Tomasz Jachowicz

Structure and tensile properties evaluation of samples produced by Fused Deposition Modeling

Abstract This paper presents the result of a study evaluating the influence of alternative path generation strategy on structure and some mechanical properties of parts produced by Fused Deposition Modeling (FDM) technology. Several scientific investigations focused on resolving issues in FDM parts by modifying a path generation strategy to optimize its mechanical properties. In this study, an alternative strategy was proposed with the intention of minimizing internal voids and, thus, to improve mechanical properties. Polycarbonate samples made by this alternative path generation strategy were subjected to tensile strength test and metro-tomography structure evaluation. The results reveal that the structure observed on build models differs from a structure expected from path generation predicted by software Insight 9.1. This difference affected the tensile strength of samples.

Quantitative Assessment of the Microscopic Structure of Extruded and Injected Low-Density Polyethylene Modified with Microspheres by Image Analysis

The paper investigates the macroscopic structure of low-density polyethylene modified with polymer microspheres. The analysis is performed on specimens produced by extrusion and injection molding with the following contents of the modifying agent: 0.25%, 0.5% and 1%. The structure of the specimens is examined in six measuring regions by image analysis. In addition, the number and diameter of produced micropores and their area fraction are determined.

RESEARCH ON THE INFLUENCE OF BLOWING AGENT ON SELECTED PROPERTIES OF EXTRUDED CELLULAR PRODUCTS

As a part of a more comprehensive research project, the present study was undertaken to investigate the effect of the type and content of blowing agents in the polymeric materials being processed on the structure and selected physical and mechanical properties of the obtained extrusion parts. In the experiment, the content of the blowing agent (0–2.0% by mass), fed into the processed polymer were adopted as a variable factor. In the studies presented in the article, the blowing agents of endothermic decomposition characteristics (Hydrocerol BIH 70, Hydrocerol BM 70) and the exothermic decomposition characteristics (PLC 751) occurring in the granulated form with a diameter of 1.2 to 1.8 mm were used. Based on the results of investigating porosity, porous structure image analysis as well as microscopic examination of the structure, it has been found that the favorable content of the blowing agent in the polymeric material should be of up to 0.8% by mass. With such a content of the blowing agent in the polymeric material, favorable strength properties are retained in porous parts, the pore distribution is uniform and the pores have similar sizes.

Influence and Optimization of the Setting of Input Parameters of Laser Profilometry by the Surface Measurement Manufactured by the AWJ Technology

The publication deals with the measurement and evaluation of roughness parameters by means of laser profiling, and its main task is to determine the effect of selecting the internal gain adjustment (Gain mode) on measured roughness values of the surface treated by the water beam technology. The publication details the software, hardware, and other parts of the device designed to measure the roughness of different types of surfaces. It further describes the behavior of individual parts of the apparatus as a whole and methods of measuring the roughness of the surface along a defined profile section by means of the triangulation principle of laser profiling. The measured sample was cut by a thick (rough) cut at pressure of 380 MPa. As an abrasive, the Australian Grenade with the grain Mesh 50 was used.The experiment was carried out at the Faculty of Production Technologies in the Laboratory of Roughness Measurement at the Department of technical systems design and monitoring in Prešov. Measurement of surface roughness parameters was performed on an optical measuring system to control surface parameters and the contact roughness meter Mitutyo SJ400.

EFFECT OF SMALL ADDITIVES OF POLYAMIDE MODIFIED BY POLYVINYLPYRROLIDONE AND MONTMORILLONITE ON POLYPROPYLENE TECHNOLOGICAL PROPERTIES AND HEAT RESISTANCE

The effect of small polyamide additives modified with polyvinylpyrrolidone and montmorillonite on polypropylene technological properties and heat resistance has been researched in the work. It has been determined that the melt flow index of the obtained composites increases by more than 2 times in comparing with pure PP. It has been shown that adding a small amount of polyamide modified by montmorillonitepolyvinylprolidone mixture to polypropylene significantly increases heat resistance of the material. The displacement of the beginning of thermal-oxidation destruction and burning samples into the range of higher temperatures on 114-123oC, dependently on the modified polyamide content has been observed.

Optimization of Production Processes Using the Yamazumi Method

Manufacturing companies are now placing great emphasis on competitiveness and looking for ways to utilise their resources more efficiently. This paper presents optimum efficiency improvement of the automotive transmission assembly production line by using line balancing. 3 assembly stations were selected to optimize where waste management requirements are not met for achieving the production capacity. Several measures were proposed on the assembly lines concerned to reduce operations by using eliminating unnecessary activities of the assembly processes, reducing the cycle time, and balancing manpower workload using line balancing through Yamazumi chart and Takt time. The results of the proposed measures were compared with the current situation in terms of increasing the efficiency of the production line.

Rheological Properties of Compositions Based on Modified Polyvinyl Alcohol

Developed of a method for producing structured waterproof films based on polyvinyl alcohol (PVA) and montmorillonite-polyvinylpyrrolidone mixture (MPM) to research the impact of borax, pH-environment and MPM content on the rheological properties PVA solutions and water absorption capacity of films based on them. The MPM mixture significantly affects on viscosity the characteristics of the solution polyvinyl alcohol provided their mixing in the ultrasonic field have been established. Composition of traces of sodium tetraborate in the aqueous solution eminent by the highest rates of viscosity. Also, designed compositions considerable influence pH at the viscosity, particularly compositions obtained in weakly alkaline environment with higher values of relative viscosity than compositions obtained in neutral and acidic environments.

The effect of blowing agents on the effectiveness of poly(vinyl chloride) extrusion

The cellular extrusion is a method for manufacturing profiles, bars, low density cellular coatings and other cellular products that have no hollow cavities on the surface and show minimal processing shrinkage, while their properties are similar to those of products produced by conventional extrusion. The paper deals with cellular extrusion of PVC. The investigation of the process was conducted using state-of-the-art endothermic and exothermic blowing agents that were dosed in up to 1.5% by weight. The experiments involved measuring output, energy consumption and energy efficiency of the process.

Investigation of Selected Properties of Injection-Molded Parts Subjected to Natural Aging

This article provides general information about the aging process of polymer plastics. It also reports the experimental results of investigations undertaken to determine changes in the mechanical properties of polypropylene injection-molded samples with the oxo-biodegradable additive d2w which were subjected to natural aging for two years. A decrease of tensile strength and elongation at yield as well as an increase of hardness were observed during the experiment.

RESEARCH ON THE CONTENT AND FILLER TYPE ON INJECTION SHRINKAGE

The paper presents the phenomenon of injection shrinkage. The definition of shrink age and shrinkage types are presented. The main factors affecting shrinkage value of injection-molded part are discussed. Based on the experimental tests conducted using injection-molded parts made from polypropylene filled with glass fiber and talc, the dependence of injection-molded part shrinkage on filler content and selected param eters of the injection molding process has been determined.