Wyniki wyszukiwania - BazTech

1

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

|

2024

|

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.

2

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

|

2024

|

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.

3

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

Zmarzły Paweł, Klamka Magdalena, Szwej Wiktoria, Wróblewska Eliza

Zarządzanie Przedsiębiorstwem

|

2023

|

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.

4

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

|

2023

|

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.

5

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

|

2023

|

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.

6

A review on machinability in the milling processes

Demirpolat Havva, Kuntoğlu Mustafa, Binali Rüstem

Sustainable Production, Instrumentation and Engineering Sciences

|

2023

|

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.

7

Wpływ kwasów organicznych na strukturę betonów w budownictwie rolniczym

Witkowska-Dobrev Joanna, Francke Barbara

Przegląd Budowlany

|

2023

|

R. 94, nr 11-12

149--153

PL

W artykule omówiono nowatorską metodę wstępnej oceny trwałości konstrukcji betonowych narażonych podczas eksploatacji na działanie agresywnych kwasów organicznych, ze szczególnym uwzględnieniem wpływu 10% kwasu octowego. Przedstawiono założenia ww. metodyki badawczej oraz omówiono wyniki badań próbek betonów o różnych wyjściowych klasach wytrzymałości, poddanych działaniu wspomnianych czynników agresywnych przez okres 210 dni. Szczegółowo zaprezentowano podstawowe narzędzie wykorzystywane w proponowanej metodyce badawczej, tzn. ocenę mikrostruktury powierzchni poddanej ekspozycji kwasu organicznego, z wykorzystaniem mikroskopu optycznego. Wyniki tych badań uzupełniono o ocenę zmian wytrzymałości i masy badanych próbek powstałych w efekcie ww. agresywnych oddziaływań chemicznych.

EN

The paper discusses an innovative method for the preliminary assessment of the durability of concrete structures exposed during operation to aggressive organic acids, with particular reference to 10% acetic acid. The assumptions of the above-mentioned research methodology are presented, and the results of testing concrete samples of different initial strength classes, exposed to the above-mentioned aggressive agents for a period of 210 days, are discussed. The basic tool used in the proposed research methodology, i.e. the assessment of the microstructure of the surface exposed to organic acid, using an optical microscope, is presented in detail. The results of these tests are supplemented by an evaluation of changes in the strength and mass of the tested samples resulting from the above-mentioned aggressive chemical interactions.

8

Badanie zespolenia betonu zwykłego z lekkim betonem kruszywowym

Gołdyn Michał, Urban Tadeusz

Przegląd Budowlany

|

2023

|

R. 94, nr 5-6

61--67

PL

W artykule przedstawiono badania eksperymentalne dotyczące zespolenia pomiędzy betonem zwykłym a betonem lekkim z kruszywem ze spiekanych popiołów lotnych. Parametry zmienne stanowiły: wytrzymałość betonu nadkładu, sposób przygotowania powierzchni oraz stopień zbrojenia styku. Badania potwierdziły wpływ wytrzymałości betonu nadkładu na siły adhezji. Wykazały jednocześnie, że przygotowanie powierzchni zespolenia poprzez bruzdowanie udarowe może prowadzić do uszkodzenia struktury betonu i ograniczyć nośność połączenia. Zachowanie minimalnego stopnia zbrojenia zespalającego według fib Model Code 2010 pozwoliło na uzyskanie ciągliwego zachowania styku, który po zarysowaniu charakteryzował się pewną nośnością rezydualną.

EN

The paper presents the experimental investigations on the connection between ordinary concrete and lightweight concrete with sintered fly ash aggregate. The variable parameters were the strength of the concrete overlay, the surface preparation method and the interface reinforcement ratio. The study confirmed the effect of the strength of the concrete overlay on the adhesive forces. At the same time, they demonstrated that surface preparation by impact grooving can lead to damage to the concrete structure and limit the load carrying capacity of the connection. Maintaining a minimum shear reinforcement ratio according to the fib Model Code 2010 allowed for a ductile behaviour of the elements, which were still characterised by a residual capacity after cracking.

9

Synergistic performance degradation of marine structural elements: case study of polymer-based composite and steel hybrid double lap joint

Baykal Halis Haluk, Neser Gokdeniz

Polish Maritime Research

|

2023

|

nr 3

111--118

EN

The degradation of structures under the influence of a marine environment tends to be rapid and disruptive compared to that of structures that are far away from these influences. Efforts to consider these impacts in the design phase are increasing, with a view to the construction of more sustainable structures. However, experimental data from which designers and builders can benefit cannot be found in the relevant literature, especially when it comes to the effects of composite degradation. In this study, we experimentally investigate the combined effects of degradation factors such as a drying-wetting cycle, the shape of the structure, the variety of materials used in the structure, and the differences in the manufacturing of the materials . The structure chosen as an example is a hybrid structural double lap joint composed of epoxy resin, fibreglass composite, and steel, which is widely used in ship structures. The experiments considered four aging periods (zero, 30, 60 and 90 days) under a wet-dry cycle in a programmable corrosion chamber, two overlap lengths (short and long), two surface roughnesses of the steel parts (50 and 90 μm), and two surface preparation alternatives (uncoated and coated with epoxy primer). The synergistic effects of these parameters on the tensile strength, deformation and toughness of the joints were evaluated, and suggestions are made for ship designers. The attention of interested parties, and particularly ship designers, is drawn to the comparative effects of these degradation agents on performance.

10

Influence of aluminum alloys surface treatment on the durability of glued joints

Kowalik Joanna, Tworek Magdalena, Smaruj Michał

Polimery

|

2023

|

Vol. 68, nr 10

523--529

EN

The aim of the work was to analyze the method of preparing the aluminum surface in terms of the functional properties of glued joints with the use of one-component polyurethane adhesive. Six methods of surface treatment of EN AW-5251 aluminum alloy were tested. In addition, changes in the shear strength of adhesive joints after environmental exposure were determined. The best surface preparation processes were atmospheric plasma and anodizing.

PL

Celem pracy była analiza sposobu przygotowania powierzchni aluminium pod kątem właściwości użytkowych połączeń klejonych z zastosowaniem jednoskładnikowego kleju poliuretanowego. Zbadano sześć metod obróbki powierzchni stopu aluminium EN AW-5251. Ponadto określono zmiany wytrzymałości połączeń klejonych na ścinanie po ekspozycji środowiskowej. Najlepszym sposobem przygotowania powierzchni była plazma atmosferyczna i anodowanie.

11

Effect of acidic saliva on monomer leaching and surface roughness of 3D-printed and milled denture-base materials

Al-Otaibi Hanan, Basaqer Rafal, Almania Sarah, Alfouzan Afnan, Al Taweel Sara, Alshehri Huda, Labban Nawaf

Polimery

|

2023

|

Vol. 68, nr 3

149--156

EN

The study evaluated the effect of different acidic salivary pH values on monomer leaching and surface roughness of conventional and CAD/CAM processed (milled and 3D-printed) denture base materials. High-performance liquid chromatography was used to determine the quantity of residual methyl methacrylate monomer leaching after 30 days of immersion in acidic saliva. The surface roughness (Ra) before and after incubation was recorded using a non-contact optical profilometer. The monomer leaching and the surface roughness of the tested materials depended on the pH value of the saliva. The conventional denture framework material exhibited the highest and lowest leaching rates at pH=4.5 and pH=3.5, respectively, regardless of the treatment method. Among the CAD/CAM processed materials, the 3D-printed material showed the highest and lowest leaching at pH=5.5 and pH=3.5, respectively. Regardless of the pH, roughness after incubation was the lowest for conventional materials, and the highest for 3D printing.

PL

W pracy oceniono wpływ pH śliny na wymywanie monomerów i chropowatość powierzchni konwencjonalnych oraz wytworzonych metodą CAD/CAM (frezowanych i wydrukowanych w 3D) materiałów na podbudowy protez dentystycznych. Metodą wysokosprawnej chromatografii cieczowej oznaczono ilość wymytego monomeru (metakrylan metylu) po 30-dniowym zanurzaniu w kwaśnej ślinie. Chropowatość powierzchni (Ra) przed i po inkubacji rejestrowano za pomocą bezkontaktowego profilometru optycznego. Wymywanie monomerów oraz chropowatość powierzchni badanych materiałów zależały od wartości pH śliny. Konwencjonalny materiał na podbudowę protezy wykazywał największy i najmniejszy stopień wymywania odpowiednio przy pH=4,5 i pH=3,5, niezależnie od sposobu obróbki. Spośród materiałów poddanych obróbce CAD/CAM, materiał drukowany wykazał największe i najmniejsze wymywanie przy odpowiednio pH=5,5 i pH=3,5. Niezależnie od pH, chropowatość po inkubacji była najmniejsza w przypadku materiałów konwencjonalnych, a największa otrzymanych metodą druku 3D.

12

Multi-technique characterisation of InAs-on-GaAs wafers with circular defect pattern

Boguski Jacek, Wróbel Jarosław, Złotnik Sebastian, Budner Bogusław, Liszewska Malwina, Kubiszyn Łukasz, Michałowski Paweł P., Ciura Łukasz, Moszczyński Paweł, Odrzywolski Sebastian, Jankiewicz Bartłomiej, Wróbel Jerzy

Opto-Electronics Review

|

2023

|

Vol. 31, Special Issue

art. no. e144564

EN

The article presents the results of diameter mapping for circular-symmetric disturbance of homogeneity of epitaxially grown InAs (100) layers on GaAs substrates. The set of acceptors (beryllium) doped InAs epilayers was studied in order to evaluate the impact of Be doping on the 2-inch InAs-on-GaAs wafers quality. During the initial identification of size and shape of the circular pattern, non-destructive optical techniques were used, showing a 100% difference in average roughness between the wafer centre and its outer part. On the other hand, no volumetric (bulk) differences are detectable using Raman spectroscopy and highresolution X-ray diffraction. The correlation between Be doping level and circular defect pattern surface area has been found.

13

Cost-effective titania layers over 100 nm thick : effect of annealing on the structural, morphological, and optical properties

Zięba Magdalena, Tyszkiewicz Cuma, Gondek Ewa, Wojtasik Katarzyna, Nizioł Jacek, Dorosz Dominik, Starzyk Bartłomiej, Szymczak Patryk, Pakieła Wojciech, Rogoziński Roman, Karasiński Paweł

Opto-Electronics Review

|

2023

|

Vol. 31, No. 4

art. no. e147913

EN

Titania dioxide (TiO₂) layers were synthesized via the acid-catalysed sol-gel route using titania (IV) ethoxide, and then annealed at temperatures varying in the range of 150-700 °C. The research concerned the effect of annealing temperature on the structure of TiO₂ layers, their surface morphology, and their optical properties. Further, X-ray diffractometry, and Raman spectroscopy were used to determine the structure of TiO₂ layers. Scanning electron and atomic force microscopy were used to study the surface morphology of TiO₂ layers. Transmittance, reflectance, absorption edge, and optical homogeneity were investigated by UV-VIS spectrophotometry, while the refractive index and thicknesses of TiO₂ layers were measured using a monochromatic ellipsometer. Chromatic dispersion characteristics of the complex refractive index were determined using spectroscopic ellipsometry. Structural studies have shown that the TiO₂ layers annealed at temperatures up to 300 °C are amorphous, while those annealed at temperatures exceeding 300 °C are polycrystalline containing only anatase nanocrystals with sizes increasing from 6 to 20 nm with the increase of the annealing temperature. Investigations on the surface morphology of TiO₂ layers have shown that the surface roughness increases with the increase in annealing temperature. Spectrophotometric investigations have shown that TiO₂ layers are homogeneous and the width of the indirect optical band gap varies with annealing temperature from 3.53 eV to 3.73 eV.

14

Visual detection of milling surface roughness based on improved YOLOV5

Lv Xiao, Yi Huaian, Fang Runji, Ai Shuhua, Lu Enhui

Metrology and Measurement Systems

|

2023

|

Vol. 30, nr 3

531--548

EN

Workpiece surface roughness measurement based on traditional machine vision technology faces numerous problems such as complex index design, poor robustness of the lighting environment, and slow detection speed, which make it unsuitable for industrial production. To address these problems, this paper proposes an improved YOLOv5 method for milling surface roughness detection. This method can automatically extract image features and possesses higher robustness in lighting environments and faster detection speed. We have effectively improved the detection accuracy of the model for workpieces located at different positions by introducing Coordinate Attention (CA). The experimental results demonstrate that this study’s improved model achieves accurate surface roughness detection for moving workpieces in an environment with light intensity ranging from 592 to 1060 lux. The average precision of the model on the test set reaches 97.3%, and the detection speed reaches 36 frames per second.

15

Simulation of the influence of cutting speed and feed rate on tool life in hard turning of AISI 4140 steel

Paengchit Phacharadit, Saikaew Charnnarong

Materials Science Poland

|

2023

|

Vol. 41, No. 2

311--324

EN

Tool life performances of Al2O3+TiC and TiN+AlCrN tool inserts were investigated experimentally under different cutting conditions in turning AISI 4140 steel. The tool life model is defined in accordance with a maximum surface roughness of 0.8 μm for the tool life criterion. The relationships between machining factors (i.e., cutting speed and feed rate) and tool life were obtained by Taylor’s formular. The sensitivity of cutting speed and feed rate to tool life was evaluated by Monte Carlo simulation. The results showed that turning with high cutting speeds and feed rates decreased the tool life of both inserts. At different cutting speeds and feed rates, Al2O3+TiC exhibited better tool life performance than TiN+AlCrN. In addition, the simulation results indicated the average tool life of Al2O3+TiC was approximately 40% greater than that of TiN+AlCrN by varying cutting speeds below and above the cutting speed of 220 m/min while keeping the feed rate constant at 0.06 mm/rev. Similarly, when keeping the cutting speed constant at 220 m/min, the average tool life of Al2O3+TiC was approximately 45% greater than that of TiN+AlCrN by varying feed rates below and above the feed rate of 0.06 mm/rev. Variations of tool life values by varying cutting speeds were more sensitive than those by varying feed rates for both tool inserts.

16

Surface roughness investigation through interplay of cutting speed and thermal-assisted machining in high-speed machining of SKD11 steel

Bui Long-Vinh, Mac Thi-Bich, Nguyen Duc-Toan

Journal of Machine Engineering

|

2023

|

Vol. 23, No. 4

33--42

EN

This study aims to investigate the interplay between cutting speed and Thermal-Assisted Machining (TAM) concerning surface roughness during the high-speed machining of SKD11 steel. The integration of pre-cutting workpiece heating introduces a temperature factor that intricately affects surface roughness. The primary objective is to ascertain optimal speed and temperature ranges that synergistically enhance machining efficiency, curtail costs, and elevate surface quality. The experimental protocol initiates with room temperature milling of SKD11 steel, progressively elevating the temperature gradient to systematically appraise temperature's impact on surface roughness under both conventional and elevated cutting speeds. Subsequent experimentation, conducted within specific temperature thresholds, entails stepwise augmentation of cutting speed to elucidate the influence of high-speed conditions on surface roughness. The ensuing analysis meticulously examines the ramifications of distinct cutting speed intervals on surface roughness. Ultimately, the study furnishes pragmatic recommendations for judiciously selecting cutting speeds and heating temperature parameters across diverse machining scenarios.

17

Multi-objective optimization of the rotary turning of hardened mold steel for energy saving and surface roughness improvements

Doan Tat Khoa, Nguyen Trung Thanh, Van An-Le

Journal of Machine Engineering

|

2023

|

Vol. 23, No. 4

101--121

EN

In this investigation, the specific cutting energy (SCE) and average surface roughness (Ra) were decreased using the hard-rotary turning (HRT) factors, including the inclined angle (I), depth of cut (D), feed rate (f), and spindle speed (S). The Bayesian regularized feed-forward neural network was applied to develop the SCE and Ra models. The entropy method and vibration and communication particle swarm optimization (VCPSO) algorithm were employed to compute the weights and determine optimal factors. The optimizing outcomes presented that the optimal I, D, f, and S were 35 deg., 0.45 mm, 0.50 mm/rev., and 1200 rpm, respectively, while the SCE and Ra were decreased by 37.4% and 6.6%, respectively. The total turning cost was saved by 7.5% at the selected solution. The valuable outcomes could be applied to the practical HRT process to decrease performance measures, while the developed HRT operation could be utilized for machining difficult-to-cut materials.

18

Analysing the impact of cutting force and vibration on surface roughness in external cylindrical grinding of SKH2 steel

Hoang Long, Nguyen Linh Tuan

Journal of Machine Engineering

|

2023

|

Vol. 23, No. 3

130--140

EN

The surface roughness of a part during external cylindrical grinding is directly impacted by cutting force and vibration, which are intermediate parameters. To improve the quality of finished parts, studying and controlling these parameters is essential. In this research, the Taguchi method combined with ANOVA analysis was utilized to analyse the effects of feed rate, cutting depth, and rotational speeds on cutting force and vibration amplitude. The test material used was SKH2 steel, which was heat-treated to a hardness of 60 HRC. The research aimed to investigate the relationship between cutting force, vibration, and surface roughness. The study concludes with an analysis of the influence of cutting force and vibration on the surface roughness of parts during external cylindrical grinding. The results show that as cutting force and vibration increase, the surface roughness of the workpiece in external grinding will also increase, and conversely when cutting force and vibration decrease, the surface roughness will decrease.

19

A comprehensive review of polymer materials and selective laser sintering technology for 3D printing

Jabri F. E., Ouballouch A., Lasri L., Alaiji R. El

Journal of Achievements in Materials and Manufacturing Engineering

|

2023

|

Vol. 118, nr 1

5--17

EN

Purpose This review analyses different approaches used to study selective laser sintering (SLS) technology of polymer materials. These main approaches concern: thermal behaviour, fatigue and surface roughness. Design/methodology/approach Regarding the first behaviour, researchers extensively studied the impact of process parameters, including scan speed, laser, power and laser energy density, on the thermal behaviour of 3D printed parts. Numerical and experimental analyses are used to conduct process parameter evaluations. Findings Laser power and scan speed are the most significant parameters of the laser energy density. For the second, according to test protocols and quantitative analysis performed, the authors concluded that the combination of small and large laser energy density particles generates higher sintering and better fatigue resistance. Moreover, tensile analysis in different environments showed that testing in the water decreased the fatigue life of polymer samples. The influence of process parameters on the mechanical properties and surface roughness of 3D parts is also analysed. In addition, the investigators found that the additives increase the surface roughness of 3D printed parts. Practical implications This review shows that researchers can focus on creating a combination of these approaches to expand the use of this process for industrial part production. Originality/value All these investigations have made it possible to determine the optimal process conditions to ensure higher quality, optimal surface quality and better fatigue strength.

20

Influence of EDM process parameters of novel Al7010/B4C/BN hybrid metal matrix nanocomposite

Dirisenapu Gopichand, Salavaravu Laxmanaraju, Dumpala Lingaraju

Composites Theory and Practice

|

2023

|

R. 23, nr 4

191--196

EN

In this present research work, the electrical discharge machining (EDM) characteristics of an Al7010/2%B4C/2%BN (the reinforcement particles are taken as wt.%) hybrid metal matrix nanocomposite (HMMNC) are discussed. The effect of the EDM process variables like the discharge current (I), pulse on time (Pon), pulse off time (Poff) and gap voltage (Vg) on the response characteristics like the material removal rate (MRR), tool wear rate (TWR), and surface roughness (SR) are presented. The results revealed that the MRR, TWR, and SR grew with an increase in Ip and Pon. MRR, TWR, and SR increased with a rise in Poff up to 25 μs then declined. MRR, TWR, and SR decreased with an increment in gap voltage. The highest MRR was observed for a discharge current of 8 A, Pon of 60 μs, Poff of 25 μs and Vg of 30 V. SR and TWR were the smallest at Ip of 2 A, Pon of 15 μs, Poff of 55 μs and Vg of 60 V. The scanning electron microscope (SEM) micrographs of the machined surfaces revealed voids, craters and micro cracks.