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Titanium grade 2 plates were modified by a pulsed nanosecond laser beam. The aim was to determine the surface properties after the machining process in two different liquid media. The samples were processed in distilled water and paraffin oil. It was found that a surface with half-surface roughness values with a number of cracks was formed in distilled water. The presence of water reduced the size of the heat-affected zone.

Production of multi-rifled seamless steel tubes employing cold draw process using multi-rifled mandrel is quite a modern technology. The important characteristic of the tube drawing process, unlike the tube with internal rifling, is the corner filling which influences the dimension accuracy of the internal shape of the tube. In this study, the influence of drawing tool dimensions and mandrel shape on to final rifling filling was investigated. Draw process has been simulated by using the three-dimensional rigid-plastic finite element method (FEM) by using DEFORM 3D software. The results of numerical simulation show that the shape of drawing tools and process conditions have a significant influence on the forming process and final shape and properties of the workpiece.

The most comprehensive steel tube portfolio is used to produce all kinds of modern energy production and the corresponding auxiliary unit such as boilers and heat exchangers. Multi-rifled seamless steel tubes are distinguished by maximum pressure, heat resistance, strength and durability. Production of multi-rifled seamless steel tubes by cold draw process using multi-rifled mandrel is quite a new technology. Shape and dimension of the drawing tool depend on drawing tube reduction degree, i. e. on the original diameter of the initial tube and final diameter of the tube. The technology of drawing tubes is influenced by process parameters, dimensions of tools and cold forming process conditions. Optimization of the whole forming process naturally involve the FEM analyses and simulation. One of the most important information of the cold drawing process is the load stroke of the tools. The contribution is concerned at the usability of FEM simulation on an evaluation of cold draw forming process condition and prediction of load stroke of the forming tools. DEFORM 2D/3D FEM software is used to compare the result of the drawing force and to determine the appropriate methodology to set FEM simulation of cold forming.

The article deals with the local plastic deformation analysis after cold forming. The technology of drawing seamless steel tubes was used to obtain cold-formed samples. The tubes were manufactured by a Tinius Olsen 300ST tensile tester with a 6 ° and 12 ° die drawn without and with an inner mandrel. Based on orientation size recalculated by stereology and applying Monte Carlo method a mathematical conversion model was developed. Implemented model together with surface measurements and structure characteristics were used to get the orientation to the size of the deformation. Thus, the actual (logarithmic) deformations and local stresses were determined. Comparison of experimentally measured values of the actual local plastic deformation with the deformation calculated found on the model simulation in the Deform program defined the significance of the differences assessed by means of a statistical T-test. All differences in the values of the local plastic deformation with respect to the position were evaluated as statistically insignificant and therefore the difference between the experimental calculation and the simulation is random.

The process of cold die drawing of tubes is ranked among frequently used methods of production of seamless tubes and is performed in drawing tool which is characterized by simple design. Shape and dimensions of the drawing tool depend on tube reduction degree, i. e. on original diameter of initial tube and final internal diameter of the tube. Tube wall thickness is not determined by any tool. The technology of cold die drawing of tubes is influenced by various process parameters, i.e. geometry of the die itself, strain degree and strain rate, force conditions, conditions of friction, method of lubrication and the type of used lubricant. The contribution is concerned with evaluation of influence of the selected process parameters using FEM simulation. Designed graphs illustrate the impact of coefficient of friction and reduction cone of drawing tool on the size of drawing force.

We prepared overlap soldered joints of high-temperature superconducting tapes, using various materials and preparation conditions. In order to select the joints with optimal performance, we correlated their electrical properties (derived from current–voltage curves) with the microstructure of the respective joint cross-section by scanning electron microscopy. With the first group of joints, we focused on the effect of used materials on joint resistivity and critical current, and we found that the dominant role was played by the quality of the internal interfaces of the superconducting tape. Initial joint resistivities ranged in the first group from 41 to 341 nΩ·cm2. The second group of joints underwent a series of thermal cyclings, upon which the initial resistivity range of 35‒49 nΩ·cm2 broadened to 25‒128 nΩ·cm2. After the total of 135 thermal cycles, three out of four joints showed no signs of significant degradation. Within the limit of 100 thermal cycles, reliable soldered joints can be thus prepared, with normalized resistivity not exceeding 1.4 and with normalized critical current above the value of 0.85.

This paper deals with the influence of laser surface texturing on tribological performance of two different tool steels: (a) Bohler K100 produced by conventional production technology and (b) Bohler K390 Microclean® produced by powder metallurgy. The surface of heat-treated tool steels was modified using three different texture patterns. Impact of laser surface texturing was analyzed after different treatments. Furthermore, selected samples were borided to evaluate the combined influence of laser surface texturing and boriding on tribological performance of surface-treated samples. The results show that boriding was not beneficial for wavy surface type, and the steel production technology had a certain influence on the spinning tool. The laser surface texturing had an effect on decreasing the coefficient of friction on the K100 tool steel; however, it did not influence the tribological performance of the K390 Microclean® tool steel. Boriding process was efficient in decreasing the coefficient of friction for both steels. The low coefficient of friction values did not have a positive influence on the wear depth.

Paper deals with the design of assembly workplaces and systems. The aim is to provide a solution to the problems in the field of the assembly systems design and planning. One of the goals is to design a solution to the design of assembly workplaces. The focus of the research is therefore a proposal of the design methodology of the assembly workplaces and systems, and thus the development of integrated methodological procedure and tools. The introductory part is devoted to the current state of assembly workplaces, assembly systems and their planning. On the basis of the theoretical knowledge, an analysis of the assembly systems and workplaces is carried out according to the pre-selected criteria. It is necessary to develop the classification of assembly systems and workplaces in terms of product or assembled entities. Individual sections of the paper are devoted to the design of databases for the needs of designing the assembly workstations and systems.

The purpose of this article is to describe the methodology to define coefficient of friction between a tool and a forming material during tube cold draw technology process. In this regard, an experimental drawing process was done by using the tensile testing machine. The tensile testing machine was modified by additional equipment that allows drawing the tube. During the drawing, the force was recorded. Subsequently, the finite element simulation of cold draw forming was used to generate load-stroke curves with different friction coefficient. The friction coefficient was estimated by comparing the load stroke and the force recorded curves.

The morphological texturing of forming tool surfaces has high potential to reduce friction and tool wear and also has impact on the surface layers properties of formed material. In order to understand the effect of different types of tool textures, produced by nanosecond fibre laser, on the tribological conditions at the interface tool-formed material and on the integrity of formed part surface layers, the series of experimental investigations have been carried out. The coefficient of friction for different texture parameters (individual feature shape, including the depth profile of the cavities and orientation of the features relative to the material flow) was evaluated via a Ring Test and the surface layers integrity of formed material (surface roughness and subsurface micro hardness) was also experimentally analysed. The results showed a positive effect of surface texturing on the friction coefficients and the strain hardening of test samples material. Application of surface texture consisting of dimple-like depressions arranged in radial layout contributed to the most significant friction reduction of about 40%. On the other hand, this surface texture contributed to the increase of surface roughness parameters, Ra parameter increased from 0.49 μm to 2.19 μm and the Rz parameter increased from 0.99 μm to 16.79 μm.

In many present applications is requested decreasing of weight of components and increasing of their strength. Often unique properties are required. These properties could be solved by using of composite materials. However, different material properties of matrix and reinforcing material cause issues during machining, such as rapid tool wear and delamination of composite. Therefore there is afford to enhance machining process by different ways to decrease tool wear as well as delamination of composite. This article deals with comparison of conventional milling and ultrasonic assisted milling of glass fibre reinforced polymer (GFRP) composite material by special designed cutting tool.

The paper presents the simulation model of turning the process of C45 non-alloy steel with a tool made of carbide insert. A 3D final element model used a lagrangian incremental type and re-meshing chip separation criterion was experimentally verified by measure cutting forces using piezoelectric dynamometer. In addition, stresses and temperature in the tooltip were predicted and examine. This work could investigate failure the tooltip, which would be great interest to predict wear and damage of cutting tool.

The article is focused on optimization of four-facet drill for 3D drilling numerical modelling. For optimization, the process of reverse engineering by PowerShape software was used. The design of four-facet drill was created in NumrotoPlus software. The modified 3D model of the drill was used in the numerical analysis of cutting forces. Verification of the accuracy of 3D models for reverse engineering was implemented using the colour deviation maps. The CAD model was in the STEP format. For simulation software, 3D model in the STEP format is ideal. STEP is a solid model. Simulation software automatically splits the 3D model into finite elements. The STEP model was therefore more suitable than the STL model.

Finite element modelling (FEM) of machining is a widely applied way to get information about the phenomena occurring during the cutting process. This paper discusses experimental work and FEM analysis to investigate the mechanism of CK45 (1.0503) carbon steel chip formation during orthogonal turning process. Local strain in cutting zone is estimated by measurement of deformation of metallographic cut using stereological evaluation of the gain boundary orientation. Estimated local strain in cutting zone was compared to deformation analysis for orthogonal cutting was made, based on simulation results in numerical modelling software DEFORM 2D. Stress, temperature, tool wear is also discussed in the last part of this paper.

This paper deals with precision seamless tube drawing process in Železiarne Podbrezová, considering a three-pass drawing technology without the intermediate annealing. The material chosen was the E235 steel grade, cold-drawn from the initial dimension of ∅ 70 x 6.3 mm to the final dimension of ∅ 44 x 3.0 mm. Strength and deformation analyses for each drawing pass were made, based on simulation results in numerical modelling software DEFORM 2D. The deformations calculated for all passes served as a guideline for further process optimization. Furthermore, the effect of a particular reduction on mechanical properties was investigated (yield pointRe, ultimate tensile strengthRm, ductilityA, and hardnessHV). The research shown here is a part of the Research Project No. 3-2014/ŽPVVC “TUMIFORM – Optimization of precision tube drawing technology considering dislocation theory, microstructure, and plasticity limit“, being solved at ŽP VVC s.r.o. in Podbrezová, Slovakia. This project deals with the optimization of tube drawing technology utilizing the multi-pass drawing approach. This approach allows for skipping the intermediate annealing between each two successive draws.

Many nowadays researches are focused on decreasing the weight of components and increasing their strength, or obtaining unique properties. One of the results of the researches are composite materials. However, different material properties of matrix and reinforcing material cause certain problems during conventional machining, such as rapid tool wear and delamination of composite. Therefore, other researches start focusing on machinability of this kind of materials. Scientists have discovered several ways of how to satisfactorily machine composite materials. Seco Tools Company starts developing a new design of the tools. Researchers of the Stanford University have devised a diamond-like carbon (DLC) coating available to effectively cut matrix as well as reinforce fibers. DMG Mori Company has implemented ultrasonic assistance into machining process and reached enhanced machinability. This article compares conventional milling and ultrasonic assisted milling of the carbon fiber reinforced polymer (CFRP) composite material by a special designed cutting tool. The results could be applied to determine when ultrasonic assistance is advantageous and what advantages it brings about.

This paper deals with the deformation of precision seamless tubes during the cold drawing process, using Finite Element Methods. The value of strain obtain by stereology measurement of degree grain boundaries deformation are compared with simulation result for each drawing pass. The material chosen was the E235 and E355 steel grade, which is drawn from the initial dimension of Φ 70 × 6.3 mm to the final dimension of Φ 50 × 3.75 mm by two passes. FEM Software DEFORM 2D with the Lagrangian method is used to numerical analyses of the cold drawing process.

A cold forming technology (cold drawing) produces precise seamless tubes, which can be found in various industries and applications. A high shape accuracy is achieved while the material is reinforced due to plastic deformation during cold forming. The reinforcement of the material in the forming process largely depends on the degree of deformation and plastic properties of the material. The purpose of this study is to compare results of stereological methods used in metallography with data from FEM simulation obtained using software DEFORM and Lagrangian method. Values of strain obtained experimentally and by FEM simulations are supplemented by results of Vickers hardness measurements and mechanical properties obtained by tensile testing after each cold draw operation.

An article deals with a measurement of flatness of thin-walled parts with low rigidity. The flatness is important for quality thin-walled parts made by milling. Measurement of the variation in the flatness of thin-walled components conventional 3-axis, high-speed 3-axis milling was done. In the first part is description of flatness and definition of thin-walled parts. Second part characterizes the measuring system, the principle of measurement and experimental setup. The last part of this work is evaluation of the experiment, which compares different factors to determinate flatness during machining of thin-walled parts.