Monitoring End-Mill Wear and Predicting Tool Failure Using Accelerometers

1999 ◽  
Vol 121 (4) ◽  
pp. 559-567 ◽  
Author(s):  
J. T. Roth ◽  
S. M. Pandit
Keyword(s):  
Early Warning ◽  
End Milling ◽  
Cutting Conditions ◽  
Catastrophic Failure ◽  
End Mill ◽  
Systems Methodology ◽  
Tool Failure ◽  
Detection Scheme ◽  
Acceleration Data ◽  
Life Tests

Autoregressive models are fit to end-milling acceleration data and the Data Dependent Systems methodology is utilized to isolate the modal energies of the first and second multiples of the tooth pass frequency. The modal energies are shown to be closely linked to the wear curve and a detection scheme is developed that is capable of tracking the end-mill’s wear and providing an early warning of impending failure. Six life tests are conducted under varying conditions to demonstrate the capabilities of the detection scheme: standard cutting conditions, extreme cutting conditions, premature catastrophic failure and accelerometer placement. In all six cases, the detection scheme was able to provide a warning of impending failure several centimeters before the failure occurred.

scholarly journals Influence of Chatter of VMC Arising During End Milling Operation and Cutting Conditions on Quality of Machined Surface

1970 ◽  
Vol 2 (1) ◽  
Author(s):  
A.K.M.N. Amin, M.A. Rizal, and M. Razman
Keyword(s):  
Surface Roughness ◽  
Metal Cutting ◽  
Metal Removal ◽  
End Milling ◽  
Cutting Speed ◽  
Cutting Conditions ◽  
End Mill ◽  
Machined Surface ◽  
Operating Cycle ◽  
Wide Range

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.

Development of a Cutting Direction and Sensor Orientation Independent Monitoring Technique for End-Milling

1999 ◽  
Author(s):  
John T. Roth ◽  
Sudhakar M. Pandit
Keyword(s):  
End Milling ◽  
Multivariate Models ◽  
Actual Event ◽  
Monitoring Technique ◽  
Sensor Orientation ◽  
Acceleration Data ◽  
Life Tests ◽  
Multivariate Autoregressive Models ◽  
Cutting Direction ◽  
Warning Time

Abstract In the authors’ previous work, univariate models were fit to acceleration data to predict impending tool failure. Numerous end-milling life tests, conducted under a wide variety of cutting conditions, demonstrated that the method could consistently warn of impending failure between 6 inches (15 cm) and 8 inches (20 cm) prior to the actual event. This paper presents an improved method that increases the warning time and allows the technique to function independent of the cutting direction or sensor orientation. Using multivariate autoregressive models fit to tri-axial accelerometer signals, monitoring indices are developed, verified and the results are compared with those from the univariate models. The multivariate models detected impending failure 30 inches (76 cm) prior to its occurrence, 23.5 inches (60 cm) earlier than with the univariate models. Furthermore, the multivariate models are able to monitor the condition of the tool, regardless of the cutting direction or sensor orientation.

Development of a Cutting Direction and Sensor Orientation Independent Monitoring Technique for End-Milling

1999 ◽  
Vol 122 (4) ◽  
pp. 671-677 ◽  
Author(s):  
John T. Roth ◽  
Sudhakar M. Pandit
Keyword(s):  
End Milling ◽  
Multivariate Models ◽  
Actual Event ◽  
Monitoring Technique ◽  
Sensor Orientation ◽  
Acceleration Data ◽  
Life Tests ◽  
Multivariate Autoregressive Models ◽  
Cutting Direction ◽  
Warning Time

In the authors’ previous work, univariate models were fit to acceleration data to predict impending tool failure. Numerous end-milling life tests, conducted under a wide variety of cutting conditions, demonstrated that the method could consistently warn of impending failure between 6 inches (15 cm) and 8 inches (20 cm) prior to the actual event. This paper presents an improved method that increases the warning time and allows the technique to function independent of the cutting direction or sensor orientation. Using multivariate autoregressive models fit to tri-axial accelerometer signals, monitoring indices are developed, verified and the results are compared with those from the univariate models. The multivariate models detected impending failure 30 inches (76 cm) prior to its occurrence, 23.5 inches (60 cm) earlier than with the univariate models. Furthermore, the multivariate models are able to monitor the condition of the tool, regardless of the cutting direction or sensor orientation. [S1087-1357(00)01003-0]

Optimization of Cutting Conditions with an End Mill According to the Criterion of the Smallest Amplitude of Vibration

2021 ◽  
Vol 1037 ◽  
pp. 239-244
Author(s):  
Dmitriy Y. Topolov ◽  
Igor S. Boldyrev
Keyword(s):  
Vibration Amplitude ◽  
End Milling ◽  
Cutting Speed ◽  
Forced Vibrations ◽  
Cutting Conditions ◽  
Cutting Condition ◽  
End Mill ◽  
Optimal Values ◽  
The Relationship

The article discusses the issues of chatter damping during milling. The relationship between the amplitude of forced vibrations and the cutting speed has been established. The choice of the optimal values ​​of the cutting condition during end milling is proposed to ensure the minimum vibration amplitude.

Condition Monitoring With Round Ceramic Inserts While Face Milling Using Acceleration Data

2010 ◽  
Author(s):  
Justin L. Milner ◽  
John T. Roth
Keyword(s):  
Condition Monitoring ◽  
End Milling ◽  
Low Cost ◽  
Milling Operations ◽  
Tool Monitoring ◽  
Wear Life ◽  
Acceleration Data ◽  
Life Tests ◽  
The Fourier Transform ◽  
Machining Operations

In order to automate machining operations, it is necessary to develop robust tool condition monitoring techniques. In this paper, a tool monitoring strategy for round whisker-reinforced ceramic end milling tools is presented based on the Fourier transform and statistical analysis of the vibrations of the tool during the machining operations. Using a low-cost tri-axial piezoelectric accelerometer, the presented algorithm demonstrates the ability to accurately monitor the condition of the tools as the wear increases during linear milling operations. One benefit of using accelerometer signals to monitor the cutting process is that the sensor does not limit the machines capabilities, as a workpiece mounted dynamometer does. To demonstrate capabilities of the technique for round coated and uncoated ceramic tooling, six tool wear life tests were conducted under various conditions. The indirect method discussed herein successfully tracks the tool’s wear, even with the occurrence of minor chipping, and is shown to be sensitive enough to provide sufficient time to replace the insert prior to damage of the machine tool, cutter, and/or workpiece.

Surface Roughness Identification in End Milling Using Vibration Signals and Fuzzy Clustering

2016 ◽  
Author(s):  
Issam Abu-Mahfouz ◽  
Amit Banerjee ◽  
A. H. M. Esfakur Rahman
Keyword(s):  
Surface Roughness ◽  
Fuzzy Clustering ◽  
Wavelet Transforms ◽  
Fourier Transforms ◽  
End Milling ◽  
Cutting Conditions ◽  
Depth Of Cut ◽  
Cutting Condition ◽  
Machined Surface ◽  
Vibration Signals

The study presented involves the identification of surface roughness in Aluminum work pieces in an end milling process using fuzzy clustering of vibration signals. Vibration signals are experimentally acquired using an accelerometer for varying cutting conditions such as spindle speed, feed rate and depth of cut. Features are then extracted by processing the acquired signals in both the time and frequency domain. Techniques based on statistical parameters, Fast Fourier Transforms (FFT) and the Continuous Wavelet Transforms (CWT) are utilized for feature extraction. The surface roughness of the machined surface is also measured. In this study, fuzzy clustering is used to partition the feature sets, followed by a correlation with the experimentally obtained surface roughness measurements. The fuzzifier and the number of clusters are varied and it is found that the partitions produced by fuzzy clustering in the vibration signal feature space are related to the partitions based on cutting conditions with surface roughness as the output parameter. The results based on limited simulations are encouraging and work is underway to develop a larger framework for online cutting condition monitoring system for end milling.

Analysis of Cutting Forces and Machining Error in Ball End Milling of Cylindrical Surfaces

2011 ◽  
Vol 328-330 ◽  
pp. 560-564
Author(s):  
Ba Sheng Ouyang ◽  
Guo Xiang Lin ◽  
Yong Hui Tang
Keyword(s):  
Cutting Forces ◽  
End Milling ◽  
Cutting Conditions ◽  
Machining Error ◽  
Machined Surface ◽  
Convex Surfaces ◽  
Machining Errors ◽  
End Mills ◽  
Tool Deflections ◽  
Cutting Modes

Cutting forces and machining error in contouring of concave and convex surfaces using helical ball end mills are theoretically investigated. The cutting forces are evaluated based on the theory of oblique cutting. The machining errors resulting from the tool deflections due to these forces are evaluated at various points of the machined surface. The influence of various cutting conditions and cutting modes on machining error is investigated and discussed.

Monitoring of End-Mill Temperature with Infrared Thermography and Wireless Tool Holder System

2014 ◽  
Vol 1017 ◽  
pp. 624-629 ◽  
Author(s):  
Masatoshi Shindou ◽  
Ryo Matsuda ◽  
Tatsuya Furuki ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama
Keyword(s):  
End Milling ◽  
Small Diameter ◽  
Sampling Time ◽  
End Mill ◽  
Monitoring Tool ◽  
Tool Temperature ◽  
Wireless System ◽  
Response Measurement ◽  
Tool Holder ◽  
Novel Method

Nowadays, infrared thermographic technology has been attracting attention in various industrial fields. We therefore focus on it as a novel method for monitoring tool temperature to improve end-milling conditions for difficult-to-cut materials. However, a problem has emerged; it is difficult to measure the tool temperature when there is a coolant because the coolant prevents monitoring of the surface of the end-mill tool. Thus, we developed a wireless tool holder system equipped with a thermocouple in the end mill to monitor the tool temperature under coolant conditions. In this report, we compared the temperature measured by infrared thermographic imagery with that measured by a wireless tool holder system when end milling the stainless steel under dry coolant conditions. The thermocouple, which has a small diameter of 0.12 mm, was used to ensure high response measurement in the proposed wireless tool holder. We obtained the tool temperatures by infrared thermographic imagery and by wireless tool holder equipped with a thermocouple at a sampling time of 1/30 of a second. We confirmed that the temperature measured by the wireless tool holder agrees with that measured by infrared thermographic imagery. As a result, we demonstrated that the developed method with a wireless system is effective to estimate the tool temperature in end-milling processes and makes it feasible to measure it under coolant conditions.

Surface Roughness Analysis for Radius End Mill in Cross Feed Direction Both Contour and Scanning Line Machinings

2020 ◽  
Author(s):  
Hirohisa Narita
Keyword(s):  
Surface Roughness ◽  
Inclination Angle ◽  
End Milling ◽  
Contour Line ◽  
End Mill ◽  
Good Surface ◽  
Corner Radius ◽  
Feed Direction ◽  
Scanning Line ◽  
Influence Degree

Abstract An optimum experimental condition, which realize good surface roughness in cross direction both contour and scanning lines, for radius end mill against some inclined surfaces is obtained and some features is these cutting processes is discussed in this paper. The optimum experimental condition, which consists of cutting type (or feed direction), spindle speed, feed rate, depth of immersion, inclination angle, corner radius of end mill and cross feed, is obtained and the influence degree of these parameters is calculated by using Taguchi method. The experiment is carried out based on L18 orthogonal array. Based on the influence degree and geometric contact status due to unique shape of radius end mill, some feature of radius end milling is introduced. As a result of the contour line machining, a scallop height is very influenced by the inclination angle and the corner radius, and surface machined by bottom edge must not be remained. Regarding the scanning line machining, “go-up” is good for the feed direction. Big corner radius is also suitable because side edge does not contact to workpiece. In other words, the cutting force in radial direction becomes small. Furthermore, the surface roughness of the scanning line machining is smaller than the one of the contour line machining.

Development of the cBN Electroplated End-Mill for High Precision Machining of CFRP

2020 ◽  
Author(s):  
Shinnosuke Yamashita ◽  
Tatsuya Furuki ◽  
Hiroyuki Kousaka ◽  
Toshiki Hirogaki ◽  
Eiichi Aoyama ◽  
...  
Keyword(s):  
Surface Roughness ◽  
End Milling ◽  
Drop Out ◽  
End Mill ◽  
Machined Surface ◽  
Side Milling ◽  
Reinforced Plastics ◽  
Milled Surface ◽  
Grinding Conditions ◽  
Grinding Tool

Abstract Recently, the demand of carbon fiber reinforced plastics (CFRP) has been rapidly increased in various fields. In most cases, CFRP products requires a finish machining like cutting or grinding. In the case of an end-milling, burrs and uncut fibers are easy to occur. On the other hand, a precise machined surface and edge will be able to obtain by using the grinding tool. Therefore, this research has been developed a novel the cBN electroplated end-mill that combined end-mill and grinding tool. In this report, the effectiveness of developed tool was investigated. First, the developed tool cut the CFRP with side milling. As the result, the cBN abrasives that were fixed on the outer surface of developed tool did not drop out. Next, the end-milled surface of CFRP was ground with the developed tool under several grinding conditions based on the Design of Experiment. Consequently, the optimum grinding condition that can obtain the sharp edge which does not have burrs and uncut fibers was found. However, surface roughness was not good enough. Thus, an oscillating grinding was applied. In addition, the theoretical surface roughness formula in case using the developed tool was formularized. As the result, the required surface roughness in the airplane field was obtained.

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