Cutting Edge Geometry Effect on Plastic Deformation of Titanium Alloy

The paper presents experimental studies of ОТ4 titanium alloy machining with cutting edges of various geometry parameters. Experiments were performed at a low speed by the scheme of free cutting. Intensity of plastic shear strain was set for defining of cutting edge geometry effect on machining. Images of chip formed are shown. Estimation of strain magnitude was accomplished with digital image correlation method. Effect of rake angle and cutting edge angle has been studied. Depth of deformed layer and the area of the plastic strain is determine. Results showed that increasing the angle of the cutting edge inclination results in a change the mechanism of chip formation

Estimating the cutting force when skiving with a radius cutter

The paper considers the method of determining the components of the cutting force under cutting completed with a radius cutter. The authors provide the design of the experimental study. The authors provide the data on the cutting force change in the process of turning with a radius cutter according to the cutting edge inclination, cutting depth and supply obtained experimentally and calculated analytically. The paper also provides the results of experimental work approximation and theoretical error checking related to experimental data

Experimental estimation of chip shrinkage under cup-tip cutting with straight and radius cutters

In the given work we present the results of experimental estimation of chip shrinkage under turning with straight and radius cutters for two schemes of cutting: "direct" and "reverse". Ratios of thickening, broadening and longitudinal shrinkage of the chip were established as shrinkage parameters. The given paper presents the graphic charts showing dependences of shrinkage upon cutting depth, supply and cutting edge inclination which indicate the deformations taking place in the cutting area when cutting with cup-tip cutters. The authors show the significant difference in the character and degree of chip shrinkage when working according to various schemes of cutting

Experimental Study of Sliding Friction for PET Track Membranes

The article is presented results of a study of the process for a dry friction metal-polymer couple on scheme disc-finger. Track membrane from polyethylene terephthalate was a research material. Membrane had pores with 0.4 and 0.8 μm diameters. The effect of the sliding velocity for membranes with pores of 0.8 microns was determined. Research was shown that increasing pore's diameter caused a reduction of the friction coefficient and downturn its magnitude vibrations. The study showed that track membrane have adequate resistance to wear and can be successfully used in surgical procedures in the layers of the cornea

Sensors of vibration and acoustic emission for monitoring of boring with skiving cutters

Diagnosing processing system conditions is a key area in automation of modern machinery production. The article presents the results of a preliminary experimental research of the boring process using conventional and skiving cutters under the conditions of the low stiffness processing system. Acoustic emission and vibration sensors are used for cutting process diagnosis. Surface roughness after machining is determined using a laser scanning microscope. As a result, it is found that the use of skiving cutters provides greater stability of the cutting process and lower surface roughness as compared with conventional cutters

Quality Estimation of Dry Grinding of Skiving Cutters With Organic Bonding Diamond Wheels

Engineering process preparation requires proper preparation of cutting tools. It influences not only the performance of the tools but also the quality of workpiece surface machining. One of the promising environmentally friendly trends of mechanical treatment is grinding without using lubricating cooling liquid. This method can considerably influence the quality of cutting tools grinding. Smoothing skiving turning is an effective treatment method providing high efficiency and workpiece quality. Proper preparation of cutting edges is especially important in this process. For that purpose we have carried out a research in grinding changeable carbide inserts for skiving turning by means of grinding wheels with different grain size. The influence of different combinations of wheels on roughness of the inserts front and rear surfaces and quality of cutting edge was studied with the help of laser confocal microscopy

Experimental Research Into Generation of Acoustic Emission Signals in the Process of Friction of Hadfield Steel Single Crystals

The results of experimental research into dry sliding friction of Hadfield steel single crystals involving registration of acoustic emission are presented in the paper. The images of friction surfaces of Hadfield steel single crystals and wear grooves of the counterbody surface made after completion of three serial experiments conducted under similar conditions and friction regimes are given. The relation of the acoustic emission waveform envelope to the changing friction factor is revealed. Amplitude-frequency characteristics of acoustic emission signal frames are determined on the base of Fast Fourier Transform and Short Time Fourier Transform during the run-in stage of tribounits and in the process of stable friction

Mathematical support for automated geometry analysis of lathe machining of oblique peakless round–nose tools

Automatization of engineering processes requires developing relevant mathematical support and a computer software. Analysis of metal cutting kinematics and tool geometry is a necessary key task at the preproduction stage. This paper is focused on developing a procedure for determining the geometry of oblique peakless round-nose tool lathe machining with the use of vector/matrix transformations. Such an approach allows integration into modern mathematical software packages in distinction to the traditional analytic description. Such an advantage is very promising for developing automated control of the preproduction process. A kinematic criterion for the applicable tool geometry has been developed from the results of this study. The effect of tool blade inclination and curvature on the geometry-dependent process parameters was evaluated

Les droits disciplinaires des fonctions publiques : « unification », « harmonisation » ou « distanciation ». A propos de la loi du 26 avril 2016 relative à la déontologie et aux droits et obligations des fonctionnaires

The production of tt‾ , W+bb‾ and W+cc‾ is studied in the forward region of proton–proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98±0.02 fb−1 . The W bosons are reconstructed in the decays W→ℓν , where ℓ denotes muon or electron, while the b and c quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions.The production of $t\overline{t}$, $W+b\overline{b}$ and $W+c\overline{c}$ is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 $\pm$ 0.02 \mbox{fb}^{-1}. The $W$ bosons are reconstructed in the decays $W\rightarrow\ell\nu$, where $\ell$ denotes muon or electron, while the $b$ and $c$ quarks are reconstructed as jets. All measured cross-sections are in agreement with next-to-leading-order Standard Model predictions