Wyniki wyszukiwania - BazTech

1

Physical properties of masking coating systems used in military technology

Michalski Marek, Radek Norbert

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

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2025

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nr 82 (154)

69--79

EN

This paper presents the results of experimental tests on coating systems for military applications. The evaluation of properties is performed based on measurements of thickness, gloss, hardness, and surface roughness. The spectral characteristics of the tested systems and color parameters are presented. The tests are conducted for two-layer masking coating systems made in three variants: coating system (SP1), coating system modified with carbon nanotubes (SP2), and coating system modified with glass microspheres (SP3). Analysis of the obtained results reveals that these coating systems exhibit similar thickness, gloss, and spectral characteristics. The SP2 system is characterized by lower hardness, while the SP2 and SP3 systems have higher roughness.

2

Tribological Properties and Surface Roughness of Printed Ti-6Al-4v/PE-UHMW Friction Pair Elements

Musiał Janusz, Zasińska Katarzyna, Ligaj Bogdan, Kałaczyński Tomasz, Dykha Oleksandr

Tribologia

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2025

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nr 1

29--36

EN

The article presents tribological research on the cooperation of a kinematic pair composed of metallic and polymer biomaterials. In the sample tests, a material widely used in orthopaedics and dentistry was used (the medical titanium alloy Ti-6Al-4V obtained both by traditional manufacturing methods, i.e. casting, and the additive manufacturing method SLM/DLMS (3D printing)) and a counter sample (high-density polyethylene PE-UHMW). The friction pair selected in this way was subjected to tribological tests on a PT-3 tribometer under specific operating conditions. After the tribological tests, the change in tribological parameters, i.e. the coefficient of friction or abrasive wear on the surfaces of the tested biomaterials, was evaluated. The obtained results also enabled the assessment of the changes occurring in the geometric structure of the surface of the Ti-6Al-4V/ PE-UHMW friction pair for titanium samples obtained via drawn rod and 3D printing.

PL

W artykule przedstawiono badania tribologiczne dotyczące współpracy pary kinematycznej złożonej z biomateriałów metalicznych i polimerowych. W badaniach na próbki zastosowano materiał szeroko stosowany w ortopedii i stomatologii – medyczny stop tytanu Ti-6Al-4V otrzymany tradycyjną metodą wytwarzania, tj. odlewaniem oraz addytywną metodą wytwarzania SLM/DLMS (druku 3D), zaś na przeciwpróbkę – polietylen o wysokiej gęstości PE-UHMW. Tak dobraną parę cierną poddano badaniom tribologicznym na tribometrze PT-3 w określonych warunkach eksploatacyjnych. Po przeprowadzonych badaniach tribologicznych ocenie poddano zmianę parametrów tribologicznych, tj. współczynnik tarcia czy zużycia ściernego na powierzchniach badanych biomateriałów. Otrzymane wyniki pozwoliły również na ocenę zmian zachodzących w strukturze geometrycznej powierzchni pary ciernej Ti-6Al-4V/PE-UHMW dla próbek tytanowych otrzymanych w postaci pręta litego oraz druku 3D.

3

Application of the Tensile Bending Test to Determine the Tribological Behavior of DC01 Steel Sheets

Szewczyk Marek, Szwajka Krzysztof, Trzepieciński Tomasz, Zielińska-Szwajka Joanna, Barlak Marek

Tribologia

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2025

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nr 1

67--76

EN

The article presents the results of the analysis of changes in the coefficient of friction occurring on the edge of the punch during sheet metal plastic processing. Experimental studies were conducted using the friction method in bending and stretching. A tribometer developed by the authors was used. The research material consisted of 0.8 mm thick DC01 low-carbon steel sheets. The evolution of changes in the coefficient of friction during friction tests was studied in dry friction conditions and lubrication of the sheet metal surface with S100 Plus and S300 oil (Naftochem). Countersamples made of 145Cr6 tool steel, and additionally modified by applying anti-wear coatings were used. The obtained results showed that the coefficient of friction depended on the coating used, and the nature of this change depended on the friction conditions. In the analyzed friction conditions, a decrease in the values of the Sa and Ssk parameters was observed, and an increase in the Sku parameter in relation to the sheet metal in the delivery state.

PL

W artykule przedstawiono wyniki analizy zmian współczynnika tarcia zachodzących na krawędzi stempla w procesach obróbki plastycznej blachy. Badania eksperymentalne przeprowadzono metodą tarcia przy zginaniu i rozciąganiu. Zastosowano opracowany przez autorów tribometer. Materiał badawczy stanowiły blachy ze stali niskowęglowej DC01 o grubości 0,8 mm. Badano ewolucję zmian współczynnika tarcia podczas badań tarcia w warunkach tarcia suchego i smarowania powierzchni blachy olejem S100 Plus i S300 (Naftochem). Zastosowano przeciwpróbki wykonane ze stali narzędziowej 145Cr6, które zostały dodatkowo zmodyfikowane poprzez naniesienie powłok przeciwzużyciowych. Uzyskane wyniki wykazały zależność wartości współczynnika tarcia od zastosowanej powłoki, a charakter tej zmiany zależy od warunków tarcia. W analizowanych warunkach tarcia zaobserwowano zmniejszenie wartości parametrów Sa i Ssk oraz zwiększenie parametru Sku w stosunku do blachy w stanie dostawy.

4

Analysis of Connecting Rod Bearing Wear

Sienkiewicz Judyta, Lipiński Hubert

Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa

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2025

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Vol. 16, Nr 2 (60)

27--44

EN

This paper analyses the wear mechanisms occurring in connecting rod bearings, which are exposed to various mechanical failures, such as incorrect assembly, high loads, extreme temperatures, unsuitable operating conditions, or loss of lubrication. The investigation was conducted on previously collected post-service samples, each evaluated for factors contributing to their wear or damage. The samples came from eight engines belonging to two groups – four- and six-cylinder BMW units installed in vehicles produced during the same time period. Advanced research techniques, such as optical microscopy, surface profilometry, and hardness measurements, were employed for the bearing analysis. Several wear mechanisms were identified, including sliding wear, fatigue wear (characterised by visible cracks and material pull-out), surface discolouration, as well as two-body and three-body abrasive wear (evidenced by friction marks). The research enabled a detailed characterisation of bearing wear mechanisms and improved understanding of the factors influencing their durability under various operating conditions.

PL

W niniejszej pracy przeprowadzono analizę mechanizmów zużycia występujących w panewkach korbowodowych, które są narażone na różnorodne awarie inżynieryjne, takie jak nieprawidłowy montaż, duże obciążenia, ekstremalne temperatury, nieodpowiednie warunki pracy czy utrata smarności. Badania przeprowadzono na wcześniej zgromadzonych próbkach po eksploatacji, z których każda została poddana ocenie pod kątem czynników przyczyniających się do jej zużycia lub uszkodzenia. Próbki pochodziły z ośmiu egzemplarzy silników dwóch grup – cztero- i sześciocylindrowych jednostek BMW, montowanych w pojazdach produkowanych w zbliżonym okresie. Do analizy panewek wykorzystano zaawansowane techniki badawcze, takie jak mikroskopia optyczna, profilometria powierzchni oraz pomiary twardości. Zidentyfikowano różne mechanizmy zużycia, w tym zużycie ślizgowe, zużycie zmęczeniowe z widocznymi pęknięciami i wyrwanym materiałem, przebarwienia powierzchni oraz zużycie ścierne o charakterze dwu- i trójpłaszczyznowym (ślady tarcia). Przeprowadzone badania pozwoliły na scharakteryzowanie mechanizmów zużycia panewek oraz zrozumienie czynników wpływających na ich trwałość w różnych warunkach eksploatacyjnych

5

Corrosion resistance of masking coating systems used in military technology

Michalski Marek, Łabęcka Paulina, Kozieł Tomasz

Ochrona przed Korozją

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2025

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nr 5

138--143

PL

Przedstawiono wyniki badań eksperymentalnych systemów powłokowych do zastosowań militarnych. Ocenę właściwości przeprowadzono na podstawie badań przyspieszonego starzenia w komorze solnej oraz badań odporności korozyjnej metodą potencjodynamiczną i impedancyjną. Badania przeprowadzono dla maskujących dwuwarstwowych systemów powłokowych wykonanych w trzech wariantach: system powłokowy (SP1), system powłokowy modyfikowany nanorurkami węglowymi (SP2) i system powłokowy modyfikowany mikrosferami szklanymi (SP3). Analiza uzyskanych wyników wykazała, że systemy powłokowe charakteryzowały się podobną odpornością korozyjną. System SP3 charakteryzował się najmniejszym rozwarstwieniem i korozją wokół zarysowania.

EN

The results of experimental tests of coating systems for military applications were presented. The assessment of properties was carried out on the basis of accelerated ageing tests in a salt spray chamber and in corrosion resistance tests using the potentiodynamic method and impedance studies. The tests were carried out for masking twolayer coating systems made in three variants: coating system (SP1), coating system modified with carbon nanotubes (SP2) and coating system modified with glass microspheres (SP3). Analysis of the results showed that the above coating systems were characterized by similar corrosion resistance. The SP3 system was characterized by the smallest delamination and corrosion around the scratch

6

Analysis of the influence of the dressing feed rate of a grinding wheel with sintered corundum on the surface roughness of AMS6308 steel after carburising in plunge grinding

Habrat Witold, Sałata Marcin, Ordon Tomasz

Mechanik

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2025

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R. 98, nr 8-9

6--9

EN

The influence of the grinding wheel dressing speed on the surface roughness of AMS6308 steel after carburising during plunge grinding was investigated. A single-grain CVD diamond dresser and a grinding wheel with a 50% admixture of sintered corundum were applied. An increase in the dressing feed rate resulted in an increase in the surface roughness parameters after grinding.

PL

Badano wpływ prędkości obciągania ściernicy na chropowatość szlifowanej powierzchni stali AMS6308 po nawęglaniu podczas szlifowania wgłębnego. Zastosowano jednoziarnisty obciągacz słupkowy z diamentu CVD oraz ściernicę z 50% domieszką korundu spiekanego. Wzrost posuwu obciągania powodował wzrost parametrów chropowatości powierzchni po szlifowaniu.

7

Investigation of burr formation and surface integrity in micro-milling of aluminum alloy LF21 slot

Wu Chao, Li Weimin, Tang Zhaoqing, Feng Shuai, Liang Jixiang, Li Jiahui

Materials Science Poland

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2025

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Vol. 43, No. 2

23--39

EN

Due to the nature of LF21 aluminum alloy material, it is difficult to process and easily prone to plastic deformation; hence, micro-milling process is prone to produce larger burrs and rougher surface. Currently, there are fewer investigations on LF21 slot micro-milling. So, this article uses a combination of finite element simulation and experimentation to analyze the effects of different cutting parameters on the LF21 slot exit, top burr size, and the surface quality of the bottom of the slot. The results of the investigation show that the top burr and exit burr sizes as well as the surface roughness at the bottom of the groove show a monotonically decreasing trend as the spindle speed increases, especially on the up-milling side where the burr size is significantly smaller than that on the down-milling side. Variation in feed rate plays a pivotal role in burr size and groove bottom roughness. The smallest burr size, along with the best surface quality, is achieved when the feed per tooth is close to the tool edge radius. Furthermore, as the cutting depth increases, both the burr size and surface roughness also increase. This effect becomes particularly pronounced at larger cutting depths, where surface valleys are markedly higher and grooves become significantly deeper. The results of this investigation are instructive for practical micro-milling of aluminum alloy LF21, which is important for improving machining efficiency.

8

Effect of Hybrid Composite Electrode (Cu/Cr/Wc/Ag) on Surface Integrity of Stainless Steel 304l Machined by EDM

Abdulwahhab Ahmed Basil, Ibrahim Abbas F.

Management Systems in Production Engineering

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2025

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nr 1 (33)

136--143

EN

Electrical Discharge Machining (EDM) is a modern technique extensively utilized across various industries to eliminate material using electrical discharges. Within the realm of EDM, a key obstacle involves identifying appropriate electrode materials capable of withstanding elevated temperatures and effectively eroding material from workpieces. Composite electrodes are becoming more commonly employed to tackle this issue, as a result of their exceptional electrical and thermal properties. The performance of a composite electrode that has been specifically improvement with (Cu-3%Cr-0.5%WC-1%Ag) is evaluated in this study using the stir casting technique. The investigation utilized stainless steel 304L as the workpiece material, and the performance of the composite electrode was evaluated against traditional pure copper electrodes. The results indicate that composite electrodes can decrease electrode wear and increase machining efficiency. The tool wear rate (TWR) for the composite electrode decreased to 0.0398 gm/min with a current of 10 A and a pulse-on time of 50 µs, along with a pulse-off time of 50 µs. In contrast, under the same conditions, the copper tool exhibited a TWR of 0.514 gm/min. The composite electrode achieved the highest material removal rate (MRR) at 59.7917 mm3/min, surpassing the copper electrode which had the lowest MRR at 54.5588 mm3/min. Additionally, the Surface Roughness (SR) of the composite electrode was measured at 3.253 μm, lower than the 3.967 μm of the pure copper electrode. These findings suggest that composite electrodes could serve as a viable substitute for conventional EDM electrodes.

9

The influence of construction parameters and the type of substrate on the conductivity value of multilayer structures made of NiFe and SiO2

Wilczyńska Aleksandra

International Journal of Electronics and Telecommunications

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2025

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Vol. 71, No. 1

123-129

EN

This article presents a method of obtaining multilayer NiFe-SiO2 nanocomposites by non-reactive magnetron sputtering. Structures with different numbers and thicknesses of layers were made on two different types of dielectric substrates. Electrical parameters were tested in the frequency range from 4 Hz to 8 MHz, as well as measurements of the surface roughness of the substrates. Based on the results, the influence of design parameters and the aging effect on the AC properties of the structures was determined.

10

Study of the effect of process factors on the wear rate and surface integrity in incremental point forming of AA6061 aluminum alloy

Mughir Walaa Amer, Jasim Hussein Hatem

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 3

84--95

EN

Incremental point forming is a contemporary method employed in sheet metal forming to achieve great flexibility in fabrication of intricate forms, eliminating the requirement for specific mold. According to its exceptional mechanical characteristics and low weight, this method is particularly employed in the production of aluminium alloys. The essential aim of this research is to examine the deformation mechanisms and discuss the mechanical properties of aluminium during the incremental forming process. The aim was to examine how various process parameters influence the surface properties, hardness, and wear resistance of the workpieces using aluminium alloy type AA6061. The parameters under investigation are increment step down size, feed rate, and spindle rotational speed. Furthermore, the impact of these factors on the forming process was investigated using several methodologies, including the Taguchi method for parameter optimization and surface analysis. The findings of this study demonstrate that spindle rotation speed exerted a substantial influence on both surface roughness and hardness, accounting for 63.41% for hardness and 52.19% for roughness. In terms of wear rate, the step size had the most significant impact, accounting for 48.53%.

11

Optimization of fused deposition modeling parameters to enhance tensile strength and surface roughness of polyethylene terephthalate glycol

Shabeeb Alaa Hassan, Abdulwahhab Ahmed Basil, Ismael Hameed S., Ghazi Safaa Kadhim

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 8

345--358

EN

The wide examination of FDM as an industrial additive manufacturing technique appears because it provides design freedom alongside improved material efficiency and reasonable cost. This study's main objective is to investigate the relationship of Fused Deposition Modeling (FDM) process parameters with the tensile properties and surface roughness of Polyethylene terephthalate glycol (PETG) parts. A response surface methodology (RSM) utilizing Box–Behnken design methodology studied three essential parameters consisting of infill density and layer height, together with plate temperature. The analysis demonstrated that layer height proved to be the main element affecting tensile strength because it contributed 80.9% of the experimental variations, while infill density stood out as the leading determinant of surface roughness, which was responsible for 78% of the contribution. Experimental testing proved that the predictive model showed accurate results when validated through measurements of tensile strength, which produced maximum errors of 1.28%, and surface roughness, which yielded maximum errors of 6.54%. A desirability analysis indicated that the ideal parameters of the roughness and tensile strength of the printed parts included an infill density of 64.24% combined with a layer height of 0.1813 mm and plate temperature of 51.46°C. These outcomes provide a comprehensive understanding of process parameter effects that result in quality PETG parts with mechanical performance. The two-axis optimization methodology for PETG also enhances its use in functional engineering systems that require simultaneous mechanical durability and manufacturing accuracy.

12

Enhancing laser cutting quality of stainless steel 201 by controlling dross formation and surface roughness using multi-factor experimental design

Zabon Anwar Hassan, Abbas Tahseen Fadhil, Bedan Aqeel Sabree

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 7

458--470

EN

A better process and products are thought to require characterization, evaluation of effects, and understanding of the damage extension caused by the Laser Cutting (LC) process on the surface integrity of the cut workpieces, given its many benefits and applications in the industry. In this work, 32-run CCD was used under Response Surface Methodology (RSM) to examine the laser cutting of stainless steel 201 (SST 201) utilizing a 32-run experimental design. Laser power (Pu), cutting speed (V), frequency (F), focal position (FP), and gas pressure (P) are chosen as parameters for the input process, where the surface roughness and dross formation are taken into account as response variables in this process. Each parameter's relevance and impact was evaluated by a thorough statistical analysis that included Analysis of Variance (ANOVA), counters plots, main effect plots, and residual plots. The ANOVA results for surface roughness (Ra) and dross generated area (DA) are closely related since both are influenced by process parameters. While improving assist gas pressure enhances the surface quality and lowers the accumulation, increasing the laser power and cutting speed decreases both roughness and dross.

13

Analysis of fused filament fabrication / fused deposiotion modelling applications for production of casting patterns used in sand casting

Bernat Łukasz, Kroma Arkadiusz

Advances in Science and Technology. Research Journal

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2025

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Vol. 19, no. 7

427--439

EN

This paper presents an analysis of FFF/FDM (Fused Filament Fabrication / Fused Deposiotion Modeling) applications for production of casting patterns used in sand casting, with particular emphasis on short-run and prototype production. For this purpose, casting patterns of different shape and height of incremental layer (0.29 mm, 0.19 mm, 0.14 mm and 0.09 mm) were made of Z-ABS filament produced by Zortrax. Geometrical and dimensional analysis of the patterns was carried out, surface roughness parameters were measured, and a visual analysis of the surface was performed. In order to evaluate the conclusions observed based on the analysis of casting patterns, 130 x 102.5 x 37.5 mm sized shaped castings were designed and manufactured from aluminum and grey cast iron, which were also subjected to analysis. The last element of the research was a visual analysis of the reproduction of markings on the castings.

14

The influence of PCBN inserts microgeometry on cutting forces, surface roughness, and tool wear when milling Inconel 718

Szpunar Marcin, Zwolak Marek, Ostrowski Robert

Advances in Mechanical and Materials Engineering

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2025

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Vol. 42, nr 1

121--133

EN

This study investigates the effect of cutting edge microgeometry on the milling of Inconel 718, a superalloy widely used in aircraft engine components. Face milling tests were conducted using a Ø63 mm tool with unevenly distributed polycrystalline cubic boron nitride (PCBN) inserts, comparing inserts with a chamfered cutting edge (15° × 0.2 mm) and sharp cutting edges. The experiments examined cutting forces, surface roughness (parameters Ra and Rz), and tool wear at various cutting speeds (80–300 m/min). The results revealed that sharp inserts generated lower cutting forces compared to chamfered inserts, with the axial force being the greatest component for chamfered tools and the lowest for sharp ones. The dominant tool wear mechanism for both insert types was chipping; however, sharp inserts also exhibited built–up edge formation and, in one case, a significantly deeper crater compared to chamfered inserts which showed smaller crater depths. The study concludes that the cutting edge microgeometry significantly influences the machining performance in terms of cutting forces, surface quality, and tool wear when milling Inconel 718.

PL

W niniejszym badaniu zbadano wpływ mikrogeometrii ostrza na proces frezowania Inconelu 718, stopu wysokotemperaturowego powszechnie stosowanego w komponentach silników lotniczych. Przeprowadzono testy frezowania czołowego za pomocą narzędzia o średnicy Ø63 mm z nierównomiernie rozmieszczonymi płytkami PCBN, porównując płytki z fazowanym ostrzem (15° × 0.2 mm) i ostrymi krawędziami skrawającymi. Eksperymenty dotyczyły analizy sił skrawania, chropowatości powierzchni (parametry Ra i Rz) oraz zużycia narzędzia przy różnych prędkościach skrawania (80–300 m/min). Na podstawie wyników stwierdzono, że frezowanie z użyciem frezów ostrych generowało niższe siły skrawania w porównaniu do frezów z fazką, przy czym osiowa siła skrawania była największą składową dla narzędzi z fazką, a najmniejszą dla narzędzi ostrych. Dominującym mechanizmem zużycia narzędzia dla obu typów płytek było wykruszanie; jednakże frezy ostre wykazywały również tworzenie się narostu oraz, w jednym przypadku, znacznie głębszy krater w porównaniu do frezów z fazką, które charakteryzowały się mniejszymi głębokościami kraterów. Wyniki badań dowiodły, że mikrogeometria ostrza znacząco wpływa na parametry obróbki pod względem sił skrawania, jakości powierzchni i zużycia narzędzia podczas frezowania Inconelu 718.

15

Quality and efficiency analysis of edge preparation in S355J2N steel for welding applications

Kawiak Michał, Sajek Adam

Advances in Materials Science

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2025

|

Vol. 25, nr 2(84)

17--35

EN

The process of edge preparation for welding plays a crucial role in ensuring the quality of welded structures, affecting both their mechanical properties and overall economic efficiency. The aim of this article is to present a comparative analysis of traditional oxy-fuel cutting and modern milling methods for edge preparation of S355J2N low-alloy steel, focusing on surface quality, microstructural changes, as well as economic aspects. The study was conducted on plates with thicknesses ranging from 8 to 20 mm, using bevel angles of 30° and 45°. Both straight and curved beveled edges were investigated, utilizing a self-propelled OMCA 900 beveling machine, Gerima MMB 400B and SMA 60 BER milling machines, and a PERUN PC-211A/Y11 gas torch. Surface roughness measurements, macroscopic analysis of the edges, and HV1 microhardness testing were performed. Operation times were recorded to enable a cost analysis. The results demonstrated that milling significantly reduces edge roughness—Ra values decreased by a factor of 6 to 10 compared to oxy-fuel cutting. In the case of oxy-fuel cutting, a heat-affected zone approximately 2–3 mm thick and localized surface hardening up to 250–450 HV1 were observed, while milling did not cause changes in hardness. Cost analysis showed that under Polish labor rates, the total beveling costs were comparable for both methods (approximately 2 EUR/m), whereas under average EU labor rates, milling became the more economically viable solution.

16

Innovative approach to ensuring the quality of gas turbine engine parts produced by selective laser sintering for UAV

Vyshnepolskyi Yevhen, Pavlenko Dmytro, Tumarchenko Larysa

Zeszyty Naukowe. Transport / Politechnika Śląska

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2024

|

z. 124

243--260

EN

The research objects are gas turbine engines parts, manufactured using an innovative method of additive manufacturing - selective laser sintering. The main problem solved in this work is the low quality of the surface layer and the residual porosity of the parts obtained by this method, which significantly limits their operational characteristics and durability. As a result of the experimental studies, rational operating parameters of diamond smoothing were established. This allowed to significantly improve the surface quality and increase the operational characteristics of parts made of heat-resistant alloys INCONEL 718 and an intermetallic alloy based on titanium aluminide OX45-3ODS. The effectiveness of diamond smoothing is explained by local plastic deformation and compaction of the surface layer of parts under the influence of high contact pressures and temperatures. This leads to a significant reduction in surface roughness, an increase in the surface hardness due to strain hardening and a significant reduction in the size and number of residual pores. A characteristic feature of the obtained results is the ability to control the quality parameters of the surface layer by varying the diamond smoothing operating parameters - smoothing force, feed, radius, and geometry of the smoother's working part. The established regularities of the smoothing operating parameters have an impact on the quality characteristics of the surface. This information can be utilized in the development of highly efficient technological processes for the production and restoration of gas turbine engines, critical components of unmanned aerial vehicles, obtained through selective laser sintering. Implementing the elaborated technological recommendations will permit broadening the range of goods produced by additive manufacturing and enhancing their capacity and dependability during operation under conditions of cyclical loads and extreme temperatures.

17

Machinability analysis of thin-walled carbon fiber reinforced ceramic composites based on wire electrical discharge machining

Poroś Dariusz, Wiśniewska Magdalena

Zeszyty Naukowe Politechniki Morskiej w Szczecinie

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2024

|

nr 77 (149)

5--13

EN

We propose employing wire electrical discharge machining (WEDM) for shaping thin-walled, multidirectional, carbon fiber reinforced silicon carbide (Cf-SiC) composite parts. Ceramic matrix composite Cf-SiC combines the outstanding mechanical properties of the carbon fiber with oxidation, abrasive wear, corrosion resistance, and high strength at the high temperature of the silicon carbide matrix. The impact of time-related electrical discharge machining parameters (pulse ON-time and break OFF-time) on the material removal rate and surface roughness are analyzed. The material removal rate of the Cf-SiC is proved to be 36% lower than that for machined steel grade 55. The high thermal stresses and interaction of the composite accompanying WEDM are also discussed. Furthermore, an alternative mechanism to the WEDM of metals has been investigated and confirmed by a scanning electron microscopy (SEM) analysis. The morphology of the machined Cf-SiC surface demonstrates the dominance of the carbon fibers’ fracture mechanism, both the transverse and longitudinal forms, with interphase detachment over craters and micro-cracks, pitting, and spalling on the SiC matrix. Satisfactory roughness indicators (Sa = 2 µm) are obtained in 3D topography measurements of the Cf-SiC surfaces. Concluding, the WEDM should be considered a good alternative to Cf-SiC abrasive machining when cutting holes, grooves, keyways, splines, and other complex shapes.

18

Impact Analysis of Surface Roughness of the Plate-Plate Measuring System on Resistance Torque in Interaction with Mr Fluid

Stępień Barbara, Horak Wojciech

Tribologia

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2024

|

nr 1

117--125

EN

Magnetorheological (MR) fluids are complex suspensions of magnetic particles in a non-magnetic carrier fluid. They exhibit ‘smart’ properties that enable them to change their rheological parameters in response to a change in the external magnetic field applied. This behavior is used in some engineering solutions, e.g. MR clutches or brakes. For such systems to work correctly, the resistance torque achieved by contact with the MR fluid must be properly determined. This paper demonstrates how surface roughness of a contact surface between the solid and the MR fluid affects the resistance torque value. Measurements were made on a dedicated rotational rheometer using a shear mode fluid, most closely replicating the way MR clutches and brakes work. Plate-plate geometry was used, in standard design, and modified by pasting sandpaper with different grit levels. The tests have shown that the roughness of the mating surface affects the resistance torque results.

PL

Ciecze magnetoreologiczne (MR) to złożone zawiesiny cząstek magnetycznych w niemagnetycznej cieczy nośnej. Wykazują one właściwości „inteligentne”, dzięki którym wraz ze zmianą oddziałującego pola magnetycznego mogą zmieniać swoje parametry reologiczne. Takie zachowanie jest wykorzystywane w niektórych rozwiązaniach inżynierskich, np. sprzęgłach lub hamulcach MR. W tych układach krytyczne dla ich poprawnej pracy jest właściwe określenie uzyskiwanego momentu oporu ruchu spowodowanego kontaktem z cieczą MR. W pracy zaprezentowano, jak chropowatość powierzchni ciała stałego w styku z cieczą MR wpływa na uzyskiwaną wartość momentu oporu ruchu. Pomiary przeprowadzono na reometrze rotacyjnym na cieczy dedykowanej do pracy w trybie ścinania, najlepiej odwzorowując sposób pracy sprzęgieł i hamulców MR. Wykorzystano geometrię płytka–płytka w standardowym wykonaniu oraz zmodyfikowanym poprzez naklejanie papierów ściernych o różniej gradacji. Przeprowadzone badania wykazały, że chropowatość powierzchni współpracującej ma wpływ na uzyskiwane wyniki momentu oporu ruchu.

19

Analysis of Surface Roughness of Refrigeration Compressor Friction Nodes Due to Insufficient Lubrication

Górny Kasper, Stachowiak Arkadiusz, Tyczewski Przemysław, Zwierzycki Wiesław

Tribologia

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2024

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nr 2

21--30

EN

The article presents an attempt to evaluate the roughness profiles of the components of the friction nodes in refrigeration compressors due to insufficient lubrication. The damaging impact on the compressor operation under various unfavorable operating conditions, including with little or no lubricant at all, was analyzed for a real refrigeration system using a dedicated test stand. The Embraco Aspera NE9213GK refrigeration compressor used was originally filled in by the manufacturer with a polyester lubricant; for the purpose of the study, the R407C lubricant was applied. An accelerated damage-controlled procedure was carried out on the compressor by reducing the amount of lubricant in subsequent operating cycles of the system. The amount of oil was adjusted by removing lubricant during shutdown periods using a dedicated spigot in the body of the semi-hermetic compressor casing. The testing continued until the refrigeration compressor seized up. The test stand was used to analyze electrical power measurements at the time of intentional damage to the compressor caused as a result of forced absence of lubrication. Additionally, the authors analyzed surface roughness profiles of the compressor sliding elements prone to wear, including crankshaft journals, piston surface, and a cylinder surface.

PL

W artykule przedstawiono próbę oceny profili chropowatości elementów węzłów tarcia sprężarek chłodniczych wskutek niewystarczającego smarowania. Proces uszkodzenia rzeczywistej sprężarki zrealizowano na stanowisku na bazie rzeczywistego układu chłodniczego. Stanowisko umożliwia odzwierciedlanie różnych niekorzystnych warunków pracy instalacji, w tym pracę sprężarki w różnych ilościach oraz przy braku środka smarnego. Wykorzystana sprężarka chłodnicza Embraco Aspera NE9213GK została napełniona przez producenta poliestrowym środkiem smarnym, a rzeczywista instalacja czynnikiem chłodniczym R407C. Przeprowadzono przyspieszoną procedurę kontrolowanego uszkodzenia sprężarki przez zmniejszanie ilości środka smarnego w kolejnych cyklach pracy instalacji. Ilość oleju regulowano poprzez usuwanie środka smarnego podczas postoju za pomocą dedykowanego króćca w korpusie semihermetycznej obudowy sprężarki. Testy kontynuowano aż do zatarcia sprężarki chłodniczej. Wykonano analizę pomiaru mocy elektrycznej przez stanowisko badawcze podczas celowego uszkadzania sprężarki wskutek wymuszania efektu braku smarowania. Dodatkowo przeprowadzono analizę profili chropowatości powierzchni najczęściej zużywających się elementów ślizgowych sprężarki: czopów wału korbowego, powierzchni tłoka, powierzchni cylindra.

20

Właściwości warstwy wierzchniej wybranych stopów metali po cięciu laserem

Skoczylas Agnieszka

Stal, Metale & Nowe Technologie

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2024

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nr 3-4

31--40

EN

The article analyses the properties of the surface layer of the C45, X5CrNi18-10, 1.7218, 700MC steel elements after laser cutting, focusing on the stereometric and physical properties of the surface layer. The parameters of 2D and 3D surface roughness and microhardness of the surface layer on diagonal sections are analysed and imperfections are determined. Due to the occurrence of zones of different surface roughness on the surface of the cut elements, the roughness parameters Ra, Rpk and Rvk were measured in the “entrance zone” and “exit zone” of the laser beam. In the case of the C45 and X5CrNi18-10 steel samples, a large difference in the surface quality between the zones was found. For the elements made of the C45, 700 MC and 1.7218 steel, imperfections are located at the lower edge. In the case of all the engineering materials, an increase in microhardness was obtained, ranging from 11% to 137%, and the thickness of the heat affected zone ranged from 10 μm to 250 μm.