Search results for "cutting"
showing 10 items of 164 documents
Experimental investigation of the influence of adhesion on the frictional conditions in the cutting process
1999
Abstract This paper presents the results of an experimental study on the influence of adhesion on the tribological characteristics of the tool-chip interface. It was established that under orthogonal cutting conditions both the high interface temperature and severe plastic deformation result in relatively strong adhesion between steel and uncoated carbide. In particular, the molecular–mechanical theory of friction was applied to estimate the shear strength of the local adhesive junction, and to divided the rake face friction into two terms—an adhesion term (the interfacial coefficient of friction) and the deformation term. It should be pointed out that the data obtained provide a new approa…
Finite difference analysis of the thermal behaviour of coated tools in orthogonal cutting of steels
2004
Abstract Temperature measurement and prediction have been a major focus of machining for several decades but now this problem became more important due to the wider use of advanced cutting tool coatings. Practically, there is a lack of simulation programs for prediction of the temperatures in the cutting zone when machining with differently coated cutting tools. In all literature items cited the finite difference methods (finite difference approaches) were used to find the distribution of temperature inside the uncoated tool body or along the tool–chip interface for continuous (turning) and interrupted (milling) machining processes. The algorithm applied overcomes this limit. In this study,…
Positron Annihilation Study of Defects Induced by Various Cutting Methods in Stainless Steel Grade 304
2011
We report in this article the comparison of the subsurface zones (SZs) in austenitic stainless steel 304 samples created by three cutting techniques, i.e., the laser cutting (LC), abrasive water jet (AWJ), and traditional milling cutting (MC). The crystal lattice defects distribution in this zone were investigated using the positron annihilation method. It was shown that the MC creates the great number mainly edge dislocations decorated by vacancies. Their concentration decreases with the increase of the depth from the cut surface. The total depth of the SZ is extended up to 150 μm from the cut surface. Similar dependency was observed for the AWJ machining but the total depth is much lower,…
Influence of machining parameters on surface roughness in WEDM cutting
2020
Wire Electrical Discharge Machining is a cutting method used for obtaining parts with complex geometries or for cutting hard metals. This рарer ѕeekѕ to emрhаѕіze the іmрortаnce of thіѕ unconventіonаl technology аnd more ѕрecіfіcаlly the іmрortаnce of knowіng the раrаmeterѕ of а рroceѕѕ before рlаnnіng the рroductіon of а benchmаrk. Cylіndrіcаl metаl cаrbіde раrtѕ wіth а hаrdneѕѕ of 1620 HV / 92 HRC were cut durіng the analysis9, uѕіng the mіnіmum аnd mаxіmum vаlueѕ of the cutting раrаmeterѕ: wire feed rаte, wire rotаtіon ѕрeed, wіre tenѕіon, dіelectrіc рreѕѕure, electrіcаl current(Α) аnd electrіcаl рotentіаl (V). The roughneѕѕ of the obtаіned ѕurfаceѕ has been meаѕured after being cut аnd …
Tribology of Metal Cutting
2008
This chapter provides comprehensive knowledge regarding tribological behaviour of the cutting zone and characterizes specific features of the tool–chip contact that influence friction mechanisms in this area. Adhesion, plastic deformation of contacting asperities and ploughing action of the cutting edge are selected as three predominant mechanisms controlling sliding friction between the tool and the chip. The two-zone model of the tool–chip contact distinguishing seizure and sliding regions is characterized, along with experimental evidence based on photoelastic and material flow line techniques. Corresponding stress distributions for plane and restricted-contact cutting tools are provided…
Cutting performance and indentation behaviour of diamond films on Co-cemented tungsten carbide
2000
Abstract Diamond films were grown by Hot Filament Chemical Vapour Deposition (HFCVD) on differently pretreated ISO-grade K10 cemented carbide (WC-5.8 wt.%Co) cutting inserts. Etching with diluted HNO3 and surface roughening by Murakami's reagent were used as substrate pretreatments. The adhesion of the films was evaluated by indentation tests. In order to obtain a reliable estimation of the adhesion by the slope of the crack radius–indentation load curves, a careful SEM measurement of the crack lengths was performed. Bare and diamond-coated cutting inserts were used for turning tests of Al2O3-reinforced aluminum alloy. The adhesion levels obtained from the indentation curves correlated well…
The effect of wear on the tetragonal-to-monoclinic transformation and the residual stress distribution in zirconia-toughened alumina cutting tools
1998
Abstract Zirconia-toughened alumina cutting tools have been examined after machining an AISI 1040 steel. The Raman spectrum of zirconia and the fluorescence spectrum from alumina have been used to determine the extent of the tetragonal-to-monoclinic (t-m) transformation and the residual stresses in and around the worn-out crater, respectively. Although about 15% vol. m-zirconia is present even in a brand new cutting tool, it was shown that the crater region undergoes the t-m transformation up to 40% vol. In both cases, the transformed zone is concentrated near the surface. The residual stresses in alumina are slightly compressive in the new cutting tool and away from the crater region, but …
Orthogonal and Oblique Cutting Mechanics
2008
This chapter provides the engineering knowledge and modelling techniques applied in description of the material behaviour in the cutting zone resulting in chip formation and its separation from the bulk material. Geometrical and kinematical characteristics of orthogonal and oblique cutting models are classified and specified. Forces acting on the cutting tools and their measurement methods for several machining operations, such as turning, milling, drilling, boring and grooving, are presented. Moreover, forces acting in the cutting zone and their resolution on the shear plane and the rake and flank faces, along with stress distributions, are presented. The chapter highlights how components …
The influence of laser beam-width and focusing angle about the precision of cutting metallic materials
2005
To realize a high precision cutting operation, we must know the position and pointing of the beam axis- which are defined in accordance with ISO, by the centers of gravity of energy density distributions at different distances from the exit lens of laser. The angle of focalization must be related at least with; material width, beam energy, cutting speed, precision requirements and workpiece destination. Authors have realized experimental set-up for simultaneous measurement of energy density distributions, correlated with the mentioned working parameters. Besides the geometrical details, the authors studied also the influence of different values of beam density, about the zone affected by he…
A genetic algorithm for the minimum generating set problem
2016
Graphical abstractDisplay Omitted HighlightsWe propose a novel formulation for the MGS problem based on multiple knapsack.The so-conceived MGS problem is solved by a novel GA.The GA embeds an intelligent construction method and specialized crossover operators.We perform a thorough comparison with regards to state-of-the-art algorithms.The proposal proves to be very competitive, specially for large and hard instances. Given a set of positive integers S, the minimum generating set problem consists in finding a set of positive integers T with a minimum cardinality such that every element of S can be expressed as the sum of a subset of elements in T. It constitutes a natural problem in combinat…