bluuebunny/crossref_metadata_2025 huggingface dataset:
Penerapan Model Pembelajaran Problem Based Learning (PBL) Untuk Meningkatkan Kemampuan Pemecahan Masalah Matematika Siswa Di Kelas XI-IPA SMA Islam Al-Ulum Terpadu Medan
Authors: Sari Tri Wulan
Published: December 2021

The aim of this research is (1) to know the implementation strategy of Problem Based Learning (PBL) that is used to improve mathematically ability students in the Linear Progamming (2) to know the increasing of mathematically ability students in the Linear Progamming in class XI-IPA SMA Islam Al-Ulum Terpadu Medan T.A 2016/2017 after the implementation of Problem Based Learning (PBL) material Linear Progamming in class XI-IPA SMA Islam Al-Ulum Terpadu Medan T.A 2016/2017. Subjects in this research were students of class XI-IPA SMA Islam Al-Ulum Terpadu Medan T.A 2016/2017 totaling 38 students and the object of this study is used to improve mathematically ability students in the Linear Progamming in class XI-IPA SMA Islam Al-Ulum Terpadu Medan T.A 2016/2017. The research instrument used is observation, tests and documentation. From the test mathematically ability results, it can be concluded that the implementation strategy of Problem Based Learning (PBL) that is used to improve mathematically ability students in the Linear Progamming in class XI-IPA SMA Islam Al-Ulum Terpadu Medan T.A 2016/2017.
Analisis Kompetensi Guru Madrasah Tsanawiyah Dalam Memanfaatkan Tik Pada Proses Pembelajaran Dan Pengembangan Diri
Authors: Irawani Dandan
Published: December 2021

This research aims to describe the average value of the competence of the skills of tsanawiyah madrasah teachers in utilizing information and communication technology in the learning and self-development process in the implementation of training in the work area (PDWK) at the office of the ministry of religious affairs mandailing Natal district with a sample of 30 participants. This type of research is descriptive quantitative with survey methods. The data taken is skill value data during the training process. From the results of secondary data processing, for the training eye of making blocks the average value is 87 with a good predicate and the most value of 90 as many as 5 participants; the eyes of the online class creation training using the popular application average score of 88 with a good predicate and the most value of 95 as many as 5 participants; eye training in making attractive percentages using popular applications average value 92 with excellent predicate and the most value of 93 as many as 17 participants; Interactive video content creation training eyes averaged 86 with good predicate and the most value of 80 as many as 15 participants. While the average skill score for all subjects and all participants is 88 with a good predicate and the most value of 86 as many as 6 participants. So the implementation of information technology training of tsanawiyah madrasah teachers in the working area of Mandailing Natal kankemenag conducted by Medan Religious Training Center has been good in improving teacher competence for skills to utilize ICT in the learning and self-development process.
Role of Statistical Methods in Pedagogical Research
Authors:   ", Penchev Delyan ,   St. Cyril and Methodius",   University of Veliko Tarnovo
Published: December 2021

The increasing role of statistical methods in social sciеnces and particularly in pedagogy cannot be argued. Especially in quantitative research, these methods provide a high degree of objectiveness and precision that cannot be achieved with other methods or procedures. That is why educationalists have to acquire deeper knowledge of the specifics of statistical methods and the features of their application. In the analysis of these aspects of pedagogical research in this article, the most commonly used statistical methods in them are outlined. For this purpose, the author has explored 96 doctoral dissertations with regard to the application of different statistical methods for data processing.
General Didactic Principles About University Education in Music in the Midst of a Pandemic
Authors: Nedialkov Bojin , Nedialkova Nadia
Published: December 2021

This article discusses some of the most important prerequisites for building and organizing the didactic structure of music education at the university level in the midst of a pandemic. The emphasis is on the methodology in designing online learning. The principles of carrying out the preliminary preparation for the transition to the new synchronous1 and asynchronous2 training are described. The basic rules for building and organizing online lectures in the conditions of distance learning are systematized. Models for asynchronous lectures according to already established principles are presented. An analysis of the difficulties and dangers of constant home office work has been performed. The authors of this article share their pedagogical experience regarding the specifics of conducting individual and group music disciplines in the context of distance learning, giving basic recommendations on the structuring of the learning process, which can be used not only in a pandemic situation, but also in the future for more flexible, modern and effective education related to constantly improving technologies.
THE ROLE OF ENTREPRENEURIAL EDUCATION IN FIELD OF INDUSTRIAL ENGINEERING
Authors:   “Gheorghe Asachi” Technical University of Iasi-Romania, Department of Machine Manufacturing Technology, Boca Mihai
Published: December 2021

All of us we are agreeing the idea according with that the entrepreneurship activity represent the engine of the economic sector. Through innovative activities developed in different sectors of the economy, as well as the investments into an idea, there will be registrated significant increases in the quality of services and also into the obtained products or goods. Therefore, the activity of entrepreneurs and the entrepreneurship represent the optimal solution for a good and strength economy of Romania. More than that, the future graduated students from the technical domain and not only these, are welcome to be trained to develop smart ideas in this area. The purpose of this study is to analyse and reflect, based on a SWOT analysis, the actual state of prerspectives that young graduated students have at their disposal to become good entrepreneurs. Also, in this study is presented a short review of the current situation of entrepreneurship at Romania. Beside this, some answers to a short questionnaire concerning the trend of the students from the industrial engineering domain are exposed, in order to express the actual opinion of them related to the entrepreneurial developing direction. This study represents a small step in order to define the main objectives and organizing activities to be sustained for the universities in order to prepare the future entrepreneurs among from graduated students.
INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE AWJ PROCESS PERFORMANCE
Authors:   “Gheorghe Asachi” Technical University of Iasi, Department of Machine Manufacturing Technology, Mazurchevici Simona-Nicoleta , Popa Ramona Iuliana ,   “Gheorghe Asachi” Technical University of Iasi, Department of Machine Manufacturing Technology, Mărguță Daniel ,   “Gheorghe Asachi” Technical University of Iasi, Department of Machine Manufacturing Technology
Published: December 2021

The present study aims to perform a comparative analysis of the technological parameters influence on the output parameters for two biodegradable polymeric materials, Arbofill Fichte and Arboblend V2 Nature. The varied input parameters during abrasive water jet cuuting (AWJ) were water jet pressure, traverse speed and abrasive material flow. The quantitative and qualitative output parameters proposed are the amount of material removed (MR) and the inclination angle - α° of the resulted surfaces. The measured MR and α° values highlighted the fact that they fall within the admissible parameters, so that the obtained parts by cutting the Arbofill Fichte and Arboblend V2 Nature samples can be used in industrial applications that require this type of processing and more. Was also achieved the optimization of the technological parameters used for processing according to the next criteria: minimum inclination angle and minimum amount of material removed.
CHOOSING THE OPTIMUM TECHNOLOGICAL ALTERNATIVE FOR 3D PRINTING
Authors:   S.C. NECOM S.R.L., Mindru Daniel , Carausu Constantin ,   “Gheorghe Asachi” Technical University of Iasi-Romania, Department of Machine Manufacturing Technology
Published: December 2021

The period between the design of a product and the moment from which the product is no longer profitable on the market represents its life cycle. Decreasing the profitability of the product on the market means that the company must find solutions to launch a new product. The new products can be assimilated in the manufacture by own conception at the level of the enterprise, on the basis of the purchased manufacturing licenses and on the basis of the reference models of a similar product existing on the market. The paper presents the methodology for choosing the optimal technological variant for a part manufactured by 3D printing using two technological variants, through the criterion of unit technological cost and the criterion of total technological cost. Depending on the relationship between the size of the manufacturing batch and the calculated critical size of the manufacturing batch, respectively between the unit technological cost and the total technological cost for the two technological variants, the optimal technological variant of manufacturing can be established.
PLANNING AND SCHEDULE OF MAINTENANCE WORKS FOR INJECTION MACHINES
Authors:   “Gheorghe Asachi” Technical University of Iasi-Romania, Department of Machine Manufacturing Technology, Popa Ramona-Iuliana , Catana Maria ,   “Gheorghe Asachi” Technical University of Iasi-Romania, Department of Machine Manufacturing Technology, Cimpoesu Gabriel ,   “Gheorghe Asachi” Technical University of Iasi-Romania, Department of Machine Manufacturing Technology, Burlea Lucian ,   "Grigore T. Popa" University of Medicine and Pharmacy of Iasi, Cărăușu Constantin ,   “Gheorghe Asachi” Technical University of Iasi-Romania, Department of Machine Manufacturing Technology
Published: December 2021

Keeping the equipment and machinery in working order is a very important activity in the field of industrial production, being specific to the maintenance department within an enterprise. Ensuring an optimal in operation of the manufacturing systems is closely related to the prevention of defects, an action that must be found in a planning and scheduling of preventive-planned maintenance works. In the paper, in addition to the introductory part on the main objectives and implementation of the maintenance system and maintenance-specific operations, a case study is conducted for the planning and organization of maintenance in a company equipped with plastic injection machines. The main stages developed consisted in elaborating the maintenance plan, establishing the optimal moment for replacing the machine tools, choosing the optimal type of machine tool and establishing the elements of random wear of the machine tools. It is concluded that the optimal type of injection molding machine that will be chosen to replace the T10 injection molding machine is T14, because it has a minimum average cost of acquisition, maintenance and repair, respectively 42.286 UV.
Delamination ASSESSMENT during MACHINING OF laminated POLYMER nanocomposite
Authors:   Materials and Morphology Laboratory, Department of Mechanical Engineering, Madan Mohan Malviya University of Technology, Kumar Jogendra , Kumar Verma Rajesh ,   Materials and Morphology Laboratory, Department of Mechanical Engineering, Madan Mohan Malviya University of Technology
Published: December 2021

Nanomaterials are gaining extensive application in the manufacturing sector due to favorable properties. Its rapid growth in highly sensitive, robust, and lightweight sensors and biomedical components has attracted considerable attention worldwide. Nanomaterial uses with fiber-reinforced polymeric material have increased significantly. In order to manufacture structural components in a near-net shape, laminated nanocomposite machining is required. Due to the need for product assembly in mechanical structures, Milling is the primarily machining process in the manufacturing industry to create slots, channels, etc. The present work optimized the process variables affecting the Milling process by adopting the minimize criterion to control the delamination factor using the Taguchi method. The process parameters include cutting speed, feed, depth of cut, and filler material Graphene Oxide. The optimized conditions were found as cutting speed (Vc) 37.12 m/min, spindle feed (F) 80 mm/min, depth of cut (D) 0.5 mm and filler material Graphene Oxide (G) 1 wt.%. The percentage contribution of the process parameter on the delamination factor (Fd) was determined using the Analysis of Variance (ANOVA) method, and it has been found the feed rate (62.60%) is the most influencing factor. The delamination factor obtained in the confirmatory experiments carried out under optimized conditions was found lower than the Taguchi design test runs. The findings indicate that process parameter optimization under the given set of experimental conditions is effective for a manufacturing environment.
OPTIMIZATION USING RESPONSE SURFACE METHODOLOGY AND ARTIFICIAL NEURAL NETWORK IN GEARED DRILLING
Authors:   Department of Mechanical Engineering, Acharya Nagarjuna University, Shireesha Yegireddi ,   Department of Mechanical Engineering, GMR Institute of Technology, Govind Nandipati ,   Department of Mechanical Engineering, R.V.R & J.C College of Engineering
Published: December 2021

Drill on different layered composite causes to force the layers ahead of it, creating unacceptable delamination on the leaving side. The current work describes the influence of different process parameters like spindle speed, feed, diameter of drill bit and addition of filler material on delamination damage on carbon and jute hybrid fiber composites during drilling operation. The experimental output for delamination is optimized by RSM-Response Surface Methodology and ANN-Artificial Neural Network Model. The experimental prediction model was established by considering DOE (design of experiments) of three levels performed with drilling operation by varying above said process parameters The optimum values for minimized delamination damage conditions found to be at (J-C-C-J) +5g of filler (fly-ash) composite. This is drilled with 8.5mm diameter drill bit with a feed of 0.08mm/rev at 875rpm speed. From the theoretical results it is recognized that cutting-speed and filler-material have much influencing factors on responses (delamination), and their individual contribution in an order of 47.25% and 47.32% respectively. By using Box-Behnken design RSM model is developed, with a feed-forward back-propagation method to develop the predictive ANN model which consists of 15 neurons in its hidden layer along with ANN Model. Here ANN Results (R2=0.99and RMSE=1.99) showed that the developed model is performing better to predict content of delamination when compare to RSM results (R2=0.97and RMSE=2.24).
Optimization and Nanoreinforcements of Lubricant Concentration for Steel Sheet Forming Process
Authors:   Departamento de Ingeniería, Universidad de Monterrey, Taha-Tijerina Jaime ,   Department of Manufacturing and Industrial Engineering University of Texas Rio Grande Valley, Calderón Ruben ,   Departamento de Ingeniería, Universidad de Monterrey, Rodriguez Bárbara ,   Departamento de Ingeniería, Universidad de Monterrey
Published: December 2021

In metal-mechanic industry, lubricants are applied to improve products’ quality and tools useful life, while reducing friction and wear, also removing the generated heat during the material processing. Tribological evaluations are performed varying the water content of two widely used lubricants in automotive metal-forming operations. Evaluations are first performed to determine the optimal lubricant dilutions, followed by reinforcement of 2D-nanostructures of hexagonal Boron Nitride (h-BN). Tribological characterization under extreme pressures (EP) are performed with a four-ball tribometer according to the Institute for Sustainable Technologies –National Research Institute (ITeE-PIB) Polish method under scuffing conditions. The optimized concentrations are determined for Ecodraw and Montgomery lubricants, representing a 28% and 3% improvement in pressure loss limit at 1:8 and 1:6 concentrations, respectively. Block-on-ring tribotest is used to determine the coefficient of friction (COF) of the optimized lubricant dilutions and h-BN nanolubricants, which represent ~10% improvement. These results could be attributed to diverse factors such as a layering mechanism of the 2D nanostructures, soft van der Waals forces between 2D h-BN layers, and the deposition of h-BN on the worn surface, decreasing the shearing stress and COF. Finally, thermal conductivity evaluations showed an enhancement by 30% and 15% with addition of h-BN, demonstrating the potential of 2D nanostructures for improving the efficiency on antiwear and thermal transport.
FEM-based comparative study of SQUARE & RHOMBIC INSERT machining performance during turning of AISI-D3 steel
Authors:   University of Western Macedonia, Department of Product and Systems Design Engineering, Tzotzis Anastasios , Efkolidis Nikolaos ,   University of Western Macedonia, Department of Product and Systems Design Engineering, Oancea Gheorghe ,   Transilvania University of Brasov, Manufacturing Engineering Department, Kyratsis Panagiotis ,   University of Western Macedonia, Department of Product and Systems Design Engineering
Published: December 2021

Nowadays, employment of the Finite Element Method (FEM) in machining simulation is a common practice to decrease development times and costs, as well as to investigate numerous parameters that affect machining processes. In the present work, the 3D modelling of AISI-D3 hard turning with both square and rhombic inserts is being presented by utilizing a commercially available Finite Element Analysis (FEA) software. Eighteen tests were carried out based on cutting conditions that are recommended for the used tools. Specifically, three levels of cutting speed (75m/min, 110m/min and 140m/min), three levels of feed (0.12mm/rev, 0.16mm/rev and 0.20mm/rev) and depth of cut equal to 0.40mm for all tests, were applied. In order to describe the complex factors that define the model, such as the friction forces, the heat transfer and the pressure due to contact between the tool and the workpiece, a number of acknowledged models were utilized. A comparison of the performance between the two types of tools was made with respect to the developed machining forces and temperature distribution on the workpiece. The findings of the investigation indicate that the specific square tools produce higher values of forces compared to the rhombic ones and approximately the same temperature patterns on the workpiece. The average increase on the produced cutting forces is about 26.4%.
Using taguchi approach for investigating mechanical properties of recycled carbon fibre reinforced thermoplastics for injection moulding applications
Authors:   Faculty of Mechanical Engineering Technology, Universiti Malaysia Perlis, Zainudin Syairah , Shuaib Norshah Aizat ,   Faculty of Mechanical Engineering Technology, Universiti Malaysia Perlis, Ya Omar Nur’ain Wahidah ,   Faculty of Mechanical Engineering Technology, Universiti Malaysia Perlis, Azmi Azwan Iskandar ,   Faculty of Mechanical Engineering Technology, Universiti Malaysia Perlis
Published: December 2021

Demand for carbon fibre reinforced plastic (CFRP) increases due to its popular demand in sectors such as automotive and aerospace. This leads to high volume of manufacturing and end of life CFRP waste. The challenge is to recycle the heterogenous waste and utilise the recycled carbon fibre (rCF) in potential applications, including the injection moulding process. However, the effect of processing parameters such as type of new thermoplastics, filler weight loading and particle size on product mechanical properties is not well understood. This study carried out experimental trials based on L4 Taguchi orthogonal design. It is found that the mechanical and physical properties significantly depend on the selected parameters. Optimisation of the parameters should depend on final application of the product. This study highlights potential use of rCF in reinforcing pure thermoplastics, as well as an alternative material to virgin carbon fibre (CF).
AUTOMATION OF SHEET METAL COMBINATION DIE DESIGN PROCESS
Authors:   Mechanical Engineering Dept., Faculty of Engineering, Helwan University, Hussein Hussein M.A. , Salem Hossam ,   Mechanical Engineering Dept., Faculty of Engineering, Helwan University, Abdelzaher Walla ,   Mechanical Engineering Dept., Faculty of Engineering, Helwan University, Naranje Vishal ,   Mechanical Engineering Department, Amity University Dubai, Ghobrial Morcos I. ,   Mechanical Engineering Dept., Faculty of Engineering, Helwan University, Barakat Azza ,   Mechanical Engineering Dept., Faculty of Engineering, Helwan University
Published: December 2021

This paper proposed a novel methodology for designing and manufacturing of sheet metal dies based on features of sheet parts. Also, combination is designed according to die cupping and punching features of sheet metal parts. The proposed approach is an attempt to make seamless integration of computer aided design with computer aided manufacturing. The features used in this study are taken from MusumiTM Catalogue as well as from various small and medium scale sheet metal industries. Work is divided into two phases. In the first phase, the relevant geometrical and topological data is extracted by reading STEP AP 203. In the second phase, a combine adjacency matrix and rule-based system is developed to recognize sheet metal features for die manufacturing. The system showed excellent performance for all types of features contained in the MusumiTM catalog and for different sheet metal industries. The proposed system for automated design of combination dies for sheet metal parts has been tested successfully for various types of industrial deep drawn parts. It reduces the die compoment design time from hours to minutes. selection of die components and drawings generated by the system were found to be reasonable and very similar to those actually used in the sheet metal industries for production of these typical components on combination dies.
A COMPARATIVE STUDY OF FFT ALGORITHMS FOR CONVOLUTION CALCULATION IN NON-PERIODIC ELASTIC CONTACTS
Authors:   Department of Mechanics and Technologies, Stefan cel Mare University of Suceava, Cerlinca Delia ,   Integrated Center for Research, Development and Innovation in Advanced Materials, Nanotechnologies, and Distributed Systems for Fabrication and Control (MANSiD), Stefan cel Mare University, Suceava, Romania, Spinu Sergiu ,   Department of Mechanics and Technologies, Stefan cel Mare University of Suceava; Integrated Center for Research, Development and Innovation in Advanced Materials, Nanotechnologies, and Distributed Systems for Fabrication and Control (MANSiD), Stefan cel Mare University, Suceava, Romania
Published: December 2021

Department of Mechanics and Technologies, Stefan cel Mare University of Suceava; Integrated Center for Research, Development and Innovation in Advanced Materials, Nanotechnologies, and Distributed Systems for Fabrication and Control (MANSiD), Stefan cel Mare University, Suceava, Romania
EXPERIMENTAL MILLING STUDIES ON HARDENED STEELS - A REVIEW
Authors:   University of Pitesti, Regional Research and Development Center for Innovative Materials, Processes and Products for the Automotive Industry (CRC&D-Auto), Malea Claudiu Ionuț , Nițu Eduard Laurențiu ,   University of Pitesti, Mechanics and Technology Faculty, Manufacturing and Industrial Management Department (DFMI), Iordache Monica Daniela ,   University of Pitesti, Mechanics and Technology Faculty, Manufacturing and Industrial Management Department (DFMI), Rizea Alin Daniel ,   University of Pitesti, Mechanics and Technology Faculty, Manufacturing and Industrial Management Department (DFMI)
Published: December 2021

Hardened steels have numerous applications in the construction of molds and dies due, in particular, to their outstanding thermo-mechanical characteristics, such as wear resistance and high stiffness, but especially dimensional stability at high temperatures. Machined surfaces are conditioned to have important tribological characteristics. Thus, a high quality of machined surfaces is achieved by milling processes with high cutting speeds. These types of processes even manage to replace grinding or electro-erosion machining processes with a solid electrode. The paper presents a review of experimental studies in recent years from industry and scientific research. Issues are outlined which justify the utility of machining hard metals by machining processes, with a focus on machining by milling processes. Starting from input parameters, such as technological parameters, blank material, cutting tool material and machining environment, their influence is analysed on output parameters, such as chip morphology, cutting tool wear and surface integrity.
A COMPARISON OF LASER AND STRUCTURED LIGHT SCANNING TECHNOLOGIES FOR ARCHAEOLOGICAL APPLICATIONS
Authors:   Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, Papas Nikolaos , Tsongas Konstantinos ,   Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, Karolidis Dimitrios ,   Archeological Museum of Thessaloniki, Tzetzis Dimitrios ,   Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University
Published: December 2021

Reverse engineering and in particular three-dimensional digitization have become an essential part of the documentation of archaeological findings. 3D scanning produces a high-precision digital reference document. The factors that influence the quality of the 3D scanned data are the scanned object’s surface colour, its glossiness and geometry, and the ambient light during the scanning process. However, the actual equipment and scanning technologies are of primary importance. The current paper presents a qualitative and quantitative comparison between two 3D scanning devices of different technologies; structured light 3D scanning and laser 3D scanning. The benchmark for this comparison is an ancient Roman vase from the city of Thessaloniki, Greece. The object was scanned with every possible setting on each scanner, but only one configuration of settings on each device was selected for the final comparison. The main criterion for the final selection of the two 3D models acquired with the use of the two technologies was the proximity in the number of points and polygons produced for digitally restoring the ancient vase in the best possible way. The results indicate important differences regarding the accuracy of the final digital model. The laser technology produced better accuracy but with a significant cost in scanning time and model data size. On the other hand, the structured light technology achieved the optimal combination of scanning quality and accuracy, along with reduced acquisition time of scan data.
RESIN FLOW SIMULATION DURING THE RTM METHOD OF COMPOSITES PRODUCTION
Authors:   Silesian University of Technology, Faculty of Mechanical Engineering, Department of Computational Mechanics and Engineering, Paździor Pawel , Szczepanik Miroslaw ,   Silesian University of Technology, Faculty of Mechanical Engineering, Department of Computational Mechanics and Engineering
Published: December 2021

Processes of plastic injection molding are often under analyzes in industry and science. Many of these considerations apply to epoxy resins with additional reinforcement, often with glass or carbon fiber inside the closed mould. The simulations of injection molding processes in the production of composite elements is not as common, as thermoplasts. Hence the idea to carry out the work described in this article. The RTM (Resin Transfer Molding) method is dedicated to serial production with the possibility of producing visual carbon fiber elements for aesthetic reasons. Simulations can help to better refine the products. This allows to take appropriate precautions and solve many issues before implementation. The article presents possible situations that could occur in real conditions. Various shapes models were prepared as basis of the numerical calculations. The analyses highlighting the possible issues were performed. The influence of resin pressure and flow rate on the final product was also considered. The aim was to present the characteristic phenomena and their causes that often occur in reality to technologists working with the RTM. Conclusions related to the work carried out are included. Based on the analyzes and conclusions drawn, it is possible to improve the quality of production processes.
The influence of plasma gas on changes in chemical composition and structures during the cutting process
Authors:   Silesian University of Technology, Mechanical Engineering Faculty, Department of Welding Engineering, Rzeźnikiewicz Agnieszka , Górka Jacek ,   Silesian University of Technology, Mechanical Engineering Faculty, Department of Welding Engineering
Published: December 2021

Cutting is usually one of initial and basic operations of the manufacturing process of welded structures and realization constructions elements. Thermal cutting, in particular plasma arc cutting is often used to prepare elements. The plasma arc cutting process involves melting and ejecting the liquid metal from the cutting gap with a highly concentrated plasma electric arc which is generated between the non-consuable electrode and the workpiece. The paper presents the results of research on the influence of plasma gas on structural changes and chemical compositions changes resulting unalloyed steel cutting by air plasma arc. It was shown that in the air plasma arc cutting process the amorphous layer with a very high nitrogen content (about 1.6%) and a hardness of 750 HV 0.2 was used. This high nitriding effect is due to the diffusion of nitrogen from the plasma gas. As a result of the interaction of air plasma arc gases on the liquid metal, the cutting surface is carburized (about 0.5%). The alloy components are also burnt according to the theory of selective oxidation of chemical elements. The material structure after the air plasma cutting process shows the structures between the structure formed after oxygen cutting processs and nitrogen plasma cutting process. The process of argon-hydrogen plasma cutting has the least influence on the cut material.
FABRICATION CYCLES COMPARISON OF ASSEMBLIES AND MONOLITHIC PARTS MADE BY 3D PRINTING METHOD
Authors:   Future Industry Platform, Skrzek Kinga , Hetmanczyk Mariusz Piotr ,   The Silesian University of Technology, Faculty of Mechanical Engineering
Published: December 2021

The article presents an analysis of the time-consuming, energy-consuming, and cost-consuming nature of 3D printing a three-dimensional polymer components made in two separate approaches: assembly and monolith structure of various materials (automatic filament change required). The introduction includes the definition of 3D printing, its advantages and examples of practical applications, as well as the reason for undertaking the researches described in the article. The justification of the form of 3D sample models was discussed in detail, as well as the methodology adopted by the authors for comparing the print characteristics and the steps of the printing cycles (print preparation, the course of the printing process and post-processing). A comparison of the materials consumption in the phasess of manual and automatic filament change in the mixer were also described. The test printout was made on the Prusa i3 MK3S printer for filament deposition (FDM or FFF methods). For automatic filament mixing, the Palette 2 Pro device was used. The conclusions also include guidelines for the design and production of models made in one continuous printing cycle (using automatic filament feeding devices). Monolithic elements are less accurate, while elements with replaceable filaments are cheaper, less energy-consuming and the material consumption is lower.
Influence of assembly procesS condition of A gantry crane on the corrosion resistance of welds
Authors:   Research Network Łukasiewicz – Welding Institute (Instytut Spawalnictwa), Staniszewski Krzysztof , Topolska Santina ,   Silesian University of Technology, Faculty of Mechanical Engineering, Department of Welding, Gwiazda Aleksander ,   Silesian University of Technology, Faculty of Mechanical Engineering, Department of Engineering Processes Automation and Integrated Manufacturing Systems
Published: December 2021

The article presents an analysis of the manufacturing process of gantry crane elements in the unit production regime. Gantry cranes are one of the most important heavy-duty mechanical components designed for lifting and loading heavy and bulky loads. In the analyzed case, the assembly of large-size elements in the form of a welding process was carried out outside. Therefore, there was a problem with the corrosion resistance of the elements produced in this way. In this article, special attention is paid to the performance of welded joints of such large elements and their disadvantages related to the conditions of the assembly process. These joints were made on the basis of typical, low-carbon structural steel (grade S355J2, steel with the number 1.0562) and Nickel alloy (Alloy 59, X2CrNiMoCuN22-5-3, steel with the number 2.4605) using the metal electrode. The weldability of investigated joints was assessed. The aim of the article is to analyze the influence of assembly conditions and subsequent corrosion protection of joints on their corrosion resistance under operating conditions. Appropriate tests have been carried out for this purpose. The tests showed the negative influence of external conditions on the corrosion resistance of the entire gantry crane structure.
CAD-BASED AUTOMATED G-CODE GENERATION FOR DRILLING OPERATIONS
Authors:   University of Western Macedonia, Department of Product and Systems Design Engineering, Tzotzis Anastasios , Manavis Athanasios ,   University of Western Macedonia, Department of Product and Systems Design Engineering, Efkolidis Nikolaos ,   University of Western Macedonia, Department of Product and Systems Design Engineering, Kyratsis Panagiotis ,   University of Western Macedonia, Department of Product and Systems Design Engineering
Published: December 2021

The automated generation of G-code for machining processes is a valuable tool at the hands of every engineer and machinist. Nowadays, many software systems exist that provide automated functions related to G-code generation. Most free software require the import of a Drawing Exchange Format (DXF) file and cannot work directly on a 3D part. On the contrast, the equivalent commercially-available software systems are feature-rich and can provide a variety of automated processes, but are usually highly priced. The presented application aims to supplement the existing free Computer Aided Manufacturing (CAM) systems by providing a way of generating G-code for drilling operations, using already owned commercial 3D Computer Aided Design (CAD) systems such as SolidWorksTM. Thus, in the case of 3D part drilling, a standard 3D CAD system is sufficient since the code can be adopted by most modern CAD software with minor changes. Moreover, no specialized CAM software is required. In order to achieve this automation, the Application Programming Interface (API) of SolidWorks™ 2018 was utilized, which allows for the design of visualized User Interfaces (UI) and the development of code under the Visual Basic for Applications (VBA™) programming language. The available API methods are employed to recognize the features that were used to design the part, as well as extract the geometric parameters of each of these features. In addition, an embedded calculator automatically defines the cutting conditions (cutting speed, feed and tool) based on the user selections. Finally, the application generates the Computer Numerical Control (CNC) code for the summary of the discovered holes according to the standardized G-code commands; the output can be a typical TXT or NC file that can be easily converted to the preference of the user if necessary.
ADDITIVE MANUFACTURING OF HOLLOW MICRONEEDLES FOR INSULIN DELIVERY
Authors:   Laboratory of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, Aristotle University of Thessaloniki, Xenikakis Iakovos , Tsongas Konstantinos ,   Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, Tzimtzimis Emmanouil K ,   Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, Tzetzis Dimitrios ,   Digital Manufacturing and Materials Characterization Laboratory, School of Science and Technology, International Hellenic University, Fatouros Dimitrios ,   Laboratory of Pharmaceutical Technology, Department of Pharmacy, School of Health Sciences, Aristotle University of Thessaloniki
Published: December 2021

Microneedles (MN) are miniature devices capable of perforating painlessly stratum corneum and delivering active ingredients in the inner epidermal layers. Hollow microneedles (HMNs) are highly detailed objects due to their internal microchannels and thus, their fabrication with Additive Manufacturing (AM) is a challenging task. Vat polymerization techniques provide a sufficient accuracy for such microstructures. Differentiated from other approaches where stereolithography and 2-photon polymerization were adopted, this paper presents the 3D-printing of HMNs purposed for insulin delivery, using the more economic Liquid Crystal Display (LCD) method. First, different geometries (hexagon, square pyramid, beveled) were 3D printed with constant height and varying curing time, printing angle and layer resolution. Quality features in each case were captured with optical and scanning electron microscopy (SEM). The most promising geometry was found to be the beveled one due to the more refined tip area and the feasibility of non-clogged microchannel formation. Among printing parameters, printing angle proved to be the most influential, as it affects resin flow phenomenon during printing process. Lastly, optimized HMN geometry was the beveled configuration, where the average height was measured 900μm, 3D printing angle was set at -45°, the curing time was 10s per layer and the optimal layer height was 30μm.
A NUMERICAL APPROACH TO THE CONTACT OF NOMINALLY FLAT SURFACES
Authors:   Department of Mechanics and Technologies, Stefan cel Mare University of Suceava, Cerlinca Delia ,   Integrated Center for Research, Development and Innovation in Advanced Materials, Nanotechnologies, and Distributed Systems for Fabrication and Control (MANSiD), Stefan cel Mare University, Spinu Sergiu ,   Department of Mechanics and Technologies, Stefan cel Mare University of Suceava; Integrated Center for Research, Development and Innovation in Advanced Materials, Nanotechnologies, and Distributed Systems for Fabrication and Control (MANSiD), Stefan cel Mare University
Published: December 2021

Machined surfaces can be described by heights and wavelengths of the surface asperities that show a statistical variation. Considering that a regular wavy surface with a sinusoidal profile is the crudest model for a rough surface, studying the contact of regular wavy surfaces is a good approximation for the contact of nominally flat surfaces. Such contact problems exhibit periodicity that can be simulated with the aid of computational techniques derived for contact mechanics in the frequency domain. The displacement calculation, which is a necessary step in the resolution of the contact problem, is mathematically a convolution product that can be calculated in the frequency domain with increased computational efficiency. The displacement induced by a unit surface load can be expressed in the frequency domain by the frequency response functions, which are counterparts of the space domain solutions to half-space fundamental problems such as the Boussinesq problem. The displacement induced by a periodic pressure distribution can be computed by executing the convolution product between the frequency response function and pressure on a single period. It should be noted that the convolution calculation in the spectral domain implies that the contributions of all neighbouring pressure periods are accounted for. The need to treat numerically only a single period results in remarkable computational efficiency, allowing for high density meshes that can capture the essential features of any textured real surface. The displacement calculation promotes the solution of the contact problem by an iterative approach. The advanced method is benchmarked against existing analytical solutions for the 3D contact of surfaces possessing two-dimensional waviness. This essentially deterministic model, supported by a direct numerical solution that can be obtained for samples of real rough surfaces, presents itself as a worthy alternative to the existing statistical models for rough contact interaction.
ROTATION JOINTS FRICTION IN A TRANSVERSAL MOBILE COUPLING
Authors:   “Transilvania” University of Brasov, Product Design Faculty, Mechatronics and Environment Department, Gavrila Cornel Catalin , Lates Mihai ,   “Transilvania” University of Brasov, Product Design Faculty, Mechatronics and Environment Department
Published: December 2021

The transversal mobile couplings are used in movement and torque transmission between two main shafts having parallel axis, with the possibility to undertake misalignments in the transversal plane. These shaft misalignments are usually named transversal movements. The paper presents, starting from some kinematic aspects regarding relative movements between the coupling parts, the kinematic equations useful in determining position of the intermediary elements, depending by the transversal misalignments. Following this, using the inside relative movement in rotation joints between parts and corresponding adequate materials, the friction coefficient is studied. The friction which appears in coupling’s rotation joints between the involved parts has an important influence on their dynamic behaviour, wear and lifetime. The most significant friction and also wear is given by the alternant rotation movements in joints between parts, at the ends of their angular stroke. Due to this, the study of the friction between some materials to be used in coupling manufacturing is required, but also difficult because of some particularities, as reduced rotation in joints, for reduced transversal misalignments between the main shafts. There are presented, in the paper final part, the results and conclusions.
ASPECTS REGARDING OPTIMAL DESIGN FOR THE WORM-GEAR DRIVE
Authors:   Faculty of Engineering and Agronomy Braila, “Dunarea de Jos” University of Galati, Ghelase Daniela , Daschievici Luiza ,   Faculty of Engineering and Agronomy Braila, “Dunarea de Jos” University of Galati
Published: December 2021

It is known that, from the point of view of the accuracy of a machine-tool, at its design, the dynamic behaviour of each element of the kinematic chains prevails. Worm-gear drives are widely used in the different machine-tools and robots. Therefore, it is important that during meshing, as far as possible, there are no vibrations, shocks, power losses, noise and low durability. These requirements can be met if, for example, the gear ratio is constant during meshing, without transmission errors, which means that the worm-gear drive should have a high accuracy. The accuracy improvement of the worm-gear drive has long been a focus of attention for machine-tools designers. Thus, this paper presents various approaches to solving such problems, based on modelling and simulation, such as: estimating the load share of worm-gear drives and to calculate the instantaneous tooth meshing stiffness and loaded transmission errors; the desired worm-gear drive design configuration by altering the optimum set of worm-gear drive design parameters which are suitable for the required performance by associating it with SVM (Support Vector Machine); optimization approach for design of worm-gear drive based on Genetic Algorithm; design optimization of worm-gear drive with reduced power loss; etc. The optimization of the worm-gear design is an important problem for the research because the design variables are correlated to each other. An optimal design algorithm developed by the authors of this paper, for worm-gear drive, is also presented.
ELEMENTS OF SPACE ORGANIZATION MANAGEMENT OF ENTERPRISES IN THE METAL MATERIALS INDUSTRY
Authors: Ioana Adrian , Iorga Craciunica Monica , Petcu Florin-Stefan , Deonise Dumitru , Juganaru Daniela Ionela , Solea Roxana Marina , Ene Bianca Cezarina ,   University Politehnica of Bucharest-Romania, Department of Engineering and Management of Metallic Materials,   University Politehnica of Bucharest-Romania, Department of Engineering and Management of Metallic Materials,   University Politehnica of Bucharest-Romania, Department of Engineering and Management of Metallic Materials,   University Politehnica of Bucharest-Romania, Department of Engineering and Management of Metallic Materials,   University Politehnica of Bucharest-Romania, Department of Engineering and Management of Metallic Materials,   University Politehnica of Bucharest-Romania, Department of Engineering and Management of Metallic Materials,   University Politehnica of Bucharest-Romania, Department of Engineering and Management of Metallic Materials
Published: December 2021

The article has as a starting point the presentation and analysis of the advantages of spatial organization of enterprises, as a management method. Thus, we analyze: creating the optimal conditions for the rhythmic realization of the production process; ensuring greater flexibility in the use of means of production; the possibility of carrying out a maintenance and repair activity of the equipment without disturbing the technological production process; ensuring an efficient management of the production unit. We also analyze, critically and comparatively, the disadvantages of spatial organization, such as: the need for a high qualification of workers; the need for a very high volume of transport and handling; technical quality control is much more complex in the conditions of a diversified production; the production cycle of manufactured products is long.