Příspěvek k soustružení slitiny na bázi Ni nástrojem z řezné keramiky

This article deals with dry turning of nickel superalloy - Inconel 718. The different ceramic inserts were applied for cutting process. These inserts were produced by Greenleaf Corporation company. This paper discusses durability of cutting inserts, the different intensity of tool wear at various cutting parameters. The most suitable cutting conditions are chosen in the scope of applied tools.Příspěvek se zabývá suchým soustružením niklové slitiny – Inconel 718, při němž byly aplikovány vyměnitelné destičky Z řezné keramiky Z produkce firmy Greenleaf Corporation. V článku je provedena diskuse trvanlivosti těchto destiček, související S rozdílným opotřebením nástroje při různých řezných podmínkách. Jsou vyhodnoceny nejlepší řezné podmínky a doporučeny pro praktickou aplikaci

The influence of surface treatment of PVD coating on its quality and wear resistant

The article deals with a determination of the influence of a cutting edge preparation on the quality and wear resistance of coated cutting tools. Cutting inserts made from a sintered carbide with a deposited layer of PVD coating were selected for measurement. Non-homogeneity caused by the creation of droplets arises in the application layer during the process of applying the coating by the PVD method. These droplets make the surface roughness of the PVD coating worse, increase the friction and thereby the thermal load of the cutting tool as well. Also, the droplets could be the cause of the creation and propagation of droplets in the coating and they can cause quick cutting tool wear during machining. Cutting edge preparations were suggested for the improvement of the surface integrity of deposited layers of PVD coating, namely the technology of drag finishing and abrasive jet machining. After their application, the areal surface roughness was measured on the surface of coated cutting inserts, the occurrence of droplets was tracked and the surface structure was explored. A tool-life test of cutting inserts was carried out for verification of the influence of surface treatment on the wear resistance of cutting inserts during the milling process. The cutting inserts with a layer of PVD coatings termed as samples A, B, and C were used for the tool-life test. The first sample, A, represented the coating before the application of cutting edge preparations and samples B and C were after the application of the cutting edge preparation. A carbon steel termed C45 was used for the milling process and cutting conditions were suggested. The visual control of surface of cutting inserts, intensity of wear and occurrence of thermal cracks in deposited PVD layers were the criterion for the evaluation of the individual tests.Web of Science97art. no. 43

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

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

Optimization coating of cylindrical tools with fixture for increasing machine capacity

The coating technology is integral part of industrial production. In the tooling field, coating is an essential part. For the vast majority of tooling materials today, a coating that has abrasion resistance, high hardness, high temperature stability, as well as overall wear resistance of the cutting edge is a matter of course and necessity. However, coating machines are designed for a maximum predetermined number of tools. It would be possible to increase the capacity of the coating machine by means of a jig designed specifically for the given machine with given kinematics. The topic of this article is the design of the jig for increasing the capacity of the coating PVD machine. The main part is the design and construction of the jig, where the construction of the movement system is described. Then follows the design of the material and description of the main principle operation of the product. The jig will be designed for coating cylindrical tools, the monolithic milling cutters and drills made mostly of cemented carbide. When coating such tools with the PVD method, care must be taken to avoid so-called "shadow effects". This fact must also be reflected in the design of the fixture. Increasing the capacity of the PVD of the machine will lead to an increase in the production batch and thus an increase in profit.Web of Science20203845384

Heat distribution when nickel alloy grinding

Stvaranje i razdioba topline tijekom obrade odvajanjem čestica jedna je od fenomenoloških karakteristika tih postupaka, koja znatno utječe na funkcionalnost obrađenih površina. Rad se bavi proučavanjem distribucije topline tijekom brušenja nikaljnih legura i njenim utjecajem na kvalitetu brušenih površina uslijed pojave napetosti (zaostalih naprezanja). Analiza razdiobe topline temelji se na mjerenju kontaktnih temperatura između brusnog kotača i obradka te tangencijalne komponente sile rezanja. Razdioba topline tijekom brušenja nikaljnih legura različita je od one tijekom brušenja uobičajenih željeznih legura, primjerice čelika za kotrljajuće ležajeve, prvenstveno zbog njihove niže toplinske provodnosti. Također, uporaba bor-nitridnih (CBN) i dijamantnih bruseva značajno smanjuje toplinska opterećenja obradaka, prvenstveno uz uporabu rashladnih fluida. Ta činjenica znatno utječe na pojavu napetosti nakon brušenja. Rezultati analize pokazuju da postoji povezanost između razdiobe toplinske energije i napetosti.Heat distribution in machining is one of the phenomenological characteristics of this process because it significantly influences functional properties of machined surfaces. This paper deals with heat distribution during grinding of Ni alloy and its relationship to the quality of ground parts in terms of residual stresses. The analysis of the heat distribution is based on measurement of the temperature in the contact of the grinding wheel and the workpiece, and the tangential component of cutting force. The heat distribution when Ni alloy grinding differs from the heat distribution when grinding a conventional Fe alloy such as roll bearing steel mainly because of the low heat conductivity of Ni alloys. Also, the application of CBN and diamond grinding wheels significantly reduce the thermal exposition of the ground parts, primarily when applying cutting fluid. This fact significantly influences the residual stresses after grinding. The results of the analysis show that there is correlation between energy partitioning and residual stresses

High-efficiency of PVD coating process by applying an additional rotation

This article analyzes PVD coatings (physical vapor deposition-the coating material is vaporized and deposited by sputtering or arc evaporation, and PVD coatings are applied at lower substrate temperatures and thus can be applied to a wider range of substrates) applied to samples which are located in a fixture. This fixture enables additional rotation of the sample via the coating process. The fixture allows an increase of coated tools in one batch, and therefore an increase of the current capacity of the coating machine. The introductory section of the article describes the process of product design, including its modifications. The experimental section is focused on the functionality checking of the proposed design. The coating process was carried out on a machine named INNOVA. To guarantee the correct coating application during the process, it is necessary to research the coating thickness and the chemical composition of the samples and compare these results with the results of samples which were coated without using a designed fixture. Round bars with a diameter of 10 mm were chosen as test samples. On these samples, a FUTURA monolayer was applied on a TiAlN base. Chemical composition and coating thickness were evaluated using a scanning electron microscope (SEM). Using a fixture with a fourth rotation, the same chemical composition and coating thickness were achieved as those samples which were coated in a process without the use of a fourth rotation. Therefore, it was possible to confirm a capacity increase of the coating machine.Web of Science126art. no. 83

Deformations after heat treatment and their influence on cutting process

Ovaj se članak bavi utjecajem toplinske obrade na deformacije dijelova i strojnom obradom koja slijedi. Režim toplinske obrade znatno utječe na takva gledišta materijala kao što je struktura, tvrdoća i inducirano naprezanje. Različit proces toplinske obrade rezultira različitim deformacijama dijelova i promjenama s obzirom na njihove dimenzije. Sva su ova gledišta povezana s uzastopnim operacijama rezanja, kao što je brušenje ili grubo tokarenje, njihovom stabilnosti, preciznosti proizvedenih dijelova, itd. Deformacija dijelova također je povezana sa strukturom materijala prije toplinske obrade, postavljanjem u peći, režimom toplinske obrade i raspodjelom naprezanja oko dijelova. Rezultati ovog eksperimentalnog istraživanja prikazani u ovom članku pokazuju povezanost između različitih režima toplinske obrade i obrade dijelova koja slijedi.This paper deals with the influence of heat treatment on the deformation of parts and the following machining process. The regime of heat treatment significantly affects such aspects of material as structure, hardness and induced stress. Different process of heat treatment results in different deformation of parts and changes considering their dimensions. All these aspects are connected with the consecutive cutting operations such as grinding or hard turning, their stability, precision of produced parts, etc. Deformation of parts is also connected with the structure of material before heat treatment, placement in the furnace, regime of heat treatment and stress distribution around the parts. The results of the experimental study presented in this paper illustrate the connection between different heat treatment regimes and the following processing of parts