Papers by Keyword: Carbide Tool

Abstract: This paper discusses the experimental study and the mechanism of chip formation, sliding and cutting in processing wood milling surface. The main objective is to determine chip thickness upon the coefficient k and tool tip radius ρ. Technically, when analysing we use FCCCD's second-order response surfaces method and analysis of variance (ANOVA) for determining the coefficient k upon the factors of milling cutter diameter D, the feeding per tooth Sz and tool tip radius ρ. According to the obtained experimental results, we determined the value domain of the machine's working factors so that the cutter tool tip can slide or cut the chip on the milled surface of tropical wood materials. From the coefficient k, we can determine the slide length L_sl which gives reason for the abrasion phenomenon of the front or rear sides of the cutter. The results allow us to choose the geometrical parameters ​​for milling cutter, apart from the working parameters for processing the surface of wood materials with the highest quality as possible.

Abstract: Comparative investigations of the effect of discrete surface hardening by standard ion-plasma technology and discrete oxidation technology on the structure and hardness of high-speed steels are carried out. It is shown that, after hardening in the ion-plasma installation on the surface and in the thickness of the layer, droplet-shaped defects, craters and bundles are formed. Metallographic studies showed that the hardened discrete oxidation layer after repeated hardening has a dense, uniform structure. It has been established that the discrete oxidation technology allows to increase the wear resistance of a complex-profile cutting tool 2 times more, compared to a tool hardened by standard ion-plasma technology after regrinding.

Abstract: In terms of machinability are titanium alloys classified in the group of difficult to cut materials. The main factors determining this status are limited tool life, high generated cutting forces (torque) and temperature in cutting zone caused by low thermal conductivity as well as chemical reactivity with cutting tool. Solid carbide drills still remain as preferred choice in hole making process when machining Ti6Al4V alloy. Besides cutting conditions, tool and cutting edge geometry significantly affect the value of torque. Reduction of process energy requirements can be achieved by appropriate optimization of these parameters. Mathematical model describing influence of cutting speed, feed rate, clearance angle and cutting edge radius on investigated variable with high reliability coefficient (R²=96.72%) was found. Drilling experiments were designed and carried out using Taguchi orthogonal array L₁₆.

Abstract: The aim of this paper is to study physical and chemical properties of nanostructured multi-layered composite coating based on three-layered architecture of Ti-TiN-(ZrNbTi)N, deposited to a carbide substrate, as well as to study the mechanism of wear and failure of carbide tools with coatings under the conditions of stationary cutting. The coating obtained by the method of filtered cathodic vacuum arc deposition (FCVAD). The microstructure of carbide cubstrate with coating on transverse cross-section were investigated, as well as its hardness, strength of the adhesive bond to the substrate, chemical composition and phase composition. The studies of cutting properties of the carbide inserts with developed coating was conducted on a lathe in longitudinal turning of steel C45 (HB 200). Analysis of mechanisms of coated tool wear and failure was carried out, as well as - the study of processes of diffusion and oxidation in the surface layers of the coated substrate.

Abstract: Thin hard coatings are widely used in the protection of cutting tools, dies and molds to prolong their wear resistance and lifetime. Superior properties of different coatings can be combined with multilayer design, and especially a higher microhardness can be obtained by nanocomposite structures. In this study, a multilayer design composing of TiAlSiN, TiSiN and TiAlN layers was applied on carbide cutting tools. The top TiAlSiN layer has a nanocomposite structure of crystalline fcc-TiAlN and amorphous Si₃N₄ phases. The multilayer nanocomposite TiAlSiN/TiSiN/TiAlN coating was deposited on the carbide cutting tool using an industrial magnetron sputtering system. Wear behavior of the coated tools was investigated in the milling of hardened AISI D2 steel (~55 HRc). The changes in tool wear and surface roughness as a function of cutting distance were recorded. Wear mechanisms and types were investigated using optical and scanning electron microscopy in combination with energy dispersive spectroscopy. It was found that the multilayer nanocomposite TiAlSiN/TiSiN/TiAlN coating provides at least 1.2 times higher wear resistance and a longer lifetime than single layer TiN and TiAlN coatings. Main wear mechanisms are abrasion and adhesion of the workpiece material on the cutting edge. As a result, wear types are notch wear and build-up-edge formation.

Abstract: In the 1960s, Opitz discovered the formation of complex oxide protective layers (Belag) on worn surfaces of tools when cutting Ca deoxidized steel. Belag formation is used in a free-cutting technique for steel and cast iron because it significantly reduces diffusional wear by preventing direct contact between the tool and work material; hence, tool life can be dramatically prolonged. For Belag to form, one condition is that the tool material should contain TiC. It has been reported that Belag adheres to tool surfaces because TiC in the tool oxidizes and reacts with Belag. Our study aims to clarify the formation and adhesion mechanisms of Belag. In this study, Ca deoxidized steel was machined with noncoated carbide P10 tools, and the state of the interface between the tool and Belag layer was investigated by transmission electron microscopy (TEM) and elemental analyses. As a result, we found that Belag directly adhered to Ti carbide (Ti–W–C) particles on tool surfaces. In contrast, Belag did not directly adhere to WC or Co on tool surfaces. Unlike previous studies, we could not confirm the formation of the TiC oxide or its oxide layer near the interface to which Belag adhered. In addition, when we machined a Ca deoxidized steel containing MnS, a CaS layer formed in Belag at the interface between the tool and Belag layer.

Abstract: There are many factors having effects on the cutting performance and useful time of cutting-tools, such as cutting-tools material, geometry parameters, structure and the optimization of cutting parameter, etc. But the condition of cutting-tools edge shouldnt be ignored. As is known to all, the micro gaps of cutting edge extend easily in the process of cutting, and accelerates the wear and damage of tools. As for the current situation of low passivation efficiency in edge, high loss of passivation and uncontrollability in blade shape, some improvements and new technology for applying to tools passivation are proposed based on the analysis and research about carbide tool passivation. Whats more, some exploration experiment will be done. The results show that those passivation technology can improve the processing efficiency of metal-cutting, cutting tool expectancy and reduce manufacturing cost.

Abstract: The problem of increasing performance of carbide too lin machining hard-to-machine materials has been studied. Composite material was developed comprising carbide with heat-resistant bond Co-Re, significantly increasing resistance of carbide to thermoplastic deformation, and nanodispersed multilayer composite coating, significantly reducing thermomechanical impact on cutting part of tool.Studies to find the performance of tool made of developed composite material in turning hardened steel40H and heat-resistant nickel alloy HN77TYUR have shown its superiority compared to commercial carbides with coatings of modern generation.Studies have found out practicability of using VRK-13 cobalt-rhenium carbides with reduced content of expensive rhenium from 9% (weight) Re to 6% (weight), and it is highly competitive by heat resistance with VRK-15 carbide and is significantly superior to it by its strength.Results of cutting properties research forultra-dispersed Re-added WC-Co-carbides with Ti-TiN-TiCrAlNnano-dispersed multilayer composite coating are presented at longitudinal turning of constructional steels and hard-to-machine alloys. It is shown that the combination of ultra-dispersedheat-resistant WC-(Co,Re)-carbides and wear-resistant Ti-TiN-TiCrAlN coatings increase cutting properties of tool in some times.

Abstract: Abstract. There is growing interest in laser machining as an alternative to abrasive processes for creating cutting tool micro geometries. This technology is also suitable for creating micro geometries on cutting edges of superhard cutting tools. The pulsed nanosecond lasers, which are commonly used for this type of application, induce a high thermal load in the tool. This heat is believed to result in tensile residual stresses at the cutting edge surface, which are generally unfavorable for cutting tool performance because of the tendency to crack formation and propagation. Different levels of compressive residual stress exist after each step (sintering, grinding, shot peening, etching and PVD-coating). From investigations of commercial processes for manufacturing PVD-coated carbide cutting tools it is known that the final residual stress state of the carbide subsurface is a result of superposition of the stress states resulting from the individual process steps. In contrast to that, a laser machining process is expected to produce tensile residual stress due to the heat input. The present work describes the influence of a process chain alteration for PVD-coated carbide cutting tools by a laser machining process on the residual stress state in the finished tools.

Abstract: This research study aimed to investigate the effect of main factors on the surface roughness in oil palm wood turning process for manufacturing furniture parts using carbide tools. The main factors, namely, cutting speed, feed rate and depth of cut were investigated for the optimum surface roughness in furniture manufacturing process. The result of preliminary trial shown that the depth of cut had no effect on surface roughness. Moreover, the experiment was found that the factors affecting a surface roughness were cutting speed and feed rate, with having tendency for reduction of roughness value at lower feed rate and greater cutting speed, Therefore in the turning process of oil palm wood, it was possible to determine a cutting condition by means of the equation R_a = 19.8-0.00742 Cutting Speed+3.98 Feed rate, This equation can be best used with limitation of cutting speed at 122-450 m/min, feed rate at 0.1-0.5 mm/rev and depth of cut does not over 1 mm,. To confirm the experiment result, a comparison between the equation value and an actual value by estimating a prediction error value was calculate with the surface roughness and margin of error does not over 10%. The experimental result reveals the mean absolute percentage error (MAPE) of the equation of surface roughness is 3.24%, which is less than the predicted error value and it is acceptable.