On-Line Tool Wear Estimation Using Force Measurement and a Nonlinear Observer

1992 ◽  
Vol 114 (4) ◽  
pp. 666-672 ◽  
Author(s):  
Jong-Jin Park ◽  
A. Galip Ulsoy
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Process Model ◽  
Metal Cutting ◽  
Flank Wear ◽  
Force Measurement ◽  
Nonlinear Observer ◽  
Model Parameters ◽  
Force Measurements ◽  
On Line

On-line tool wear monitoring in metal-cutting operations is essential for an on-line process optimization. In this paper, tool flank wear is estimated on-line by utilizing a nonlinear observer with the feedback of cutting force measurements. Based on a previously developed cutting process model for turning, a nonlinear observer is designed such that the estimated flank wear converges to the actual flank wear development in the presence of poor initial estimates. The stability analysis for the resulting observer error dynamic system is carried out using a physical limitation of the actual flank wear development and the Total Stability Theorem. The experimental results show that the proposed nonlinear observer estimates the flank wear quite well not only in the presence of poor initial estimates but also in the presence of unexpected fluctuations in the cutting force measurements. However, the method has drawbacks resulting from difficulties in obtaining accurate model parameters. An adaptive version of the presented nonlinear observer, periodically calibrated by off-line direct tool wear measurements using computer vision, is considered to be a promising strategy for industrial implementation.

Monitoring of Tool Wear Distribution With Cutting Force Measurement in Drilling

2020 ◽  
Author(s):  
Shoichi Tamura ◽  
Kodai Sekigawa ◽  
Takashi Matsumura
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Normal Force ◽  
Flank Wear ◽  
Force Measurement ◽  
Cutting Edge ◽  
Drilling Process ◽  
Machining Processes ◽  
Tool Performance ◽  
Edge Damage

Abstract In the automated machining processes, tool damage should be managed to assure product qualities, promote machine tool performance and reduce production time and cost. In drilling process, the cutting process changes along the cutting edge; and the tool wear is not uniform. This paper presents a monitoring of the tool wear distribution with measuring the cutting force in drilling with a twist drill. The cutting force increases with the cutting area in the edge penetration into workpiece in drilling. In the proposed approach, the cutting edges are divided into small discrete segments. The increasing rate of the cutting force at a segment is associated with the normal forces loaded at the cutting area. The normal force distributions, then, are estimated for the cutting edge damage. The widths of flank wear lands along the cutting edge is monitored based on the increase of the normal force distribution. The cutting tests were conducted to validate the presented approach with measuring the cutting force in drilling of carbon steel. The presented approach estimates the tool wear distribution on the edge with the cutting time. The average stress distribution loaded on the flank wear land is also estimated in the regression analysis.

Predictive Modeling of Flank Wear in Turning Under Flood Cooling

2006 ◽  
Vol 129 (3) ◽  
pp. 513-519 ◽  
Author(s):  
Kuan-Ming Li ◽  
Steven Y. Liang
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Metal Cutting ◽  
Flank Wear ◽  
Cutting Temperature ◽  
Machining Process ◽  
Analytical Models ◽  
Dynamic Strain ◽  
Process Conditions ◽  
Force Analysis

The objective of this paper is to present physical and quantitative models for the rate of tool flank wear in turning under flood cooling conditions. The resulting models can serve as a basis to predict tool life and to plan for optimal machining process parameters. Analytical models including cutting force analysis, cutting temperature prediction, and tool wear mechanics are presented in order to achieve a thermo-mechanical understanding of the tool wear process. The cutting force analysis leverages upon Oxley’s model with modifications for lubricating and cooling effect of overhead fluid application. The cutting temperature was obtained by considering workpiece shear deformation, friction, and heat loss along with a moving or stationary heat source in the tool. The tool wear mechanics incorporate the considerations of abrasive, adhesion, and diffusion mechanisms as governed by contact stresses and temperatures. A model of built-up edge formation due to dynamic strain aging has been included to quantify its effects on the wear mechanisms. A set of cutting experiments using carbide tools on AISI 1045 steels were performed to calibrate the material-dependent coefficients in the models. Experimental cutting data were also used to validate the predictive models by comparing cutting forces, cutting temperatures, and tool lives under various process conditions. The results showed that the predicted tool lives were close to the experimental data when the built-up edge formation model appropriately captured this phenomenon in metal cutting.

Erfahrungen mit alternativen Kraftmessungen/Experiences with alternative force measurements - Comparing sensor-integrated toolholders to traditional piezo-based measurement technology

2020 ◽  
Vol 110 (01-02) ◽  
pp. 24-31
Author(s):  
Patrick Georgi ◽  
Ssrah Eschelbacher ◽  
Thomas Stehle ◽  
Hans-Christian Möhring
Keyword(s):  
Cutting Force ◽  
Force Measurement ◽  
Milling Process ◽  
The Other ◽  
Strain Gauges ◽  
Measurement Technology ◽  
Optimal Parameters ◽  
Force Measurements ◽  
Measuring Systems ◽  
The One

Die Prozessüberwachung spielt in der Zerspanung eine immer wichtiger werdende Rolle. So können zum Beispiel mittels Zerspankraftmessungen ökonomisch optimierte Parameter in Zerspanprozessen gefunden werden, die zu einer Verbesserung der Auslastung von Werkzeug und Maschine führen. Des Weiteren kann über die Zerspankraft auf den aktuellen Verschleißzustand der Werkzeuge im Prozess sowie auf die jeweils erreichbare Bearbeitungsgenauigkeit zurückgeschlossen werden. Für Zerspankraftmessungen gibt es eine Vielzahl an zur Verfügung stehenden Kraftmesssystemen; zum einen traditionelle Messtechnik auf Basis von Piezosensoren zur Kraftmessung und zum anderen Kraftmesstechnik auf der Basis von Dehnmessstreifen (DMS). Dieser Beitrag untersucht die Kraftaufnahme bei Fräs- und Bohrprozessen, bei denen beide Kraftmesssysteme simultan eingesetzt wurden.   Process monitoring plays an increasingly important role in machining. For example, through cutting force measurements, it is possible to find economically optimal parameters in the milling process, which lead to an improvement in the utilization of the tool and the machine. Furthermore, the cutting force can be used to deduce the state of wear of the tools in the process. There are varieties of available force measuring systems for this purpose; on the one hand, traditional measuring technology based on piezo sensors for force measurement and the other force measuring technology based on strain gauges (strain gauges). This article examines the force absorption in milling and drilling processes where both force-measuring systems were used simultaneously.

scholarly journals Investigation of AlCrN-Coated Inserts on Cryogenic Turning of Ti-6Al-4V Alloy

Metals ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 1338
Author(s):  
Lakshmanan Selvam ◽  
Pradeep Kumar Murugesan ◽  
Dhananchezian Mani ◽  
Yuvaraj Natarajan
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Physical Vapor Deposition ◽  
Metal Cutting ◽  
Cutting Speed ◽  
Depth Of Cut ◽  
Machining Parameters ◽  
Machined Surface ◽  
Coated Carbide ◽  
Cryogenic Conditions

Over the past decade, the focus of the metal cutting industry has been on the improvement of tool life for achieving higher productivity and better finish. Researchers are attempting to reduce tool failure in several ways such as modified coating characteristics of a cutting tool, conventional coolant, cryogenic coolant, and cryogenic treated insert. In this study, a single layer coating was made on cutting carbide inserts with newly determined thickness. Coating thickness, presence of coating materials, and coated insert hardness were observed. This investigation also dealt with the effect of machining parameters on the cutting force, surface finish, and tool wear when turning Ti-6Al-4V alloy without coating and Physical Vapor Deposition (PVD)-AlCrN coated carbide cutting inserts under cryogenic conditions. The experimental results showed that AlCrN-based coated tools with cryogenic conditions developed reduced tool wear and surface roughness on the machined surface, and cutting force reductions were observed when a comparison was made with the uncoated carbide insert. The best optimal parameters of a cutting speed (Vc) of 215 m/min, feed rate (f) of 0.102 mm/rev, and depth of cut (doc) of 0.5 mm are recommended for turning titanium alloy using the multi-response TOPSIS technique.

On-Line Monitoring the Hard Turning Using Distribution Parameters of Acoustic Emission Signal

2015 ◽  
Vol 787 ◽  
pp. 907-911
Author(s):  
J. Bhaskaran
Keyword(s):  
Acoustic Emission ◽  
Tool Wear ◽  
Hard Turning ◽  
Metal Cutting ◽  
Cubic Boron Nitride ◽  
Emission Signal ◽  
Distribution Parameters ◽  
On Line ◽  
Ae Signal ◽  
Wear Monitoring

In hard turning, tool wear of cutting tool crossing the limit is highly undesirable because it adversely affects the surface finish. Hence continuous, online tool wear monitoring during the process is essential. The analysis of Acoustic Emission (AE) signal generated during conventional machining has been studied by many investigators for understanding the process of metal cutting and tool wear phenomena. In this experimental study on hard turning, the skew and kurtosis parameters of root mean square values of AE signal (AERMS) have been used for online monitoring of a Cubic Boron Nitride (CBN) tool wear.

Predictive Models for Flank Wear in Near Dry Machining

2005 ◽  
Author(s):  
Kuan-Ming Li ◽  
Steven Y. Liang
Keyword(s):  
Tool Wear ◽  
Cutting Force ◽  
Flank Wear ◽  
Cutting Temperature ◽  
Dominant Factor ◽  
Force Model ◽  
Temperature Model ◽  
Dry Machining ◽  
Cutting Force Model ◽  
Wear Model

The objective of this paper is to present a methodology to analytically model the tool flank wear rate in near-dry turning. The resulting models can serve as a basis to minimize time-consuming machining tests in predicting tool life. Analytical models, including cutting force model, cutting temperature model, and tool wear model, are presented. The cutting force model was established based on Oxley’s model with modifications for lubricating and cooling effect due to the air-oil mixture in near-dry machining. The cutting temperature was obtained by considering a moving or stationary heat source in the tool. The tool wear model contained abrasive mechanism, adhesion mechanism, and diffusion mechanism. The important factors related to this model were contact stresses and temperatures that were obtained from the cutting force model and the cutting temperature model. To develop these models, a set of cutting experiments using carbide tools on AISI 1045 steels were performed to calibrate the coefficients in the models and to verify the proposed flank wear mechanisms. The comparisons between the model-predictive flank wear and experimental results showed that the flank wear in near dry machining can be estimated well by the proposed models. It was also found that the cutting velocity was a dominant factor among the cutting conditions.

Analytical Investigation of the Effect of Tool Wear on the Temperature Variations in a Metal Cutting Tool

1976 ◽  
Vol 98 (1) ◽  
pp. 251-257 ◽  
Author(s):  
E. K. Levy ◽  
C. L. Tsai ◽  
M. P. Groover
Keyword(s):  
Wear Rate ◽  
Tool Wear ◽  
Metal Cutting ◽  
Analytical Study ◽  
Analytical Investigation ◽  
Transient Temperature ◽  
Temperature Variations ◽  
Line Measurement ◽  
On Line ◽  
Metal Cutting Tool

An analytical study of the effect of crater wear on the response of a remote thermocouple sensor is described. The remote thermocouple sensor is at present being developed as a device for the on-line measurement of tool wear. This technique depends for its operation on the strong influence of wear on the transient temperature variations in the tool. The two-dimensional transient temperature variations in the chip and tool regions are determined using a numerical finite-difference technique. Results are obtained under idealized cutting conditions with a zero wear rate, a normal wear rate, and an accelerated wear rate. Comparisons are made between the three cases to develop relationships for the effect of wear on the temperature at the remote thermocouple location.

On-Line Flank Wear Estimation Using an Adaptive Observer and Computer Vision, Part 2: Experiment

1993 ◽  
Vol 115 (1) ◽  
pp. 37-43 ◽  
Author(s):  
Jong-Jin Park ◽  
A. Galip Ulsoy
Keyword(s):  
Computer Vision ◽  
Flank Wear ◽  
Vision System ◽  
Adaptive Observer ◽  
Cutting Conditions ◽  
Model Parameters ◽  
Computer Vision System ◽  
Integrated Method ◽  
On Line ◽  
The Difference

An on-line flank wear estimation system, using the integrated method presented in Part 1 of the paper, is implemented in a laboratory environment, and its performance is evaluated through turning experiments. A computer vision system is developed using an image processing algorithm, a commercially available computer vision system, and a microscopic lens. The developed algorithm is based on the difference between the intensity of the reflected light from a flank wear surface and that from the background. The difference is very significant and an appropriate selection of the intensity threshold level yields an acceptable binary image of the flank wear. This image is used by the vision computer for the calculation of the flank wear. The flank wear model parameters that need to be known a priori are determined through several preliminary experiments, or from data available in the literature. Cutting conditions are selected to satisfy the assumptions made on the design of the adaptive observer presented in Part 1. The resulting cutting conditions are typical of those used in finishing cutting operations. The integrated method is tested in turning experiments under both constant and time varying cutting conditions, and yields very accurate on-line estimation of the flank wear development.

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