Ivan Gajdoš

Optimization of FDM Prototypes Mechanical Properties with Path Generation Strategy

This paper present result of a study evaluating the influence of path generation strategy on mechanical properties of Fused Deposition Modeling (FDM) prototypes. Several scientific studies were researching the problematic of path generation and internal structure of FDM prototypes. Mostly the influence on mechanical properties was observed. This paper is aimed on determine the influence of outline number and internal air-gap on tensile strength of parts built from ULTEM 9085. For this two variables was determined the influence on built time and consumption of modeling material. Result show that proper model orientation when the orientation of load is known, can help to reduce the build time and material consumption.

Flexural Properties of FDM Prototypes Made with Honeycomb and Sparse Structure

The rapid prototyping (RP) process is capable of building parts of any complicated geometry in least possible time without incurring extra cost due of absence of tooling. Fused deposition modeling (FDM) is a fast growing RP technology due to its ability to build functional parts having complex geometrical shape in reasonable time period. The quality of built parts depends on many process variables. The presented study focus on assessment of mechanical property flexural strength of part fabricated using fused deposition modeling (FDM) technology. The 3-point bending test was used, to determine flexural strength. Samples were made of polycarbonate on Fortus 400 mc machine from polycarbonate with slice height 0.127mm. The experiment was focused on influence of air-gap size between fibers and number of outline contours on selected mechanical properties of FDM prototypes determined 3-point bending test. The results show possibility to obtain weight reduction in printed parts with sparse structure with sufficient flexural strength and with reduced build time, compared to structure printed with default machine setting,. To obtain optimal processing parameters for 3D printing prototypes, it is necessary to execute further experiments, which could verify gathered results.

THE SENSITIVITY OF A PHOTOGRAMMETRIC METHOD IN FORMABILITY ANALYSIS

Abstract Nowadays is a possible to implement numerical simulation and photogrammetric inspection to the complex process chain of inspection. In the recent years there has been significant progress in accuracy improving of these methods of inspection in pre-production or post-production stage of manufacturing. This article discusses these two methods from sensitivity and comparison point of view. Most attention has been paid to the photogrammetric method and his sensitivity to using different approaches. Results were compared with the result of numerical simulation and experiment. Numerical simulation was performed in static implicit finite element code Autoform. For this purpose, GPS cover of galvanized steel of DQ category was used for inspection. In this paper was proved that photogrammetric method of strain measurement is highly sensitive on the various external factors. Further results and findings are included in the next chapters of this paper

Clinching - An Innovative Trend in Joining of Combined Materials in Car Body Production

Various ferrous and non-ferrous materials and their combinations are used in car body production in automotive industry. The most commonly used method for joining the materials is resistance spot welding. Some materials or combinations of materials are very difficult or impossible to join by resistance spot welding. Therefore, car producers are seeking for alternative joining methods. One of the innovative joining alternatives is clinching. The paper presents the results of evaluation of clinched joint properties. The high-strength dual-phase steel sheet DP600 in combination with the drawing grade steel sheets DC06, DX53D+Z and DX51D+Z were used for experiments. The influence of position of the sheets relative to the punch and die of the tool on the carrying capacities of the clinched joints was observed as well. The tension test and metallographical analysis were used for the evaluation of clinched joint properties.

Surface Finish Techniques for FDM Parts

Additive manufacturing technologies decrease production time and costs in engineering industry but also in other industries. Parts produced with Fused Deposition Modeling (FDM) have typical low surface finish quality. This paper is aimed on research of surface finishing technologies applicable to improve the quality of FDM prototypes surface finish. Pretreated samples were blasted with sodium bicarbonate and glass beads. The values of Ra and Rz were measured on the samples and compared the impact of selected pre-treatment, blasting medium and blasting conditions on surface finish quality of FDM prototypes.

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.

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 of Welding Parameters on the Quality of Resistance Spot Welded Joints of DP600 Steels

Advanced high-strength dual-phase steel was developed specifically for automotive industry in order to benefit from its excellent formability and great crash absorption ability in comparison with conventional AHSS. Resistance spot welding is the dominant and effective method of joining metal sheets in automobile industry. After spot welding, important changes occur in mechanical and metallurgical properties of the spot welded areas and heat affected zones. The investigation into these changes is very important for safety, which depends on the strength of the welded joints. Weldability of the DP steel is one of the key factors governing its application in automotive industry. The influence of the primary welding parameters, especially welding current, on the weld quality was investigated by testing microhardness and tensile shear load bearing capacity of resistance spot welds of DP600 steel sheets.

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.

Assessment of the Resistance to External Factors of Low-Density Polyethylene Modified with Natural Fillers

The study reports the results of investigation of basic processing and thermal properties of low-density polyethylene modified with two types of natural filler: wheat bran and pumpkin seed hulls, their content ranging from 5% to 15% relative to the matrix. In addition, physical properties of the produced granulates are determined, i.e. the relationship between their density and the applied contents of the tested fillers. Furthermore, the study reports the results concerning longitudinal shrinkage, abrasion resistance and cold water absorption of injection molded tensile specimens.