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Surface roughness is an important index to evaluate the quality of a machined surface. In order to accurately predict the surface roughness for slow tool servo (STS) turning, taking toric surface as an example, response surface methodology (RSM) was used to perform the process test. The second-order response surface prediction model was established and the variance analysis and reliability test were carried out. The results showed that the average prediction error was 7.6%. In order to obtain the best process parameters, standard particle swarm optimization (PSO) was used. The results showed that the global optimization ability of standard PSO was poor. In order to solve the problem, compression factor was introduced and particle swarm optimization with compression factor (WCF-PSO) was constructed, which enhanced the convergence of PSO effectively. WCF-PSO was used to optimize the process parameters and the results obtained were Rt=0.87mm, af =0.01mm/r, ap=0.05mm, Δθ=8.70°, with a corresponding surface roughness of Ra=0.0486μm. The results of the verification test showed that the actual value was Ra=0.0520μm, and the error was only 7.0%, indi-cating that WCF-PSO had a better optimization effect.

The article deals with the wear of the blades of the delimber device of harvester head. An input analysis of the materials of the fixed knife and movable arm parts was performed. It consisted of chemical analysis, evaluation of microstructure and hardness measurement by HRC and HB methods. The original welded joint was analyzed, which ensured the connection of the blade and the fixed, resp. movable arm mechanism. Based on the findings, two blade replacement solutions have been proposed. The first was the application of hard metal by an OK 84.58 electrode and second use HARDOX 450 by welding with a fixed part or a mechanical gripping with screws. This was recommended based on previous research at the Faculty of Technology. The hardnesses of the original blade material were compared with the proposed solutions. The correctness of the proposed methods will be verified in the future and in operation.

There are regional differences, variety differences and maturity differences in fresh lotus seeds. The parameters of husking and peeling machine working parts need to be adjusted in real time according to the processing effect. In response to the problems with the machine on the market including complicated transmission, difficult interconnectedness and adjustment of various working parts, etc., an automatic husking and peeling machine for fresh lotus seeds with the husking module and peeling module as the core devices has been designed. On the basis of the kinematic analysis of fresh lotus seed circulation process, a grooved wheel feeding mechanism and an arc track have been designed to realize the feeding and circulation of fresh lotus seeds. Experimental research has been conducted on the influence of working parameters on the film removal effect and the interaction between working parameters using the response surface method. In addition, the correctness of the above analysis has been verified by husking and peeling experiments. According to the experiment results, processing qualification rate and damage rate processing efficiency of this machine can meet the use requirements of lotus farmers. This research can provide a theoretical basis for the structural design and parameter optimization of related equipment.

This article seeks to compare roughness characteristics of surfaces created through unconventional machining technologies, specifically utilizing plasma and laser. Cuts of different thickness of material were taken for this purpose. Furthermore, the article presents an evaluation of surfaces obtained from an impression material SILOFLEX®, followed by the determination of similarities between these impressions and original surfaces. In this work, we mainly aimed to statistically find and determine the differences inbetween the evaluation of surfaces in concert with ISO 4287, ISO 4288, and ISO 25 178. Next, investigation analysis of the machined and replicated surfaces was done utilizing the contactless profilometer and the follow-up statistical evaluation of measured data from compared surface groups.

Selective laser melting (SLM) technology has strict demand to its powder materials which is needed to be spread evenly and conducted laser sintering layer by layer. Therefore, the uniformity and flatness of powder bed are the basic conditions for processing. Ball milling is an important composite powder preparation process of SLM. Three kinds of ball milling processes, dry ball milling, wet ball milling and hollow milling with various parameters are adopted to prepare TC4 / TiB2 composite powder. It is concluded that a balling time 8 h at a speed of 230 rpm without milling ball is proved the optimal working condition to make the composite powder maintain good spherical shape and ensure the mixing uniformity. The mechanism of three kinds of powder mixing effects is revealed by analyzing the dynamic relationship and hardness of the milling ball, TC4 and TiB2 particle. This work provides an important reference for the preparation of high quality TC4 / TiB2 composite powder for SLM.

Precipitation hardening is one of the most frequently used methods of the post-processing heat treatments of 3D printed tool steel 1.2709, as it increases the yield and ultimate tensile strengths of the steel. Within this work, the broad temperature range of 250°C – 550°C was tested with five differ-ent holds at each temperature to study the effect of processing parameters on the microstructure and mechanical properties. Maraging tool steel 1.2709 was produced by selective laser melting (SLM) technology and obtained results were compared with conventionally produced steel of the same chemical composition. Mechanical properties were established by hardness measurement and tensile test and the microstructure was characterised mainly by light and scanning electron microscopy. The peak hardening was for both steels reached after 6 hours of precipitation at 500 °C, however, apparent hardening effects of heat treatment were observed already after low-temperature heat treatments.

The use of secondary aluminium alloys gives manufacturers in many industries the opportunity to produce their products more economically and environmentally friendly. The secondary aluminium alloy production is sustainable in the long term. As aluminium does not lose its excellent properties through recycling, secondary aluminium alloys have the potential to replace primary aluminium in many applications. However, recycled aluminium alloys have the disadvantage of insufficient sorting and thus a higher content of impurities in their chemical composition. The most common undesirable element in Al-Si-Mg cast alloys is iron. It adversely affects mechanical properties, fatigue behaviour and corrosion resistance. The influence of iron can be reduced by the addition of manganese. This paper deals with the effect of manganese on the morphology of Fe-phases and corrosion resistance of AlSi7Mg0.6 secondary alloy with higher iron content (0.75 % and 1.26 %).

This study is focused on testing the ballistic resistance of composite materials to define their limit thicknesses according to the US STANDARD NIJ 0101.06, level III. The materials Twaron CT 747, Twaron CT 747 TH110 and Endumax Shield XF33, which are widely used in the manufacture of the ballistic protection systems, were tested. A method known as the Taylor Anvil Test (TAT) was used to verify their ballistic resistance. The missile 7.62 mm M80 was used to test the ballistic resistance of these materials. Within the experimental part, the deformation processes of composite materials were examined after impact by this missile. The value of the traumatic effect according to the US STANDARD NIJ 0101.06 was also measured. The results of the experiment provide an idea of the ballistic resistance of selected materials. Based on the results, TAT proved to be the perspective measurement method for further development and optimalization of the multilayer composite armor.

This paper describes some tools usable for quality control in plastic injection moulding. The introductory part presents tools for quality management, the use of which is demonstrated in the next part using a practical example. The selection of suitable methods was based on proven methods for quality management. They were selected to work in synergy. The author's contribution is the modification of the PDCAI method, which was enriched by another step, namely, innovation. The last part of the article presents is a demonstration of FMEA, Ishikawa diagram, and Pareto diagram.

The paper describes the course, conditions and results of the impact test of the supporting frame of the test station for dynamic tests of gears. The test station makes it possible to simulate different gears operating conditions. The basic support frame structure of the test station was evalu-ated as unsufficient based on the results of measurement and processing of the measured low and high fre-quency vibration values in the verification series of experimental tests. The basic failure of the origi-nal design were the significant resonance actions that were the results of the dominant sources of vibration being near the natural frequencies of the vertical and horizontal beams of the test station base. A structural design of the test station supporting frame was designed and implemented. The goal was to increase the rigidity of the frame and eliminate unwanted resonance phenomena. The impact tests were used to determine the values of the natural frequencies of the most stressed parts of the supporting structure - vertical and horizontal beams, before and after implementation of struc-tural modifications. The comparability of the impact test results was determined by adherence to identical measurement conditions.

Based on the previous research on the 304 stainless steel lapping and polishing in our research group, the tribochemical fixed-abrasive lapping platen for 304 stainless steel lapping and polishing were developed. The effects of the different pressure, the rotation speed, the lapping time and the abrasive size on the surface roughness and the material removal rate (MRR) were researched. It was concluded that when the abrasive size is 28 µm, the lapping time is 15 min, the lapping speed is 90r/min, the lapping pressure is 27.580 KPa, and the maximum MRR is 412.524 nm/min. When the lapping time is 15 minutes, the rotating speed is 15 r/min, the lapping pressure is 13.790 KPa, the surface roughness Ra drops to 41nm. These findings show that the influence degree on the MRR from better to worse is the abrasive size, the lapping pressure, the rotation speed of the lapping platen and the lapping time. The order of the influence degree on the surface roughness from better to worse is the abrasive size, the rotation speed of the lapping platen, the lapping pressure and the lapping time. The results can give an important reference for next study on the tribochemical mechanical lapping of fixed-abrasive.

Mechanical alloying and subsequent compaction with spark plasma sintering was chosen for the fabrication of investigated CoCrFeNiTi alloy method. The alloy was characterized in terms of chemical and phase composition with X-ray fluorescence spectroscopy and X-ray diffraction spectrometry, respectively. The microstructure was examined using light microscopy and scanning electron microscopy equipped with an energy dispersion spectrometer. The alloy showed an ultra-fine grained uniform microstructure composed mainly of an FCC solid solution with a volume fraction of HCP Laves phases. Regarding mechanical properties, the prepared specimen reached an ultimate compressive strength of 1340 MPa with the hardness of 757 HV 30. The wear rate of the sample reached 1.19 · 10-4 mm3·N-1·m-1 showing traces of adhesive-abrasion wear mechanism.

Nowadays the electromagnetic induction quenching approach has been widely applied in the surface treatment process, especially for the parts made by metal materials such as the crankshafts. In this paper, quantitative study was adopted in researching the strengthening effect of this technique. First the multi-physics simulation was achieved to carry out the key information caused by this approach such as the temperature and residual stress distribution property. Then the fatigue limit load prediction was conducted based on the simulation results and the theory of critical distance. Finally corresponding experimental verification was performed to check the accuracy of the predictions. The results showed that the combination of the critical point method and the Goodmen mean stress model can provide highest accuracy in the prediction. While for the critical line method, the Gerbera mean stress model is the most suitable choice.

Main goal of this study is to describe and design manufacturing system which is using Additive manufacturing technology for production of semi-finished products and conventional machining technology for finishing operations, then demonstrate requirements of such production on simulation model on production planning and then analyze and summarize the outputs of the production model. The model is made with aid of modern Digital Factory tools. The main purpose of the model is to provide a complex tool for this study in order to analyze and optimize the fictive production system in needed range and complexity. The topic of Rapid Prototyping and Additive manufacturing technologies is very recent topic in industry. But still, there are only few examples of production systems, which are really using Rapid Prototyping technologies as a part of the production or production line. The advantage of these technologies is their versatility, but on the other hand, as a part of production system, they can have different demands on for example production planning, area consumption or maintenance, that can affect whole production system.

In the current world, the business faces different challenges, as it was in the 1950th. Today, most of the manufacturing companies have a very strict approach to increasing market needs of Safety, Quality, Delivery and Cost key performance indicators (KPI). To stay competitive, it is needed, that a holistic approach on the improvement of strategic KPIs is needed in order to be successful. The target of this paper is to show the application of the Value stream mapping methodology, used in a case study for a finish good assembly line in an Electronic Manufacturing Facility. The study is showing the improvement of quality, delivery and productivity KPIs over a time period of 3 consecutive years. The result is the increase of production output from 500 pcs/shift to 1050 pcs/shift, decreasing the number of quality returns from 3 to 0 and improving the delivery performance from 95 to 100% against customer requested date.

The research described in this contribution is focuses on fractographic analysis of the fracture area of AlSi7Mg0.3 alloy with modified strontium. Modification is an effective tool for improving the mechanical properties of aluminum alloys and affecting the microstructure of the material. The aim of the paper is to revise the microstructure of the modified AlSi7Mg0.3 alloy and to determine its strength properties. Within the experiment, the character of the refraction was evaluated and the presence of foreign particles and elements in the material fracture was monitored. Optical microscopy identified structural parameters of the castings just below the fracture surface as well as the course of the fracture line. Using a scanning electron microscope, the fracture area of the sample was analyzed, the EDS analysis was performed and the results of these analyzes were evaluated. An increased number of O, C and F elements occurred on the surface of the samples. The occurrence of these elements most likely results in a material breakage, which also confirms the results achieved by the static tensile test. On the basis of the obtained results from the analyzes carried out, the mechanisms of the breach were determined.

The main aim of this scientific article is to assess the contribution of surface layers by determining the experimental investigation and practical measurement of surface roughness Ra and selected components of cutting forces while external turning of AlCu3MgMnPb aluminium alloy. In these experimental procedures, a number of turning tests have been carried out by using a universal lathe machine tool and cutting forces and surface roughness scientific measuring devices. These realized measurements have been successively investigated and experimentally verified with the prepared trial samples. These presented experimental measurements describes the authors investigation of cutting forces while turning by the piezoelectric dynamometer Kistler type 5001 and surface roughness Ra with the Talysurf CLI 100 measuring device. This scientific article, together with measured and calculated results, is the fundamental that will help to optimizing the quality and used other technological and cutting parameters of turning technological process.

The aim of this paper is an analysis of dependability of an injection press. Collected data - operating times between failures and times to restoration for a year of the use of the press were processed using the Weibull distribution, for which the following basic steps were applied in compliance with ČSN EN 61649:2009 standard. The output includes Weibull distribution parameters and basic functions of reliability and maintainability, i.e. probability of failure and of reliability, density and intensity of failures, then also probability of restoration and restoration probability density. Last but not least, mean time between failures and mean time to restoration including steady-state availability were calculated. The results obtained can be useful for internal benchmarking in an organization with a higher number of presses and for developing a maintenance strategy.

The aim of the paper is to describe the design of the manipulation system for the raw ceramic chimney pipe raw blank to avoid deformation of the pipe during handling and to increase the productivity of the manufacturing process. The process of manufacturing of a ceramic chimney pipe begins with extrusion of the raw refractory material. The extruded semi-finished product is then processed and then transferred by hand to a kiln car on which it is dried and fired. It is this manipulation that heavily contributes in the deformation of the fired chimney pipes. Due to the low stiffness of the raw ceramic chimney pipe, deformation occurs by manual handling. In order to avoid these deformations, it is necessary to design a suitable concept and construction solution of the manipulation system. Due to the nature of the chimney pipe, the automation of manipulation is rather difficult. The pipe is very soft in the raw state, its surface is rough, wet and greasy. This paper deals with the design of an optimal solution for the manipulation of ceramic chimney pipes, which will prevent the chimney pipe from deforming, negatively affecting its quality and making it possible to increase the productivity of ceramic chimney pipes production.

Reliable method to detect relative machinability is based on constructing Taylor relation of tool durability on cutting speed for both observed materials. Optimal cutting speed for the observed material at constant durability can be detected from the relation. However, longterm test requires longer time of machining and consumption of material. Therefore a number of authors have observed the possibility of shortening the tests. There is a widespread opinion that shortened methods posses low reliability. On the other hand, those methods cannot be replaced in the conditions of actual operation. Some of them are analysed and modified as follows.

The use of recycled or remelted alloys is one of the most common ways to reduce production costs. As the number of remelting increases, also chance of the chemical composition and the microstructure alteration is increasing, which has a major impact on the resulting mechanical properties. The microstructure of recycled alloys mostly affects the presence of iron and its negative effect on casting properties. The paper deals with the degree and the way of influence of the remelting on the microstructure of AlSI9Cu3 alloy with increased iron content to 1.4 wt. %. In the work are progressively evaluated changes of microstructures focused on the morphology and shape of the iron phases, dendritic structure change and pore formation due to remelting on AlSI9Cu3 alloy after natural aging and after the heat treatment (T5). The obtained results point to degradation of the microstructure due to multiple remelting with the possibility of partial improvement when applying heat treatment (T5).

Use of means of technical diagnostics gains in today's period increasing importance in all areas of industrial activity. Due to the tightening of the limits, software and hardware solutions improving is the diagnosis of the building one of the most important area in manufacturing and non-manufacturing organizations. The aim of the article is to clarify the possibility of using diagnostic procedures in the form of georadar to monitoring of location and status of reinforcement in a ferroconcrete bearing wall. For measuring was used radar system Mala CX12 with accessoriesand based on selected aspects has been diagnosed the exact location and status of the construction reinforcement. The result of this monitoring is to detect variations in the position of reinforcement and recorded corrosive damage. We investigated the humidity of concrete wall through the diffusion of EM waves while the evident product of decrease of the diffusion speed was the increased moisture of structure.The main outcome is to propose corrective measures in the form of the concrete carrying wall remediation necessity, as indicated by the results of this monitoring. By early use of the diagnostic means in the form of monitoring using georadar, it is possible to prevent the economic and environmental impacts.

Heat transfer evaluation in a plate heat exchanger (PHE) is one of the most common issue which is widely used in many engineering processes. The objective of this paper determine to formulate a global energy balance in a PHE and to study the heat losses, firstly focuses to study the heat transfer in countercurrent and parallel flow and to measure the temperature profile and to determine the number of transfer units (NTU) effectiveness of a plate heat exchanger. An addition to calculate the overall heat transfer coefficient using criteria equations, also focused to draw the temperature profile of the heat exchanger for both configurations countercurrent and parallel flow with temperature on the axial axis and thermocouple position on the horizontal axis. Furthermore discussed the behaior of temperature across the heat exchanger, compare the countercurrent and parallel flow arrangements, cpaing the experimental heat exchanger effectiveness with that estimated by the NTU method, the NTU effectiveness method application in the calculation of the output temperatures of a PHE. This concentric plate heat exchanger allows the study of heat transfer between hot water flowing through an internal sheets and cold water flowing in the ring area lying between the internal and external sheets, the plate heat exchanger allows measuring hot and cold water temperatures in different points of the heat exchanger.

The paper is concerned with the analysis of tensile stress conditions and microstructure of cast iron with spheroidal, lamellar and vermicular type of graphite. To prepare a geometrical model, quantitative metallography has been used as it enables us to evaluate the structure of the material on the basis of image analysis. The computing structure model has been created in 2-D area by linear triangular elements. On the basis of real structure of the cast iron with spheroidal, lamellar and vermicular type of graphite, a model was created from numerical analysis of tension deformation conditions by finite element method in ADINA software environment. This calculation program helps to solve a very difficult task and has the advantage that the generated model can reflect the actual geometry of the object very well. For the calculation and following statistic evaluation objects, it is necessary to generate a greater number of geometrical models in the future. This theory on modelling of microstructure of materials and following numerical analysis opens new areas and outlooks for usage of computing instruments when analysing the state of the material structure in the area of tension, absorption or frequency qualities of the material. Stress concentration is increased with irregularities of graphite particles shapes.

This paper deals with numerical simulations and with experimental testing of chassis of low-floor trams. This chassis was designed with respect to low-floor construction, low weight, good driveability of a tram and with respect to fulfillment of standards and regulations. The chassis is in a numerical simulation burdened by load conditions according to EN 13749:2011 even during an experimental testing. The simulation is performed using the FEM Nastran solver implemented in the CAD system Siemens NX 11. Based on FEA the locations for strain gauges during testing were found. A total number of 40 strain gauges were used to measure the strain which was then recalculated to uniaxial stress. The testing was performed on hydraulic test bench Inova. The results of FEA and of an experimental testing were compared.

Passive vibration isolator with lower natural frequency has always been a challenge due to structural integrity issues. This study presents the use of RSM statistical tool to analyze and optimize the mechan-ical responses of BCC lattice structure for structural integrity in a passive vibration isolator application. The optimization was done to obtain low stiffness for low natural frequency but high yield stress for optimum load-bearing capability with unit cell size and strut diameter design parameters tweak. From the results, the significance and contribution of each design parameter on each mechanical response through compression test can be understood. Results indicated changes in strut diameter produced lin-ear growth while changes in the unit cell size produced inverse exponential responses. From optimiza-tion, a combination of 3.9 mm strut diameter with 10 mm unit cell size produced the optimum result. Therefore, it was demonstrated that RSM can provide statistical importance and contribution between input factors and their influence on each mechanical response with minimal test and cost.

The experiments aimed to verify the use of a focused ion beam (FIB) to create structures analogous to the natural surface and then use the two-step imprinting method to prepare replicas of the surface creat-ed by FIB. The surface of the petal leaves of pansy (Viola x wittrockiana) was selected as a natural sur-face pattern. The TESCAN AMBER FIB-SEM microscope was used for the preparation of an analo-gous surface. The molds for the replication process were made of President Light Body elastomer. PVB, PVA, CMC, PCL, EP were used for the preparation of polymer replicas. Scanning electron micro-scope was used to evaluate the quality of the prepared polymer replicas. The dimensions of the replicat-ed convex and concave structures were 25 x 20 µm. The polymers showed a different ability to copy the structure in detail. For PVA, CMC, and PCL, surface structuring at the nanometer level was described in this study. Due to the dimensions of the cones of convex and concave structures, the color was ob-served on all samples.

Nitriding is a technology that leads to an increase in the utility value of the product. It’s most im-portant benefits include increased corrosion resistance, abrasion resistance, wear resistance, increased resistance to fatigue failure under cyclic loading, and many others. The design of a suitable nitriding technology not only on the basis of empirics requires a closer study of the relationship between the structure of the nitriding layer, its properties and the course of a particular degradation process. Be-cause the life of most components is related to abrasion on the surface, the occurrence of fatigue cracks and corrosion effects, it is crucial to influence the mechanical and other properties in this sur-face area. High functional requirements are placed on the functional surfaces of steels for weapons production, which lead to a long service life, reliability and dependability of the components of the weapon system and its safe use. The paper discuss the influence of selected nitriding technologies on the mechanical properties of steel 42CrMo4 and 34CrNiMo6, especially on the hard and microhard-ness of surface layers, change of its structure and next to change the surface texture and dimension of component. The steels were nitrided in plasma and gas. Nitriding in gas led to more significant struc-tural changes in the surface layer of both steels compared to plasma nitriding.

In this paper, innovative resistance element welding (REW) technology for joining galvanized steel sheets to thermoplastics (PMMA) is introduced. The essence of the innovation is in the use of a special bimetallic joining element consisting of the core made of a Sn60Pb solder, and the sleeve made of a Cu tube. During resistance heating, the solder melts, thus allowing the formation of a metallurgical joint with galvanized steel sheet. Since Sn60Pb solder melting occurs at temperatures (from 183 to 190 °C) be-low the thermal decomposition temperature of most thermoplastics (for PMMA above 300 °C), there is no thermal destruction of the PMMA material around the joint. The mechanical fixation of the thermo-plastic material at the overlap joint is provided by the sleeve made of Cu tube which has a substantially higher strength than a Sn60Pb solder.

Thanks to today’s computer programs, engineers can derive a large amount of information from chemical com-position of a material. This information includes phase transformation temperatures Ac1, Ac3, Ms and Mf. CCT and TTT diagrams for austenite decomposition can be determined as well. When steel is heated, austenite grains nu-cleate and grow in the initial microstructure. On cooling, the grains decompose into pearlite, ferrite, cementite and hardening phases. Transformations of this kind are thoroughly described in literature: the ways the individual phases form and the speed of their formation and temperatures involved. However, in-situ visual recordings of such transformations are relatively rare. With Linkam TS1400XY high-temperature stage and chamber integrat-ed in an optical microscope, one can observe phase transformations in situ during heating and cooling. This paper explores microstructural evolution in 42SiCr steel in the course of heat treatment in a high-temperature chamber on an optical microscope stage which offers observation of changes in the material right under the microscope objective.