Study on Cutting Temperature Modeling of Machined Workpiece in End Milling In-Situ TiB2/7050Al MMCs

Author(s):  
Yifeng Xiong ◽  
Wenhu Wang ◽  
Ruisong Jiang ◽  
Kunyang Lin

During metal cutting, it is well known that the cutting temperature has great influence on the machined surface integrity, especially on the residual stress and machining defects. At present, a lot of analytical modeling work has been done on the cutting temperature of tool, chips and workpiece machined by the side cutting edge during end milling process. To the workpiece surface machined by the bottom cutting edge, the study of temperature modeling is rarely reported. Besides, as a new kind of particulate metal matrix composites (MMCs) with improved mechanical and physical properties, the machining study of in-situ TiB2/7050Al MMCs is not many and no analytical temperature modeling of MMCs has been published up to now. Our study aims to establish an analytical cutting temperature model of workpiece machined by the bottom cutting edge in end milling in-situ TiB2/7050Al MMCs. In this model, the moving heat source method was applied. To meet the actual cutting process, the effect of heating time was also taken into account. With validation, the temperature model shows good agreement with experimental results. It was found that the heat partition ratio conducted from the shear plane heat source to the workpiece increased linearly as thermal number increased, due to the influence of increasing heat conducted into chip by the side cutting edge. The proposed cutting temperature model was of great significance for both the temperature modeling work of end milling and study of Al-MMCs.

1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman

Machine tool chatter is a dynamic instability of the cutting process. Chatter results in poor part surface finish, damaged cutting tool, and an irritating and unacceptable noise. Exten¬sive research has been undertaken to study the mechanisms of chatter formation. Efforts have been also made to prevent the occurrence of chatter vibration. Even though some progress have been made, fundamental studies on the mechanics of metal cutting are necessary to achieve chatter free operation of CNC machine tools to maintain their smooth operating cycle. The same is also true for Vertical Machining Centres (VMC), which operate at high cutting speeds and are capable of offering high metal removal rates. The present work deals with the effect of work materials, cutting conditions and diameter of end mill cutters on the frequency-amplitude characteristics of chatter and on machined surface roughness. Vibration data were recorded using an experimental rig consisting of KISTLER 3-component dynamometer model 9257B, amplifier, scope meters and a PC.  Three different types of vibrations were observed. The first type was a low frequency vibration, associated with the interrupted nature of end mill operation. The second type of vibration was associated with the instability of the chip formation process and the third type was due to chatter. The frequency of the last type remained practically unchanged over a wide range of cutting speed.  It was further observed that chip-tool contact processes had considerable effect on the roughness of the machined surface.Key Words: Chatter, Cutting Conditions, Stable Cutting, Surface Roughness.


Author(s):  
Wei-Hong Zhang ◽  
Gang Tan ◽  
Min Wan ◽  
Tong Gao ◽  
David Hicham Bassir

In milling process, surface topography is a significant factor that affects directly the surface integrity and constitutes a supplement to the form error associated with the workpiece deformation. Based on the tool machining paths and the trajectory equation of the cutting edge relative to the workpiece, a new and general iterative algorithm is developed here for the numerical simulation of the machined surface topography in multiaxis ball-end milling. The influences of machining parameters such as the milling modes, cutter runout, cutter inclination direction, and inclination angle upon the topography and surface roughness values are studied in detail. Compared with existing methods, the basic advantages and novelties of the proposed method can be resumed below. First, it is unnecessary to discretize the cutting edge and tool feed motion and rotation motion. Second, influences of cutting modes and cutter inclinations are studied systematically and explicitly for the first time. The generality of the algorithm makes it possible to calculate the pointwise topography value on any sculptured surface of the workpiece. Besides, the proposed method is proved to be more efficient in saving computing time than the time step method that is commonly used. Finally, some examples are presented and simulation results are compared with experimental ones.


2014 ◽  
Vol 592-594 ◽  
pp. 38-42 ◽  
Author(s):  
S. Samsudeensadham ◽  
Vijayan Krishnaraj

The heat produced in metal cutting process is one of the most critical issue in machining of titanium alloys. High temperature in metal cutting degrades the tool life, surface integrity, size accuracy and machining efficiency dramatically. The temperature generated during end milling of titanium alloy, has been measured using Thermo camera. Surface roughness plays a vital role in evaluating and measuring the quality of the machined surface. During the experiments, cutting speed and feed rate have been changed to analyse the effect of temperature and surface roughness. It is observed that cutting speed has the greater effect on temperature and surface roughness during end milling of titanium alloy. The regression equations generated have better fit which can be used for optimization.


2019 ◽  
Vol 13 (5) ◽  
pp. 639-647
Author(s):  
Keiji Ogawa ◽  
Takumi Imada ◽  
Haruki Kino ◽  
Heisaburo Nakagawa ◽  
Hitomi Kojima ◽  
...  

The demand for micro-end-milling for products in fields such as the medical, optical, and electronics industry is increasing. However, when machining with a small diameter end-mill (micro-end-mill) with diameters such as 0.5 mm, the rigidity of the tool itself is low; hence, the cutting conditions must be set to low values to achieve stable machining. Therefore, we examined various cutting phenomena that occur during actual machining processes to achieve high machining accuracy, high finished-surface quality, and long tool life. Some studies on micromachining achieved high accuracy, high-grade machining by considering the cutting phenomena. In previous papers, we dealt with the side-cutting phenomena in micro-end-milling of hardened die steels using a high-speed air-turbine spindle with rolling bearing. Cutting experiments were carried out by measuring the cutting force and flank wear of a cutting tool to investigate the difference in cutting phenomena caused by cutting direction in high-speed micro-end-milling. Observation of the machined surface and measurement of the profile of the cutting edge and machined surface were demonstrated. It was revealed that machining quality in high-speed up-cut milling was better than that in down-cut milling. Shoulder cutting, in which both peripheral and bottom cutting edges act simultaneously on the workpiece, was also investigated. A novel small diameter end-mill with left-hand helical tool with right-hand cut was developed to avoid damaging the cutting edge in the initial cutting stage. In the present study, high-quality shoulder cutting of a vertical wall using the new tool was proposed and demonstrated.


Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7143
Author(s):  
Anshan Zhang ◽  
Caixu Yue ◽  
Xianli Liu ◽  
Steven Y. Liang

Ball-end cutters are widely used for machining the parts of Ti-6Al-4V, which have the problem of poor machined surface quality due to the low cutting speed near the tool tip. In this paper, through the experiments of inclined surface machining in different feed directions, it is found that the surface adhered damages will form on the machined surface under certain tool postures. It is determined that the formation of surface adhered damage is related to the material adhesion near the cutting edge and the cutting-into/out position within the tool per-rotation cycle. In order to analyze the cutting-into/out process more clearly under different tool postures, the projection models of the cutting edge and the cutter workpiece engagement on the contact plane are established; thus, the complex geometry problem of space is transformed into that of plane. Combined with the case of cutting-into/out, chip morphology, and surface morphology, the formation mechanism of surface adhered damage is analyzed. The analysis results show that the adhered damage can increase the height parameters Sku, Sz, Sp, and Sv of surface topographies. Sz, Sp, and Sv of the normal machined surface without damage (Sku ≈ 3) are about 4–6, 2–3, and 2–3 μm, while Sz, Sp, and Sv with adhered damage (Sku > 3) can reach about 8–20, 4–14, and 3–6 μm in down-milling and 10–25, 7–18, and 3–7 μm in up-milling. The feed direction should be selected along the upper left (Q2: β∈[0°, 90°]) or lower left (Q3: β∈[90°, 180°]) to avoid surface adhered damage in the down-milling process. For up-milling, the feed direction should be selected along the upper right (Q1: β∈(−90°, 0°]) or upper left (Q2: β∈[0°, 90°)).


Author(s):  
Yoshiki Nakamura ◽  
Fumihiro Itoigawa ◽  
Shinya Hayakawa ◽  
Satoru Maegawa ◽  
Xiaoxu Liu

Abstract In the metal cutting, generally, application of lubricant to a cutting edge is one of the methods in order to suppress temperature rise of the cutting edge by reducing frictional heat. However, the reduction in friction with lubricant disappears at higher temperature environment because of the loss of lubricant oiliness associated with temperature rise. Conversely, this reduction effect might work only in the initial stage immediately after cutting edge /work engagement because the temperature is not so high. Therefore, if the cutting duration of each blade of end-mill is shorten by limiting the cutting length per once, the cutting temperature can be suppressed to be lower than the moderate magnitude for lubrication. On the other hand, Ti-alloys with low thermal conductivity would experience quite high temperature increase during the high-speed cutting process. Therefore, it is thought that lubricant cannot be used properly with conventional cutting methods. In this study, the high-speed milling method mentioned above was used to implement the machining of Ti-alloys, and the lubricant effects of different types oils were compared from two aspects as tool wear and cutting force. As a result, when using low-viscosity synthetic ester oil, the damage to the cutting edge was suppressed most. At the same time, there was no fluctuation in cutting force by repeated machining. From this result, it was suggested that the lubricant performance, in intermittent cutting with very short cutting duration, depends on the heat resistance and permeability of the oil.


2018 ◽  
Vol 7 (4.30) ◽  
pp. 53
Author(s):  
Husni Nazra Abu Bakar ◽  
Jaharah A. Ghani ◽  
Che Hassan Che Haron

Rounded cutting-edge radius is commonly applied to finish and semi-finish cutting, precision machining and micro-machining. The optimum effect is closely related to the work and tool material as well as machining parameters. However, for numerous cutting process, the optimal radius of rounded cutting-edge radius and machining parameters applied in the AISI H13 of end-milling is yet unknown Therefore, in improving tool life and cutting tool performance, a suitable design of cutting edge geometry regarding cutting edge-radius and machining parameters need to be examined and properly selected. In this regard, the paper deals to examine the effect of cutting edge-radius in rounded form and machining parameters of cutting force, cutting temperature and chip formation through the end-milling process of AISI H13 using uncoated cemented carbide cutting tool through finite element simulation of Thirdwave AdvantEdge 7.2 software. The machining parameters applied in the simulation setup were 200 and 240m/min of cutting speed, 0.03 and 0.06mm/tooth of feed-rate and axial depth of cut of 0.1 and 0.2mm while width of cut in radial direction was kept constant at 6.0mm. The cutting geometries includes the cutting-edge radius of 0.03 and 0.05mm and 10° of rake angle. The obtained results revealed that cutting forces and cutting temperature is increase as depth of cut in axial direction and cutting-edge radius increases while increasing value of speed and feed-rate of cutting resulted in decreasing cutting forces but increasing cutting temperature. The maximum cutting temperature is 674.91℃. The value obtained is lesser than the AISI H13 austenitizing temperature, therefore a layer known as white layer is supposedly hard to be created based on the cutting geometry and machining parameters applied.  


Materials ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 4571
Author(s):  
Anne Vornberger ◽  
Tobias Picker ◽  
Johannes Pötschke ◽  
Mathias Herrmann ◽  
Berend Denkena ◽  
...  

During metal cutting, high temperatures of several hundred-degree Celsius occur locally at the cutting edge, which greatly impacts tool wear and life. Not only the cutting parameters, but also the tool material’s properties influence the arising cutting temperature which in turn alters the mechanical properties of the tool. In this study, the hardness and thermal conductivity of cemented tungsten carbides were investigated in the range between room temperature and 1000 °C. The occurring temperatures close to the cutting edge were measured with two color pyrometry. The interactions between cemented carbide tool properties and cutting process parameters, including cutting edge rounding, are discussed. The results show that cemented carbides with higher thermal conductivities lead to lower temperatures during cutting. As a result, the effective hardness at the cutting edge can be strongly influenced by the thermal conductivity. The differences in hardness measured at room temperature can be equalized or evened out depending on the combination of hardness and thermal conductivity. This in turn has a direct influence on tool wear. Wear is also influenced by the softening of the workpiece, so that higher cutting temperatures can lead to less wear despite the same effective hardness.


2011 ◽  
Vol 399-401 ◽  
pp. 1848-1851
Author(s):  
Yi Dan Zhou ◽  
Tao Wang

This paper uses a metal cutting simulation software AdvantEdge FEM as the platform, and simulates the drilling process of 42CrMo with three different honed cutting edge K-Grade carbide drills. The aim is to study the influence of different magnitude of honed cutting edge on the maximum temperature of cutting area. According to the simulation, the maximum temperature does not absolutely increase with the honed edge radius increase. The cutting temperature reaches maximum when the honed edge radius is 0.06mm in this paper, meanwhile the margin of fluctuation in the smallest.


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