scholarly journals Evaluating CBN tool life in hardened boring operations in long overhangs

2020 ◽  
Vol 10 (2) ◽  
pp. 150-154
Author(s):  
Thomas Wallyson ◽  
Zsombor Fülöp ◽  
Attila Szilágyi

This work aims to monitor the tool wear process using optical microscopy, so that the lifespan of the tool could be verified. The tool overhang was varied until it reached a limit (the deepest hole it could machine). The results show that, when the tool overhang is within its stability range, the flank wear of the tool is accentuated when the tool overhang outreaches its stability limit.

2018 ◽  
Author(s):  
Kai Guo ◽  
Bin Yang ◽  
Jie Sun ◽  
Vinothkumar Sivalingam

Titanium alloys are widely utilized in aerospace thanks to their excellent combination of high-specific strength, fracture, corrosion resistance characteristics, etc. However, titanium alloys are difficult-to-machine materials. Tool wear is thus of great importance to understand and quantitatively predict tool life. In this study, the wear of coated carbide tool in milling Ti-6Al-4V alloy was assessed by characterization of the worn tool cutting edge. Furthermore, a tool wear model for end milling cutter is established with considering the joint effect of cutting speed and feed rate for characterizing tool wear process and predicting tool wear. Based on the proposed tool wear model equivalent tool life is put forward to evaluate cutting tool life under different cutting conditions. The modelling process of tool wear is given and discussed according to the specific conditions. Experimental work and validation are performed for coated carbide tool milling Ti-6Al-4V alloy.


2017 ◽  
Vol 882 ◽  
pp. 36-40
Author(s):  
Salah Gariani ◽  
Islam Shyha ◽  
Connor Jackson ◽  
Fawad Inam

This paper details experimental results when turning Ti-6Al-4V using water-miscible vegetable oil-based cutting fluid. The effects of coolant concentration and working conditions on tool flank wear and tool life were evaluated. L27 fractional factorial Taguchi array was employed. Tool wear (VBB) ranged between 28.8 and 110 µm. The study concluded that a combination of VOs based cutting fluid concentration (10%), low cutting speed (58 m/min), feed rate (0.1mm/rev) and depth of cut (0.75mm) is necessary to minimise VBB. Additionally, it is noted that tool wear was significantly affected by cutting speeds. ANOVA results showed that the cutting fluid concentration is statistically insignificant on tool flank wear. A notable increase in tool life (TL) was recorded when a lower cutting speed was used.


1963 ◽  
Vol 85 (1) ◽  
pp. 33-37 ◽  
Author(s):  
H. Takeyama ◽  
R. Murata

This paper treats a fundamental investigation of tool wear and tool life mainly from the viewpoint of flank wear. The result reveals that the mechanism of tool wear in turning can be classified into two basic types: The mechanical abrasion which is directly proportional to the cutting distance and independent of the temperature; and the other is, so to speak, a physicochemical type which is considered to be a rate process closely associated with the temperature, of course. Although it depends upon the cutting condition which type of wear plays a more important role, the latter is predominant under usual conditions. According to the analyses and the experimental results, it has been found out that the tool life from the standpoint of flank wear can be predicted to a first approximation by the initial cutting temperature.


2010 ◽  
Vol 26-28 ◽  
pp. 1052-1055
Author(s):  
Li Fa Han ◽  
Sheng Guan Qu

The wear characteristics and life of Al2O3/(W,Ti)C ceramic tool in turning NbCp-reinforced iron-based P/M composites was investigated. Experimental results indicate that cutting parameters have an influence on tool wear, among which cutting speed and depth of cut seem to be more prominent. The maximum flank wear rapidly increases as the increase in cutting speed and depth of cut. While, it increases gradually as the decrease in feed rate. Meanwhile, an empirical model of tool life is established, from which the influence of cutting speed and depth of cut on tool life is far greater than that of feed rate. Also from the empirical model, the preferable range of cutting parameters was obtained.


2012 ◽  
Vol 488-489 ◽  
pp. 724-728 ◽  
Author(s):  
Tadahiro Wada

Using polycrystalline cubic boron nitride compact (cBN) tools, which have different cBN contents and cBN particle sizes, the influences of both the cBN content and the cBN particle size on tool wear in turning of hardened steel at various cutting speeds was experimentally investigated. Three types of cBN tools (a cBN content of 45-55% and 75%, and a cBN particle size of 0.5 μm and 5 μm, respectively) were tested. Furthermore, three kinds of chamfered and honed cutting edges were also used. The main results obtained are as follows: (1) In the case of the cBN tools with the same cBN particle size of 5.0 μm, the tool life of the cBN tool with a cBN content of 75% was longer than that of the cBN tool with a cBN content of 45% at low cutting speed. However, at high cutting speed, the tool life of the cBN tool with a cBN content of 75% was shorter. (2) The tool life of the cBN tool with both a cBN content of 55% and a cBN particle size of 0.5 μm was the longest. (3) The tool wear of cBN tools decreased with a decrease in chamfer width.


Author(s):  
Marcello Braglia ◽  
Davide Castellano

It is known that estimating the wear level at a future time instant and obtaining an updated evaluation of the tool-life density is essential to keeping machined parts at the desired quality level, reducing material waste, increasing machine availability, and guaranteeing the safety requirements. In this regard, the present paper aims at showing that the tool-life model that Braglia and Castellano (Braglia and Castellano, 2014, “Diffusion Theory Applied to Tool-Life Stochastic Modeling Under a Progressive Wear Process,” ASME J. Manuf. Sci. Eng., 136(3), p. 031010) developed can be successfully adopted to probabilistically predict the future tool wear and to update the tool-life density. Thanks to the peculiarities of a stochastic diffusion process, the approach presented allows deriving the density of the wear level at a future time instant, considering the information on the present tool wear. This makes it therefore possible updating the tool-life density given the information on the current state. The method proposed is then experimentally validated, where its capability to achieve a better exploitation of the tool useful life is also shown. The approach presented is based on a direct wear measurement. However, final considerations give cues for its application under an indirect wear estimate.


2009 ◽  
Vol 407-408 ◽  
pp. 594-598
Author(s):  
Xiao Qin Wang ◽  
Xing Ai ◽  
Jun Zhao ◽  
Pei Quan Guo

Ti6Al4V is a difficult to machine alloy with low cutting efficiency and server tool wear. A series of orthogonal turning tests with CBN (Cubic Boron Nitride) in higher speed scale was carried out on a CA6140 lathe. The experiential functions of tool life based on orthogonal experiment were developed. The tool wear morphologies were examined by scanning electron microscope (SEM) and energy disperse spectroscopy (EDS), adhesion, diffusion and micro-chipping were the major wear mechanisms of CBN tool. Finally, the cutting parameters of CBN tool in Ti6Al4V dry turning were optimized based on tool life-efficiency contour analysis, in same cutting efficiency, the higher cutting speed and small depth of cut are the better selection, it means that utilization of CBN tool enables the high cutting speed turning of Ti6Al4V.


Author(s):  
Qi Wang ◽  
Fuji Wang ◽  
Chong Zhang ◽  
Chen Chen

Ti/CFRP stacks present the key function in the aviation field due to their excellent properties. However, both titanium alloy and CFRP are hard-to-cut materials and their requirements on cutting tool performance are significantly different. When drilling Ti/CFRP stacks using a compromised tool, tool wear is affected by two materials, resulting in extremely low tool life. This paper investigates the wear process of chisel edge and main cutting edge of carbide step drill bits in the drilling of Ti/CFRP stacks, titanium alloys and CFRP, and the combined effects of various materials on the tool wear are revealed. Based on the wear analysis, it is found that tool wear is more affected by the carbon fiber/Ti-adhesion interaction which makes the rake face more susceptible to occur adhesive wear and slows down the flank wear, and severe rake wear and flank wear have a sharpening effect on cutting edge. It also reveals the relationship between thrust force and tool wear, and results indicate that the variation of thrust force is related to the flank wear and the Ti-adhesion attached to chisel edge, but not to the edge rounding. The conclusions reported in this paper can provide guidance for structural optimization of long-life stacks cutting tools.


Author(s):  
Chithajalu Kiran Sagar ◽  
Amrita Priyadarshini ◽  
Amit Kumar Gupta ◽  
Devanshi Mathur

Tungsten heavy alloys are widely used in the manufacturing of weights for aircraft, missiles, boats and race cars; penetrators; radiation shielding; and radioisotope containers. Manufacturing these components needs machining as a secondary operation. Since tungsten heavy alloys are difficult to machine, the in-depth analysis of tool wear growth and mechanism during machining of these alloys becomes essential. Hence, this work focuses on the experimental study of flank wear growth and its effect on other machining outputs for two different tool geometries (−5° and 2° rake angles) during turning of 90 tungsten heavy alloys. The predominant wear mechanism was identified as adhesion based on scanning electron microscopic analysis. Finally, three commonly used analytical tool wear rate models and one newly proposed model (modified Zhao model) were utilized for the prediction of flank wear growth and tool life. It was observed that the modified Zhao model could predict tool flank wear fairly well within error percentage of 4%–7% and thus could be used as a benchmark while machining difficult-to-cut alloys.


1978 ◽  
Vol 100 (1) ◽  
pp. 103-109 ◽  
Author(s):  
Y. Koren

A model of the flank wear of cutting tools is developed by using linear control theory. The flank wear is assumed to consist of a mechanically activated and a thermally activated component. The wear process is mathematically treated as a feedback process, whereby the progressive wear raises the cutting forces and temperature thereby increasing the thermally activated wear-rate, and contributes to the mechanically activated wear. A mathematical expression for the flank wear growth is derived and shown to be consistent with experimental results. The experimental data is fitted to the wear model for calculating the mechanical wear coefficient and activation energy for the thermally activated wear. The model yielded a new tool-life equation which is valid over a wider range of speed than Taylor tool-life equation.


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