scholarly journals Tool-Workpiece Interaction in the Cutting Process and Its Use

TEM Journal ◽  
2021 ◽  
pp. 1733-1737
Author(s):  
Karol Vasilko ◽  
Zuzana Murčinková

The paper analyzes the influence of natural tool wear on parameters of chip shaping and machining forces and proposes the adjustment of tool geometry based on natural shape of crater wear to extend time of machining. The contact of the cutting tool and the workpiece at actual cutting speed is a complex physical process, the result of which is a specific shape and characteristics of the machined surface and the modification of tool cutting characteristics. Due to the fact that there is no existing cutting material which would resist wear in the conditions of working high stress and temperature, it is necessary to take into account that tool cutting conditions change with cutting time. This is caused by the change in tool geometry after its functional areas become worn out. One of the practical effects of those changes is gradual modification of machined surface geometry, its fortification, formation of residual stress, character of chip formation and shaping, the development of friction temperature and deformation in the zone of the contact of the tool and workpiece. This means that the cut part changes its characteristics. It is up to date to eliminate or at least mitigate this negative influence of tool wear based on the results of cutting.

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1338
Author(s):  
Lakshmanan Selvam ◽  
Pradeep Kumar Murugesan ◽  
Dhananchezian Mani ◽  
Yuvaraj Natarajan

Over the past decade, the focus of the metal cutting industry has been on the improvement of tool life for achieving higher productivity and better finish. Researchers are attempting to reduce tool failure in several ways such as modified coating characteristics of a cutting tool, conventional coolant, cryogenic coolant, and cryogenic treated insert. In this study, a single layer coating was made on cutting carbide inserts with newly determined thickness. Coating thickness, presence of coating materials, and coated insert hardness were observed. This investigation also dealt with the effect of machining parameters on the cutting force, surface finish, and tool wear when turning Ti-6Al-4V alloy without coating and Physical Vapor Deposition (PVD)-AlCrN coated carbide cutting inserts under cryogenic conditions. The experimental results showed that AlCrN-based coated tools with cryogenic conditions developed reduced tool wear and surface roughness on the machined surface, and cutting force reductions were observed when a comparison was made with the uncoated carbide insert. The best optimal parameters of a cutting speed (Vc) of 215 m/min, feed rate (f) of 0.102 mm/rev, and depth of cut (doc) of 0.5 mm are recommended for turning titanium alloy using the multi-response TOPSIS technique.


2006 ◽  
Vol 532-533 ◽  
pp. 540-543 ◽  
Author(s):  
Lu Lu Jing ◽  
Gang Liu ◽  
Ming Chen

In die and mold industry, there is a tendency to use milling in the finishing machining of dies and molds as an alternative to the traditional EDM process, consequently the surface integrity in milling is considered as one of the most important indices. In this study, surface roughness, micrograph of machined surface, surface microhardness, residual stress, and metallurgical texture of the surface layer were considered. The influence of geometrical characteristics of cutting tools and tool wear on surface integrity was studied. The results showed that hard milling of hardened die steel could yield a quite satisfied surface integrity by proper process; compressive residual stress was induced on machined surface, and the compressive stress induced in transversal direction was almost 3 times of that in longitudinal direction; tool wear had a significant negative influence on surface finish and caused the machined surface soften. These conclusions revealed the effects of tool conditions on surface integrity and would play a practical significance in the machining of hardened die steel.


Author(s):  
Shoujin Sun ◽  
Milan Brandt ◽  
Matthew S Dargusch

Geometric features of the segmented chip have been investigated along with the volume of material removed at a cutting speed at which tool wear is characterized by the gradual development of flank wear when cutting Ti-6Al-4V alloy. The chip geometric variables varied with an increase in the volume of material removed as the combined effect of change in tool’s geometry and increase in cutting temperature. Plastic deformation dimples were observed as periodical regions on the machined surface, a row on each undeformed surface and region on the top of the slipping surface of the segmented chip when cutting with new tool; these dimples on the undeformed surface and machined surface are elongated in the direction of chip flow. All these dimples became less with an increase in the volume of material removed and almost disappeared when the chip was removed with the worn tool at the end of its life. A model of segmented chip formation process has been proposed to satisfactorily explain the formation of the plastic deformation dimples on the undeformed surface and machined surface of the segmented chip produced with a new cutting tool and the transition of chip geometry with the evolution of tool wear.


1999 ◽  
Vol 122 (4) ◽  
pp. 620-631 ◽  
Author(s):  
T. I. El-Wardany ◽  
H. A. Kishawy ◽  
M. A. Elbestawi

The effects of cutting conditions and tool wear on chip morphology and surface integrity during high speed machining of D2 tool steel (60–62 Hrc) are investigated experimentally and analytically in this paper. Polycrystalline Cubic Boron Nitride (PCBN) tools are used in this investigation. The chips and the subsurface of the workpiece are examined using optical and scanning electron microscopy. Microhardness measurements are performed on the surface and subsurface of the workpiece. The X-ray diffraction technique is used to measure the residual stresses induced in the machined surface. The paper is divided into two parts. Part 1 presents the results obtained from the micrographical analysis of the chips and the surfaces produced. Part 2 deals with microhardness and residual stresses of the machined surface. The micrographical analysis of the chips produced shows that different mechanisms of chip formation exist depending on the magnitude of the cutting pressure and tool wear. Saw toothed chips are produced during the machining of D2 tool steel if the cutting pressure exceeds approximately 4000 MPa. The metallographic analysis of the surface produced illustrates the damaged surface region that contains geometrical defects and changes in the subsurface metallurgical structure. The types of surface damage are dependent on the cutting conditions, tool geometry and the magnitude of the wear lands. [S1087-1357(00)00104-0]


2021 ◽  
Vol 2070 (1) ◽  
pp. 012168
Author(s):  
Narender Maddela ◽  
Ch.Sai Kiran ◽  
Aluri Manoj ◽  
M. Kapila ◽  
B. Swapna ◽  
...  

Abstract The cutting forces that are generated during metal cutting influence the work piece precision, tool wear, the nature of the machined surface, and heat generation. These cutting forces can be measured analytically however; precise outcomes may not be expected due to its included stresses, parameters of cutting, and the perplexing tool geometry. Henceforth the exploratory estimation of cutting forces is fundamental. For this reason, a milling dynamometer of three-segment is structured, created, and tried to gauge the three cutting forces which are produced during the operation of milling strain gauges can be utilized to quantify dynamic and static cutting forces through milling dynamometer. During the process of metal cutting, a dynamometer that is based on strain gauge is fit for estimating three-force segments. The dynamometer was designed based on the octagonal ring principle. The octagonal rings orientation and location of strain gauges have resolved to expand affectability and to limit cross-affectability.


Author(s):  
V. F. Bezyazychzny ◽  
A. V. Kordyukov

Analysis and comparison is presented as to processing performance levels with cutting speeds providing various optimization criteria: minimal cutting tool wear, minimal production cost and maximal cutting performance. It has been established that during machining at the cutting speed corresponding to the minimal cutting tool wear performance is close to the level of productivity when machining at the cutting speed corresponding to the minimal production cost. Results of calculations allow estimating both the performance value and the machinability level of different materials in terms of strength, not only in quality, but also in quantity. This assessment is made subject to the physical and mechanical properties of the work piece and the tool materials, the cutting mode (cutting speed and depth, feed), the tool geometry (cutter tip radius in the plan, cutting edge corner radius, face and clearance angles, major and minor cutting edge angles), as well as the economic performance of cutting (cutting time, cost of machine operation and labor cost, cutting tool operating cost).


2011 ◽  
Vol 697-698 ◽  
pp. 125-128
Author(s):  
Shen Yung Lin ◽  
Y.H. Lin ◽  
M.S. Hsu

After the processing of a clock dial, the precision dimension and uniform distribution of the tool-trace pattern on the dial surface have a connection with luster image and attractiveness, which in turn would have an impact on the additional values and prices for a clock. Through a systematic investigation among the lathe structure, process parameter and cutting-tool geometry in advance, the total results indicated that the rigidity of the lathe structure and the precision of the slider movements are excellent and they had only a little effect on the surface-related quality for a dial face turning. Hence, the combination of process parameter and cutting-tool angle becomes more essential. End face turning simulation and experiment of a copper alloy were thus conducted in this paper, and the chip formation process and machined surface-related quality are investigated, respectively. The effects of cutting tool geometry and process parameter on the results of chip formation, surface rough, tool-trace pattern and luster uniformity are investigated, and these results are also compared with each other. The results show that when larger clearance and rake angles used in conjunction with a lower feed rate, no matter how much cutting speed was enhanced, the surface-related quality of a dial surface is not good. However, when these two larger angles used combined with a larger feed rate, the quality of a dial surface would slightly be improved. By using smaller clearance and rake angles along with the higher feed rate and cutting speed would obtain a better surface-related quality with uniform luster and attractiveness.


Author(s):  
V. Kovvuri ◽  
Z. Wang ◽  
A. Araujo ◽  
M. B. da Silva ◽  
S. Bukkapatnam ◽  
...  

This paper presents experimental study on conditions for built-up-edge (BUE) formation and its effects in micromilling. Surface finish and BUE area density on a micromilled surface are used to quantify the presence of BUE. A model for surface finish is derived based on the topography of milled surface and tool geometry. Assuming no BUE formation, this empirical model shows the dependence of surface finish on chip load, tool concavity angle, and includes the effect of cutting parameters and milling modes (up-milling or down-milling). Micromilling tools of 100–400 μm diameters are used for milling stainless steel at 10–60 m/min cutting speed, 0.05–1 μm/flute chip load, in minimum quality lubrication condition (MQL). A BUE, embedded onto either a milled surface or tool cutting edge or chip, is identified by scanning electron microscopy and energy dispersive spectroscopy techniques; the severity of BUE formation is quantified as area density when observing a machined surface at high magnification with optical microscopy or interferometry. Condition for BUE formation is presented by mapping the surface finish and BUE area density against cutting speed and chip load. A microtool would fracture catastrophically at high cutting speeds and/or high chip loads due to excessive dynamic stresses on a microtool; such tool would also fail at the other extreme when low cutting speeds and chip loads promote formation and detachment of BUE on the tool surface, therefore, chipping the fragile microcutting edges of a microtool. There is an optimal zone for effective micromilling without tool failure and BUEs. The measured surface finish approaches the theoretical value when BUE is absent, i.e. micromilling in minimum quantity lubrication at cutting speed between 40–60 m/min and chip load higher than 0.15μm/tooth. The BUE area density for up-milling is lower than that for down-milling at low cutting speed; such difference gradually diminishes when selecting milling parameters in the optimal zone where BUE is practically absent.


2011 ◽  
Vol 110-116 ◽  
pp. 1855-1861 ◽  
Author(s):  
K. Kaarmuhilan ◽  
S. Karthika ◽  
Nambi Muthukrishnan

Aluminum silicon carbide Metal Matrix Composites (Al-MMC) are widely used in aeronautical and automobile industries due to their excellent mechanical and physical properties. However the harder reinforcement particles make machining difficult. Tool wear occurs more quickly and reduces the life of the tool. This paper presents the experimental investigation on turning A356 matrix metal reinforced with 20 % by weight of Silicon carbide (SiC) particles, fabricated in house by stir casting. Fabricated samples were turned on medium duty lathe with Poly crystalline Diamond (PCD) inserts of 1300 and 1500 grade exposed to various cutting conditions. Parameters such as power consumed by main spindle, machined surface roughness and tool wear are studied. Scanning Electron Microscope (SEM) images support the result. It is evident that, surface finish, and power consumed are good for 1500 grade when compared with 1300 grade at higher cutting speed and tool wear is strongly dependent on the abrasive hard reinforcement particles.


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