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Über dieses Buch

This book reports on cutting-edge research and technologies in the field of advanced manufacturing and materials, with a special emphasis on unconventional machining process, rapid prototyping and biomaterials. Based on the International Conference on Manufacturing Engineering and Materials (ICMEM 2018), held in Nový Smokovec, Slovakia on 18–22 June 2018, it covers advances in various disciplines, which are expected to increase the industry’s competitiveness with regard to sustainable development and preservation of the environment and natural resources. Condition monitoring, industrial automation, and diverse fabrication processes such as welding, casting and molding, as well as tribology and bioengineering, are just a few of the topics discussed in the book’s wealth of authoritative contributions.

Inhaltsverzeichnis

Frontmatter

Invited Papers

Frontmatter

Study Programs in STEM Field in Eastern European Countries vs. Brain Drain

Smart countries encourage students to enroll study programs in so-called STEM field in order to assure direct positive influence on their own economies. However, if students complete their study in Eastern European countries, how can those countries prevent their STEM graduates to find job in other well-developed countries, as their knowledge is relevant globally? In cases of brain drain, are the STEM studies financially supported by governments an investment or a cost? Should these governments still increase the enrollment quota for STEM field study programs by counting on income contribution from those graduates from abroad?

Dražan Kozak

Manufacturing in Times of Digital Business and Industry 4.0 - The Industrial Internet of Things Not Only Changes the World of Manufacturing

Digital business and Industry 4.0 have already significantly changed the world of manufacturing. Data related to the machines as well as process data from the manufacturing lines serve to install powerful applications and services within the entire manufacturing ecosystem. The article provides an overview on several methods used in the manufacturing with respect to process efficiency and reliability as well as quality management. Methods used today often have been designed many years ago but due to increasing computer power and IT capabilities at reasonable costs they evolve as success factor in digital business.

Jan M. Olaf, Eckhart Hanser

A New Method for Gear Chamfering

In order to chamfer the teeth of a gear wheel there are three important methods in the market: “Chamfer Cut”, roll chamfering and “Gratomat”. All of them have advantages but are not suitable in all situations. For such difficult chamfering operations and especially for smaller series a new method for accurate chamfers was created. The process is based on the geometry of the gear tooth and is simulated by mathematical calculations and therefore a special milling tool has to be manufactured for each individual gear wheel. With this tool is it possible to chamfer the teeth with very high quality in a short time and under economical conditions.

Manfred Schlatter, Niklas Müller

Water Jet Technology Session

Frontmatter

New Approach of Recycling of Abrasives for Water Jet Cutting

The recycling or reuse of material in production becomes as a saving task for sustainable and environmental competitive production. Sustainability means not only achieving cost efficient process but also eco efficient. The design of the abrasive recycling system is desirable because of the growing growth and development of the abrasive water jet cutting industry. The use of recycled abrasives greatly reduces production costs, and hence the price of products resulting from such processing and increases competitiveness. There is a large space for wide application of cutting technology with abrasive water jet, and thus the application of abrasive recycling. On the environmental side it is very important to have a controlled disposal of the abrasive used.

Miroslav Duspara, Tomislav Palatinuš, Dejan Marić, Ivan Samardžić, Željko Ivandić, Antun Stoić

The Use of Areal Parameters for the Analysis of the Surface Machined Using the Abrasive Waterjet Technology

The paper deals with areal evaluation of the surface texture of AISI 304 material created by the abrasive waterjet. The sample examined was measured using an optical profilometer and an optical microscope. The surface topography is most frequently evaluated according to the surface profile parameters defined in ISO 4287. However, for a more complex analysis of a studied surface, it is more advantageous to use an areal (three-dimensional) method which applies the knowledge acquired from the profile (two-dimensional) method extended by new research findings. The areal parameters of the surface texture are described in the standard ISO 25178-2.

Dagmar Klichová, Jiří Klich, Tomáš Zlámal

Research on Water Jet Cutting of Polymer Composites Based on Epoxy/Waste Fibres from Coconut Processing

This paper deals with a machining of polymer fibre composite materials reinforced with a waste from coconut processing by means of an unconventional technology, i.e. an abrasive water jet (AWJ) and a water jet (WJ). Short and long fibres from the waste/a by-product from the coconut processing were used as the reinforcement within the research. The composite material was made by a vacuum infusion method. These composite materials are difficult to cut by another cutting method. They are used as a design upper/view element which is applied on a basic material, e.g. chipboards. These materials have to be cut precisely according to requirements of a shape and dimensions of a final product, e.g. for furniture industry. The paper deals with a study of an influence of the abrasive water jet and the water jet at their impact on a surface of the machined polymer fibre composite material. SEM analysis proved that a considerable destruction of the material occurred at the water jet outlet, i.e. on a bottom side of the cut, under unsuitable cutting conditions and at an absence of the abrasive grains which is an undesirable factor for following applications of these materials.

Müller Miroslav, Valášek Petr, Novotný Jan, Ruggiero Alessandro, D’Amato Roberto, Habrová Karolína

Recent Developments in Pulsating Water Jets

Pulsating water jets represent one of the ways to intensify effects of water jetting technology on materials. In the first part of the paper, phenomena occurring during the impact of a drop of a liquid on a solid surface and reasons for their use leading to the generation of pulsating water jets are briefly described. In the next part, the concept of hydrodynamic nozzle for generating of pulsating water jets is briefly mentioned. The final part of the paper deals with the comparison of the erosive effects of continuous and pulsating jets generated by the acoustic generator and the hydrodynamic nozzle. Presented results proved superior performance of the pulsating jet generated by the acoustic generator. The hydrodynamic nozzle exhibits also great potential for significant improvement of water jetting performance.

Josef Foldyna

Investigation on Pulsating Liquid Jet with Physiological Saline on Aluminium Surface

The paper deals with an experimental study related to the influence of technological parameter namely standoff distance and fluid pressure over disintegration depth created on aluminium surface. The fluid used for disintegration is 0.9% physiological saline. This saline solution with density 1.008 kg/m3 higher than water 0.998 kg/m3, when impacts the surface induces a larger force leading to deeper disintegration grooves keeping other parameters constant. Special nozzle having diameter of 0.3 mm and 100 mm length was used during disintegration process. A minimal pressure ranging from 8 MPa to 16 MPa along with standoff distance of 1 mm to 6 mm is varied to observe its interactional effect over the depth formed during disintegration process. Groove depth was measured using FRT device in which 10 readings of each groove were recorded and their mean were considered for further analysis. The results concluded that for intermediate values of standoff distance (3–4 mm) and higher fluid pressure (13–16 MPa), deeper grooves were observed. Deepest mean groove observed within the experimental domain was of 183 µm deep at 2 mm standoff distance and 16 MPa fluid pressure. The experiments concluded that saline jet can be used for disintegration of material effectively.

Akash Nag, Sergej Hloch, Amit Rai Dixit, Dominik Cuha

Parametric Study During Abrasive Water Jet Turning of Hybrid Metal Matrix Composite

The growing demand of efficient materials in automobile and aircraft industries originates the development of metal matrix composites (MMCs) with excellent properties such as higher strength, hardness and stiffness, better corrosive and wear resistance and thermal properties. However, these materials are not produced at a larger scale because of its poor machining performance due to the presence of hard abrasive particle which leads to high tool wear and meager machining outputs. This paper deals with the abrasive waterjet turning of the newly developed hybrid MMC of A359/B4C/Al2O3 produced by electromagnetic stir casting method. The main aim of the study is to discuss the effect of process parameters of abrasive waterjet machining on outcomes such as surface roughness and metal removal rate. Response surface methodology and ANOVA analysis has been applied to discuss the significant level of process parameters and their mathematical relations. The results reveals that each output response considered in the study was significantly affected by the machining process parameters. The surface roughness is found in the range of 6.0545 µm to 8.3825 µm, and MRR varies from 434.72 mm3/min to 565.02 mm3/min.

Ashish Kumar Srivastava, Akash Nag, Amit Rai Dixit, Sandeep Tiwari, Vishal Shankar Srivastava

Effect of Frequency Change During Pulsed Waterjet Interaction with Stainless Steel

In the present work a detailed effect of pulsating water jet treatment with the variation of standoff distance on the flat austenitic stainless steel surface has been studied. During the experimentation, at a traverse speed of 30 mm/s accidently the change in frequency was encountered in the repeated test (under same treatment condition) which has been reported in this work. The frequency was changed from f = 20.11 kHz to f = 20.27 kHz during the treatment process at the pressure of p = 70 MPa with variation in standoff distance was increased from z = 5 mm up to z = 101 mm (with step distance of 2 mm between successive standoff distance). The change in microstructural topography of the treated surface under the above-mentioned conditions was observed using scanning electron microscopy (SEM). The strengthening mechanism on the surface and sub-surface region due to the plastic deformation phenomenon caused by the impact of the pulsating jet was evaluated by Vickers microhardness test. The micro hardness test was conducted along the depth of the treated region to analyze the effects in the sub-surface layers. Also, the erosion stages at different standoff distance was evaluated by scanning the surface by optical MicroProf FRT profilometer in order to analyze the nature of erosion phenomenon with the variation of standoff distance and frequency during the treatment process. The results obtained indicates that the change in frequency of the pulsations and the variation in standoff distance has a significant impact on the surface integrity of the treated material. As compare to the untreated surface the hardness of the treated surface was increased up to a certain depth and the higher frequency of pulsations has shown better improvement in the hardness values. The above observations elaborated the effect of an important parameter frequency and standoff distance for better and effective utilization of the technology for the surface treatment application.

Madhulika Srivastava, Sergej Hloch, Miroslav Muller, Monika Hromasová, Jaromír Cais, Somnath Chattopadhyaya, Amit Rai Dixit, Jiří Klich

Microstructure, Properties and Damage Mechanisms by Water Jet Cutting of TiB2-Ti Cermets Prepared by SPS

Process parameters of abrasive water jet (AWJ) machining of TiB2+Ti ceramic matrix composites with 10%, 15% and 20% of Ti reinforcement were investigated. The article focuses on microstructure damage processes and kerf geometry in AWJ machining of TiB2+Ti composites. Two different abrasive water jet cutting speeds and three sorts of composite materials, together with a reference monolithic one, are considered. Microstructure in machined samples was observed using scanning electron microscope. The characteristics of the cuts such as kerf top width, kerf angle and surface roughness were studied. The influence of cutting speed on abrasive process in composites with various amounts of Ti was investigated. It was found that roughness decreases and kerf taper ratio increases with increase in amount of Ti.

Viktor Puchý, Martin Fides, Róbert Džunda, Richard Sedlák, Jaroslav Kováčik, Sergej Hloch, Petr Hlaváček, Pavol Hvizdoš

Investigation on Feed Rate Influence on Surface Quality in Abrasive Water Jet Cutting of Composite Materials, Monitoring Acoustic Emissions

The paper deals an experimental study on cutting composite materials (CFRP) using abrasive water jet cutting (AWJC) process. The influence of the feed rate on surface roughness is studied using acoustic emission (AE) monitoring. For monitoring the process two acoustic emission sensors was mounted, on the CFRP workpiece and on the cutting head. This monitoring technique has proved that, between process parameter (feed rate and amplitude of AE signal) is a clear connection. The surface roughness can be predicted using online monitoring with acoustic emission (AE).

Ioan Alexandru Popan, Vlad Bocanet, Nicolae Balc, Alina Ioan Popan

Comparison of Non-destructive Sensing Methods on Surface Created by Waterjet Technology

The article is a response to the lack of information, especially in the area of non-destructive techniques suitable for wide practical application. The article deals with evaluation of the disintegrated material volume removed from the samples by a water jet. The study presents a quantified disintegrated material volume by means of an optical profilometer MicroProf FRT, a digital microscope VHX-5100 and X-ray computed micro-tomograph XT H 225 ST. Based on a comparison of measured data, it is possible to state that the methods of optical profilometer and a digital microscope give us very close volume values. While the values of the volume of removed material analysed by X-Ray μ-CT reach higher its values. After detailed analysis of the individual tomographic cross-sections in area of kerf surface it can be concluded that complex morphology of this surface can explain differences in the results. There are visible some re-entrant features like an overhangs and undercuts at the surface created by high pressure water jet.

Jiří Klich, Dagmar Klichová, Kamil Souček

Investigation of Limestone Cutting Efficiency by the Abrasive Water Suspension Jet

The paper concern to the impact of the Abrasive Water Suspension Jet (AWSJ) limestone cutting process parameters, such as abrasive flow rate, diameter and length of the forming nozzle jet under reduced pressure on the depth of cut. Achieving such a high efficiency in the processing of this rock results from the use of circular motion of the liquid to create a stream. This has become possible due to the replacement of a low-efficiency injector mixer with a new mixer in which the hydro-abrasive mixture is generated directly under high pressure. The conducted research allowed to determine the best geometric dimensions of the working nozzle and abrasive flow rate to achieve the best machining effects were achieved.

Andrzej Perec

Erosion Test with High-speed Water Jet Applied on Surface of Concrete Treated with Solution of Modified Lithium Silicates

The paper focuses on the erosion resistance test based on surface treatment by a high-speed water jet applied on concrete. A reference concrete sample and concrete samples with three types of solution of modified lithium silicates applied on the concrete surface were tested under various erosion conditions. Two different jet impact angles (45° and 90°) were investigated. A significant difference in the erosion rate in the surface layers was observed comparing the untreated concrete and the concrete treated by various solutions of modified lithium silicates, but only in the initial phase of erosion.

Petr Hlaváček, Libor Sitek, Rudolf Hela, Lenka Bodnárová

Analysis of Micro Continuous Water Jet Based on Numerical Modelling and Flow Monitoring

The paper deals with application of numerical modelling, computed tomography and optical diagnostic techniques for study of continuous micro water jet behaviors. The main emphasis is placed on numerical modelling of high speed water jet generation inside a circular nozzle and its outlet. The theoretical studies are performed based on the 3D geometry of nozzle received from the computed tomography. The models are experimentally verified by flow monitoring and visualization techniques. For the purpose of experimental testing, a closed water circuit was designed. The methods of Particle Tracking Velocimetry, Laser Induced Fluorescence and Shadowgraphy together with fluorescent seeding particles were applied for determination of jet velocity fields. A series of experiments was conducted to measure the flow conditions. Basic methods and principles used in the experiments are described in the paper. The results and analyses of the micro CWJs flow based on numerical modelling, visualization and monitoring show very good conformity of theoretical and practical tests.

Michal Zelenak, Zdenek Riha, Kamil Soucek, Frank Pude

An Acoustic Emission Study of Rock Disintegration by Pulsating Water-Jet

The collision of a high-velocity liquid mass with a solid generates short high pressures transients, which is responsible for the damage to the surface and its interior. The main advantage of the pulsating jet as compared to the continuous water-jet technology is that the impact pressure (due to hammering effect) is several times greater in pulsating water jet. The impact of the pulses induces fatigue stresses in the target material due to cyclic loading which is the most influential factor responsible for the disintegration. However, this technology is reported to the current trend of the application. During the laboratory experiments on Silesian granite were examined the relationship between the acoustic emission and parametric conditions of the pulsating water-jet. This research paper deals with an application of acoustic emission measurement as an on-line monitoring tool for analyzing the disintegration phenomenon of rock by pulsating water jet which locally affects the structural integrity of rocks. The correlation between rock disintegration and dynamic signal performance was obtained for several rock materials at various settings of jet parameters.

Rupam Tripathi, Sergej Hloch, Somnath Chattopadhyaya, Pavel Adamcik, Alok Kumar Das

Evaluation of Possibility of AISI 304 Stainless Steel Mechanical Surface Treatment with Ultrasonically Enhanced Pulsating Water Jet

Experimental study described in this article is focused on evaluation of dynamic effect of PWJ on disintegration efficiency on AISI 304 stainless steel surface. AISI304 stainless steel was disintegrated with circular nozzle diameter 1.19 mm, pressure 70 MPa, frequency 20.25 kHz and traverse speed 100 mm.s−1 (202 impacts per millimeter). Disintegration efficiency was evaluated based on surface and subsurface characteristics. Surface characteristics were evaluated based on surface topography and roughness parameters Ra [μm], Rz [μm], Rp [μm] and Rv [μm] comparison of disintegrated and non-affected area. Subsurface changes in material structure were described based on metallographic analysis and hardness measurement HV0.2 under the eroded area. The results of the disintegration efficiency evaluation of AISI 304 stainless steel surface show that was no massive erosion of material. Surface quality was slightly changed. Small microscopic craters were predominantly created on surface. Craters were characterized with predominant pitting mechanism and prevails fracture mechanism of material removal.

Dominika Lehocká, Vladimír Simkulet, Jiří Klich, Zdeněk Štorkan, Lucie Krejčí, Ján Kepič, Jaroslav Birčák

Non–traditional Machining of Inconel 600 Material

Abrasive water jet machining (AWJM) is successfully used for various industrial applications to cut extreme ductile and brittle materials. Thermal deterioration, high processing diversity, provide distinct advantages with high flexibility and small cutting forces. In this study, the Taguchi design analysis was used to determine the optimal combination of parameters for the actual cutting conditions of the Inconel 600 material. Variance Analysis (ANOVA) was also used to determine the most important factor. Common parameters such as nozzle feed rate, nozzle standoff distance and abrasive flow rate are optimized to investigate the effects of parameters on the Surface Roughness (Ra) during cutting of the Inconel 600 material.

Fuat Kartal, Sergej Hloch

(Un)conventional Technology Session

Frontmatter

Mapping Requirements and Roadmap Definition for Introducing I 4.0 in SME Environment

Industry 4.0 as a new manufacturing paradigm brings in a new wave of networked manufacturers and smart factories, which will determine future competitiveness of manufacturing companies. The aim for researchers should thus be to generate and optimize innovative solutions for different types of producers including SMEs in order to support them in meeting the challenges of Industry 4.0. The paper presents the readiness self-assessment method and roadmap model as a tools to secure a consistent implementation of technologies and devices supporting smart logistics and smart production. Proposed method has been applied by selected SMEs and it was proved that the model is easy to use in real production environment.

Vladimir Modrak, Zuzana Soltysova, Robert Poklemba

Dimensional Characterization of Prosthesis Bearings for Tribological Modelling

Prosthesis bearings are precision mechanical systems from which performance improvement represents a direct contribution to patient’s wellbeing. Spherical shape of hip prosthesis bearing approaches natural ones, but their performance become degraded in service, and the lubrication and wear mechanisms are outstanding fields of research. Because tribological phenomena are complex, attempts of modelling the bearing requires precise consideration of the boundary conditions that the real prosthesis have. Detailed experimental characterization of two ceramic hip prostheses is accomplished. Shape and roughness are measured by accurate point coordinate metrology with proper methodology through contact probing by a coordinate measuring machine, and optical measuring through confocal microscopy. The results quantify the deviation from the ideal shape and significant roughness parameters of bearing surfaces. Their influence is discussed in the spotlight of their relationship with the tribological behavior of the prosthesis. Future works direction are envisioned so geometrical boundary conditions can play an important role in prosthesis performance understanding and improvement.

Roberto D’Amato, Roque Calvo, Massimiliano Merola, Petr Valášek, Miroslav Müller

Accelerated Method of Cutting Tool Quality Estimation During Milling Process of Inconel 718 Alloy

Cutting tool wear is a natural consequence of the engagement of cutting tool and workpiece. This phenomenon can progress in a slower or quicker rate and can be attributed to various reasons, such as abrasion, adhesion, chemical reaction, thermal or mechanical phenomena, depending on machining conditions and material properties of cutting tool and workpiece. As the replacement of worn tools is directly related to the cost of machining processes, it is important to select favorable process parameters in order to avoid high wear rates, especially when machining hard-to-cut materials. The experimental determination of tool wear during machining of various materials is a costly and time-consuming process, as it requires carrying out experiments at several cutting speeds until a tool failure criterion is reached each time. In the present work, a novel method for conducting tool wear experiments at various cutting speeds at a single experiment is proposed and applied to a case of milling an Inconel 718 workpiece. Experiments were performed for three different cutting tools and for cutting speeds in the range of 90–170 m/min, at constant feed rate, axial and radial depth of cut values. The results indicate that the proposed methodology can successfully provide an indication of the performance of various cutting tool types during machining of hard-to-cut materials.

Witold Habrat, Krzystof Krupa, Nikolaos E. Karkalos

An Investigation on Tool Flank Wear Using Alumina/MoS2 Hybrid Nanofluid in Turning Operation

The present work is focused on the development of a hybrid nano-lubricant with improved tribological properties by mixing molybdenum-disulphide (MoS2) nanoparticles with alumina nanoparticles in oil-water emulsion base fluid in a fixed volumetric proportion (10:90). The tribological testing and contact angle measurement of prepared lubricants have been performed on pin-on-disc tribometer and goniometer, respectively. The hybrid lubricant has shown better results compare to base fluid (oil-water emulsion) and alumina-based monotype lubricant. Furthermore, the test results confirm the reduction in wear and coefficient of friction with increase of nanoparticle concentration. Moreover, the performance of hybrid nanofluid has been evaluated in terms of machining response using minimum quantity lubrication (MQL) technique on turning of AISI 304 steel. The addition of hybrid nanoparticles significantly reduces the tool flank wear as compared to monotype nano-lubricant and base fluid.

Anuj Kumar Sharma, Rabesh Kumar Singh, Amit Rai Dixit, Arun Kumar Tiwari, Mahip Singh

Additive Printing of Gold Nanoparticles on Paper Substrate Through Office Ink-Jet Printer

The article reports the synthesis of the concentrated Gold Nanoparticles (AuNPs) ink and its printing on the paper substrate through Office Ink Jet printer. Initially, AuNPs were synthesized from the precursor Gold (III) Acetate through Ultrasonic Spray Pyrolysis. Ellipsoidal shaped AuNPs with a size distribution of below 50 nm were confirmed through TEM and DLS measurement. Maximum absorbance wavelength of AuNPs measured through UV-vis spectroscopy was 532 nm. Further, the AuNPs ink was prepared through the rotavapour and filtered upto the Au concentration of 600 ppm determined through ICP-OES. The AuNPs printed patterns on the photo paper substrate were successfully printed and further analyzed with SEM.

Mohammed Shariq, Amit Rai Dixit, Rupert Kargl, Somnath Chattopadhyaya, Meduri Venkata Sridutt, Pasagada Venkata Keerti Vardhan, Rebeka Rudolf

Preliminary Study on Staggered Herringbone Micromixer Design Suitable for Micro EDM Milling

This paper discusses interplay between the design of a Staggered Herringbone Micromixer (SHM) and micro Electrical Discharge Machining (EDM) milling technology. SHM consists of a main channel and many herringbone lookalike grooves at the bottom, which enhance mixing. Firstly, a brief overview on how the technological model of micro EDM milling was constructed is presented. Anticorrosive stainless steel was used as a workpiece material on the basis of which the database for the technological model was established. In the second part the technological model was used for micromixer design optimization. Different SHM designs that can be machined in the same amount of time, were compered via their mixing efficiency. Mixing efficiency was estimated by performing Computational Fluid Dynamics (CFD) simulations. The results show, that smaller and shallower grooves are not efficient in the terms of mixing. An important design parameter is also the orientation of the grooves. In the end, a favorable SHM design is presented.

Izidor Sabotin, Gianluca Tristo, Andrej Lebar, Marko Jerman, Miha Prijatelj, Pavel Drešar, Joško Valentinčič

Experimental Analysis of the Cutting Force Components in Laser-Assisted Turning of Ti6Al4V

In this paper, the experimental analysis of the turning of Ti-6Al-4V titanium alloy with the laser-assisted machining was described. For the tests, a cemented carbide tool was used. The influence of the laser heating and cutting parameters on the tangential and thrust forces was determined. The beneficial effect of laser-assisted machining on components of the cutting force was established. Cutting force models were developed. The significant influence of interaction of cutting speed and laser power on tangential force components was observed. The microstructure of laser-scanned surface and the roughness parameters after turning as the process indicators connected with cutting force were analyzed.

Witold Habrat, Krzysztof Krupa, Piotr Laskowski, Jan Sieniawski

Critical Failure Analysis of Lower Grinding Ring of Ball and Race Mill

This paper highlights a methodology for failure analysis of cast grinding ring of a ball and race mill. It investigates the root cause of premature failure of cast grinding ring. The grinding ring was made of Ni Hard IV. Grinding ring of ball and race mill failed after giving the life only 2861 running hours. It was premature failure against the required useful life of 6500 running hours. The process of critical investigation of failure analysis includes visual observation, chemical analysis, microstructure analysis, and evaluation of hardness, analysis of erection process and operational analysis. The cast ring was failed with the indication of direct separation of surface from the outer periphery of ring. No evidence of faulty chemical composition, microstructure and erection procedure were observed. Hardness was found around 400 BHN and inadequate spring pressure on ring was also observed during operation of ball and race mill which had caused the radial movement of the ball in ball track of the lower ring, resulting radial thrust on the collar of the ring and it failed from that area.

Gagan Kumar Guptaa, Somnath Chattopadhyayab

The Influence of the Application of EP Additive in the Minimum Quantity Cooling Lubrication Method on the Tool Wear and Surface Roughness in the Process of Turning 316L Steel

The paper presents the influence of the application of the EP additive based on pure phosphor in minimum quantity cooling lubrication. During investigation, three methods of cooling the cutting zone have been applied in the process of turning 316L steel: dry machining, MQCL, MQCL + EP. The wear of the tool depending on the cooling method has been monitored, as well as its influence on the machined surface roughness. Scanning analysis has shown formation of a tribofilm as result of the application of the EP additive on the surface of a plate with (Ti, Al) N coating deposited by the PVD method. Experimental evidence suggests that the application of the MQCL + EP method results in reduction of the VBB parameter as compared to dry machining and cooling with emulsion mist up to the moment of the tool coating damage. It has been found that, as result of the application of the EP additive in the MQCL method, after damage of the (Ti, Al) N coating rapid increase of the tool wear takes place and, consequently, increase of the machined surface, which is due to the reaction with the base material (sintered carbide). This is caused by the chemical action of pure phosphor without the carbon matrix on the exposed area of the tool made of sintered carbide; the latter appears as result of adhesive wear of the coating

Radoslaw W. Maruda, Stanislaw Legutko, Jolanta B. Krolczyk, Szymon Wojciechowski, Wlodzimierz Kot

Time-Dependent Feed Force Modelling to Apply Feed Rate Strategies in the Drilling of Unsupported CFRP-Structures

In the drilling of flexible work pieces, the work piece movement makes the prediction of the machining time more difficult. This is due to the variance between the defined machining parameters and the effective machining conditions at the cutting edges. Consequently, feed rate strategies cannot be applied on the basis of the machining parameters. Therefore, a mechanistic modelling approach will be presented, which allows to calculate the feed forces in an unsteady drilling process. Thereby, the relative position between work piece and drilling tool can be known at any time. The model allows the consideration of the tool geometry, whereby drilling processes with state of the art step drills can be simulated. In the end, the prediction of characteristic drilling phases can be used to determine the timing to apply feed rate strategies to reduce push-out delamination. The practicability of the simulation and the efficiency of two different feed rate strategies will be shown for unsupported drilling processes with the typical aeronautics composite material M21/T800S.

Fabian Lissek, Sergej Hloch, Michael Kaufeld

Recognition of Assembly Parts by Convolutional Neural Networks

The paper describes the experiments with the use of deep neural networks (CNN) for robust identification of assembly parts (screws, nuts) and assembly features (holes), to speed up any assembly process with augmented reality application. The simple image processing tasks with static camera and recognized parts can be handled by standard image processing algorithms (threshold, Hough line/circle detection and contour detection), but the augmented reality devices require dynamic recognition of features detected in various distances and angles. The problem can be solved by deep learning CNN which is robust to orientation, scale and in cases when element is not fully visible. We tested two pretrained CNN models Mobilenet V1 and SSD Fast RCNN Inception V2 SSD extension have been tested to detect exact position. The results obtained were very promising in comparison to standard image processing techniques.

Kamil Židek, Alexander Hosovsky, Jan Piteľ, Slavomír Bednár

The Use of Technology Local Heating by Laser for Turning of Difficult to Machine Materials

The article deals with the use of the local laser heating during turning of hard machined materials. The application of heating using laser technology is applied especially to reduce the wear of cutting tools and increasing their durability and decreasing costs associated with machining process. The aim of the experiment was to compare the costs associated with production of a valve seat made of CrNi 58/41. Current machine equipment was replaced by RNC 400 Laserturn hybrid lathe. The choice of the proposed solution was verified on the basis of technical and economic evaluation.

Jakub Mesicek, Jana Petru, Tomas Zlamal, Marek Pagac, Jiri Sedivy, Ondrej Vortel, Lukas Drabek

Contributions to the Development of an Ontology in Logistics of Manufacturing

In this paper are presented some contributions to the development of an ontology in logistics of manufacturing. In the paper are presented the basic conditions required by logistics of manufacturing and the main activities of logistics of manufacturing. Also are presented the main definition of ontology, the evolution of ontology and the ontological approach to the logistics problems of manufacturing. Are proposes a core ontology that specifies the main concepts used in logistics operations. In the end of paper are presented the future directions of research for the development of an ontology in logistics of manufacturing.

Nicolae Stelian Ungureanu, Adrian Petrovan, Miorita Ungureanu

Advanced Output Characteristics of Welding Power Source for Pulsed GMAW

One of relevant nonparametric parameter characterizing the welding power source is static output characteristic. The parameter is designated by loading the source with an adjustable resistor. However, in case pulsed gas metal arc welding (P-GMAW) power source, the measurement of relationship between the output voltage and the output current is dependent on several factors and ignoring them might lead to the incorrect evaluation of the varying slope in working point. The following work introduces some aspects of analysis programmable output characteristics of welding power source. To determine power supply volt/amp characteristic during background current time and pulse duration, special value of arc parameters have been set in synergic control system of welding machine. The analysis of registered images of interelectrode space with the use of high - speed photography has been presented. It has enabled the interpretation of the impact of change in pulse current value as change in the length of the electrode extension on metal transfer and arc stability of the arc.

Krzysztof Makles, Jerzy Winczek, Marek Gucwa

Investigation of the Effect of Johnson-Cook Constitutive Model Parameters on Results of the FEM Turning Simulation

FEM simulation are of growing importance in the research of phenomena related to the machining processes. To accurately model the machining process, an appropriate constitutive model needs to be employed. A Johnson-Cook (J-C) material model is frequently used for numerical simulations of various machining processes. J-C model parameters for a range of materials are available in open literature, with substantial differences between parameter values for the same material depending on the source. The aim of this work was to investigate the effect of changes in values of J-C model parameters on the results of an FEM oblique turning simulation. Impact of parameter values was evaluated on the basis of differences in chip shape, stress distribution and cutting force values obtained for several different parameter sets. The authors have noted significant differences in simulation results. Depending on used parameter values.

Piotr Löschner, Krzysztof Jarosz

Comparative Analysis of Surface Finishing for Different Cutting Strategies of Parts Made from POM C

This paper focuses on the comparing the resulting surface after finishing holes machined with different cutting technologies. The machined material is Polyoxymethylene polymer POM C. The cutting technologies that were used are: helicoidal milling, contour milling, head boring, and reaming. The main purpose of this paper is to establish the most appropriate finishing technology for a hole, depending on its functional role. The article compares each finishing process following the qualitative differences that occur. Qualitative analysis refers to the dimensional, shape and quality precision of the obtained surface. Surface quality was evaluated through its main parameters: surface roughness and surface texture. Following the evaluation of the worked surfaces, it was found that there are considerable differences between the finishing strategies that were used. The differences are considerable enough that one should consider using one technology instead of another depending on the use case. The results of this paper help in making faster decisions about what finishing technology to use when finishing holes in a POM C part depending on the functional purpose of the machined hole.

Nicolae Panc, Glad Contiu, Vlad Bocanet

Investigation of the Effect of Process Parameters on Surface Roughness in EDM Machining of ORVAR® Supreme Die Steel

This work presents the effect of selected process parameters on surface roughness in EDM machining of hot-working die steel. Different values of pulse current and pulse voltage were assumed in combination, while individual pulse time was set as constant. The effect of EDM parameters on 3D surface roughness parameters was investigated. Two samples machined with different pulse voltages were prepared, with each sample divided into five separate areas corresponding to different values of used pulse current. 3D surface roughness measurements were performed on each area of all samples. The authors have found a substantial link between pulse current and surface roughness. Moreover, it was discovered that pulse voltage affects surface roughness in a significant way for a certain range of pulse current values, allowing to obtain better surface finish with the use of a higher voltage.

Krzysztof Jarosz, Piotr Nieslony, Piotr Löschner

The Influence of EP/AW Addition in the MQL Method on the Parameters of Surface Geometrical Structure in the Process of Turning 316L Steel

The methods of cooling with minimum lubrication, MQL, and with minimum cooling and lubrication, MQCL, are often applied in machining nowadays due to their ecological and environmental advantages. The MQL and MQCL methods are a good alternative to dry cutting, especially during machining of hard-to machine steels, where high temperature occurs in the cutting zone and process engineers want high quality of the machined surface. The paper compares four methods of cooling when turning austenitic steel, 316L: dry cutting, MQCL method, MQL method and MQL + EP/AW method. During the experiment, 2D height parameters were monitored, as well as Abbott Firestone curve with the spatial parameters and profiles of selected surfaces have been presented. Due to the large number of variables in the tests, the planning method of Parameter Space Investigation has been used. When applying the MQL cooling method with the addition of EP/AW, the smallest values of Ra and Rz parameters have been obtained in the whole range of the variable parameters of machining. The Abbott Firestone curve, together with the spatial parameters, has proved that a surface manufactured after the process of turning in the MQL + EP/AW conditions shows better exploitation properties.

Radoslaw W. Maruda, Szymon Wojciechowski, Grzegorz M. Krolczyk, Danil Yu Pimenov, Stanislaw Legutko

Change of the Substrate Surface After Removal Multiple Plasma Spraying Layers

The paper deals with the change of the surface properties of the substrate after the application of multiple plasma spraying NiCr. The influence of selected technological factors (substrate material, surface angle of the substrate and degreasing of the surface) on topography and surface quality of the substrates. Presented procedures and experimental results demonstrate surface resistance of individual materials from effect multiple plasma coatings. The best results of surface resistance have samples from chromium steel. In addition, the results of these experiments indicate which parameters are key in selecting the substrate material for the masking process in serial production of coatings by plasma spraying.

Jozef Kužma, Michal Krescanko, Sergej Hloch

Tool Wear Measurement in Single Point Incremental Forming

Forming tool in manufacturing industries plays a vital role in processing and finished part surface profile. Tool wear in single point incremental forming (SPIF) is studied in the present study with the aim to investigate the effect of input parameters. Image tool wizard of MATLAB R2010a software is used for the wear measurement. The image of tool end is transformed into the histogram plot and the difference of bar length is measured as wear. For experiment, six parameters, namely step depth, feed rate, spindle speed, thickness of material, wall angle and lubricant are considered for SPIF of aluminum AA3003-O. Experiments are being made based on the Taguchi technique followed by ANOVA analysis to study the effect of process parameters and the image analysis is used for the measurement of tool wear. The results shows that the significant input parameters are step depth, feed rate of tool and spindle speed for tool wear whereas wall angle is insignificant.

Manish Oraon, Vinay Sharma

Materials

Frontmatter

Increasing Compressor Wheel Fatigue Life Through Residual Stress Generation

Cast aluminium compressor wheels in turbochargers may fail following cyclic loading in service due to crack growth from the highly stressed bore of the wheel. In this paper it is proposed to subject wheels to a single over-speed event to generate beneficial, compressive residual stresses at the bore of the wheel and hence reduce stresses at the working speeds. A theoretical model has been identified to simulate this process and a technique developed to determine the model input parameters. This closed form analytical model shows good correlation with a detailed finite element analysis over a wide range of over-speed events.

Simon M. Barrans, Andrew Thompson, John Allport

Preliminary Study of Residual Stress Measurement Using Eddy Currents Phasor Angle

Residual stress detection and evaluation has been of crucial importance, and also problematic for many years. There are many methods of residual stresses determination based on destructive and non-destructive way of approach. Nowadays there are still undiscovered possibilities to determine these internal stresses. Opportunity to detect residual stress on line directly, without using big and expensive devices is motivation for presented work. Presented article is focused on possibility to determine the residual stresses induced in conductive materials using eddy currents phasor angle. Using eddy currents method gives opportunity for quick on line measurement of residual stresses. Induced stress causes in base material slight deviation in permeability and conductivity, which can be detected using standard eddy currents flaw detector. Experimental procedure included annealing for stress relief, manufacturing by face milling and measurement of residual stresses using x-ray diffraction and eddy currents. Results of experimental research lead to extension of knowledge in the field of residual stresses. Presented method is applicable for assessment of residual stresses in many components.

Frantisek Botko, Jozef Zajac, Andrej Czan, Svetlana Radchenko, Vladimir Simkulet, Pavol Radic, Jaroslav Bircak

Forces and Process Dynamics in Profiling of AlCu4MgSi Aluminium Alloy

This work presents the results of experimental research regarding cutting force, chatter frequency and amplitude for different cooling conditions in profiling of AlCu4MgSi aluminium alloy. The following conditions were analyzed: dry cutting, cooling with water-based emulsion, MQL and MQCL. It was determined that cooling and lubricating conditions in the cutting zone have a minimal effect on machining forces in the following range of parameters: cutting speed 300–600 m/min, depth of cut 1–2 mm, feed rate 0.1–0.5 mm/rev. Therefore, a conclusion to introduce dry machining to cut down costs was formed. Changes in cutting force components can be described by the following relation: Fc ≈ Fp > Ff. The intensity of the effect of technological parameters on cutting force components decreases in the direction of f → ap → vc. It was proven that by analyzing changes of cutting force in machining time, possibilities of chatter occurrence for different machining conditions can be assessed.

Eugene Feldshtein, Piotr Nieslony

A Polyurethane/Carbon Black Composite Absorber for Low Frequency Waves

This study proposes a Polyurethane/Carbon Black composite coating that has the ability of absorbing low frequency waves. The characteristics of coating including contact angle measurements are provided and for performance analyses, a 1 kHz amplitude-modulated signal superimposed on red and green laser beam (whose intensity is changed by square wave) sent to composite coated surface. The reflected beam from the coating was detected by BPW20RF photodetector and signal waves were measured. The results of the analyses illustrated that the composite; coating to a great extent, absorbed the waves.

Mustafa Yagimli, Hakan Tozan, H. Ergin Esen, Emin Arca

The Effect of Additional Shielding Gas on Properties and Erosion Resistance of High Chromium Hardfacing

The wear-resistant layers of the chromium cast iron structure can be made by traditional casting methods as well as by the use of welding methods. The use of hardfacing allows for the creation of a protective layer on existing elements, often in the place of their use. Especially the use of hardfacing using self-shielding core wires allows obtaining layers with the desired properties. The paper presents the results of research on high-chromium hardfacings made in self-protective technology as well as using shielding gas. It was noted that the addition of shielding gas has a positive effect on the stability of the surfacing process and on the appearance of hardfaced surfaces. The hardness tests and erosive wear tests carried out also indicate a positive effect of shielding gas on the properties of hardfacings.

Marek Gucwa, Milos Mičian, Krzysztof Makles, Jerzy Winczek

Analysis of the Legal Risk in the Scientific Experiment of the Machining of Magnesium Alloys

In the article, the legal risk of the researcher in the case of a scientific experiment in the machining of magnesium alloys was determined. The use of magnesium alloys in industry and identification of the problems associated with machining were presented. The issues concerning legal liability in the experiment and provisions ensuring a greater scope of legal protection for the researcher were indicated and challenges in the machining of magnesium alloys were analyzed. Moreover, the method to assess legal risk in experiments was proposed and its application in the experiments was presented. The analysis confirmed the applicability of the proposed method to the analysis of the legal risk.

Dorota Habrat, Dorota Stadnicka, Witold Habrat

Prediction of Tensile Failure Load for Maraging Steel Weldment by Acoustic Emission Technique

Maraging steel (Grade 250) pressurized chambers are used in booster stages for the launch vehicles and missiles. These are designed & realized with ultra high strength steels like Maraging steels in order to gain in range and pay load capabilities with optimal Factor-of-Safety(FOS). Effective manufacturing methodology and fracture control is a prime requirement however manufacturing processes give rise to defects that are inevitable. Non-Destructive Engineering techniques viz. ultrasonic testing, Radiography testing, Eddy current testing etc. address the issue of detecting passive defects only. Defects that are active i.e. critical and that could cause catastrophe shall be detected possibly during Proof pressure testing Strain gauge method adopted is restricted for strain measurements and is in-effective in detecting flaws as it is a highly localized. Acoustic Emission Technique (AET), as a whole field method, has ability to detect unstable flaws effectively. Acoustic emissions are generated due to defects, microstructural variation, presence of inclusions and second phase particles in metallic materials. AET identifies defects and discontinuities in terms of Acoustic Emission parameters. Sources of Acoustic Emission (AE) can be distinguished by their AE signature in terms of amplitude, Count and Energy. The severity can be quantified in terms of AE Parameters. In this paper an attempt is made towards predicting tensile failure load of Maraging Steel weldment with varying extents of notch thereby representing equivalent tight cracks as per Linear Elastic Fracture Mechanics (LEFM) design approach. Customized specimens were fabricated and notches were made using Electric Discharge Machining process. Tensile load has been applied to the test specimens with AE data acquisition. The AE distribution obtained from each specimen has been correlated to an equivalent Weibull distribution and represented in terms of weibull parameters. The significant Weibull parameters viz. Skewness (b value) and centroid of distribution curve (θ) are estimated. The distribution at a load of 85% of failure load is used for the prediction process. An empirical relation connecting Weibull parameters b, θ, b * θ, is proposed. It is observed that the product b * θ is linearly correlated to tensile failure load. On comparing results, predicted tensile failure load is closely matching to the recorded tensile failure load of the specimen. The average prediction capability of the proposed model is within 5–6%.

Gowri Shankar Wuriti, Tessy Thomas, Somnath Chattopadhyaya

Measurements of the Friction Coefficient: Discussion on the Results in the Framework of the Time Series Analysis

Tribology studies the interaction between surfaces in relative motion with a particular focus on the principles of friction, wear and lubrication. The measurement of the friction coefficient (COF) is extremely sensitive to experimental friction force fluctuations thus making COF direct measurement not a trivial task. In this manuscript, a novel approach toward the understanding of the friction coefficient behavior during reciprocating tests is proposed. The proposed procedure represents a first approach for a deep investigation about measured COF distribution during tribological tests. It is based on the analysis of COF data measured during the tests in the framework of time series analysis and it was applied to several real tests in dry-friction showed as example of application. Output parameters (i.e., friction, traction force) were investigated to detect trends, connected to running-in period of the tribo-couple, seasonal, connected to the periodicity induced from reciprocating motion, and residual components. After “smoothing” the COF data set by removing the trend and seasonal components, the residual component was analyzed to check the stationary of the COF data set which represents the most characteristic interval in friction measurements.

Alessandro Ruggiero, Roberto D’Amato, Roque Calvo, Petr Valašek, Nicolae Ungureanu

Experimental Description of the Aging of the Coconut Shell Powder/Epoxy Composite

The Substitution of synthetic filler with fillers prepared from renewable sources is a current trend in the field of composite materials. Natural plant sources provide a very interesting alternative to synthetic reinforcements. They are economically acceptable and the resulting materials provide satisfactory mechanical characteristics. The paper focuses on the description of adhesive properties of epoxy resin filled with coconut microparticles – coconut shell powder (CSP) in the range 0–100 μm and a description of aging of these composites. Aging can be considered as one of the key factors that affects the application area of composite materials. Adhesion and cohesion characteristics were described by shear tensile strength on steel adherents and tensile strength. The morphology of the particles used and the interfacial interaction were described by electron microscopy. The presence of the used particles does not significantly reduce the adhesion characteristics of the used epoxy resin.

Karolína Habrová, Petr Valášek, Miroslav Müller, Robert D´Amato, Alessandro Ruggiero

Fluid Film Pressure Description in Finite Turbulent Lubricated Journal Bearings by Using the Warner’s Theory

The purpose of this paper is to propose a method for the analytical description of the non-steady fluid film for the liquid-lubricated finite journal bearings operating in a fully developed turbulent regime. The analytical description takes in account a symmetrical rigid rotor supported on two lubricated journal bearings under the classical assumptions of the Reynolds theory. The proposed methodology represents an extension of the Warner’s approach and allows to solve analytically in approximate way the equation governing the distribution of pressure in the bearing oil gap and then to obtain the analytical expressions for the unsteady fluid film forces giving particular attention to their continuity in the entire definition domain, introducing original analytical functions called “jump function”. The proposed model allows not only to minimize the computation time without any significant loss of accuracy in the nonlinear dynamic analysis of rotors on turbulent journal bearings but also permits a better readability of the parameter effects on the system unsteady behavior.

Alessandro Ruggiero, Roberto D’Amato, Nicolae Ungureanu

Influence of Processing Parameters on Residual Stress in Injection Molded Parts

Residual stresses are the source of shrinkage and warpage of the parts manufactured with injection molding technology and strongly influences its final dimensions. In complicated parts residual stresses are very difficult to predict without numerical tools, along with the warpage, what leads to problems with manufacturing parts that meet the expected tolerances. Residual stresses have also strong influence on mechanical performance of the part, where its high value can results with self-cracking during ejection from the mold. In this work numerical simulations injection molding process were performed to analyze the presence of residual stresses in manufactured plastic parts by this technology. Numerical simulations were used to find the relations between the processing parameters and the distribution and magnitude of residual stresses. Occurrence of residual stresses were analyzed with new 3D residual stress model implemented in Autodesk Moldflow® software. Qualitative strain-optics observations were performed to verify the differences between different sets of processing parameters. From investigated parameters the strongest influence on residual stresses was observed with packing time, while the weakest influence was observed with injection time.

Przemyslaw Poszwa, Pawel Muszynski, Pawel Brzek, Krzysztof Mrozek

Shape Memory Alloy (SMA) as a Potential Damper in Structural Vibration Control

The utilization of smart structure technologies to mitigate the vibrations of structures have been the prime focus of numerous scientists involved in the area of structural vibration control. Smart materials serve multiple purposes like that of sensing, actuation and also exhibit the capability of modifying and adjusting the structural behavior when subjected to sudden external shock like earthquake or blast. Smart materials are basically defined as those materials possessing special features and can be applied in the design of structures to enhance the structural performance. Shape Memory Alloys (SMAs) are the most promising and prominent class of smart materials. When strained beyond 6–8%, SMAs possess the ability to regain its original shape. Reversible phase transformation is responsible for such sort of shape recovery. It can be either stress induced (pseudo-elasticity) or temperature induced (shape memory effect). This paper shows the potential of Nitinol (alloy of Ni and Ti) SMA damper to control structural vibrations when subjected to underground blast through a detailed computational study by considering a two-story steel frame as an example problem. Different bracing configurations of the damper are taken into account. A comparative study showing the effectiveness SMA braced damper over the conventional steel bracing is also carried out.

Sekhar Chandra Dutta, Rohan Majumder

Study of Cutting Tool Durability at a Short-Term Discontinuous Turning Test

The article deals with study of cutting performance and its impact on durability of cutting tool in a short-term alternate turning test. The short-time test was carried out at discontinuous machining to increase an intensity of tool wear and to reduce the time of the test. Two types of workpieces in shape of circular segments with angles of 45° and 180° were prepared from material DIN 17200 that correspond to the STN 41 1373 (11 373) steel. Cutting plates, type of SPUN 120504, from the 19 830 steels with the tool holder type of CSSPR 2525 M12 KT 716 were used at the machining. The tests were realized based on the standard ISO 3685 without cutting fluid. The process of machining and tool wear was evaluated from the energy point of view. The machine input power was measured by means of measuring equipment UNI-T UT232. The results were statistically processed. Based on the results it can be said that the durability of tools at the machining the 45° segment was higher. Also, the hypothesis considering that the work of cutting wedge is constant during machining up to the achievement of critical tool has not been confirmed.

Peter Pastucha, Vidosav Majstorovic, Marián Kučera, Pavel Beno, Srecko Krile

Behavior of the Beam with a Lightweight Porous Structure in Its Core

Structures, porosity of which have been modified, show special properties and functions that cannot be achieved by common conventional tools. A combination of the most suitable properties can be utilized in a particular application by controlling the composition of the porous structure. The article deals with the research of the influence of the volume ratio of the material on a behavior of the beam with the lightweight porous structure. For this research, the core inside the beam shell made of 1.431 steel was filled with a simple lattice structure with regular geometry. The beam was built-in on one side and loaded on the other. Using the finite element method, a static analysis of the beam was performed in the PTC Creo Simulate software, where the volume ratio of the material was controlled by the “struts” diameter, while the thickness of the beam shell remained constant. The analysis has shown that with an increasing volume ratio of the beam material, a stress value of the beam drops more sharply than a displacement value of the beam. The modal analysis of the beam was performed at the volume ratio 44.53%. Individual modes and obtained values of the natural frequencies were compared to the full-volume beam in order to evaluate the behavior of the lightweight beam under dynamic load. The results of the analysis have shown that the values of the natural frequencies of the lightweight beam are comparable to those of the solid beam and the deformation behavior of the both beams in the first six modes is similar.

Jozef Tkáč, Martin Pollák

Advanced Preparation of the NC Programs with Usage of Strategy Manager

The article deals with the possibilities of automate creation of NC programs by using the NC strategies in CAD/CAM system Edgecam 2017 R2. Emphasis is placed on the suitability of use, the limitation of the creation, and application of the NC strategies. The experiments deal with the comparison of effectiveness of the NC strategies applied especially to the components with different geometric features. The results obtained allow determining the applicability of experimental NC strategies in the process of NC programs preparation.The motivation for this type of research is a gap between levels of automation in fields of machining and pre-production stages. The research is focused on current possibilities of increasing efficiency of the machining processes creation by its automation in CAD/CAM system Edgecam.

Tomáš Dodok, Nadežda Čuboňová, Ivan Kuric

Modeling and Validation of Spindle Shaft Followed by Goal Driven Optimization

The spindle bearing system is critical component in any machining center due to its complexity and it directly affects design or selection of components. Fail-safe design is traditional design philosophy of the machine centers which leads to over-sized machine tool design including spindle bearing system. Over-sized spindle design affects the performance characteristics of the machine center and should be optimized. Therefore, this work presents a methodology for design optimization of spindle shaft that is subjected to uniformly distributed load. The deflection distribution of shaft due to given loading condition is a way for controlling the stability of spindle and its failure. In this work analytical as well as numerical methodology is presented for modeling and validation of spindle shaft deflection. The analytical modeling of spindle uses conventional beam theory whereas numerical modeling uses finite element analysis (FEA) software ANSYS. Analytical model is validated by performing static structural analysis using BEAM188 element and used further to calculate optimum bearing spacing for minimum deflection. Finally, analytically calculated optimum bearing span is used as design variable with specific range. Thus, a goal driven optimization (GDO) is performed in ANSYS with mass reduction as an objective function and deflection as design constraint.

Kahane Roshan, Somnath Chattopadhyaya, Shrikant Bhise, Dattatraya Parle

Modeling and Simulation of Technological Factors in Bakery Industry

From our early stages of research on industrial logistics particularities of baked products distribution we concluded that the bakery industry in Romania is based on a management system that does not have enough scientific research in the industrial logistics field.Managers have to make decisions based only on their own experience.Our goal is to determine and write new algorithms that can improve the physical distribution of bakery products. A clear algorithm that correlates the production with the distribution process will be improving the company’s logistics management and reduce the costs.The multitude of factors that influence the distribution of baked products raises the risk that the management decisions at current level will not be the most appropriate or efficient. Taking into account the diversity, complexity and specificity of the bakery industry, in this paper we conducted a theoretical study to identify the most widespread distribution channels in this industry, stating the factors that influence the physical distribution of bakery products. Four variants, representing a direct distribution channel and three indirect ones, analyzed in parallel, have led to the conclusion that the most complex distribution channel identified was the distribution by personal car, through daily delivery of the products on predetermined routes.In a further stage, the identified factors with the highest competitiveness will play a key role in the final algorithm that enable managers in bakery industry to track and improve much faster the gaps in the distribution chain.

Adrian Dan Pop, Gabriel Rus, Raul Florentin Drența

Numerical Study of Rapid Cooling of Injection Molds

Rapid heat cycle molding (RHCM) technology has become an alternative for classic injection molding and it is consist of the rapid control of the temperature of mold or forming surfaces. Despite widely used in the plastics industry, there are some problems with rapid, balanced cooling. The primary problem during the cooling stage is to ensure the balanced and uniform heat removal from cooled material and suitable dynamic of the entire process, as to avoid molding’s defects. This article presents the simulation research of various geometry of cooling channels, which can be used in RHCM technology to improve the efficiency of a cooling process. Authors proposed the use of finned channels, which can guarantee the most effective heat transfer. The analysis and comparison of proposed channels show the advantage over conventional channels commonly used in injection molds. To more clearly show the correlation between the geometry of cooling channels, the flow state of working fluid and the heat transfer, the dependencies of the Nusselt and the Reynolds number are evaluated and presented. The investigation results lead to possibility of reducing the cooling phase and thus the production time of entire injection cycle.

Pawel Muszynski, Przemyslaw Poszwa, Pawel Brzek

Influence of Fill Imbalance on Pressure Drop in Injection Molding

During injection molding process melted polymer is introduced into mold cavity due to the pressure delivered from injection unit. Mold design principles suggests that filling of the cavity should be balanced. It means that the furthest regions of cavity (measured from injection point) should be filled at the same time to avoid problems with differential shrinkage and injection pressure drop. Fill imbalance can lead to the significant increase of pressure drop and needed clamp force, that can be compensated with more powereful injection molding machines. In this paper the relation between fill imbalance and injection pressure needed for cavity filling were investigated with Autodesk Moldflow Insight software. In this research several different shapes with thickness change of analyzed parts were performed to measure the significance of imbalance on injection pressure drop. It was found that it is possible to find a gate location even for geometrically imbalanced part, where significant pressure drop reduction can be obtained. Additionally, It was found that lowering V/P switchover point can provide significant reduction of needed injection pressure even if gate location must be placed in unfavorable location

Przemyslaw Poszwa, Pawel Brzek, Pawel Muszynski, Marek Szostak

Assessment of the Production Reducer for Clamping the Drilling Tools

The article deals with the evaluation of the production of the reduction clamping mandrel on the milling machine. The reducer is designed to clamp the drill tool with a 16 mm diameter cylindrical shank so that it can be clamped into the clamping head of the drill with a maximum diameter of 13 mm. The clamping tool itself is secured with two screws. The billets of the reducer are selected from the available manufactured steel parts, allowing it to be maximally fast and meet the production criteria. The material of the joined parts guarantees guaranteed weldability. The technological process, the method of clamping and setting of the tooling was chosen so as to achieve the desired deviations of co-ordination of the two coupled cylindrical components. Measurement of the produced diameter of the reducer and evaluation of co-ordination was done on the THOME 3D measuring instrument. It has been measured the diameter and the deviation of the co-ordinates of the produced cylindrical surfaces with a maximum value of 0.0053 mm, with a maximum quadratic error of 0.003543 mm. The produced reducer clamp was tested for the production of cylindrical holes by a 25 mm diameter drill. By measuring, stamping and practical application of the clamping mandrel, the possibility of replacing turning operations at the CNC milling center was confirmed.

Peter Michalik, Vieroslav Molnár, Martin Ambrozy, Michal Petruš, Peter Tirpak

Evaluation of Damage of Almandine Garnet Grains by N2 Adsorption Method

Damage of abrasives (e.g. garnet abrasive) represents a current problem in the AWJ technology. Due to this, possible reuse of the garnet recyclated from sludge after the cutting by the AWJ technology is investigated. Geological origin and material properties of almandine garnets (mineralogy, granularity, grain shape and others) influence this technology significantly. New parameters of input materials, such as the specific surface area and pore distribution (criterion of the internal grain damage), are examined by the N2 adsorption method for the evaluation of damage of abrasives.Parameters of the input abrasive of almandine garnet AG80 and its recyclates AGR1 and AGR2 were compared in order to determine the degree of the internal grain damage. Results of measurement of the input abrasive AG80 showed that it is a nonporous or macroporous material with minimal damage of grains. For the recyclates, the damage of grains was evident. After cutting and subsequent recycling of garnet grains, the pore structure occurred probably due to drop out of inclusions from the garnet structure or development of a network of slits/cracks.

Lucie Ruppenthalova, Petr Martinec, Lucie Gurková

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