained from the numerical simulation were compared with those of the analytical solution. The results obtained from modeling and numerical simulation correspond to the actual values ​​with minimum deviations. The demonstrated type of the problem solved by numerical simulation and modeling confirmed the advantages and possibilities of flexible solutions for any combination of problems in the field of ​​fluid dynamics. Modeling and numerical simulation of fluid flow can provide results regarding the speed and the pressure fields in vessels and pipelines.