Tool Fracture at the End of a Cut—Part 1: Foot Formation

1988 ◽  
Vol 110 (4) ◽  
pp. 333-338 ◽  
Author(s):  
T. C. Ramaraj ◽  
S. Santhanam ◽  
M. C. Shaw
Keyword(s):  
Steady State ◽  
High Probability ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Companion Paper ◽  
The Other ◽  
Edge Chipping ◽  
High Speeds ◽  
Strong Material

Refractory metal cutting tools exhibit an unusually high probability of edge chipping and gross fracture when suddenly unloaded after cutting a strong material at high speeds and feeds. After identifying three possible mechanisms of brittle fracture when a cutting tool exits a cut, that associated with so-called “foot” formation is discussed in detail. This involves a sudden shift from steady state chip formation by concentrated shear to gross fracture of the workpiece as the end of the cut is approached. The other possible mechanisms are discussed in a companion paper to follow.

Steady-State Thermal Stresses in Wedge-Shaped Cutting Tools

1975 ◽  
Vol 97 (3) ◽  
pp. 1060-1066
Author(s):  
P. F. Thomason
Keyword(s):  
Thermal Stress ◽  
Steady State ◽  
Metal Cutting ◽  
Thermal Stresses ◽  
Heat Conduction Problem ◽  
Equivalent Stress ◽  
Cutting Tools ◽  
Thermoelastic Stress ◽  
Plastic State ◽  
Steady State Heat

Closed form expressions for the steady-state thermal stresses in a π/2 wedge, subject to constant-temperature heat sources on the rake and flank contact segments, are obtained from a conformal mapping solution to the steady-state heat conduction problem. It is shown, following a theorem of Muskhelishvili, that the only nonzero thermal stress in the plane-strain wedge is that acting normal to the wedge plane. The thermal stress solutions are superimposed on a previously published isothermal cutting-load solution, to give the complete thermoelastic stress distribution at the wedge surfaces. The thermoelastic stresses are then used to determine the distribution of the equivalent stress, and this gives an indication of the regions on a cutting tool which are likely to be in the plastic state. The results are discussed in relation to the problems of flank wear and rakeface crater wear in metal cutting tools.

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.

Regenerative Chatter Vibration Occurring in Turning With Different Side Cutting Edge Angles

1995 ◽  
Vol 117 (4) ◽  
pp. 551-558 ◽  
Author(s):  
E. Marui ◽  
M. Hashimoto ◽  
S. Kato
Keyword(s):  
Energy Supply ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Cutting Edge ◽  
The Other ◽  
Chatter Vibration ◽  
Regenerative Chatter ◽  
Edge Angle ◽  
Regenerative Effect ◽  
Two Factors

This paper deals with the regenerative chatter vibration occurring in cutting tools with different side cutting edge angles. The occurrence of regenerative chatter vibration of the cutting tool is influenced by two factors, which are closely related to the vibratory energy supply or consumption. One factor is the interference effect between the tool flank and the workpiece. Of course, this factor exists in the primary chatter, too. The other is the regenerative effect. The influence of both factors on the regenerative chatter vibration of cutting tools with different side cutting edge angles is examined experimentally. The vibratory energy supply is simulated, considering the dynamic cutting process. As a result, the property of the regenerative chatter vibration and the influence of the side cutting edge angle on the regenerative chatter vibration are clarified.

Transient Thermal Stresses in the Quarter-Plane and their Relation to the Thermal-Cracking of Cutting Tools

1974 ◽  
Vol 16 (5) ◽  
pp. 322-330
Author(s):  
P. F. Thomason
Keyword(s):  
Metal Cutting ◽  
Thermal Stresses ◽  
Cutting Tool ◽  
Crack Nucleation ◽  
Cutting Tools ◽  
Thermal Cracking ◽  
Quarter Plane ◽  
Metal Cutting Tool ◽  
Transient Thermal ◽  
Cemented Carbide Tools

The transient thermal stresses in an insulated quarter-plane, subject to an instantaneous heat source on a segment of the surface, are determined with the aid of the Green's function for a two-dimensional infinite space. Numerical results for the transient thermal stresses at the surfaces of the quarter-plane are superimposed on previous isothermal results for cutting-load stresses in a π/2 wedge, to provide a model for a metal-cutting tool in the transient stages of a cutting process. The results are related to the problem of the thermal-cracking of cutting tools, and mechanisms of crack nucleation and propagation are proposed for both ceramic and cemented-carbide tools.

Methods of Forecasting Wear Resistance of Cutting Tools Based on the Properties of their Materials

2014 ◽  
Vol 682 ◽  
pp. 491-494 ◽  
Author(s):  
Vladislav Bibik ◽  
Elena Petrova
Keyword(s):  
Tool Life ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Chemical Properties ◽  
Tool Material ◽  
Composition Structure ◽  
Metal Cutting Tool ◽  
Physical And Chemical ◽  
Thermo Physical Properties

The author considers methods of forecasting metal-cutting tool life based on characteristics of cutting tool material. These characteristics depend on differences in numerical values of physical and chemical properties of tool material due to changes in its composition, structure, and production process variables. The described methods allow obtaining the information necessary for forecasting the tool life beyond the process of cutting, for example at the stage of cutting tool manufacturing. The author suggests using the method of registration of thermo-physical properties of the tool material as a promising forecasting technique.

A Numerical Study to Investigate the Influence of Edge Preparation in Vibration Assisted Machining

2018 ◽  
Author(s):  
Salman Pervaiz ◽  
Sathish Kannan ◽  
Wael Abdel Samad
Keyword(s):  
Cutting Forces ◽  
Small Amplitude ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Numerical Study ◽  
Cutting Tools ◽  
Cutting Edge ◽  
Internal Stresses ◽  
Machining Performance ◽  
Edge Preparation

In machining operation, cutting tool performs a central role towards the overall machining performance. A user from metal cutting community always look for better cutting tools that can enhance productivity by reducing tool wear and cost. Modification in the micro-geometry of cutting edge is termed as edge preparation, and it is performed to improve the machining performance by strengthening the cutting edge, reducing internal stresses of coating and lowering the edge chipping etc. Edge preparation has a controlling influence on the formation of deformation zones, cutting temperature, cutting forces and stresses at the cutting interface. Vibration assisted machining (VAM) concept is gaining fame in the metal cutting sector community for machining difficult-to-machine materials. In VAM, cutting tool moves with a small amplitude vibration instead of moving with a constant cutting velocity. This small amplitude vibrational movement provides better machining performance for difficult-to-cut brittle materials. The current numerical study utilized different edge prepared micro-geometries such as sharp edge, round edge and chamfer edge etc. cutting tools, and then these cutting tools were used in the numerical simulations of VAM. The study shows higher magnitude of cutting forces under VAM with tools with modified geometry. The study is beneficial for the metal cutting community and opens new areas of industrial applications.

The Effect of the Cutting Parameters on the Machined Surface Roughness

2017 ◽  
Vol 260 ◽  
pp. 219-226 ◽  
Author(s):  
Viktors Gutakovskis ◽  
Eriks Gerins ◽  
Janis Rudzitis ◽  
Artis Kromanis
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Cutting Parameters ◽  
Cutting Process ◽  
Tool Geometry ◽  
Machining Parameters ◽  
Machined Surface ◽  
Machined Surface Roughness

From the invention of turning machine or lathe, some engineers are trying to increase the turning productivity. The increase of productivity is following after the breakout in instrumental area, such as the hard alloy instrument and resistance to wear cutting surfaces. The potential of cutting speed has a certain limit. New steel marks and cutting surfaces types allow significantly increase cutting and turning speeds. For the most operation types the productivity increase begins from the feeding increase. But the increase of feeding goes together with machined surface result decreasement. Metal cutting with high feeding is one of the most actual problems in the increasing of manufacturing volume but there are some problems one of them is the cutting forces increasement and larger metal removal rate, which decrease the cutting tool life significantly. Increasing of manufacturing volume, going together with the cutting instrument technology and material evolution, such as the invention of the carbide cutting materials and wear resistant coatings such as TiC and Ti(C,N). Each of these coating have its own properties and functions in the metal cutting process. Together with this evolution the cutting tool geometry and machining parameters dependencies are researched. Traditionally for the decreasing the machining time of one part, the cutting parameters were increased, decreasing by this way the machining operation quantity. In our days the wear resistance of the cutting tools increasing and it is mostly used one or two machining operations (medium and fine finishing). The purpose of the topic is to represent the experimental results of the stainless steel turning process, using increased cutting speeds and feeding values, to develop advanced processing technology, using new modern coated cutting tools by CVD and PVD methods. After investigation of the machined surface roughness results, develop the mathematical model of the cutting process using higher values of the cutting parameters.

Finite Element Modeling of Burr Formation in Orthogonal Metal Cutting

2008 ◽  
Vol 53-54 ◽  
pp. 71-76 ◽  
Author(s):  
Wen Jun Deng ◽  
C. Li ◽  
Wei Xia ◽  
X.Z. Wei
Keyword(s):  
Finite Element ◽  
Steady State ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Element Model ◽  
Burr Formation ◽  
Cutting Condition ◽  
Simulation Procedure ◽  
Chip Flow ◽  
Orthogonal Metal Cutting

A coupled thermo-mechanical model of plane-strain orthogonal metal cutting including burr formation is presented using the commercial finite element code. A simulation procedure based on Normalized Cockroft-Latham damage criterion is proposed for the purpose of better understanding the burr formation mechanism and obtaining a quantitative analysis of burrs at exit. The cutting process is simulated from the transient initial chip formation state to the steady-state of cutting, and then to tool exit transient chip flow, by incrementally advancing the cutting tool. The effects of cutting condition on the non-steady-state chip flow while tool exit can be investigated using the developed finite element model.

scholarly journals EFFECT OF CUTTING SPEED IN THE TURNING PROCESS OF AISI 1045 STEEL ON CUTTING FORCE AND BUILT-UP EDGE (BUE) CHARACTERISTICS OF CARBIDE CUTTING TOOL

SINERGI ◽  
2020 ◽  
Vol 24 (3) ◽  
pp. 171
Author(s):  
Sobron Yamin Lubis ◽  
Sofyan Djamil ◽  
Yehezkiel Kurniawan Zebua
Keyword(s):  
Cutting Force ◽  
Metal Cutting ◽  
Cutting Tool ◽  
Cutting Tools ◽  
Cutting Speed ◽  
Cutting Parameters ◽  
Cutting Process ◽  
Depth Of Cut ◽  
Aisi 1045 Steel ◽  
1045 Steel

In the machining of metal cutting, cutting tools are the main things that must be considered. Using improper cutting parameters can cause damage to the cutting tool. The damage is Built-Up Edge (BUE). The situation is undesirable in the metal cutting process because it can interfere with machining, and the surface roughness value of the workpiece becomes higher. This study aimed to determine the effect of cutting speed on BUE that occurred and the cutting strength caused. Five cutting speed variants are used. Observation of the BUE process is done visually, whereas to determine the size of BUE using a digital microscope. If a cutting tool occurs BUE, then the cutting process is stopped, and measurements are made. This study uses variations in cutting speed consisting of cutting speed 141, 142, 148, 157, 163, and 169 m/min, and depth of cut 0.4 mm. From the results of the study were obtained that the biggest feeding force is at cutting speed 141 m/min at 347 N, and the largest cutting force value is 239 N with the dimension of BUE length: 1.56 mm, width: 1.35 mm, high: 0.56mm.

Progress on Research of Machining of Difficult-to-Machine Materials Using CBN Cutting Tools

2015 ◽  
Vol 723 ◽  
pp. 910-913
Author(s):  
Shi Long Gao ◽  
Li Bao An ◽  
Xiao Chong Wang ◽  
Song Gao
Keyword(s):  
Metal Cutting ◽  
Cutting Tool ◽  
Cubic Boron Nitride ◽  
Cutting Tools ◽  
High Hardness ◽  
High Wear Resistance ◽  
High Chemical ◽  
Tool Materials ◽  
Chemical Inertness ◽  
Cutting Tool Materials

Some engineering materials have excellent performances, but the machining of these materials is a problem. It is very inadequate to meet machining requirement only using traditional cutting tool materials. Therefore, exploring the machinability of difficult-to-machine materials and applying appropriate cutting tool materials have drawn much attention in metal cutting industry for guarantied product quality and productivity. Cubic boron nitride (CBN) has been recognized as one of the most suitable cutting tool materials due to its high hardness, high wear resistance, high chemical inertness, and excellent chemical stability in high temperature. Research on various aspects of CBN cutting performances has been conducted in recent years. This paper presents the progress on machining difficult-to-machine materials using CBN cutting tools.

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