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1

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

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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.

2

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

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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.

3

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.

4

Innovative correlation relating the destruction of graphite flakes to the morphology characteristics of minerals

Wang Nailing, Xu Xinyang, Jiang Yanxin, Yuan Zhitao, Lu Jiwei, Li Lixia, Meng Qingyou

Physicochemical Problems of Mineral Processing

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2024

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Vol. 60, iss. 1

art. no. 183655

EN

The morphology characteristics (sphericity, roundness, and surface roughness) affecting the destruction of gangue minerals on graphite flakes during the grinding process were systematically analyzed. Coupled with MS and SEM, sphericity analysis showed that graphite was flaky, which was similar to muscovite but different from granulous quartz and albite, and the roundness of the four minerals from high to low was graphite, quartz, albite, and muscovite. AFM analysis showed that the surface roughness of graphite and muscovite was very low compared to that of quartz and albite (higher than quartz). The size and crystal integrity of graphite flakes were both destroyed by gangues during the grinding process, and the destruction of quartz and albite was serious compared to that of muscovite. Sphericity dominantly affected the destruction: the larger the sphericity, the more serious the destruction, which was also negatively related to roundness but positively related to surface roughness.

5

Wpływ wartości posuwu podczas cięcia laserem na chropowatość powierzchni przecięcia

Galon Marcin, Mikołajczyk Jarosław Robert

Obróbka Metalu

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2024

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nr 3

48--53

PL

W pracy przedstawiono badania mające na celu określenie wpływu wartości posuwu lasera na chropowatość powierzchni przecinanej. Stwierdzono, że parametr ten ma istotny wpływ na badaną cechę wyrobu. Zwiększenie wartości posuwu wpływa na zmniejszenie chropowatości powierzchni przecięcia. Określono korelację między parametrem chropowatości Ra oraz wartością posuwu.

EN

In the paper investigated aimed at determining the influence of the laser displacement speed on the roughness of the cross-sectional surface were presented. It was found that this parameter has a significant influence on the tested characteristic of the product. An increase in the feed value reduces the roughness of the cutting surface. The correlation between the roughness parameter Ra and the feed value P was determined.

6

A study on the Ability to Fabricate Mold Using 3D Printing Technology and Evaluate the Surface Roughness of Products in Investment Casting

Nguyen Thanh Tan, Son Dao Hai, Tran Van Tron

Journal of Machine Engineering

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2024

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Vol. 24, No. 3

106--118

EN

The investment casting (IC) process is a technique used to produce high-precision metal castings, including complex shapes and metals that are difficult to cast using conventional methods. Typically, the process begins by creating a wax pattern from a mold in the initial steps. The molds used for IC are fabricated using conventional machining techniques. However, this mold preparation approach can be challenging when it comes to fabricating complex shapes and thin walls, particularly in small-batch production scenarios. To overcome this limitation, this study explores a flexible design approach that utilizes three-dimensional printing (3DP) to fabricate IC molds. The key advantage of this approach is the combination of the flexible design mold and the surface roughness (SR) of the casted parts. The experimental results demonstrate that the SR of the casted products fabricated using the 3DP mold is comparable to that obtained from the conventional mold-making process. These findings provide an alternative strategy for preparing IC molds with high flexibility, which can accommodate various scales of production. The 3DP-based approach offers a more adaptable solution compared to conventional machining methods, particularly for complex geometries and small-batch manufacturing.

7

Experimental investigation and machining analysis of Mg/TiC composites during EDM

Dash Dharmeswar, Devarajaiah Devarasiddappa, Dash Santosh Kumar, Samanta Sutanu, Rai Ram Naresh

Composites Theory and Practice

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2024

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R. 24, nr 1

9--16

EN

Electrical discharge machining (EDM) is one of the prominent non-conventional machining processes used to machine metal matrix composites. Mg/TiC composites are found in many industrial applications and conventional machining of the same is highly challenging. This paper aims to study the machinability analysis of Mg/TiC composites using EDM with pulseon time (Ton), pulse-off time (Toff) and input current (I) as the process variables with the material removal rate (MRR) and surface roughness (SR) as the performance measures. Stir cast Mg-alloy reinforced with TiC (0, 5, 10, 15 and 20) by weight was used as the workpiece. The EDM experiments were conducted as per L25 orthogonal array (OA) and the results were analyzed to study the effect of the process variables on MRR and SR. The parametric study showed that SR increases linearly with Ton and is attributed to larger craters produced at a higher pulse energy. MRR was also observed to grows with the rise in Ton as more material melts due to high-intensity pulses. As per the ANOVA results, Ton was found to be the most influential process variable affecting SR and MRR with a 79% and 34% contribution, respectively. Surface morphology investigations using SEM micrographs revealed the presence of globules and sphere-shaped metal deposits and were found responsible for increased SR.

8

The effects of cutting speed and change in cutting tool materials on surface roughness in bone-cutting procedures

Sawangsri W., Addepalli P., Ghani S.A.C.

Archives of Materials Science and Engineering

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2024

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Vol. 126, nr 1

34--41

EN

Purpose: Surface roughness is a reliable indicator of bone cell damage in bone-cutting processes. This novel study investigates the effects of spindle speed, feed rate, and cutting tool materials on milling artificial bone specimens. Design/methodology/approach: Since bone cutting is an orthogonal cutting technique, bone machining was carried out using the milling process. As per the requirements of the objectives, four milling cuts were carried out across each workpiece using two different materials-based customized cutting tools, SS316 and ZrO2. The machining parameters used were 0.03 mm/tooth feed rate, 900 m/min and 1000 m/min cutting speed and 1.3 mm depth of cut. Surface roughness was measured in two parameters, Ra and Rz, for each machined cut from SS316 and novel ZrO2 tools. Findings: At 1000 m/mm, SS316-based cutting recorded a maximum cutting temperature of 39°C. With increased cutting speed, Ra values from both cutting tools were raised. While Rz values were unstable in 900 m/mm cuttings, they steadily increased with the rise in cutting speed. ZrO2-based cutting at 900 m/mm speed produced the maximum groove possible, measuring 9.487 mm, the closest to the tool's 9.5 mm diameter. Experiment results demonstrate that increasing cutting speed has little impact on Ra values, but it generates uniformity in Rz, which leads to minimal surface roughness. In conclusion, ZrO2-based cuttings have shown proper uniformity in Rz values against SS316. Research limitations/implications: Further experiments based on changes in cutting tool materials, cutting parameters, and types of cutting tools will provide enough data to introduce ceramic tools in bone-cutting procedures. Originality/value: The novelty of the study is the introduction of a customized ZrO2 ceramic-based cutting tool for bone-cutting procedures.

9

Selected Methods of Modifying the Surface Layer of a Carbon Composite

Kłonica Mariusz, Kubit Andrzej, Perłowski Ryszard, Bielawski Radosław, Woś Sławomir

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

270--277

EN

This article presents the results of a comparative study on the modification of the surface layer of carbon composites. Fibre-reinforced polymer (FRP) composite materials are heterogeneous and anisotropic materials, characterised by high strength, low density, corrosion resistance along with ease of processing and moulding, and are increasingly replacing metal alloys. They are widely used in aviation, automotive and transport applications. One example of a modern composite is carbon fibre-reinforced polymer (CFRP). This study presents the influence of selected modifications of the surface layer of a CFRP composite on the values of free surface energy (SFE) and surface topography. The resulting SFE values were analysed together with the contribution of the polar SFE and dispersive SFE components. The article also presents the test results related to selected 3D surface roughness parameters and includes photographs of the test specimens after surface layer modification. The results were statistically processed in compliance with good research practice.

10

Possibility of Using the Hydrostatic Burnishing Process in Marine Conditions

Labuda Wojciech, Wieczorska Agata

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 6

189--205

EN

The publication presents the results of research on the influence of hydrostatic burnishing process on the value of selected parameters of surface roughness, material ratio and surface hardness. The process was carried out on shafts made of X5CrNi18-10 stainless steel. The prepared samples were subjected to a finishing turning process with constant cutting parameters, and then hydrostatic burnishing was performed on the surface. The tests determined the influence of the variable pressure exerted by the ball on the shaft surface. The evaluation of the research results showed a significant increase in hardness in the surface layer and an improvement in surface roughness parameters and material ratio. The machining process was carried out on a conventional lathe.

11

Evaluation of the Influence of Tool Coatings on the Machinability of the Ti6Al4V Alloy Using Gray Relational Analysis

Karolczak Paweł, Adamczak Michał

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 6

13--28

EN

This paper presents a study of the turning of titanium alloy Ti6Al4V with uncoated and physically or chemically coated carbide blades. The indicators studied and measured were 3D surface roughness, cutting force, the shape of the resulting chips and the degree of blade wear. It was found that coating the cutting blades increased the cutting forces. More blade wear mechanisms also occur, including thermal and adhesive wear. The chemically applied coating makes it possible to obtain the best roughness of Sq and Sz. The coating of the cutting blades had no effect on the form of the chips produced. The Grey Relational Analysis (GRA) confirmed that the recommended blades for the machining of superalloys warranted better technological results for the machining Ti6Al4V alloy.

12

Effect of Shot Peening Parameters on Surface Properties and Corrosion Resistance of 316L Stainless Steel

Walczak Mariusz, Matijošius Jonas, Özkan Doğuş, Pasierbiewicz Kamil

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 3

296--304

EN

The present work deals with the enhancement of the surface characteristics of stainless steel 316L as a result of shot peening treatment using ceramic balls. In accordance with our own research and information available in literature, as a result of shot peening process, the shot balls can penetrate to the surface layer (permanently depositing) and modify the mechanical performance and the corrosion resistance in the products being treated in this way. Shot peening leads to a significant change to the surface hardness and topography, and consequently, to the change in corrosion behaviour dependent on the choice of processing parameters. Therefore, in this paper, steel samples were treated using two variable parameters of peening pressure (0.3 and 0.4 MPa) and peening time (30 and 60s). In the research, the reference surface were the samples subjected to mechanical polishing. The surface morphology of the samples was investigated by scanning electron microscopy (SEM). The potentiodynamic polarization tests were performed with 1 mV/s scan rate in 0.9% NalCl solution. The improved corrosion resistance (lowest current density Icorr=0.35µA/cm2 and highest corrosion potential Ecorr=-0.164V) was obtained for specimens with longer time (60s) and higher pressure of shot peening treatment (0.4MPa). Greater changes in surface roughness were observed with an increase in peening pressure than with an increase in the processing time. The treatment of the surface with ceramic shots results in an increase in the hardness of the treated surface by more than 110% (for sample 316L/0.4/60) compared to the reference surface. Moreover, an increase in average hardness values was recorded for all surfaces after shot peening (by more than 42% relative to reference samples).

13

Effect of Regular Shot Peening and Semi-Random Shot Peening Conditions on Selected Properties of the Surface Layer of Gray Cast Iron

Skoczylas Agnieszka, Zaleski Kazimierz

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 2

284--295

EN

Both dispersed and concentrated shot peening can be an effective method for the finishing of machine components. This work investigates the effect of two different shot peening (SP) processes conducted with the same technological parameters on selected properties of the surface layer of gray cast iron EN-GJL 250. Specifically, regular shot peening (RSP) and semi-random shot peening (SRSP) were investigated in the study. The results demonstrated that the surface quality of EN-GJL 250 samples was higher after RSP than after SRSP. The analyzed surface roughness parameters were lower after RSP than after SRSP, with the exception of the Rvk parameter. As a result of RSP, the analyzed roughness parameters increased from 5% to 62% in relation to their values after pre-treatment. The lowest values of the surface roughness parameters were obtained after RSP conduced with the impact energy E = 100 mJ, the distance between the dimples x = 0.3 mm, and the diameter of the shot peening element d = 14.3 mm. Assessment of the 3D surface topography showed significant differences in the formation of machining traces depending on the employed surface treatment. In RSP, the traces were arranged in a uniform manner, with the assumed step, whereas in SRSP the shot peening traces had no set pattern of orientation. The application of RSP and SRSP caused an increase in surface microhardness. The maximum surface microhardness was 75 HV0.5 for RSP and 98 HV0.5 for SRSP. Residual stresses were higher after SRSP than after RSP. Compressive residual stresses were induced in both types of shot peening process.

14

3D Optical and Mechanical Roughness Measurements of Complex and Irregular Structures on the Basis of Polypropylene Moldings

Rojewski Mateusz, Nowinka Bartosz, Czyżewski Piotr

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 5

245--257

EN

The most frequently used method for measuring surface roughness is profilographometry. However, with complex and non-homogeneous surfaces, this method may be subject to large errors because of its contact nature and limitations related to the geometry of the measuring head. In this study, the surface topography was examined on polypropylene injection moldings produced using an injection mold with a complex molding cavity surface. The moldings were modified using a Nd:YAG laser, and the obtained structures were examined using two measurement methods, i.e. contact (profilographometry) and optical (3D digital microscopy). Researchers performed a statistical analysis to determine the differences between the measurement results obtained for the two methods. Additionally, the impact of the laser parameters on the modified surface was determined. The obtained results showed significant differences between the values of measurements made using different methods, especially in the case of surfaces that were modified by the laser beam to the greatest extent (laser A parameters). In all cases where a statistically significant difference was found between the measurement results, the mechanical method showed lower roughness values than the optical method, and the average difference between these results was 15%.

15

Effect of floating-plug drawing process parameters on surface finish of inner and outer surfaces of AISI 321 stainless steel thin-walled tubes

Żaba Krzysztof, Szpunar Marcin

Advances in Mechanical and Materials Engineering

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2024

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Vol. 41, nr 1

27-37

EN

This article presents the results of the analysis of changes in the surface topography of AISI 321 (1.4541) thin-walled stainless steel tubes in single-pass Floating-Plug Drawing (FPD) process. Experimental tests were carried out with variable drawing speed (1, 2, 3, 4, 6, and 10 m/min) and different angles of floating plug (11.3°, 13° and 14°). Wisura DSO7010 (Fuchs Oil) lubricant was used in the experiments. Mean roughness Ra and ten point height of irregularities Rz were adopted as surface quality indicators. Roughness parameters were measured independently on the inner and outer surfaces of thin-walled tubes. Analysis of variance was used to analyse the relationship between process parameters (drawing speed and angle of floating plug) and surface roughness of tubes. A decrease in the values of both analyzed roughness parameters was observed as a result of the drawing process. The FPD process significantly improves the inner surface quality of AISI 321 thin-walled stainless steel tubes. The mean roughness value tends to increase with increasing drawing speed, while the angle of the floating-plug has no significant effect on the mean roughness Ra.

PL

W artykule przedstawiono wyniki analizy zmian topografii powierzchni rur cienkościennych ze stali nierdzewnej AISI 321 po procesie ciągnienia na korku swobodnym. Badania eksperymentalne przeprowadzono w jednym przejściu, ze zmienną prędkością ciągnienia (1, 2, 3, 4, 6, and 10 m/min) oraz różnymi kątami β korka swobodnego (11.3°, 13° and 14°). W badaniach eksperymentalnych wykorzystano smar Wisura DSO7010 (Fuchs Oil). Jako wskaźniki jakości powierzchni przyjęto średnie arytmetyczne odchylenie rzędnych profilu Ra oraz wysokość chropowatości według 10 punktów Rz. Parametry chropowatości mierzono niezależnie na wewnętrznej i zewnętrznej powierzchni rur cienkościennych. Do analizy związków pomiędzy parametrami procesu ciągnienia (prędkość ciągnienia i kąt korka swobodnego) wykorzystano analizę wariancji. Zaobserwowano zmniejszenie wartości obydwu analizowanych parametrów chropowatości w wyniku procesu ciągnienia. Proces ciągnienia na korku swobodnym znacznie poprawia jakość wewnętrznej powierzchni cienkościennych rur ze stali nierdzewnej AISI 321. Zaobserwowano tendencję do zwiększania się parametru Ra wraz ze wzrostem prędkości ciągnienia, podczas gdy kąt β korka swobodnego nie miał znaczącego wpływu na średnią chropowatość Ra.

16

Application of categorical boosting to modelling the friction behaviour of DC05 steel sheets in strip drawing test

Szewczyk Marek, Szwajka Krzysztof, Najm Sherwan Mohammed, Mohammed Salwa O.

Advances in Mechanical and Materials Engineering

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2024

|

Vol. 41, nr 1

69-78

EN

It is challenging to model the coefficient of friction, surface roughness, and related tribological processes during metal contact because of flattening, ploughing, and adhesion. It is important to choose the appropriate process parameters carefully when creating analytical models to overcome the challenges posed by complexity. This will ensure the production of sheet metal formed components that meets the required quality standards and is free from faults. This research analyses the impacts of nominal pressure, kinematic viscosity of lubricant, and lubricant pressure on the coefficient of friction and average roughness of DC05 deep-drawing steel sheets. The strip drawing test was used to determine the coefficient of friction. This work utilises the Categoric Boosting (CatBoost) machine learning algorithm created by Yandex to estimate the COF and surface roughness, intending to conduct a comprehensive investigation of process parameters. A Shapley decision plot exhibits the coefficient of friction prediction models via cumulative SHapley Additive exPlanations (SHAP) data. CatBoost has outstanding prediction accuracy, as seen by R2 values ranging from 0.955 to 0.894 for both the training and testing datasets for the COF, as well as 0.992 to 0.885 for surface roughness.

PL

Modelowanie współczynnika tarcia, chropowatości powierzchni i powiązanych procesów tribologicznych podczas kontaktu powierzchni blachy i narzędzi jest trudnym wyzwaniem ze względu na spłaszczanie, bruzdowanie i sczepianie nierówności powierzchni. Podczas tworzenia modeli analitycznych ważne jest, aby ostrożnie wybierać odpowiednie parametry procesu. Zapewni to produkcję elementów formowanych z blachy spełniających wymagane standardy jakościowe i pozbawione wad. W pracy analizowano wpływ ciśnienia nominalnego, lepkości kinematycznej smaru i ciśnienia smaru na współczynnik tarcia i średnią chropowatość powierzchni blach stalowych głęboko tłocznych DC05. Do wyznaczenia współczynnika tarcia wykorzystano test przeciągania pasa blachy. W pracy tej wykorzystano algorytm uczenia maszynowego CatBoost, stworzony przez firmę Yandex, w celu oszacowania wartości współczynnika tarcia ni chropowatości powierzchni. Przeprowadzono kompleksowe badania parametrów procesu tarcia. Modele przewidywania współczynnika tarcia na podstawie funkcji SHapley Additive exPlanations (SHAP)przedstawiono za pomocą wykresu decyzyjnego Shapleya. CatBoost charakteryzuje się wyjątkową dokładnością przewidywania potwierdzoną wartością R2 w zakresie od 0.955 do 0.894 zarówno w przypadku zbiorów danych uczących, jak i testowych dla współczynnika tarcia, a także od 0.992 do 0.885 w przypadku średniej chropowatości powierzchni.

17

Badanie płaskości oraz chropowatości powierzchni modeli cienkościennych wykonanych technologią przyrostową Fused Deposition Modeling

Zmarzły Paweł, Klamka Magdalena, Szwej Wiktoria, Wróblewska Eliza

Zarządzanie Przedsiębiorstwem

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2023

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Vol. 26, nr 2

27--32

EN

3D printing technologies are gaining popularity year by year. They allow for a significant improvement in the production of prototypes and utility models. In addition, 3D printing facilitates the production of thin-walled elements and complex shapes, which is difficult when using traditional manufacturing methods. It should be noted that the technological parameters of 3D printing, such as the printing orientation and the thickness of a single layer, are very important because they affect the printing time, material expenditure and the dimensional accuracy of the printed details. There are many types of 3D printers, the operating principle of which and the building material used are different. However, one of the most popular and available types of additive manufacturing is Fused Deposition Technology. Therefore, detailed studies of this technology are particularly desirable by economic entities. The article presents research aimed at assessing the influence of the print direction and the thickness of a single layer of a building material on the flatness deviation and the 3D surface roughness parameters. Special thin-walled models were designed and printed from PLA material using a printer named MakerBot Replicator+. The research results presented in the article showed that the direction of printing and the thickness of a single layer of building material in the Fused Deposition Modeling Technology affect the roughness parameters, flatness and printing time of the produced models.

18

Selection of materials for repairing punctures of metal skin of semi-monocoque structures using composite patches

Godzimirski Jan, Rośkowicz Marek, Barca Iga

Technologia i Automatyzacja Montażu

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2023

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nr 2

19--32

EN

For repairing punctures of skin of semi-monocoque structures under field conditions, simple methods are sought to guarantee the reliability of the repaired structure. Therefore, adhesive joints and composite materials are being increasingly used in repairs. During repairs using adhesion, an important aspect that affects the quality of the joint is the selection of the adhesive and the quality of surface preparation of the parts to be joined. This is necessary to get the right bond strength and durability of the joint in working environments characterized by extreme temperatures and exposure to chemicals and moisture. The purpose of the study was to select an adhesive with good strength properties for bonding AW2024T3 aluminum sheets to carbon and glass composites, and to analyze the effect of metal surface preparation on the strength of adhesive joints (grinding, sandblasting and chemical surface preparation). The tests were carried out on overlap (metal-composite) specimens. For selected adhesives, strength tests were also carried out on specimens replicating the repaired damage with a diameter of 20 mm of metal skin repaired by different methods, including composite patches and adhesive joints. The specimens were loaded in tension and loss of stability. The tests made it possible to determine the requirements for composite patches used for repairing upper and lower airframe wing skins.

PL

Do napraw przebić pokryć konstrukcji półskorupowych w warunkach polowych, poszukuje się prostych metod, które zagwarantują niezawodność naprawianej struktury. Dlatego coraz częściej w naprawach wykorzystuje się połączenia adhezyjne i materiały kompozytowe. Podczas napraw z zastosowaniem klejenia ważnym aspektem, który wpływa na jakość połączenia, jest dobór odpowiedniego kleju oraz jakość przygotowania powierzchni klejonych elementów. Jest to niezbędne do uzyskania odpowiedniej siły wiązania i trwałości połączenia w środowisku pracy, które cechują ekstremalne temperatury oraz narażenie na działanie chemikaliów i wilgoci. Celem badań był dobór kleju o dobrych właściwościach wytrzymałościowych do łączenia blach AW2024T3 z kompozytami węglowymi i szklanymi oraz analiza wpływu przygotowania powierzchni metalowych na wytrzymałość połączeń adhezyjnych (szlifowanie, piaskowanie i chemiczne przygotowanie powierzchni). Badania przeprowadzono na próbkach zakładkowych (metalowo-kompozytowych). Dla wybranych klejów wykonano również badania wytrzymałościowe próbek imitujących naprawione uszkodzenie o średnicy 20 mm pokrycia metalowego naprawianego różnymi metodami, w tym z zastosowaniem łat kompozytowych i połączeń adhezyjnych. Próbki obciążano na rozciąganie i utratę stateczności. Przeprowadzone badania pozwoliły określić wymagania dotyczące łat kompozytowych stosowanych do napraw górnych i dolnych pokryć skrzydeł płatowców.

19

Relationship between 3D surface roughness parameters and load capacity of adhesive joints after shot peening

Zielecki Władysław, Świrad Sławomir, Ozga Ewelina

Technologia i Automatyzacja Montażu

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2023

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nr 3

35--43

EN

The aim of the article was to investigate whether roughness parameters in a 3D system can be used to assess the load capacity of adhesive lap joints strengthened in the shot peening process. The analyzes were carried out for single-lap adhesive joints made of EN AW-2024-T3 aluminum alloy, whose overlaps were shot peened for 60 to 180 s using balls with a diameter of 0.5 to 1.5 mm with a compressed air pressure of 0.3 to 0.5 MPa. As a result of the regression and correlation analysis, it was found that within the adopted range of input parameters variability, the load capacity of adhesive joints subjected to shot peening is most closely related to the roughness parameter Sdr. It has been shown that increasing the value of the Sdr parameter contributes to increasing the load capacity of adhesive joints. A mathematical model describing the impact of treatment time, balls diameter and compressed air pressure on the value of the Sdr parameter was also built. The model was built in accordance with the the Hartley's PS/DS-P:Ha3 plan methodology. The obtained results allow to conclude that the Sdr parameter can be used to predict the load capacity of adhesive joints after shot peening and thus to assess the strengthening treatment (within the assumed range of input parameters variability). Additionaly, the simplicity and low cost of roughness measurements justify the use of this method in industrial purposes.

PL

Celem artykułu było zbadanie, czy parametry chropowatości w układzie 3D mogą być stosowane do oceny nośności zakładkowych połączeń klejowych, umacnianych w procesie pneumokulkowania. Analizy przeprowadzono dla połączeń klejowych jednozakładkowych ze stopu aluminium EN AW-2024-T3, których zakadki pneumokulkowano w czasie od 60 do 180 s, kulkami o średnicy od 0,5 do 1,5 mm z ciśnieniem wynoszącym od 0,3 do 0,5 MPa. W wyniku przeprowadzonej analizy regresji i korelacji stwierdzono, że w przyjętym zakresie zmienności parametrów wejściowych, nośność połączeń klejowych poddanych pneumokulkowaniu jest najsilniej związana z parametrem chropowatości Sdr. Wykazano, że zwiększanie wartości parametru Sdr, przyczynia się do zwiększania nośności połączeń klejowych. Zbudowano również model matematyczny, opisujący wpływ czasu obróbki, średnicy kulek i ciśnienia sprężonowego powietrza na wartość parametru Sdr. Model zbudowano zgodnie z metodyką planu Hartleya PS/DS-P:Ha3. Uzyskane wyniki pozwalają na stwierdenie, że parameter Sdr może być wykorzystywany do przewidywania nośności połączeń klejowych po pneumokulkowaniu, a tym samym do oceny obróbki umacniającej (w przyjętym zakresie zmienności parametrów wejściowych), a prostota i niskie koszty pomiarów chropowatości przemawiają za słusznością użycia tej metody w celach przemysłowych.

20

A review on machinability in the milling processes

Demirpolat Havva, Kuntoğlu Mustafa, Binali Rüstem

Sustainable Production, Instrumentation and Engineering Sciences

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2023

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vol. 1, nr 1

27--36

EN

This review paper focuses on the up-to-date machinability characteristics of milling processes such as cutting forces, surface roughness and tool wear and their impacts on the cutting mechanism. The methodology pur-sued in this paper is to analyze the previous research articles published between 2019–2022 classifying them into the subcategoriesthat usemill-ing operation as manufacturing strategy. As known, milling is one of the most used machining processes in industry and often applied for academic studiesforawide range of materials. Therefore, used sensor systems, main aim and the preferred methodology were summarized in the context of this paper. Seemingly, a great number of machinability papers have been published recently which focuses on the several types of engineering ma-terials and utilized various types of sensor system to improve the surface roughness and tool life. In addition, the investigation showed that optimi-zation approaches have been applied broadly to detect the best machining conditions. Also, it was observed that several modeling approaches such as finite element analysis is a good alternative to analyze the process.