Evaluation Of Tool Wear Research Articles

Experimental evaluation of tool wear throughout a continuous stroke blanking process of quenched 22MnB5 ultra-high-strength steel

Steel is the most common material used in vehicles’ chassis, which makes its research an important topic for the automotive industry. Recently developed ultra-high-strength steels (UHSS) provide extreme tensile strength up to 1,500 MPa and combine great crashworthiness with good weight reduction potential. However, in order to reach the final shape of sheet metal parts additional cutting steps such as trimming and piercing are often required. The final trimming of quenched metal sheets presents a huge challenge to a conventional process, mainly because of the required extreme cutting force. The high cutting impact, due to the materials’ brittleness, causes excessive tool wear or even sudden tool failure. Therefore, a laser is commonly used for the cutting process, which is time and energy consuming. The purpose of this paper is to demonstrate the capability of a conventional blanking tool design in a continuous stroke piercing process using boron steel 22MnB5 sheets. Two different types of tool steel were tested for their suitability as active cutting elements: electro-slag remelted (ESR) cold work tool steel Bohler K340 ISODUR and powder-metallurgic (PM) high speed steel Bohler S390 MICROCLEAN. A FEM study provided information about an optimized punch design, which withstands buckling under high cutting forces. The wear behaviour of the process was assessed by the tool wear of the active cutting elements as well as the quality of cut surfaces.

Deep hole drilling of AISI 1045 via high-speed steel twist drills: evaluation of tool wear and hole quality

Review of the available literature has revealed that limited data has been reported on tool wear pattern of twist drills and hole quality for the case of deep hole drilling of AISI 1045. Considering that AISI 1045 has widespread applications as mould material, this paper presents the findings of an experimental investigation on the performance of high-speed steel twist drills of 10-mm diameter for drilling deep holes with L/D >10 in AISI 1045. It is found that the combination of the lowest spindle speed (200 rpm), feed rate (10 mm/min) and peck depth (3 mm) results in better tool life producing 32 holes. Maintaining the lowest spindle speed and feed rate and an increase in peck depth from 3 to 5 mm deteriorated tool life by ~18% due to restricted cooling during the cut. All variable factors were found to be significant with feed rate showing the highest percentage contribution (PCR) of ~50%. Evaluation of the cutting tool indicated fracture at the chisel edge and built-up edge (BUE) formation in all trials. As for the hole quality, it is seen that test performed at 5-mm peck depth outperforms the test conducted at 3 mm producing better surface finish and less errors associated with diameter, roundness and cylindricity. This can be attributed to lesser numbers of times the tool re-engages with workpiece for the case of higher peck depth to reach desired depth thus translating into better stability and reduced errors. A strain hardened layer extending up to the depth of 300 μm was observed irrespective of peck depth and number of holes drilled. Approximately, 30% higher hardness on average was observed in close vicinity of the machined surface (within 30 μm).

Composite Fiber Reinforced Plastic one-shoot drilling: Quality inspection assessment and tool wear evaluation

This work focuses on the analysis of Composite Fiber Reinforced Plastics (CFRP) drilling performed during the assembly of aeronautical components. One-shoot operations are desired to minimize positional errors, enhance tight tolerances and reduce process time. Also, it is usually included the countersinking cycle to maintain the aerodynamic shape of the component.Wear testing was carried out on test specimens representative of aeronautical materials and with cutting parameters similar to real production in order to increase composites drilling know-how and improve efficiency of the operations by extending the useful life of the tools.

Tool material, tool wear and machined hole quality evaluation at CFRP drilling

Because of increasingly stricter safety rules, requirements regarding the quality of the components used in the airline industry have increased. Besides the materials used in aircraft components and areas where they are machined, these components must comply certain standards for quality and tolerances of the machined surfaces.Due to high hardness of carbon fibers, hole machining in carbon fiber reinforced plastics has always been a challenge. Wear that occurs in the cutting tool leads to the appearance of workpiece defects such as delamination, peeling, fiber pulling out, etc. Besides cutting tool geometry, a very important role on tool wear, it is owned by the material from which it is made. This paper will make a quantitative assessment of defects that occur in the process of CFRP (carbon fiber reinforced plastics) drilling and a cutting tool wear evaluation. In order to obtain conclusive results for this study will be used three drill bits with the same geometry but different carbides.The aim of this paper is to find which one of this three carbide used is more feasible for holes machining in composite materials reinforced with carbon fibers.

Evaluation of tool wear in EPB tunneling of Tehran Metro, Line 7 Expansion

Wear of cutting tools and other components of the pressurized face tunnel boring machine which come in contact with the muck is an important parameter in soft ground tunneling. This is due to the need for cutterhead inspection and tool maintenance under pressurized conditions or “hyperbaric interventions” which is a time consuming, dangerous, risky, and costly activity. This study investigates the tool wear of an EPB-TBM used in Tehran metro line 7 over the initial 6500m of tunnel. The ground along the tunnel alignment is mostly alluvial deposits, composed of gravely sand with clay/silt and sandy gravel with clay. In this project, the number of cutting tools replaced were 1169, including 654 rippers, 357 scrapers and 153 disc cutters. In this paper the influence of geological parameters and operational factors on tool wear is examined. The results show that by increasing TBM thrust, earth pressure, and torque, the cutter consumption generally increases. Also, soil conditioning plays an important role in controlling cutter wear, so that the tool wear can be reduced even in coarse-grained soils by improving the soil conditioning parameters. Quantitative analysis of these parameters for this project and a brief discussion of their implications is offered. Also, multiple linear regression analysis was used to seek the best correlation between the cutter wear and ground / opening variables, and correlation coefficient of up to 0.98 have been observed. This highlights the potential of developing models for tool wear prediction by multiple regression, if sufficient data is collected in soft ground tunneling projects.

Tool Wear Evaluation of Selected Inserts after Turning by Electron Microscopy

Using of cutting inserts is currently a normal part of the manufacturing process. The article deals with the tool wear evaluation of selected inserts for turning by electron microscopy. Use of electron microscopy helps on closer analysis of machining consequences forthese plates, because the microscope images captured with electronmicroscope have a greater depth of sharpness and can display examined object with greater plasticity. It is yet another way to explore objects and extends the possibilities for obtaining large quantities of information. These analyzes were realized in other experiments performed at the Faculty of Production Technology and Management of Jan Evangelisty Purkyně University in Usti nad Labem. As a experimental material the hardened steel class 16 343 according to CSN 41 0002 has been machining.

High-Speed Edge Trimming of CFRP and Online Monitoring of Performance of Router Tools Using Acoustic Emission.

Carbon fiber reinforced polymers (CFRPs) have found wide-ranging applications in numerous industrial fields such as aerospace, automotive, and shipping industries due to their excellent mechanical properties that lead to enhanced functional performance. In this paper, an experimental study on edge trimming of CFRP was done with various cutting conditions and different geometry of tools such as helical-, fluted-, and burr-type tools. The investigation involves the measurement of cutting forces for the different machining conditions and its effect on the surface quality of the trimmed edges. The modern cutting tools (router tools or burr tools) selected for machining CFRPs, have complex geometries in cutting edges and surfaces, and therefore a traditional method of direct tool wear evaluation is not applicable. An acoustic emission (AE) sensing was employed for on-line monitoring of the performance of router tools to determine the relationship between AE signal and length of machining for different kinds of geometry of tools. The investigation showed that the router tool with a flat cutting edge has better performance by generating lower cutting force and better surface finish with no delamination on trimmed edges. The mathematical modeling for the prediction of cutting forces was also done using Artificial Neural Network and Regression Analysis.

An in-process tool wear evaluation approach for ultra-precision fly cutting

Ultra-precision fly cutting (UPFC) is an intermittent cutting process, which is widely used in the fabrication of non-rotational symmetric micro structures with sub-micron form accuracy and nanometric surface roughness. In UPFC, the occurrence of tool wear certainly affects the accuracy of machined micro structures. Aimed at the close relations between tool wear and chip morphologies and the truth that cutting chips are fully formed in a cutting cycle, this research developed a tool wear evaluation approach based on cutting chips. Chip morphology features related to tool failure patterns were identified and then parameterized to predict the tool failure patterns, the surface topography, and surface roughness under the effects of tool failure patterns. Predictions were then verified by experimental results. Research results show that chip morphologies were successfully used to present tool failure pattern, following the well-designed identification procedures, the tool failure patterns are accurately identified. This approach is practical since it can in-process identify tool failure patterns and their effects on surface quality.

Investigation of Stress Formation and Wear Effect of Tool by Finite Element Simulation

The paper presents aspects related to simulation of metal cutting for titanium and its alloys. Detailed study on progression and wear mechanism at the cutting edge of carbide tools were carried out at cutting speed of 30, 60 and 90 m/min, feed rate of 0.2 mm/rev. Firstly, milling finite element model is given based on orthogonal cutting principle, and then the influence laws of cutting parameters on chip formation are analyzed by using different simulation parameters. For simulations, the software based on finite element method DEFORM 2D was used. Machining simulations were conducted using Ti6Al4V and uncoated carbide for workpiece and tool material respectively. DEFORM 2D, a widely used software tool employed for modelling and simulating the orthogonal machining process with different cutting speeds and feed rates. The pattern of wear progression on the flank face of the carbide tools consist of three stages for all the cutting speed simulated. Wear mechanism such as abrasive and adhesive wear were observed on the flank face. Crater wear due to diffusion was also observed on the rake race. The flank wear results most commonly from abrasion on the cutting edge of the tool. The maximum land width is used as an indication of the extent of the flank wear. The severity of the flank wear increases until a critical point is reached. Abrasion and deformation resistance of the tool material can be increased in order to minimize the flank wear. In order to investigate the cutting tool stress analysis, FEM is conducted with ANSYS software. The overall objective of this study is to develop a methodology to predict the tool wear evaluation and stress formation in orthogonal cutting.

Tool Wear Monitoring and Hole Surface Quality During CFRP Drilling

The present investigation focuses on the evaluation of tool wear and surface integrity in the context of CFRP cutting. Series of drilling experiments were performed on CFRP plates using cemented carbide solid drills with the aim to investigate correlations between tool damage, cutting forces, temperature and hole surface quality. In particular, a new methodology has been developed to measure the drilling temperature and to assess the quality of the hole surfaces where occurred uncut fibers. As the surface roughness criterion is not relevant for such work materials, a discussion on the definition of the surface topography is proposed for CFRP work material.

Influence of strontium in AlSi7Mg0.3 alloy on the tool wear

Al-Si alloys are leading casting alloys based on aluminum. Machining of aluminum alloys is currently frequently used and it is an important area of production. The paper deals with an experiment that was conducted at the Faculty of Production Technology and Management, University of Jan Evangelista Purkyně in Usti nad Labem, where was machined alloy AlSi7Mg0,3. Samples were made for processing from the master alloy AlSi7Mg0,3, subsequently unmodified and modified of strontium Sr. This paper describes the evaluation of tool wear in terms of how or strontium modification may affect (reduce) the tool wear.

Methodology of evaluation of abrasive tool wear with the use of laser scanning microscopy

Grinding is one of the basic precise material removal methods. Abrasive and shape wear, as well as smearing of the tools' active surface handicap the processing results. The loss of cutting capacity in abrasive tools or alteration of their shape influences the surface quality and precision of the workpiece dimensions and its shape. Evaluation of the abrasive tool surface is the basic criterion of forecasting the tools' durability and the process results. The applied method of laser scanning made determination of the surface coordinates and subsequently of its geometric features with micrometric accuracy possible. Using the information on the abrasive tool surface geometric structure, a methodology of evaluation of the level of changes in geometric features of the tool during the grinding process was developed. Criteria for evaluation of the level of abrasive grains attritious wear, the degree of smearing of the abrasive tool surface and evaluation of the cutting capability of the abrasive tools were determined. The developed method allowed for evaluation of the level of abrasive tools' wear, and subsequently formed foundations for assessment of the influence of the grinding parameters on the durability of abrasive tools, evaluation of the influence of the parameters of the process of shaping the abrasive tools' active surfaces on their geometric characteristics and evaluation of the level of correlation between the monitored process parameters and the degree of the abrasive tools' wear.

FVM based Methodology for Evaluating Adhesion Wear of Cutting Tools

In the machining processes, surface quality of the worked pieces depends strongly on the tool conditions. Tool wear has, by that, a determinant influence on the surface finishing quality of the machined products. Tool wear has been commonly associated with the loss of tool material. Standards, procedures and methodologies have been developed for evaluating tool wear under that idea. How- ever, currently, the tool wear concept must be considered in a wider meaning. In effect, nowadays, tool wear must be related to the changes in the cutting tool caused by the machining process. These changes contain both its geometrical and physicochemical prop- erties variations. The first of them involves not only the loss of material but also the incorporation of machined material to the cut- ting tool, as in the secondary adhesion wear, where workpiece material is adhered to the tool in two well-defined zones: rake face, giving rise to the Built-Up Layer (BUL); edge and clearance face, giving rise to the Built-Up Edge (BUE). Up to the present, the evaluation of BUL and BUE has not been satisfactorily solved and, by that, the secondary adhesion tool wear is hardly evaluated. Only some indirect methods can be found based in output variables and parameters (Cutting Forces, Surface Quality Parameters). In this paper, a BUL and BUE measuring methodology, based in the reproduction of BUL-BUE 3D surfaces through Focus Varia- tion Microscopy, has been proposed. This methodology can serve as a first reference for standardizing the evaluation of secondary adhesion tool wear.

Statistical analysis of acoustic emission signals generated during turning of a metal matrix composite

Acoustic emission technique (AET) has been used to monitor the progress of tool wear during turning of silicon carbide (20 wt.%) dispersed Al alloy metal matrix composite. Acoustic emission (AE) signals generated beyond a specific cutting distance increase abruptly. Statistical analysis based on assumed β distribution of AE energy showed that skewness and kurtosis vary with cutting time. Comparison of these results with bparameter of amplitude distribution of AE hits presented in an earlier investigation has shown that while b-parameter is useful for monitoring tool wear up to 0.4 mm, skewness and kurtosis can better monitor the wear beyond that. Uncertainty measurement of AE energy for different cutting distances was determined as per ISO GUM. The combined uncertainty for the measurement of AE energy lies in the range of 0.38 to 1.69, with higher values for the cutting distance between 213.8 mm and 454.5 mm. Different parameters such as skewness and kurtosis of the statistical distribution, b-parameter of amplitude distribution and uncertainties can be used in a complimentary manner for comprehensive evaluation of tool wear.

Tool wear for lesser known tropical wood species

This study investigated the relationship between tool wear and some chemical and physical properties for four different Mozambican lesser known tropical species,: Pseudolachnostylis maprounaefolia (ntholo), Sterculia appendiculata (metil), Acacia nigrescens (namuno) and Pericopsis angolensis (muanga). Tool wear is an important aspect for sawmilling and for the woodworking industry. For Mozambique, the utilization of available lesser known wood species will help to increase domestic industry and the economic usage viability of sustainable forest management. A set of experiments was performed on a shaper with a mechanical feed mechanism. Tools of a cemented carbide grade for woodworking were used, and the cutting parameters were fixed. Edge recession and tool wear radius were measured for monitoring tool wear. The wear mechanism was investigated using a scanning electron microscope. The experimental results showed that the chemical properties of the wood species have a great effect on tool wear. Wood silica content was the most important factor affecting tool wear. Wood density and extractives had a low influence on tool wear. The highest tool wear was observed in ntholo, which also had the highest ash and silica contents. A single parameter for evaluation of tool wear was not sufficient to describe the amount of total tool wear.

505 フラクタル次元による工具摩耗の評価(切削・研削・研磨加工I)

505 フラクタル次元による工具摩耗の評価(切削・研削・研磨加工I)

Tool wear evaluation in drilling by acoustic emission

A drilling process with different degrees of wear in the drill bit was studied to find relationships between acoustic emission (AE) and torque measured during the drilling process, and also with the degree of wear of the tool.SAE 1040 steel samples were drilled, making holes with 5 mm diameter twist drill bits in continuous feed. The drill bits were modified with “artificial” (produced by spark-erosion) and “real” (obtained by regular mechanical use) failures such as different degrees of wear in the cutting edge and the outer corner. For every drilled hole, torque and AE were simultaneously measured and acquired.In the first part of this work, the correlation between the AE parameters and torque measured during the drilling process is studied. Torque was measured as a control parameter to follow the dynamic behaviour of the drill bit. An alternative AE feature, called Mean Power (MP) showed a good correlation with torque when the moving average (MA) was computed.In the second part, the AE mean power (MP) was related to different degrees of wear in drill bits. Clusters for the different levels of wear in a 2-D plot were obtained. In that plot the moving variance of the MP vs. the moving average of the MP, for each case of wear, were represented.This application aims at repetitive manufacturing operations, where many signals per second may be obtained with fixed parameters as shape, drill bit diameter, spindle speed, feed, and a good statistical study can be done.

Criterion to evaluate diffusive wear in 3D simulations when turning AISI 1045 steel

This paper deals with the simulation of cutting processes. In particular, 3D FE simulations were carried out in order to estimate tool wear development during turning operations. An analytical model taking into account diffusive wear mechanism has been implemented in a proper software subroutine for the tool wear evaluation. Preliminarily conducted experimental tests allowed the analytical expression coefficients evaluation. The adopted wear model gave the possibility of correctly defining the tool wear during both the (initial) transient phase and the steady-state of the analyzed turning operation. A comparison between experimental and simulative results showed a general good agreement. The final goal of the research is to identify a FE based strategy to be reliably used to forecast tool geometry and cutting parameters influences on tool wear.

Tool condition monitoring in micromilling based on hierarchical integration of signal measures

This paper presents a tool wear monitoring strategy in micromilling of cold-work tool steel, 50 HRC with a ball endmill d = 0.8 mm. The strategy is based on a large number of AE and cutting forces signal features and a hierarchical algorithm. In the first stage of the algorithm, the tool wear is estimated separately for each signal feature. In the second stage, the results obtained in the first stage, are integrated into the final tool condition evaluation. The obtained results prove that the proposed algorithm enables reliable evaluation of tool wear in spite of strongly disturbed signal features.

202 フラクタル次元による工具摩耗の評価(切削・研削・研磨加工I)

202 フラクタル次元による工具摩耗の評価(切削・研削・研磨加工I)