Wyniki wyszukiwania - Biblioteka Nauki

1

Problems of the compensation of centrifugal force in lathe chucks

100%

Kozior T. , Bochnia J.

Journal of Machine Construction and Maintenance - Problemy Eksploatacji

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2018

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tom no. 2

45--51

EN

Modern machining technology facilitates mechanical machining at high spindle speeds, which determines the use of machining lathe chucks that guarantee the correct clamping force of the workpiece. The work discusses the problems associated with the compensation of negative effects of centrifugal force acting on the jaws of lathe chucks. Calculations and constructional solutions including the author’s own patent application and a description of a model made using additive technology are presented.

PL

Współczesne maszyny technologiczne umożliwiają obróbkę mechaniczną przy dużych prędkościach obrotowych wrzecion, co determinuje stosowanie uchwytów obróbkowych gwarantujących odpowiednią siłę zacisku przedmiotu obrabianego. W pracy omówiono problematykę związaną z kompensacją negatywnych skutków siły odśrodkowej działającej na szczęki uchwytów tokarskich. Przedstawiono obliczenia i rozwiązania konstrukcyjne, w tym własne objęte ochroną patentową oraz opis modelu wykonanego przy pomocy technologii przyrostowej.

2

Falownik klasy DE 13,56 MHz/450 W – wpływ nieliniowej pojemności wyjściowej tranzystora Mosfet na sterowanie metodą AM

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Kasprzak M.

Przegląd Elektrotechniczny

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2012

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tom R. 88, nr 4b

122-127

PL

W artykule przedstawiono wyniki badań falownika klasy DE sterowanego metod. AM. Wyznaczono teoretyczne charakterystyki sterowania mocy wyjściowej uwzględniające wpływ nieliniowej pojemności wyjściowej tranzystora. Opisano elementy falownika: układ sterowania, półmostek tranzystorow Mosfet oraz odbiornik rezonansowy z opornikiem 50 �[omega]. Przedstawiono oscylogramy dla kilku napięć zasilania, zmierzone charakterystyki sterowania mocy oraz wyniki obliczeń sprawności (71-81%). Podano wytyczne projektowe dla falownika sterowanego metod. AM.

EN

Results of study of AM controlled Class DE inverter have been presented in the paper. The output power control theoretical characteristics with influence of nonlinear Mosfet output capacitance have been determined. Modules of the inverter were described: control circuit, half-bridge Mosfet power board and resonant load with 50[omega] resistor. Oscillograms, measurements of output power characteristics and inverter efficiency calculation (71-81%) were presented.

3

Manufacturing graphene based polymer matrix composites (GPMCs) via 3D printing (additive manufacturing) : a review

85%

Kaleem M. A.

Composites Theory and Practice

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2019

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tom R. 19, nr 3

126--132

EN

The exponential increase in the potential applications of graphene has forced its inclusion in composites. Presently, composites containing graphene have been manufactured by many conventional processes. Since 3D printing (additive manufacturing) offers a wide range of advantages for manufacturing, researchers from the composite industry are now adopting novel techniques to manufacture graphene based composites via additive manufacturing. When selecting materials for composites, polymers stand out as the top choice for manufacturers because polymers require a low temperature to mold their shape and they are easy to handle when compared to ceramics and metals. Hence, substantial focus of the composite industry is now shifting towards manufacturing graphene based polymer matrix composites. In this regard, this paper provides a brief review of the 3D printing (additive manufacturing) processes which to date have been adopted to manufacture ‘graphene based polymer matrix composites’. The promising physical properties of graphene based polymer matrix composites and the future prospects of functionalizing graphene in polymer based composites is also highlighted.

4

Effect of pore architecture of 3D printed open porosity cellular structures on their resistance to mechanical loading. Part I, Experimental studies

85%

Bernacka M. , Aladag M. , Dubicki A. , Zgłobicka I.

Acta Mechanica et Automatica

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2024

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tom Vol. 18, no. 3

419--426

EN

The development of additive manufacturing (AM) techniques has sparked interest in porous structures that can be customized in terms of size, shape, and arrangement of pores. Porous lattice structure (LS, called also lattice struct) offer superior specific stiffness and strength, making them ideal components for lightweight products with energy absorption and heat transfer capabilities. They find applications in industries such as aerospace, aeronautics, automotive, and bone ingrowth applications. One of the main advantages of additive manufacturing is the freedom of design, control over geometry and architecture, cost and time savings, waste reduction, and product customization. However, the designation of appropriate struct/pore geometry to achieve the desired properties and structure remains a challenge. In this part of the study, five lattice structs with various pore sizes, with two volume fractions for each, and shapes (ellipsoidal, helical, X-shape, trapezoidal, and triangular) were designed and manufactured using selective laser sintering (SLS) additive manufacturing technology. Mechanical properties were tested through uniaxial compression, and the apparent stress-strain curves were analyzed. The results showed that the compression tests revealed both monotonic and non-monotonic stress-strain curves, indicating different compression behaviors among the structures. The helical structure exhibited the highest resistance to compression, while other structures showed similarities in their mechanical properties. In Part II of this study provides a comprehensive analysis of these findings, emphasizing the potential of purpose-designed porous structures for various engineering applications.

5

The Interconnections Between ICT, Industry 4.0 and Agile Manufacturing

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Mohammed I. K. , Trzcielinski S.

Management and Production Engineering Review

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2021

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tom Vol. 14, No. 4

99--110

EN

Technological progress is the driving force behind industrial development. It is a multidimensional and multi-level phenomenon. In this article we focus on its three manifestations: information and communication technologies (ICT), Industry 4.0 and agile manufacturing. The aim of this article is to analyse the relationship between these constructs as they are undoubtedly interrelated. ICT plays a key role, but it is not a goal itself. They are a prerequisite for the implementation of Industry 4.0, but together with it they serve to achieve agility by the manufacturing system and, as a result, achieve a competitive advantage by companies operating in turbulent and unpredictable environment. The literature findings in this paper are part of a broader study conducted on the impact of ICT on agility of SMEs operating in India. Therefore, we include also subsections showing the level of this relationship in Indian SMEs.

6

Microplasma spraying of hydroxyapatite coatings on additive manufacturing titanium implants with trabecular structures

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Kadyroldina A. , Alontseva D. , Voinarovych S. , Łatka L. , Kyslytsia O. , Azamatov B. , Khozhanov A. , Prokhorenkova N. , Zhilkashinova A. , Burburska S.

Materials Science Poland

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2022

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tom Vol. 40, No. 4

28--42

EN

This paper presents new results of microplasma spraying (MPS) of laboratory-synthesized hydroxyapatite (HA) powder coatings onto trabecular substrates obtained by selective laser melting (SLM) of a certified titanium medical alloy powder. The aim of the study was to establish the possibility of combining the technologies of MPS and additive manufacturing (AM) for the possible production of custom-designed implants with increased surface biocompatibility, as well as to establish the MPS parameters that ensure chemical purity of the HA coating and satisfactory adhesion of the coatings to the substrate. The structural-phase compositions of the initial HA powder and the plasma-sprayed HA coating were studied by X-ray diffraction analysis and transmission electron microscopy, and the adhesion strength of the coating was tested according to the F1147 standard of the American Society for Testing and Materials (ASTM). The main results of the study are the following: the application of the MPS technology for HA coating with an average thickness of 150±50 μm on trabecular substrates obtained by the SLM method has been shown. The parameters of MPS of HA coatings onto titanium implants with a trabecular surface have been established. It is also proved that using the appropriate MPS parameters, it is possible to obtain a HA coating with a 95% level of HA phases, 93% level of crystallinity, and the adhesion strength to the trabecular substrate of 24.7±5.7 MPa, which complies with the requirements of the international medical standard (International Organization for Standardization [ISO] 13779-2:2018). These results are of significance for a wide range of researchers developing plasma spray technologies for the manufacture of biocompatible coatings.

7

Przegląd dostępnego oprogramowania do sterowania ścieżką pracy głowicy dla personalnych drukarek przestrzennych

71%

Olejarczyk M. , Gruber K. , Ziółkowski G.

Technical Issues

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2015

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tom nr 3

48--55

EN

Personal 3D printers, based on fused deposition modeling (FDM) technology, established a relatively new category in Additive Manufacturing (AM) systems. Adding material layer by layer allows to manufacture complex parts at low cost. Recent dynamic demand growth in this segment forced 3D printer manufacturers to simultaneously develop machines and dedicated software, which enables to convert CAD 3D model to toolhead path control codes (G-code). The work presented in this paper compares currently available 3D printers software: Cura, Slic3r, Voxelizer, Matter Control. The aim of presented study was to investigate dimensions and shape precision of test specimens using computed tomography (CT). Specimens used in the study were designed to capture a representative set of geometrical features for comparison. Specimens were made of PLA (polylactide), a widely used FDM material, on Hbot 3D (personal 3D printer from 3D Printers Ltd, Poland). CT systems enable to measure external and internal dimensions with high precision. In the study, analysis of specimens external geometry, including diameters, distances and angles measurement, was performed. Standard deviation was estimated through comparison of reference values from CAD model with measurement results. In order to analyze the internal geometry, cross-section verification was done. The fundamental result of the paper demonstrates the influence of different 3D printer software on geometrical accuracy. Although the most important process parameters for each software were set up in the same way, there were significant differences between the models. Based on these results, it is concluded that the best results were obtained using Cura software.

8

Computational intelligence in development of 3D printing and reverse engineering

71%

Rojek I. , Mikołajewski D. , Nowak J. , Szczepański Z. , Macko M.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

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tom Vol. 70, nr 1

art. no. e140016

EN

Computational intelligence (CI) can adopt/optimize important principles in the workflow of 3D printing. This article aims to examine to what extent the current possibilities for using CI in the development of 3D printing and reverse engineering are being used, and where there are still reserves in this area. Methodology: A literature review is followed by own research on CI-based solutions. Results: Two ANNs solving the most common problems are presented. Conclusions: CI can effectively support 3D printing and reverse engineering especially during the transition to Industry 4.0. Wider implementation of CI solutions can accelerate and integrate the development of innovative technologies based on 3D scanning, 3D printing, and reverse engineering. Analyzing data, gathering experience, and transforming it into knowledge can be done faster and more efficiently, but requires a conscious application and proper targeting.

9

Environmental analysis of a product manufactured with the use of an additive technology – AI-based vs. traditional approaches

57%

Dostatni E. , Dudkowiak A. , Rojek I. , Mikołajewski D.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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tom Vol. 71, nr 1

art. no. e144478

EN

This paper attempts to conduct a comparative life cycle environmental analysis of alternative versions of a product that was manufactured with the use of additive technologies. The aim of the paper was to compare the environmental assessment of an additive-manufactured product using two approaches: a traditional one, based on the use of SimaPro software, and the authors’ own concept of a newly developed artificial intelligence (AI) based approach. The structure of the product was identical and the research experiments consisted in changing the materials used in additive manufacturing (from polylactic acid (PLA) to acrylonitrile butadiene styrene (ABS)). The effects of these changes on the environmental factors were observed and a direct comparison of the effects in the different factors was made. SimaPro software with implemented databases was used for the analysis. Missing information on the environmental impact of additive manufacturing of PLA and ABS parts was taken from the literature for the purpose of the study. The novelty of the work lies in the results of a developing concurrent approach based on AI. The results showed that the artificial intelligence approach can be an effective way to analyze life cycle assessment (LCA) even in such complex cases as a 3D printed medical exoskeleton. This approach, which is becoming increasingly useful as the complexity of manufactured products increases, will be developed in future studies.

10

Study on the applicability of the SCS CN based models to simulate foods in the semi arid watersheds of northern Algeria

57%

Abdi I. , Meddi M.

Acta Geophysica

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2021

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tom Vol. 69, no. 1

217--230

EN

Algeria has experienced catastrophic foods over the second half of the twentieth century, causing many deaths and extensive material damage. This study was conducted to fnd a suitable event-based rainfall-runof (RR) model for semi-arid conditions, where continuous data are not available in all regional basins. The study compared, based on data availability, the SCS-CN model based on the antecedent moisture conditions (AMC) and four modifed SCS-CN models incorporating antecedent moisture amounts (AMA) in order to fnd the best model to reproduce the food hydrographs in two catchments. The modi fed models were predominant over the SCS-CN method. Nonetheless, the Singh et al. (Water Resour Manag 29:4111–4127, 2015. https://doi.org/10.1007/s11269-015-1048-1) model (M4) and the Verma et al. (Environ Earth Sci 76:736, 2017a. https ://doi.org/10.1007/s12665-017-7062-2) model (M5) were superior and demonstrated more stable structures. Coupled with the Hayami routing model, the models showed promising results and were able to reproduce the observed hydrographs’ shape. However, it was impossible to choose the preferred model since they each excelled as to a criterion. Therefore, the corresponding outputs were combined using the simple average (SA) method and the weighted average (WA) method. We found that the WA method showed better results in the two catchments and allowed a more accurate prediction according to the performance criteria.

11

Virtual additive manufacturing based on semicrystalline polymer polyetheretherketone (PEEK)

57%

Bajerski P. , Pęcherski R. B. , Chudy D.

Engineering Transactions

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2019

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tom Vol. 67, iss. 2

157--165

EN

Virtual additive manufacturing (AM) is one of the new directions of research that is necessary to improve AM technology. Abaqus/SIMULIA software allows to simulate the whole process using user subroutines to expand solver capabilities. Two of the most important subroutines are UepActivationVol and UMATHT. The UepActivationVol is related to an activation of elements in accordance with the defined path of the process. The second one the UMATHT is used to implement and combine thermal and crystallization process [2]. The presented investigations describe the dual crystallization kinetics model for considered high temperature thermoplastic material Polyetheretherketone (PEEK). Furthermore, it is shown how to analyse the overall process with use of Abaqus/SIMULIA software. The innovation of the presented approach lies in the proper interpreting of the G-Code from Computeraided manufacturing software (CAM), which is an input for the real machines dedicated to AM. The path (coordinates of discrete points) and time of particular steps of the manufacturing process are extracted from the G-Code and are included as input parameters in the simulation code. The discretized part is simplification of the Computer-aided design (CAD) geometry. The final results show the effect implemented in user subroutines. Additionally, Differential Scanning Calorimetry (DSC) test results are presented in order to calculate crystallization and melting parameters. The presented work is the basis of the following investigations covering prediction of residual stresses, volumetric shrinkage and deformations.