Surface microhardening studies on steels after high feed milling

The paper deals with the impact of high-speed machining production methods on the integrity of component surfaces. One has to point out that cutting conditions during machining have a significant impact on the final properties of surface and subsurface layers of the workpiece. The conclusion summarizes and analyzes the achieved results of experimental activities on stainless austenitic steel 1.4301, hardened tool steel 1.2343 and high-speed steel 1.3344 (ASP 2023). The results of the work experimental parts demonstrate the influence of cutting parameters on selected surface integrity ones, specifically strengthening the surface and subsurface layers. The performed experiments show that microhardness of a surface layer of the machined material can be influenced by suitable cutting conditions and other cutting process parameters.Web of Science12223022

Checking the Geometric Accuracy of a Machine Tool for Selected Geometric Parameters

This paper deals with the control parameters for selected geometric accuracy measurements for a machine tool. The parameters were needed after a refurbished milling machine was purchased. After setting up the machine, it was necessary to check the geometric accuracy that can be used for precise milling. The whole check was performed in accordance with ISO 10791. Only selected parameters of geometric accuracy were inspected, and they were later compared with the prescribed values. On the basis of a comparison of these values we were able to determine whether the machine tool can be used for accurate machining

Návrh 3D montážního postupu zdvihacích plošin

The contribution is dealing with semi-automatic assembly process of elevated platforms. At the beginning of the work dealing with general problems of assembly then focusing on specific assembly. It is also an analysis of the current assembly process. Based on the current process was developed a new proposal assembly. The last step is carried out technical - economic evaluation. That contribution is based on form a completed assembly at company Pars Komponenty s.r.o.Příspěvek se zabývá návrhem montážního postupu poloautomatické zdvihací plošiny. V úvodu se práce zabývá obecnou problematikou montáže, dále pak zaměřením se na konkrétní montáž. Dále je proveden rozbor stávajícího postupu montáže. Na základě současného postupu byl vypracován nový návrh montáže. Jako poslední krok se provedlo technicko – ekonomické zhodnocení. Tento článek vychází Z realizované montáže ve společnosti Pars Komponenty s.r.o

Svojstva i usporedba PVD slojeva premaza

Development and application of new materials in mechanical engineering practice create a lot of questions concerning their technological application. This paper focuses on research problems related to the PVD coated cemented carbide. The theoretical part of the paper informs about principle of PVD coating technology and describes the arc evaporation method used for coating in greater detail. It also deals with coating materials and types, their properties, possible applications and finally principles of the experimental methods used for coatings testing are explained. In the experimental part of the paper, the measuring and testing procedures are described and the test results are listed. Adhesion and layer durability were compared by cutting inserts with different PVD – nanostructure and nanolayer coatings. The tests were carried out by milling of carbon engineering steel 1.1191 (C45), because this steel is widely used in many industrial applications and it is used as reference material too. In conclusion the testing results are evaluated on the basis of obtained information.Razvoj i primjena novih materijala u strojarskoj praksi dovode do mnoštva pitanja u odnosu na njihovu tehnološku primjenu. Ovaj je rad usmjeren na istraživanje problema povezanih s cementiranim karbidom premazanim primjenom PVD (Physical Vapour Deposition) metode. U teorijskom dijelu rada upoznaje se PVD tehnologija nanošenja sloja i detaljnije opisuje metoda isparavanja luka. Opisuju se također materijali i vrste slojeva, njihova svojstva, moguće primjene i na kraju objašnjavaju načela eksperimentalnih metoda primijenjenih u ispitivanju slojeva. U eksperimentalnom dijelu rada opisuju se postupci mjerenja i ispitivanja te daju rezultati ispitivanja. Adhezija i trajnost slojeva uspoređeni su na izrezanim umetcima s različitim PVD – premazi s nanostrukturom i nanoslojem. Ispitivanja su provedena glodanjem ugljičnog čelika 1.1191 (C45) budući da se taj čelik uvelike rabi u mnogim industrijskim primjenama, a također i kao referentni material. Na kraju se ocjenjuju rezultati ispitivanja na temelju dobivenih podataka.Web of Science23257456

Influence of cutting speed on intensity of the plastic deformation during hard cutting

The paper deals with an analysis of deformation processes and the aspects related to a chip formation such as the chip thickness, the chip ratio, the shear angle and the chip segmentation during turning the hardened steel 100Cr6. This paper investigates the influence of the cutting speed through a metallographic analysis, a calculation of significant aspects of deformation processes and the resulting experimental study. This experimental study is based on an application of acoustic emission. The results of this study indicate that the cutting speed significantly affects the parameters such as the chip ratio, deformation angle or the speeds in the cutting zone. On the other hand, the experimental study allows an analysis of the specific characters of deformation processes and their real intensity.Web of Science47675574

Preiskava vpliva hitrosti rezanja na zdržljivost vložka za rezanje pri rezanju jekla DIN 1.4301

The main aim of this paper is to assess the tool life T = f(vc) during the dry turning of 1.4301 austenitic stainless steel with a CNMG 120408 coated carbide cutting insert. Experimental tests of the selected material were realized in an Aero Turn BT-380 CNC machine tool with a Fanuc 21i TB control system. The effect of the applied cutting parameters on the surface finish, tool wear, tool life and surface roughness were investigated during the realized experiments. The aim of the present paper is to focus scientific research on the impact of the various cutting speeds during the outer longitudinal turning. The presented approach and results will be helpful for understanding the machinability of 1.4301 austenitic stainless steel during dry turning. This paper, together with the achieved results, is a basis to optimize the performance of the machining (i.e., turning) of austenitic stainless steel 1.4301 used for special industrial applications with their dominant functional areas.Glavni namen članka je oceniti preiskovano zdržljivost orodja T = f(vc) pri struženju, brez mazanja avstenitnega nerjavnega jekla 1.4301, s karbidnim rezalnim vložkom CNMG 120408 s prevleko. Preizkusi izbranega materiala so bili izvršeni na CNC stroju Aero Turn BT-380 s Fanuc 21i TB kontrolnim sistemom. Med preizkusi je bil preiskovan vpliv uporabljenih parametrov pri rezanju na kvaliteto površine, obrabo orodja, zdržljivost orodja in hrapavost. Namen članka je usmeriti raziskavo na vpliv različnih uporabljenih vrednosti hitrosti rezanja pri zunanjem vzdolžnem struženju. Vsi predstavljeni približki in rezultati bodo pomagali pri razumevanju obdelovalnosti avstenitnega nerjavnega jekla 1.4301 pri struženju brez mazanja. Dobljeni rezultati so osnova za optimiranje struženja avstenitnega nerjavnega jekla 1.4301, ki se ga, na podlagi posebnih lastnosti, uporablja pri posebnih industrijskih namenih.Web of Science50344543

Properties and comparison of PVD coatings

Razvoj i primjena novih materijala u strojarskoj praksi dovode do mnoštva pitanja u odnosu na njihovu tehnološku primjenu. Ovaj je rad usmjeren na istraživanje problema povezanih s cementiranim karbidom premazanim primjenom PVD (Physical Vapour Deposition) metode. U teorijskom dijelu rada upoznaje se PVD tehnologija nanošenja sloja i detaljnije opisuje metoda isparavanja luka. Opisuju se također materijali i vrste slojeva, njihova svojstva, moguće primjene i na kraju objašnjavaju načela eksperimentalnih metoda primijenjenih u ispitivanju slojeva. U eksperimentalnom dijelu rada opisuju se postupci mjerenja i ispitivanja te daju rezultati ispitivanja. Adhezija i trajnost slojeva uspoređeni su na izrezanim umetcima s različitim PVD – premazi s nanostrukturom i nanoslojem. Ispitivanja su provedena glodanjem ugljičnog čelika 1.1191 (C45) budući da se taj čelik uvelike rabi u mnogim industrijskim primjenama, a također i kao referentni material. Na kraju se ocjenjuju rezultati ispitivanja na temelju dobivenih podataka.Development and application of new materials in mechanical engineering practice create a lot of questions concerning their technological application. This paper focuses on research problems related to the PVD coated cemented carbide. The theoretical part of the paper informs about principle of PVD coating technology and describes the arc evaporation method used for coating in greater detail. It also deals with coating materials and types, their properties, possible applications and finally principles of the experimental methods used for coatings testing are explained. In the experimental part of the paper, the measuring and testing procedures are described and the test results are listed. Adhesion and layer durability were compared by cutting inserts with different PVD – nanostructure and nanolayer coatings. The tests were carried out by milling of carbon engineering steel 1.1191 (C45), because this steel is widely used in many industrial applications and it is used as reference material too. In conclusion the testing results are evaluated on the basis of obtained information

Use of Convolutional Neural Network for Fish Species Classification

Fish population monitoring systems based on underwater video recording are becoming more popular nowadays, however, manual processing and analysis of such data can be time-consuming. Therefore, by utilizing machine learning algorithms, the data can be processed more efficiently. In this research, authors investigate the possibility of convolutional neural network (CNN) implementation for fish species classification. The dataset used in this research consists of four fish species (Plectroglyphidodon dickii, Chromis chrysura, Amphiprion clarkii, and Chaetodon lunulatus), which gives a total of 12859 fish images. For the aforementioned classification algorithm, different combinations of hyperparameters were examined as well as the impact of different activation functions on the classification performance. As a result, the best CNN classification performance was achieved when Identity activation function is applied to hidden layers, RMSprop is used as a solver with a learning rate of 0.001, and a learning rate decay of 1e-5. Accordingly, the proposed CNN model is capable of performing high-quality fish species classifications

Učinak brzine posmaka na trajnost i trošenje izmjenljivih pločica tijekom rezanja Ni-625

This paper deals with the process of cutting of nickel superalloy and selection of suitable cutting parameters for its easy and effective cutting. The experimental part proposes three exchangeable inserts and determines the effect of feed rate cutting parameter during machining on durability and wear of the cutting tool. Depending on selected cutting feed rate and the amount of wear of these exchangeable cutting inserts, the quality of turned surface is evaluated and height roughness parameters are determined. In closing we show our observations obtained while machining Inconel 625, determine the effect of feed rate on durability and wear of cutting inserts, evaluate and recommend practical steps, describe the mechanisms of cutting wedge wear, determine the durability of the tool and roughness of the turned surface.Rad se bavi postupkom rezanja super legure nikla i odabirom odgovarajućih parametara rezanja za njezino lako i učinkovito rezanja. U eksperimentalnom dijelu predlažu se tri izmjenljive pločice i određuje učinak parametra posmaka tijekom obrade na trajnost i trošenje reznog alata. Ovisno o izboru posmaka rezanja i količini trošenja tih izmjenljivih pločica, procijenjena je kvaliteta tokarene površine i određeni parametri visine hrapavosti. U završnom dijelu iznosimo opažanja do kojih smo došli tijekom obrade Inconel 625, određujemo učinak posmaka na trajnost i trošenje pločica, procjenjujemo i preporučujemo praktične korake, opisujemo mehanizme trošenja reznog klina, određujemo trajnost alata i hrapavost tokarene površine.Web of Science2416

Artificial neural network for predicting values of residuary resistance per unit weight of displacement

This paper proposes the usage of an Artificial neural network (ANN) to predict the values of the residuary resistance per unit weight of displacement from the variables describing ship’s dimensions. For this purpose, a Multilayer perceptron (MLP) regressor ANN is used, with the grid search technique being applied to determine the appropriate properties of the model. After the model training, its quality is determined using R2 value and a Bland-Altman (BA) graph which shows a majority of values predicted falling within the 95% confidence interval. The best model has four hidden layers with ten, twenty, twenty and ten nodes respectively, uses a relu activation function with a constant learning rate of 0.01 and the regularization parameter L2 value of 0.001. The achieved model shows a high regression quality, lacking precision in the higher value range due to the lack of data