Fractal Estimation of Flank Wear in Turning

1999 ◽  
Vol 122 (1) ◽  
pp. 89-94 ◽  
Author(s):  
Satish T. S. Bukkapatnam ◽  
Soundar R. T. Kumara ◽  
Akhlesh Lakhtakia
Keyword(s):  
Metal Cutting ◽  
Cutting Tool ◽  
Flank Wear ◽  
Fractal Dimensions ◽  
Machining Dynamics ◽  
Wavelet Representation ◽  
Fractal Properties ◽  
Sensor Signals ◽  
Signal Processing Methods ◽  
First Time

A novel fractal estimation methodology, that uses—for the first time in metal cutting literature—fractal properties of machining dynamics for online estimation of cutting tool flank wear, is presented. The fractal dimensions of the attractor of machining dynamics are extracted from a collection of sensor signals using a suite of signal processing methods comprising wavelet representation and signal separation, and are related to the instantaneous flank wear using a recurrent neural network. The performance of the resulting estimator, evaluated using actual experimental data, establishes our methodology to be viable for online flank wear estimation. This methodology is adequately generic for sensor-based prediction of gradual damage in mechanical systems, specifically manufacturing processes. [S0022-0434(00)02401-1]

scholarly journals Bases of variational method for calculating of metal-cutting systems accuracy

2018 ◽  
Vol 224 ◽  
pp. 01038
Author(s):  
Olesya Anikeeva ◽  
Alexander Ivakhnenko ◽  
Oleg Erenkov
Keyword(s):  
Mathematical Model ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Variation Method ◽  
Joint Influence ◽  
Processing Accuracy ◽  
General Mathematical Model ◽  
First Time ◽  
Cutting System

The bases of a variation method to calculate the metal-cutting systems accuracy for the first time are systemically stated in this paper. The main attention is paid to a problem of joint influence of geometrical accuracy of machine tools and cutting tools parameters on the details processed surfaces accuracy. The general mathematical model of metal-cutting systems accuracy is presented in this work. The general model is the basis to develop the full mathematical model of turning metal-cutting system accuracy. The results of accuracy modeling at turning with a wide cutter are received when studying nature of influence of the lathe and the cutting tool geometrical errors on processing accuracy of cylindrical and face surfaces. The directions of further researches in the field of calculations of metal-cutting systems accuracy at difficult surfaces processing by the shaped cutting tool and also when accounting rigidity of the systems elements and the proceeding processes are revealed in the presented work.

Dynamics of the processes in metal machining

1998 ◽  
Vol 2 ◽  
pp. 115-122
Author(s):  
Donatas Švitra ◽  
Jolanta Janutėnienė
Keyword(s):  
High Frequency ◽  
Machine Tools ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Low Frequency ◽  
Metal Cutting Machine ◽  
Cutting Machine ◽  
Metal Machining

In the practice of processing of metals by cutting it is necessary to overcome the vibration of the cutting tool, the processed detail and units of the machine tool. These vibrations in many cases are an obstacle to increase the productivity and quality of treatment of details on metal-cutting machine tools. Vibration at cutting of metals is a very diverse phenomenon due to both it’s nature and the form of oscillatory motion. The most general classification of vibrations at cutting is a division them into forced vibration and autovibrations. The most difficult to remove and poorly investigated are the autovibrations, i.e. vibrations arising at the absence of external periodic forces. The autovibrations, stipulated by the process of cutting on metalcutting machine are of two types: the low-frequency autovibrations and high-frequency autovibrations. When the low-frequency autovibration there appear, the cutting process ought to be terminated and the cause of the vibrations eliminated. Otherwise, there is a danger of a break of both machine and tool. In the case of high-frequency vibration the machine operates apparently quiently, but the processed surface feature small-sized roughness. The frequency of autovibrations can reach 5000 Hz and more.

Experimental investigation of a slip-line field model for a worn cutting tool

2013 ◽  
Vol 228 (8) ◽  
pp. 1398-1404 ◽  
Author(s):  
Alper Uysal ◽  
Erhan Altan
Keyword(s):  
Wear Rate ◽  
Slip Line ◽  
Field Model ◽  
Cutting Tool ◽  
Flank Wear ◽  
Cutting Speed ◽  
Chip Thickness ◽  
Rake Angle ◽  
Uncut Chip Thickness ◽  
Line Field

In this study, the slip-line field model developed for orthogonal machining with a worn cutting tool was experimentally investigated. Minimum and maximum values of five slip-line angles ( θ1, θ2, δ2, η and ψ) were calculated. The friction forces that were caused by flank wear land, chip up-curl radii and chip thicknesses were calculated by solving the model. It was specified that the friction force increased with increase in flank wear rate and uncut chip thickness and it decreased a little with increase in cutting speed and rake angle. The chip up-curl radius increased with increase in flank wear rate and it decreased with increase in uncut chip thickness. The chip thickness increased with increase in flank wear rate and uncut chip thickness. Besides, the chip thickness increased with increase in rake angle and it decreased with increase in cutting speed.

Cutting Tool Wear and Mechanisms of Chip Formation During High-Speed Machining of Compacted Graphite Iron

2007 ◽  
Author(s):  
Niniza S. P. Dlamini ◽  
Iakovos Sigalas ◽  
Andreas Koursaris
Keyword(s):  
Tool Wear ◽  
Surface Finish ◽  
Failure Criterion ◽  
Cutting Tool ◽  
Flank Wear ◽  
Cutting Tools ◽  
Compacted Graphite Iron ◽  
Crater Wear ◽  
Compacted Graphite ◽  
Cutting Speeds

Cutting tool wear of polycrystalline cubic boron nitride (PcBN) tools was investigated in oblique turning experiments when machining compacted graphite iron at high cutting speeds, with the intention of elucidating the failure mechanisms of the cutting tools and presenting an analysis of the chip formation process. Dry finish turning experiments were conducted in a CNC lathe at cutting speeds in the range of 500–800m/min, at a feed rate of 0.05mm/rev and depth of cut of 0.2mm. Two different tool end-of-life criteria were used: a maximum flank wear scar size of 0.3mm (flank wear failure criterion) or loss of cutting edge due to rapid crater wear to a point where the cutting tool cannot machine with an acceptable surface finish (surface finish criterion). At high cutting speeds, the cutting tools failed prior to reaching the flank wear failure criterion due to rapid crater wear on the rake face of the cutting tools. Chip analysis, using SEM, revealed shear localized chips, with adiabatic shear bands produced in the primary and secondary shear zones.

Hard Nano-Crystalline Coatings for Cutting Tools

2007 ◽  
Vol 567-568 ◽  
pp. 185-188 ◽  
Author(s):  
Miroslav Piska
Keyword(s):  
High Speed ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Dry Cutting ◽  
Nano Crystalline ◽  
The Right ◽  
Machining Productivity ◽  
Hard Cutting ◽  
Cutting Tool Materials

Modern trends in metal cutting, high speed/feed machining, dry cutting and hard cutting set more demanding characteristics for cutting tool materials. The exposed parts of the cutting edges must be protected against the severe loading conditions and wear. The most significant coatings methods for cutting tools are PVD and CVD/MTCVD today. The choice of the right substrate or the right protective coating in the specific machining operation can have serious impact on machining productivity and economy. In many cases the deposition of the cutting tool with a hard coating increases considerably its cutting performance and tool life. The coating protects the tool against abrasion, adhesion, diffusion, formation of comb cracks and other wear phenomena.

scholarly journals Graph fractal dimension and the structure of fractal networks

2020 ◽  
Vol 8 (4) ◽  
Author(s):  
Pavel Skums ◽  
Leonid Bunimovich
Keyword(s):  
Complex Networks ◽  
Evolutionary Biology ◽  
Real Life ◽  
Fractal Dimensions ◽  
Network Models ◽  
Self Similarity ◽  
Descriptive Complexity ◽  
Network Communities ◽  
Fractal Properties ◽  
Continuous Objects

Abstract Fractals are geometric objects that are self-similar at different scales and whose geometric dimensions differ from so-called fractal dimensions. Fractals describe complex continuous structures in nature. Although indications of self-similarity and fractality of complex networks has been previously observed, it is challenging to adapt the machinery from the theory of fractality of continuous objects to discrete objects such as networks. In this article, we identify and study fractal networks using the innate methods of graph theory and combinatorics. We establish analogues of topological (Lebesgue) and fractal (Hausdorff) dimensions for graphs and demonstrate that they are naturally related to known graph-theoretical characteristics: rank dimension and product dimension. Our approach reveals how self-similarity and fractality of a network are defined by a pattern of overlaps between densely connected network communities. It allows us to identify fractal graphs, explore the relations between graph fractality, graph colourings and graph descriptive complexity, and analyse the fractality of several classes of graphs and network models, as well as of a number of real-life networks. We demonstrate the application of our framework in evolutionary biology and virology by analysing networks of viral strains sampled at different stages of evolution inside their hosts. Our methodology revealed gradual self-organization of intra-host viral populations over the course of infection and their adaptation to the host environment. The obtained results lay a foundation for studying fractal properties of complex networks using combinatorial methods and algorithms.

scholarly journals Structure and Strength of Artificial Soils Containing Monomineral Clay Fractions

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4688
Author(s):  
Grzegorz Jozefaciuk ◽  
Kamil Skic ◽  
Agnieszka Adamczuk ◽  
Patrycja Boguta ◽  
Krzysztof Lamorski
Keyword(s):  
Fine Particles ◽  
Structural Parameters ◽  
Fractal Dimensions ◽  
Soil Strength ◽  
Uniaxial Compression Test ◽  
Mineral Particle ◽  
Type Curve ◽  
Surface Fractal ◽  
First Time

Structure and strength are responsible for soil physical properties. This paper determines in a uniaxial compression test the strength of artificial soils containing different proportions of various clay-size minerals (cementing agents) and silt-size feldspar/quartz (skeletal particles). A novel empirical model relating the maximum stress and the Young’s modulus to the mineral content basing on the Langmuir-type curve was proposed. By using mercury intrusion porosimetry (MIP), bulk density (BD), and scanning electron microscopy (SEM), structural parameters influencing the strength of the soils were estimated and related to mechanical parameters. Size and shape of particles are considered as primary factors responsible for soil strength. In our experiments, the soil strength depended primarily on the location of fine particles in respect to silt grains and then, on a mineral particle size. The surface fractal dimension of mineral particles played a role of a shape parameter governing soil strength. Soils containing minerals of higher surface fractal dimensions (rougher surfaces) were more mechanically resistant. The two latter findings appear to be recognized herein for the first time.

scholarly journals FRACTALS, NATURAL DISASTERS AND ECOLOGICAL PROBLEMS OF MALDIVES

2018 ◽  
pp. 18-25
Author(s):  
Boyko Ranguelov ◽  
Fathimath Shadiya
Keyword(s):  
Local Population ◽  
Fractal Dimensions ◽  
Point Of View ◽  
Negative Consequences ◽  
Fractal Nature ◽  
Fractal Properties ◽  
Level Increase ◽  
Ocean Level ◽  
Ecological Problems ◽  
Negative Phenomena

A new idea about the fractal nature of Maldives archipelago is under investigation. The origin of this famous Maldivian islands’ country is still questionable from geodynamic point of view. The present study is focused to the assessment of the fractal properties and the coefficients of the nonlinearity (fractal dimensions) of the areal spatial distribution of the major atolls of the Maldives. This is the most vulnerable area in the world from point of view of the global warming and the possible negative consequences to the country and population from the ocean level increase. From another side the natural hazards (tsunamis, storms, etc.) are common negative phenomena attacking the country. The strongly developed tourism – more than 30% of the GDP and the increased urbanization is another factor creating ecological problems to the local population. The relationships between the fractal nature and the possible ways to avoid the pollution are also in the focus of this research.

scholarly journals SYSTEM FOR CONTROLLING MASS BALANCE OF GASES AND REAGENTS DURING FORMATION OF ION-PLASMA COATINGS

2020 ◽  
pp. 67-75
Author(s):  
K. V. Diadiun
Keyword(s):  
Mass Balance ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Tool Material ◽  
Automated System ◽  
Effective Control ◽  
Ion Plasma ◽  
Physical Deposition ◽  
Plasma Coatings ◽  
Metal Cutting Tool

Providing an increase in the working capacity of a metal-cutting tool, it is possible to significantly increase the productivity of mechanized labor, thereby reducing the cost of purchasing a new tool and saving on other accompanying technological components. During the operation of the cutting tool, the main load is transferred to its working part, this, as a rule, leads to partial wear or complete destruction of the planes and cutting edges. There are a number of technologies for processing working surfaces, which provides them with additional strengthening, the most effective of which is the method of applying special coatings to the surface of the cutting tool. Taking into account the specifics of the processes of formation of coatings, they can be divided into three main groups [1]. The first group includes methods in which the formation of coatings is carried out mainly due to diffusion reactions between saturating elements and structures of the instrumental material. The second group includes methods of forming coatings by a complex mechanism. The third group includes methods of forming coatings due to chemical and plasma-chemical reactions of particle flux simultaneously in volumes of space immediately adjacent to the saturable surfaces of the instrumental base. One such technology is the CIB (condensation and ion bombardment) method, which is a physical deposition of coatings. The most characteristic feature of coatings produced by this method is the absence of a transition zone between the coating and the tool material. This makes it possible to obtain a complex of properties on the working surfaces of the tool without deteriorating its original properties. The article is devoted to the issues of increasing the efficiency of ion-plasma technologies through the development and implementation of an automated system for analyzing and controlling the mass balance of reagent gases under conditions of several gases supply. Thus, the improvement of the technology of coating the working surfaces of the cutting tool, namely, the effective control of the process of applying ion-plasma coatings with the introduction of an automated system for analyzing and controlling the mass balance of reagent gases under conditions of supplying several gases is an urgent task.

Size Reduction of Cellulosic Biomass in Biofuel Manufacturing: Effects of Milling Orientation on Sugar Yield

2011 ◽  
Author(s):  
Meng Zhang ◽  
Xiaoxu Song ◽  
P. F. Zhang ◽  
Q. Zhang ◽  
Z. J. Pei ◽  
...  
Keyword(s):  
Experimental Study ◽  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Metal Cutting ◽  
Sugar Yield ◽  
Size Reduction ◽  
Cellulosic Biomass ◽  
Poplar Wood ◽  
Cellulosic Biofuels ◽  
First Time

Cellulosic biofuels can reduce greenhouse gas emissions and the nation’s dependence on foreign oil. In order to convert cellulosic biomass into biofuels, size reduction of biomass is a necessary step. Most related studies in the literature claimed that smaller particles produced higher sugar yields. However, some researchers reported that this claim was not always true. The literature does not have satisfactory explanations for the inconsistence. This paper presents an experimental study on size reduction of poplar wood using a metal cutting process (milling). The results provided one explanation for this inconsistence. It was found for the first time that milling orientation had a strong effect on poplar wood sugar yield. Although smaller poplar particles had a higher sugar yield when they were milled from the same orientation, this trend did not exist for particles milled from different orientations.

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