Effects of the Size of Built-Up Layer on the Wear of Uncoated Cemented Carbide Tools in Dry Cutting of SUS304 Stainless Steel

Author(s):  
Xiaoqi Song ◽  
Yukio Takahashi ◽  
Tohru Ihara ◽  
Weiming He

Abstract Built-up layer (BUL) formed on the tool rake face during cutting has the tool protective effect. As BUL can change the shape of tool resulting in variation of rake angle and edge radius during cutting, it also has significant influences on the cutting phenomena such as tool wear, cutting forces and surface integrity. SUS304 stainless steel is very difficult to cut, leading to the rapid tool wear and poor surface quality. It also has a high tendency to form BUL during cutting due to its high work hardening rate and high chemical affinity. To actively and purposely utilize BUL, the effects of the size of BUL on the wear of uncoated cemented carbide tools in dry cutting of SUS304 were investigated using experimental and analytical methods in this study. The cutting parameters were chosen to induce the stable BUL formation. After cutting, the worn cutting tools were analyzed using the laser confocal microscopy and scanning electron microscopy. It was confirmed that BUL can reduce the tool flank wear rate in the steady-state wear when its height is equal to or less than the uncut chip thickness. The results also showed that BUL formed at cutting speed 40 m/min can not only reduce the tool flank wear rate but also induce a significant improvement in cutting forces and surface integrity. Meanwhile, using the obtained experimental results and proposed model, simulation was conducted to evaluate the effects of the size of BUL on the tool flank wear formation. It was confirmed that BUL, especially when its height is close to the uncut chip thickness, which reduces the real rake angle to negative, can reduce the normal stress on the tool flank face and lead to a decrease in the tool flank wear rate.

Author(s):  
Alper Uysal ◽  
Erhan Altan

In this study, the slip-line field model developed for orthogonal machining with a worn cutting tool was experimentally investigated. Minimum and maximum values of five slip-line angles ( θ1, θ2, δ2, η and ψ) were calculated. The friction forces that were caused by flank wear land, chip up-curl radii and chip thicknesses were calculated by solving the model. It was specified that the friction force increased with increase in flank wear rate and uncut chip thickness and it decreased a little with increase in cutting speed and rake angle. The chip up-curl radius increased with increase in flank wear rate and it decreased with increase in uncut chip thickness. The chip thickness increased with increase in flank wear rate and uncut chip thickness. Besides, the chip thickness increased with increase in rake angle and it decreased with increase in cutting speed.


2015 ◽  
Vol 1115 ◽  
pp. 117-121
Author(s):  
A.K.M. Nurul Amin ◽  
Siti Aminatuzzuhriyah B. Haji Subir ◽  
Muammer Din Arif

Tool wear, especially flank wear, is a major concern in the manufacturing industry. Increased tool wear is caused by chatter and leads to increased surface roughness, reduced productivity and higher operating costs. It is more pronounced in the machining of difficult to cut materials such as stainless steel, tool steel, Inconel and hardened Ti alloys. Additionally, unpredictable tool wear can lead to frequent shutdowns of the machining process making it difficult for full automation. Therefore, to increase productivity and to reduce costs associated with increased and unpredictable tool wear, numerous research studies have been carried out. In this research, two permanent ferrite bar magnets of 1500 Gauss strength were used to dampen the vibration of the tool shank in the turning of stainless steel AISI 304 using titanium nitride (TiN) coated carbide inserts. Mild steel fixtures were used to place the magnets beside and below the tool shank in the carraige of a Harrison M390 engine lathe. The tool overhang was kept constant at 120 mm. A small central composite design (CCD) approach in response surface methodology (RSM) was used to model the tool wear as a response of the three primary cutting parameters: cutting speed, feed, and depth of cut. Design Expert software (version 6) was used to generate the 14 experimental runs needed to develop and verify the empirical mathematical model of tool flank wear. The resultant tool flank wear was measured using both optical and scanning electron microscopes (SEM). Finally, an empirical quadratic mathematical model of tool wear was found. This model was then used as the objective function in the optimization of tool wear using genetic algorithms (GA). The optimization results predicted that the minimum tool wear was 0.0427 mm. This prediction was subsequently validated experimentally.


2010 ◽  
Vol 431-432 ◽  
pp. 479-482
Author(s):  
Dao Chun Xu ◽  
Ping Fa Feng ◽  
Ding Wen Yu ◽  
Zhi Jun Wu

With increasing spindle speed the cutting will be easy to enter into micro-feed cutting region. In the paper, the chip thickness and shape of high-speed and micro-feed cutting was researched in orthogonal milling. The cutting times in different fz was analyzed. We calculate the effective rake angle, friction angle and shear angle Furthermore, we measure cutting edge arc wear and tool flank wear of micro-feed cutting. Shown as the research results, the phenomenon of empty cutting and pure extrusion is very obvious as the feed rate per tooth is lower than 0.011mm/z. As the feed rate per tooth is lower than 0.005mm/z, the tool wear form is mainly cutting edge arc wear. As fz achieves 0.015mm/z, tool wear will decrease obviously and the tool appears the self-sharpening phenomenon.


The cutting tool in the manufacturing industry is a key factor. The fulfilment of machining operation mainly depends on the tool material to improve the cutting life of the tool during machining with austenite stainless steel, however the austenite stainless steel difficult to machine and less amount of heat dissipation during machining in order to overcome. The aim of the investigation is to apply; the cryogenic treatment (CT) to the tungsten carbide insert, besides no study has been claimed on the chip thickness (tc), tool wear of machining with AISI 304. The machining test was conducted by three different speed and unchanged feed rate and depth of cut. The maximum flank wear was measured by using digital microscope also measured the chip thickness for both insert. The experimental results found that to reach the maximum flank wear for CT insert in all three speed was less in comparison with untreated insert (UT), chip thickness was also less in case of CT insert, built up edge were clearly observed in the UT insert, over all CT insert performed more desirable in compared with UT. The improvement in the microstructure properties of the CT insert owing to development of Eta (η) phase carbide and homogenous distribution in the tungsten carbide material, SEM and XRD tests are confirmed these results


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.


1999 ◽  
Vol 122 (3) ◽  
pp. 384-390 ◽  
Author(s):  
Jairam Manjunathaiah ◽  
William J. Endres

A new machining process model that explicitly includes the effects of the edge hone is presented. A force balance is conducted on the lower boundary of the deformation zone leading to a machining force model. The machining force components are an explicit function of the edge radius and shear angle. An increase in edge radius leads to not only increased ploughing forces but also an increase in the chip formation forces due to an average rake angle effect. Previous attempts at assessing the ploughing components as the force intercept at zero uncut chip thickness, which attribute to the ploughing mechanism all the changes in forces that occur with changes in edge radius, are seen to be erroneous in view of this model. Calculation of shear stress on the lower boundary of the deformation zone using the new machining force model indicates that the apparent size effect when cutting with edge radiused tools is due to deformation below the tool (ploughing) and a larger chip formation component due to a lower shear angle. Increases in specific energy and shear stress are also due to shear strain and strain rate increases. A consistent material behavior model that does not vary with process input conditions like uncut chip thickness, rake angle and edge radius can be developed based on the new model. [S1087-1357(00)01302-2]


2011 ◽  
Vol 188 ◽  
pp. 38-42
Author(s):  
Dong Dong Wan ◽  
Xu Hong Guo ◽  
Chi Hong Wang

Three different cutting tools (ceramics CC6050, cubic boron nitride CB7025, carbide GC2025) were used for dry cutting of 3 groups of ADI which were heat-treated separately under different quenching temperatures. With the unified cutting parameters, the wear of tool flank of each cutter was studied and the main influencing factors of the wear were analyzed. Results showed that when the cutting parameters ap =0.2mm, f =0.16mm/r, vc =108m/min and the cutting tool was determined, the higher the quenching temperature was the lower the hardness of the test bars were and the tool flank wear was less; When the quenching temperature was determined, the more the produced BUE (build up edge) of the cutting tool was the less the tool flank wear was.


2014 ◽  
Vol 695 ◽  
pp. 676-679 ◽  
Author(s):  
Abdullah Yassin ◽  
Chong Yaw Teo

This paper presents an experimental investigation on effects of pressure and nozzle angle of minimal quantity lubrication (MQL) on cutting temperature and flank wear in turning. In manufacturing industries, there are always demands for the optimum cutting conditions for the most economical manufacturing cost. Hence, reduction in tool wear is essential for less expenditure with the knowledge of optimum cutting conditions of MQL. MQL, also known as near dry machining, has been acknowledged as an effective cooling technique in machining by applying vegetable oils in replacing the conventional flooding method due to environmental issues. By varying the operating pressures and nozzle angle with respect to the cutting zone, cutting temperature and flank wear are measured using a calibrated tool work thermocouple and SPG video microscope. Comparison was made between dry cutting, water mist cooling and MQL method with palm oil. Results showed that MQL with palm oil exhibits best cooling efficiency at 5 bar pressure and nozzle angle of 20o with reduction of 35% in tool wear and 23% in cutting temperature at higher cutting speeds.


2021 ◽  
Author(s):  
Cristian Cappellini ◽  
Andrea Abeni

Abstract This paper concerns the tool wear in hard turning of AISI 52100 hardened steel by means of PCBN tools. The purposes of this work are the development of a tool wear model and its implementation in a FEM-based procedure for predicting crater and flank wear progression during machining operations for studying the influence of tool wear on the process in terms of tool geometry modifications and stress variation on the tool. Deform 2D FEM software has been utilized to simulate the orthogonal cutting process and the tool wear model has been implemented into the software by means of a dedicated subroutine able to estimate the wear rate and to update the geometry of the worn tool. Previous performed research showed the employment of analytical models for the evaluation of crater wear of flank wear separately, and FEM models only for the crater depth evolution without pointing their attention on the behavior of flank width. A new analytical model, concerning both crater and flank wear, has been proposed and validated by the authors. The validation of the model has been achieved by the comparison between experimental and simulated wear parameters. For doing this, an extended experimental campaign has been accomplished. The comparison results have shown good agreement. Once validated, the FEM strategy has been utilized for examining the influence of tool wear on the effective rake angle and the related tool stresses, individuating the excessive positive rake angle value as the final tool breakage mechanism.


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