Effect of the Cutting Edge Radius and its Manufacturing Procedure, on the Milling Performance of PVD Coated Cemented Carbide Inserts (original) (raw)
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Surface and Coatings Technology, 2003
The fatigue and wear behavior of PVD coatings on cemented carbide substrates in milling are investigated experimentally and Ž . analytically through Finite Elements Method FEM simulation of the cutting process. Cutting inserts with different cutting edge radii and at various feedrates were examined. The initiation and progress of the tool failure is depicted through Scanning Ž . Electron Microscopy SEM and Energy Dispersive X-ray microspectral investigations of the used cutting edges. The FEM simulation of the contact between the tool and the workpiece enables a quantitative description of the influence of mechanical stress components on the coating fatigue failure. Hereby critical coating fatigue stresses determined by means of the impact test were considered. The experimental and computational results exhibit quantitatively the effect of tool radius and feed rate on the coating fatigue failure as well as on the overall cutting performance for various substrates and film structures. In order to utilize the superior characteristics of coatings towards improving the cutting performance, it is highly recommended to optimize the cutting insert wedge radius, as well as the cutting conditions. Herewith a premature coating failure and a consequent rapid wear development can be prevented. ᮊ
Surface & Coatings Technology, 2004
The film deposition conditions on individual specimens in the vacuum chamber during a physical vapour deposition coating procedure cannot be considered as constant. Depending among others on the magnetic field distribution in the vacuum chamber as well as on the specimen fixture geometry and kinematics, the coating hardness and mechanical properties may vary. In order to investigate the effect of coating hardness and strength on the cutting performance in milling, (Ti Al )N films having thickness 46 54 from 3 to 10 mm and varying hardness were deposited on cemented carbides inserts. The coating material properties and especially their stress-strain laws were determined from the nanoindentation measurement results using a finite elements method (FEM) based evaluation procedure. The initiation and progress of the coating and tool wear in milling were studied using scanning electron microscopy and energy dispersive X-ray spectroscopy. The investigations revealed that as the coating grows thicker, its superficial hardness and strength decreases. For the thick coatings, however, this does not affect the cutting performance as much as for the thin coatings. In the case of thin coatings, a corresponding decrease of the film hardness and strength, diminishes significantly the cutting performance. A FEM simulation of the cutting process, whereas the coating mechanical properties vs. the film thickness are considered, elucidates the aforementioned results. ᮊ
WEAR OF PVD COATED TOOLS IN MILLING AFFECTED BY THE GRAIN SIZE OF CEMENTED CARBIDE SUBSTRATES
To explain the coating and substrate wear behaviour, when applying cemented car- bide (HM) tools with different grain sizes in milling, two variations of HM inserts, a fine- and an ultra-fine-grained one were coated with the same PVD AlTiN film. These inserts were examined by nanoindentations and impact tests concerning me- chanical properties and by milling experiments regarding wear. The investigations revealed an enhanced cutting performance of the less hard and more ductile fine- grained substrate compared to the ultra-fine-grained one. In turn, the coating depos- ited on the ultra-fine-grained insert showed increased mechanical properties and impact resistance, compared to the corresponding one deposited on the fine-grained substrate. Moreover, an improved cutting performance was obtained in the latter case at a width of flank wear land less than 0.1 mm. At greater flank wear values, the fine-grained substrate withstands more effective the cutting loads, due to its bet- ter duc...
EFFECT OF THE CUTTING EDGE SHAPE ON THE PERFORMANCE OF COATED CEMENTED CARBIDED INSERTS
In the present paper, the effect of the coated cutting edge shape on the tool milling performance is described. According to the actual cutting edge profile, three groups of coated cemented carbides inserts with an AlTiN PVD film without treatment (as dep.) as well as with slight (S.G.) or intensive (I.G.) cutting edge rounding were ex- amined. The cutting edge geometry was determined by confocal white light scan- ning, while the film thickness on the tool flank and rake were registered, by micro cratering tests combined with confocal measurements. The impact resistance and corresponding fatigue properties versus the impact temperature were detected by impact tests. The cutting performance of the inserts of the various groups, was in- vestigated in peripheral milling, of hardened steel 42CrMo4 QT. The obtained re- sults were explained by FEM calculations of the material removal process enabling the determination of the developed stresses and temperature distributions in the cut- tin...
Surface and Coatings Technology, 2006
In this work, we investigated the feasibility of increasing the cutting performance of coated tools through the application of multilayered PVD film structures. A monolayer TiAlN and a multilayer TiN/TiAlN coating of the same overall thickness deposited on K35 cemented carbide inserts, were investigated concerning their mechanical, adhesion properties and wear behavior in milling operations. The mechanical properties of both applied films were determined with the aid of nanoindentations and then the evaluation of the corresponding results by appropriate FEM supported algorithms. Impact tests were also conducted to determine film fatigue and adhesion data and the film failure development after the coating fracture initiation. Based on a FEM simulation and on experimental results, the stress field in the cutting wedge region was calculated and the wear initiation and propagation in the investigated mono and multilayer coating cases was explained.
2005
This paper investigates the feasibility of increasing the wear resistance of cemented carbide tools through micro-blasting of their PVD coatings. The enhanced and graded film strength properties before and after micro-blasting are determined by means of an FEM-based evaluation of nanoindentation results. The coating topomorphy induced by micro-blasting was monitored and correlated to the substrate roughness and film adhesion. The cutting performance of inserts coated with micro-blasted films was investigated in milling and explained with the aid of a cutting process FEM simulation. The obtained results reveal a tool life growth through micro-blasting of coatings, deposited on substrates with appropriate roughness characteristics. D
Surface and Coatings Technology, 2001
The wear behavior of coated cemented carbides (HM) inserts with various substrate and coating surface mechanical treatments were investigated experimentally in milling and analytically through a finite-elements method (FEM) simulation of the cutting process. The treatments carried out were polishing and micro-and glass-blasting at various pressures. The initiation and progress of the tool failure was depicted through scanning electron microscopy (SEM) and energy-dispersive X-ray microspectral investigations of the cutting edges used. Furthermore, FEM simulation of the contact between the tool and the workpiece enabled the development of a quantitative description of the influence of the substrate and coating surface roughness on the mechanical stresses occurring, and thus on fatigue-induced coating failure and wear. The coating stress-strain curves and their fatigue endurance were determined through FEM-supported nanoindentation measurements and impact test result evaluations, respectively. In all FEM calculations conducted, multilinear constitutive laws were applied for modeling the coating and the substrate. The experimental and computational results obtained quantitatively exhibit the influence of the substrate, as well as of the coating surface treatments, on the cutting performance of the HM insert. ᮊ
Increasing tool life by adjusting the milling cutting conditions according to PVD films’ properties
CIRP Annals - Manufacturing Technology, 2008
The coated tools cutting performance in up and down milling depends significantly on the PVD film material properties. The related wear mechanisms at various cutting speeds can be sufficiently explained considering the developed tool loads and the non-linear coating impact resistance versus temperature. Various PVD coated cemented carbide inserts were tested at different cutting conditions. The corresponding cutting loads and temperatures were determined by FEM simulations and the films' impact resistance by impact tests. A correlation between the impact resistance and the cutting performance at corresponding temperatures contributed to the optimum adjustment of the cutting parameters to the film properties.
Face milling of the EN AB-43300 aluminum alloy by PVD- and CVD-coated cemented carbide inserts
International Journal of Refractory Metals and Hard Materials, 2011
Two commercially available WC-6Co cemented carbide substrates (Extramet EMT100 and Pramet H10), were industrially coated with PVD TiB 2 or CVD diamond. Subsequently, the coated inserts were submitted to dry sliding tests (slider on cylinder contact geometry) against the aluminum alloy EN AB-43300, for preliminary performance ranking and identification of basic wear mechanisms. The best substrate/coating combination (CVD-Diamond coated Extramet EMT100) was then tested in face milling EN AB-43300 with milling tool characterized by two different geometries (A and B), using PCD inserts as a reference for comparison. In milling tests, the influence of both insert geometry and cutting fluid feed rate were taken into account. The geometry of the tool was identified as the main parameter in influencing the tool performance. In particular, in the case of the A geometry, the relative flank wear of CVD coated tools increased abruptly during the test due coating detachment, whilst with the B geometry no catastrophic failure of the CVD coated insert was observed. The influence of Cutting Fluid Feed Rate (CFFR) also changed with tool geometry: in particular, with the B geometry, which allowed to obtain the best results with the CVD coated inserts, a decrease of CFFR from 100 to 25% did not affect significantly the wear resistance of CVD-coated inserts and allowed to maintain the roughness of the workpiece (R a ) below 0.6 μm, notwithstanding a slightly increased tendency towards the formation of Al-based transfer layers.
Tehnicki vjesnik - Technical Gazette, 2018
The goal of the submitted paper is to evaluate the dependence of tool life T = f(v c) in hard rough face milling process of the Armox 500 steel through the PVD coated cemented carbide cutting material with SNHF 1204EN-SR-M1 tool insert geometry. Practical tests of choice material were performed in the milling machine tool with vertical axis. The effect of applied cutting conditions on the surface finish, tool life, wear of cutting tool, such as flank wear and surface structure of applied cutting inserts, was investigated during the performed experiments. The goal of this article is to research the impact of various cutting speeds values during the process of hard face rough milling. Experiments are carried out with an aim to study tool life, surface finish and flank wear prediction on the PVD coated cemented carbide cutting material in hard milling processes. This has been observed through the REM and mathematical method of least squares for this characterization. The presented approach and acquired results will prove themselves helpful in understanding the machinability of Armox 500 steel during the hard milling process.