Flank Wear Width Research Articles

Real-Time Evaluation of Tool Flank Wear by In-Process Contact Resistance Measurement in Face Milling

This paper reports in-process detection of tool wear by using tool-work thermo-electromotive force (E.M.F.) as a sensor signal in face milling. In the case of using a single cutting edge, E.M.F. at the beginning of cut increased slowly corresponding to the width of tool flank wear. We assume this phenomenon is due to variations in electric resistance by increase of the contact area between the workpiece and the tool, so electric current between tool and workpiece was also detected. The variations of contact electric resistance calculated from both the E.M.F. and the electric current reveal that the electric resistance decreases as the tool flank wear progresses because contact areas between tool and workpiece increase. We developed a measurement system of variations of the contact resistance during face milling process. By monitoring the contact resistance using this system, the real-time detection of the width of tool flank wear can be achieved stably during intermittent cutting operations.

An Experimental Investigation of the Effects of Spindle Speed Variation on Tool Wear in Turning

Spindle Speed Variation (SSV) is a well known technique to suppress regenerative chatter vibration both in turning and milling operations but a lack of knowledge regarding the effects of non stationary cutting conditions is still limiting its diffusion in the industrial scenario. In this paper an experimental study regarding the effects of Spindle Speed Variation technique on tool wear in steel turning is presented. The experimental tool wear tests were arranged and performed following a full factorial design: the cutting speed and the cutting speed modulation were the main investigated factors. The flank wear width was the main considered process response and it was monitored continuously during wear tests up to the end of the tool life. The effects of the factors were analyzed through the Analysis of Variance (ANOVA) approach.

Effect of Tool Tilting Angle on Tool Wear and Surface Roughness in Micro Ball End Milling

This paper describes the effect of the tool tilting angle on the tool wear and the surface roughness in micro ball end milling. The cutting tests of hardened stainless steel were carried out by using of the micro ball end mill with radius of 100mm under the conditions of tilting angle from 0° to 45°. The spindle speed was fixed in a constant of 120,000 min-1. The feed per tooth, axial depth of cut and radial depth of cut were also fixed. The flank wear, the surface roughness and the cutting force were investigated. As a result, the maximum width of flank wear of the micro ball end mill tended to decrease with an increase in the tilting angle of spindle. The surface roughness became almost constant not depending on the tilting angle of the spindle.

Monitoring online cutting tool wear using low-cost technique and user-friendly GUI

Cutting tool wear is known to affect tool life, surface quality and production time. Because of this an online tool wear measurement and monitoring system has been developed, using a low-cost sensor. The system is able to detect and analyze signals relating to the deflection of the tool holder from the cutting force, and the corresponding estimation of wear is displayed on the computer screen. New statistical analysis is used to identify and characterise the changes in signals from the sensors. A two-channel strain gauge is mounted at the tool holder to measure the deflection in both tangential direction and feed direction. The signal is transmitted to the signal conditioning device, then to data acquisition, and finally to the computer system. MATLAB software is used as the platform software to develop a user-friendly graphical user interface (GUI) for online monitoring purposes. Results show that this developed online monitoring system, using the strain gauge signal, is an effective method of detecting the progression of flank wear width during machining. This is an efficient and low-cost method which can be used in the real machining industry to predict the level of wear in the cutting tool.

Real-Time Cutting Tool Condition Monitoring in Milling

Reliable tool wear monitoring system is one of the important aspects for achieving a self-adjusting manufacturing system. The original contribution of the research is the developed monitoring system that can detect tool breakage in real time by using a combination of neural decision system and ANFIS tool wear estimator. The principal presumption was that force signals contain the most useful information for determining the tool condition. Therefore, the ANFIS method is used to extract the features of tool states from cutting force signals. ANFIS method seeks to provide a linguistic model for the estimation of tool wear from the knowledge embedded in the artificial neural network. The ANFIS method uses the relationship between flank wear and the resultant cutting force to estimate tool wear. A series of experiments were conducted to determine the relationship between flank wear and cutting force as well as cutting parameters. Speed, feed, depth of cutting, time and cutting forces were used as input parameters and flank wear width and tool state were output parameters. The forces were measured using a piezoelectric dynamometer and data acquisition system. Simultaneously flank wear at the cutting edge was monitored by using a tool maker’s microscope. The experimental force and wear data were utilized to train the developed simulation environment based on ANFIS modelling. The artificial neural network, was also used to discriminate different malfunction states from measured signals. By developed tool monitoring system (TCM) the machining process can be on-line monitored and stopped for tool change based on a pre-set tool-wear limit. The fundamental limitation of research was to develop a singlesensor monitoring system, reliable as commercially available system, but 80% cheaper than multisensor approach.

Effects of microstructure on machinability of ductile iron

In this paper, ductile irons with different microstructures were machined in a group of experiments using standard testing procedure and the effect of microstructure on the machinability was investigated. Bars (diameter 90mm × 320mm) of ferritic/pearlitic, tempered martensitic, and lower ausferritic microstructures were produced by various heat treatments and then tested to evaluate their machinability. Five groups of ductile iron specimens with various microstructures were tested following ISO 3685: 1993 (E) standard. Specimens were subjected to dry cutting; cutting force, flank wear width, and surface roughness were measured to compare the machining performances. In addition, further turning tests were conducted on the specimens of austempered microstructure at various feed rates (while keeping the cutting speed and depth of cut constant), and both surface roughness and cutting force values were recorded. The influence of feed rate on the machinability of austempered ductile iron was investigated and a correlation between feed rate and machinability, in terms of cutting force and surface roughness, was established. Not only the tangential cutting force component but also the feed force component was taken into consideration in these tests.

Production of Hard Materials with Ubiquitously Fe-B System by Spark Sintering and their Characteristics

The spark sintering technique was utilized to fabricate ubiquitously hard-materials compacts which were 0, 10 and 50vol%Fe added (hereafter called, 100, 90 and 50%FeB, respectively) in as-received powders with mean composition of Fe-19.1wt%B. Rockwell hardness number on C scale was changed 63 to 70 depending on Fe contents, and the value of 100%FeB compact was the same as that of WC-7.8Co. The 100 and 90%FeB compacts showed the fracture strain of 0.32 and 0.41 %, or fracture stress of 212 and 133 MPa, respectively, in three points bending tests at room temperature. The 100%FeB compacts had the same level in fracture stress and increment of 0.1 % in fracture strain at 773 K, compared with those obtained from the bending tests at room temperature. Dynamic friction coefficient of 90 and 100%FeB compacts was lower than that of WC-7.8%Co in pin (SK2) on disk configuration. Same values were shown in both wear loss on specimens (100%FeB or WC-7.8%Co), and SK2, which meant the similar level in these compacts for the cutting performance as the tool materials. The value of flank wear width (VB) was 0.26 mm at cutting distance of 30 m for the work material of Ti-6Al-4V using the cutting tool of 100%FeB, which meant the satisfaction for its standard value of 0.3 mm as the life of tools.

Development of a tool wear observer model for online tool condition monitoring and control in machining nickel-based alloys

Online monitoring and in-process control improves machining quality and efficiency in the drive towards intelligent machining. It is particularly significant in machining difficult-to-machine materials like super alloys. This paper attempts to develop a tool wear observer model for flank wear monitoring in machining nickel-based alloys. The model can be implemented in an online tool wear monitoring system which predicts the actual state of tool wear in real time by measuring the cutting force variations. The correlation between the cutting force components and the flank wear width has been established through experimental studies. It was used in an observer model, which uses control theory to reconstruct the flank wear development from the cutting force signal obtained through online measurements. The monitoring method can be implemented as an outer feedback control loop in an adaptive machining system.

20619 超音波振動ドリルを利用したFRP積層板の穴あけに関する研究 : 超音波振動の効果(振動音響利用,一般講演)

FRP composite materials are used for many structures because of high strength ratio. FPR composite material machined in order to connect to other materials. Surface roughness becomes large because of delamination. In this paper, drilling is focused on and machined surface is improved using ultrasonic vibration. Width of flank wear, thrust force and moment using ultrasonic cutting are compared with those using conventional cutting. It is found that width of flank wear is improved when ultrasonic cutting is used.

Effect of tool wear on rolling contact fatigue performance of superfinish hard machined surfaces

This study investigates the effect of tool wear on the rolling contact fatigue performance of superfinish hard machined surfaces. The rolling contact fatigue test results indicate that the flank wear width can contribute to the prediction accuracy of fatigue life model for the CBN tool with a tool nose radius of 0.79 mm. If the relationship between tool wear and the residual stress distribution and the relationship between tool wear and the micro-hardness distribution are established, it is expected that tool wear can contribute to the prediction accuracy of fatigue life model for more general conditions.

A tool wear observer model for flank wear monitoring in the milling of Nickel-based alloys

Tool wear monitoring is of great industrial importance in machining Nickel-based alloys. This paper presents the research effort to develop a tool wear observer model for flank wear monitoring in the milling of Nickel-based alloys. It aims at an online tool wear monitoring system that is capable of predicting tool wear in real time by measuring the cutting force variation. The correlation between the cutting force components and the flank wear width has been established through experimental studies. An observer model is developed to estimate the flank wear growth from the measured cutting force signals.

Assessment of flank wear and nose radius wear from workpiece roughness profile in turning operation using machine vision

Although literature on the measurement of flank wear and crater wear in single-point turning tools using machine vision is well documented, the study on the effect of nose radius wear on the roughness profile and dimensional changes of workpiece is less explored. The measurement of flank wear using the 2-D profile of the tool nose region or the roughness profile of the workpiece has also not been attempted in the past. In this work, the nose radius wear of cutting tools and roughness profile of turned parts in a lathe operation were measured using the machine vision method. The flank wear width VBC in the nose area was determined from the nose radius wear using the tool setup and machining geometry. The nose radius wear was also determined from the roughness profile of the workpiece and used in calculating the flank wear width. Comparison between the maximum flank wear width VBCmax determined from the roughness profile and that obtained using a toolmaker’s microscope showed a mean deviation of 5.5%. This result indicates that flank wear can be determined fairly accurately from the workpiece roughness profile if the tool and machining geometry are known.

B17 ホブ切り用水溶性切削油剤に関する基礎的研究 : pHの影響(OS-6 切削加工(3))

This paper presents the influence of pH of water-soluble cutting fluids with and without synthetic lubricating additive for hobbing; Fluid A and Fluid B, on the flank wear, using TiN- and (Al,Ti)N-coated tools. Experiments were conducted by simulating hobbingby fly tool cutting on a milling machine. The following result was clarified: When using both Fluid A and Fluid B, the flank wear decreases with decreasing pH, in which the FluidAhavingpH 8.0 and the Fluid B having pH 9.0 showed the smallest flank wear width with both TiN- and (Al,Ti)N-coated tools.

INFLUENCE OF MACHINING PARAMETERS ON THE WHITE LAYER FORMATION PROCESS AND ITS CHARACTERISTICS IN TURNING OF HARDENED STEEL

This article contains results of experimental research activities of white layer formation (WLF) and its characteristics during a process of turning hardened steels (THS), which have been carried out in laboratories of DD Cimos TMD Ai Gradačac. WLF. Characteristics during the THS process were analyzed from the aspects of influence caused by machining parameters as well as tool flank wear width. Experimental tests of tool wear have been performed. The tool used in experimental tool wear was ceramic cutting insert CNGA 120408T, catalogue mark IN22 Al2O3-TiCN. In accordance with achieved results, value of tool flank wear 220 µm has been set as the criterion of wear. In accordance with defined wear criterion, determination of level and type of influence that machining parameters have on WLF and its characteristics were carried out in accordance with planned experimental methodology. Experiments have shown that cutting speed and tool flank wear width (for all other machining conditions unchanged) can be used for control of WLF and its characteristics. Structural changes in surface layer of the working piece, during the cutting process of hardened material, except for the WLF are also presented through a transition zone, e.g., dark layer, which has lower hardness than the initial material. Hard WL can take over a protection role for a machined surface from abrasive actions, while softened zone (dark layer) can take over a function of WL solder with the initial material. Analysis of achieved results points to a possibility of controlling the WLF and its characteristics, and therefore a possibility of using WL in a positive context. The basis for the above mentioned is the effect of additional plastic deformation of WL (APDWL), which occurs only under certain machining conditions. The effect seen, if follows WLF, results in decrease of machined surface roughness compared to its expected value. Accordingly there is a possibility for identification of WL on a machined surface by measuring the roughness parameters without previous metallographic preparation of samples.

End Milling of Free-machining Steel for High Speed Machining

This paper deals with the machinability of BN added Steels in end milling. The cutting tests were carried out by end milling carbon steel JIS S45C, S55C and these BN added steels with carbide tool and TiAlN coated carbide tool. Tool wear, cutting temperature, and, surface roughness were measured and discussed. In end milling BN added steel with square end mill, the progress rate of flank wear width was decreased and fracture at corner was suppressed in comparison with that in machining standard steel. In case of ball end mill, flank wear in end milling BN added steels were smaller in comparison with standard steel. In case of S45C, boundary wear was observed, however it was not observed in end milling BN added steel. BN added showed almost the same surface roughness as standard steel. The temperature of flank wear part in turning work based S55C were 50 °C higher in comparison with S45C base work. The temperature of throw away end mill was higher 100°C in comparison with solid square end mill. There were not significant difference between the temperature in end milling standard steel and BN added steels.

Study on Mild-Cooling Air Machining (2nd Report)

The object in this report is to establish “Mild-Cooling Air Machining Method” that removes cutting heat by two ways, one is mild-cooling air jet spray on just cutting point and the other is cooling water, using water flow in passage made in cutting tool. In this report, the same experiments are curried out as reported in the first report by use of the heat removing method of combination with both holder cooling and mild-cooling air jet. The experimental results indicate that the flank wear width Wb and the ten-point average roughness Rzjis are made better in accordance with the decrease in the tip temperature difference Tc. Mild-cooling air machining method is more effective than using mild-cooling air jet or holder cooling method. The method to calculate heat flow rate released around the tool edge Δq is established by evaluating tool temperature distribution. Experimental equation for predicting Wb is proposed as a function of Δq, and it's accuracy is verified. It can be also confirmed that time constant of tip temperature rise is in proportion to Tc.

Diamond Turning of Special Stainless Steel by Applying Ultrasonic Vibration with Gas Shield

Ultrasonic vibration is applied to diamond turning of special stainless steel to decrease diamond tool wear and improve the surface quality of the workpieces. It reviews the principle of diamond turning of special stainless steel by applying ultrasonic vibration combined with gas shield. Compared with the ordinary machining method, cutting temperature and cutting force are greatly reduced when machining by application of ultrasonic vibration, and the appetency between a diamond tool and Ferrous atom of a workpiece is also minimized as gas shield application. The Experiments of cutting special stainless steel workpieces show that the surface roughness Ra is less than 0.15μm and flank wear-width is less than 5μm when cutting distance is up to 2000m. It takes research on the effect of cutting parameters to surface roughness and tool wear. The experiment result shows that the amplitude is the most important factor which effects tool wear and surface roughness most.

1506 切れ刃運動型切削加工特性の検討 : S45C旋削の場合(S75-2 高速・高精度加工(2),S75 高速・高精度加工)

With the aim of the remarkable improvement of tool life, in the previous research, the possibility of edge moving type of cutting method (EMT method), is examined roughly by turning of S45C steel again. From the result, the method is ascertained useful. The influence of edge moving speed and cutting speed on the wear rate and surface roughness, in the present report, is investigated by turning of S45C steel using the method. The width of flank wear becomes larger for higher edge moving speed. Low cutting speed has a bad influence on the surface roughness because the built-up edge occurs.

超精密切削加工されたAl合金の仕上げ面性状に及ぼす工具摩耗の影響（第１報）

Geometrical quality like surface roughness and accuracy of form has been very important in ultra-precision machining. However, because of improvement of quality of finished surface with progress of ultra-precision machining technology, quality of subsurface material like affected layer also becomes important lately. Workpieces are actually machined with a worn diamond tool in machining shops whereas ultra-precision cutting with a single crystal diamond tool is well known as a machining method owing high quality finished surface to a sharp cutting edge of the tool. The purpose of this study is to find out the relation between the tool wear and the work hardened layer and residual stress of a surface machined with a worn tool in ultra-precision cutting process. Wear of cutting edge with large nose radius was observed by a scanning electromicroscope at intervals of a fixed cutting distance. The surface hardness, depth of hardened layer, and residual stress of the machined surface were also measured at the intervals. As a result of experiments and considerations, it was concluded that depth of hardened layer, Vickers hardness, and residual stress increased with increase in tool flank wear and they could be generalized by undeformed chip thickness and width of flank wear at part of cutting edge generating finished surface.

Effect of the Contact Angle between the Cutting Edge and Surface of Cut on the Flank Wear Width in Turning Operations

In metal cutting studies, the flank wear width (VB) is commonly used as a criterion or as a limit
 measure for the cutting tool life. From the point view of this work, there is a critique concerning the traditional
 limit measure (vB). The researchers in this domain do not take the diameter of the work-piece into
 consideration. In this situation, the contact angle, between the tool and the work-piece, should be determined
 from the limit measure of flank wear width. This work deals with the effect of the work-piece diameter on the
 limit measures and proposes a related limit measure for each diameter' For the experimental approach, certain
 confirmation tests were achieved. It seems that the work-piece diameter could modify the limit measure and it
 could be increased for large diameters, or decreased for small ones.