Evaluation Of Tool Wear Research Articles

Evaluation of physical indicators and tool wear during grooving of spheroidal cast iron with a novel WCCo/cBN (BNDCC) inserts

The WCCo/cBN (Boron Nitride Dispersed Cemented Carbide – BNDCC) cutting inserts fabricated by PPS (pulse plasma sintering) method constitute the novel tool materials with advantages of cemented carbide and cubic boron nitride tools. However, the cutting properties of these materials are not yet recognized. Therefore, this work is focused on the identification of BNDCC tools cutting performance during the grooving process of a hard-to-cut N-GJLA-XNiCuCr 15-6-2 spheroidal cast iron. The conducted studies involved the evaluation of a fundamental cutting process physical indicators, as cutting forces, vibrations and average coefficient of friction on the rake face. The tool wear mechanisms and tool life of the uncoated and coated (with TiN and TiAlN coatings) BNDDC inserts were identified and compared with ones obtained during cutting with a coated and uncoated cemented carbide (H3 and H10) tools. The obtained results showed that the adhesion wear mechanism of the coated and uncoated BNDCC inserts was dominant throughout the entire range of cutting speed. The application of the novel BNDCC inserts during grooving of spheroidal cast iron is more advantageous in terms of tool life, comparing to the coated cemented carbide inserts.

Evaluation of tool wear, energy consumption, and surface roughness during turning of inconel 718 using sustainable machining technique

Heat resistant alloys such as Inconel 718 present challenges to manufacturing industries during its machining. Machinability of such alloys can be improved using smart cutting conditions. Further, to seek improvements in the machinability of Inconel 718, this assessment evaluates industry-relevant machinability indicator, i.e., tool wear in terms of both flank and crater wear under indigenously developed cryogenic turning technique and compares the results with conventional dry and wet turning techniques. Experimental results show a massive improvement (133%) in tool life under cryogenic turning as compared with the dry turning. However, tool life obtained under wet and cryogenic turning is comparable. In the second part of this paper, industry-relevant machinability indicators namely energy consumption, chip reduction coefficient (CRC), and average surface roughness (Ra) were critically examined at different material removal rates (MRR) for turning of Inconel 718 under different cutting environments. A total 24 number of experiments were designed using full factorial considering two levels of cutting speed (vc) i.e., 45 and 60 m/min, four levels of feed (fr) i.e., 0.03, 0.06, 0.12, and 0.24 mm/rev, and three cutting conditions (dry, wet, and cryogenic). The results show that energy consumption in cryogenic turning reduced up to 8–17% when compared with dry and wet turning. Ra values for cryogenic turning also reduced up to 20–37% in comparison to dry and wet turning at various MRR. Improved tool life, reduced energy consumption, and Ra values obtained under cryogenic turning echo its potential to replace unsustainable conventional machining practices.

Evaluation of tool wear, surface roughness/topography and chip morphology when machining of Ni-based alloy 625 under MQL, cryogenic cooling and CryoMQL

Although nickel-based aerospace superalloys such as alloy 625 have superior properties including high-tensile and fatigue strength, corrosion resistance and good weldability, etc., its machinability is a difficult task which can be solved with alternative cooling/lubrication strategies. It is also important that these solution methods are sustainable. In order to facilitate the machinability of alloy 625 with sustainable techniques, we investigated the effect of minimum quantity lubrication (MQL), cryogenic cooling with liquid nitrogen (LN2) and hybrid-CryoMQL methods on tool wear behavior, cutting temperature, surface roughness/topography and chip morphology in a turning operation. The experiments were performed at three cutting speeds (50, 75 and 100 m/min), fixed cutting depth (0.5 mm) and feed rate (0.12 mm/rev). As a result, CryoMQL improved surface roughness (1.42 µm) by 24.82% compared to cryogenic cooling. The medium level of cutting speed (75 m/min) can be preferred for the lowest roughness value and lowest peak-to-valley height when turning of alloy 625. Further, tool wear is decreased by 50.67% and 79.60% by the use of MQL and CryoMQL compared with cryogenic machining. An interesting result that MQL is more effective than cryogenic machining in reducing cutting tool wear.

Tool wear evaluation based on vibration analysis during milling of MMC using diamond coated end mills

The aim of the research was to analyze the wear of the end mills based on the measurement of mechanical vibration accelerations. The VBB index was used as the tool wear criterion, which was measured until a specific maximum wear was obtained. The paper compares the tool wear values at different cutting speeds and determines the possibility of predicting the state of the tool wear based on the measurements of mechanical vibration accelerations.

Evaluation of tool scraping wear conditions by image pattern recognition system

An image pattern recognition system, consisting of a CMOS camera, a set of illumination devices, and a lab-developed machine vision image analysis software, has been developed for evaluation of tool scraping wear conditions. The images of the scraped surface texture on the workpiece were generated by lab-developed automatic scraping machine under controlled conditions; the image was first transformed by Haar wavelet transform with Otsu’s algorithm to discriminate the vertical details of surface patterns, and they were then emphasized by weighted calculations according to tool scraping wear conditions. The experimental results show that the average difference between the data obtained from the surface image analysis and the roughness measurement is about ± 2%, proving the feasibility of the proposed system. Furthermore, a statistic analysis reveals that the standard deviation of the non-zero proportion of the medium frequency domain obtained by image processing might be considered a significant reference for tool replacement. For the field applications, the proposed system provides the capability of online scraping tool wear evaluation for scraping process in manufacturing site, compared with the traditional scraping tool wear evaluation method, which was time consuming; user needs to remove the workpiece to measure instrument.

Cutter wear evaluation from operational parameters in EPB tunneling of Chengdu Metro

Cutterhead inspection and maintenance is an important reason for operational delays in EPB tunneling project. In order to minimize the number of maintenance stops, non-entry evaluation of cutter wear is required. This study introduces a new prediction model for cutter wear based on automatically recorded operational parameters including cutterhead torque, rotational speed and flow rate of foaming liquid. Real-time operational data was processed to obtain two robust input variables including work done by cutterhead torque and volume of foaming liquid. Field data from 20 tunnel sections of Chengdu Metro were then analyzed to develop quantitative relationships between the two input variables and cutter wear. These tunnel sections were excavated by two types of EPB machines in gravels and weathered rocks. The analyzed real-time operational data covers an excavated length of 14140 m. To ignore the influence of tunnel diameter, prediction model of cutter wear per unit volume of excavation was also developed. The proposed models provide reasonable evaluation of tool wear (R2 up to 0.857) in gravels and weathered rocks, for which cutter wear prediction based on geological parameters is rather difficult because of huge variation of the materials.

Evaluation of tool wear in high-speed face milling of Al/SiC metal matrix composites

In recent years, a new generation of composite materials has been introduced as metal matrix composites (MMCs) in order to simultaneously provide higher strength and stiffness. Industrial interests resulted in deep investigations and researches on machinability of MMCs and especially in the field of high-speed machining. High-speed machining processes offer a higher machining efficiency and reduced cost of the process, which made them the process of interest in many manufacturing industries. However, matrix reinforcement by addition of hard particle phases to the MMCs significantly increases machining difficulty, tool wear, surface quality deterioration and overall fabrication costs. In the current research, the cutting speed, feed rate, depth of cut, presence of cryogenic coolant and their effect on the tool wear of high-speed machining of Al/SiC MMC reinforced with 15 wt% SiC particles have been investigated. The results have shown that silicon carbide particles in the aluminum matrix cause a severe tool wear. However, the severity of tool wear has decreased by applying a cryogenic cooling.

Tool wear evaluation under minimum quantity lubrication by clustering energy of acoustic emission burst signals

Tool wear evaluation by Acoustic Emission (AE) is a promising non-destructive technique without stopping the machine, which can save its off-line detection time and prevent tool re-clamping error. However, the traditional tool wear evaluated by AE continuous signals Root Mean Square (RMS) is inaccurate and relative difficult especially when machining ductile material, not to mention it’s evaluation under the Minimum Quantity Lubrication (MQL). Thus, this paper proposes a non-destructive method of tool wear evaluation by clustering energy of AE burst signals under MQL cutting condition. The interface AE burst signals are firstly eliminated by properly setting the AE parameters including threshold, rise time and duration time. Then, AE burst signals are identified to three categories, which are induced by MQL, material fracture and plastic deformation. Finally, the relationship between tool flank wear and AE burst signals are established by clustering AE energy. The results show that tool flank wear can be accurately evaluated by linear fitting total energy of AE burst signals induced by fracture and plastic deformation.

Comparative study of PVD and CVD cutting tools performance in milling of duplex stainless steel

The machining process evolution has been accompanied by the improvement of tool performance, being this mainly due to the development of thin coatings, mono and multi-layered, providing the most appropriate set of properties for each machining condition. On the other hand, duplex stainless steels have registered a strong increase in demand, which, in many cases, requires the use of machining processes in order to obtain the final shape accurately. Taking into account these two aspects, this paper aims essentially to evaluate the performance of two cutting inserts with PVD and CVD coatings, used in rough milling operations of duplex stainless steel. The cutting parameters and machining conditions were those recommended by the manufacturer and were kept unchanged in all performed tests. The behavior of the PVD- and CVD-coated cutting tools was assessed using three different facets: (a) surface roughness analysis, (b) tool wear evaluation, and (c) the monitoring of vibration levels produced during each test. CVD (TiN/TiCN/Al2O3)-coated inserts showed very good suitability to be used as tools for roughing milling operations when machining super duplex stainless steels.

Evaluation of Surface Roughness and Tool Wear in High Speed Machining of Inconel 718

This research work considered the high speed milling operation of Inconel 718 using a 4 flute solid carbide end mill tool without the use of coolant. Inconel 718 is a Nickel based Heat Resistance Super Alloy (HRSA) that is vastly used in the aerospace industries due to its excellent corrosion resistance and good mechanical properties. However, Inconel 718 is considered as a difficult-to-cut super alloy, which poses several problems when machining the material. The aim of this work is to investigate the effect and the influence of cutting parameters (feed rate, spindle speed, and depth of cut) on the quality of the machined surface as well as to evaluate the tool wear after machining. This evaluation of the surface roughness was done using a CNC milling machine at various parameters range for the values of feed rate (50-150 mm/min), spindle speed (2000-4000 RPM), and depth of cut (0.05-0.1 mm). The experiment was designed using Response Surface Analysis Method with Central Composite Design (CCD) to optimize the experimentation. The resulting tool wear and surface roughness after high speed machining were then analysed using ANOVA to determine the cutting parameters which is most affecting the surface roughness.

Analiza procesu zużycia narzędzi wykonanych ze stali 1.2344 oraz stopu MP159 w procesie zgrzewania tarciowego z przemieszaniem (FSW) blach ze stopu Aluminium 7075 T6

The study presents an analysis of wear of tools made of 1.2344 steel and MP159 alloy for the process of obtaining an overlap joint in 1.0 mm and 0.8 mm sheet metal made of 7075 T6 aluminum alloy using friction stir welding (FSW) technology. Tool geometry was designed at the Czestochowa University of Technology. Evaluation of tool wear was conducted based on the measurements of geometry of working area of tools by means of a multisensory meter system and based on the assessment of the working area by means of a stereoscope after individual stages of wear tests. Furthermore, based on the results of a static tensile strength test and metallographic examinations of the specimens sampled from the joints obtained during tool wear tests, the effect of the degree of tool wear on joint quality was also evaluated. Analysis of the results revealed that both the tool made of 1.2344 steel and that made of MP159 alloy were substantially worn, increasing the risk of further use of the tools for the joint material (7075-T6) after obtaining the joint with length of 200m, which suggests their low durability. Furthermore, modification of tool geometry caused by wear led to insignificant improvements in joint strength. Therefore, the results of wear measurement set directions for further modification of tool geometry, also due to the fact that despite a substantial wear, the tools continued to yield high-quality joints without defects. As demonstrated in the study, the type of tool material does not only impact on tool life but also, as it was the case in their geometry, has a significant effect on the quality of obtained joints. Although the tool made of MP159 alloy was worn more than the tool made of 1.2344 steel, it allowed for obtaining the joints with substantially better strength parameters.

Intrinsic feature extraction using discriminant diffusion mapping analysis for automated tool wear evaluation

We present a method of discriminant diffusion maps analysis (DDMA) for evaluating tool wear during milling processes. As a dimensionality reduction technique, the DDMA method is used to fuse and reduce the original features extracted from both the time and frequency domains, by preserving the diffusion distances within the intrinsic feature space and coupling the features to a discriminant kernel to refine the information from the high-dimensional feature space. The proposed DDMA method consists of three main steps: (1) signal processing and feature extraction; (2) intrinsic dimensionality estimation; (3) feature fusion implementation through feature space mapping with diffusion distance preservation. DDMA has been applied to current signals measured from the spindle in a machine center during a milling experiment to evaluate the tool wear status. Compared with the popular principle component analysis method, DDMA can better preserve the useful intrinsic information related to tool wear status. Thus, two important aspects are highlighted in this study: the benefits of the significantly lower dimension of the intrinsic features that are sensitive to tool wear, and the convenient availability of current signals in most industrial machine centers.

Tungsten carbide micro-tool wear when micro milling UNS S32205 duplex stainless steel

In conventional machining operations, tool wear is an important aspect of machining with many relevant discussions in the literature. However, in the micromachining process, very little is known about tool wear and wear mechanism compared to conventional machining. Some considerations for tool wear from a macro machining point-of-view may not be valid for micromachining processes because of reduced geometry of the tools and the so called size effect, which affects the kinematics of micromachining and chip formation mechanism. A small wear land on a micro-tool can eliminate half of its edges, and could double the size of the shear force at the other edges of the tool. Therefore, it is necessary to discuss the types of wear and their mechanisms for tools used in micromachining to characterize end-of-life criteria. In this sense, the main goal of this work is to analyze the evolution of wear land of a carbide micro-mill tool when cutting UNS S32205 duplex stainless steel. Experiments were performed to produce micro channels using a 3-axis CNC micro milling machine and TiN coated tungsten carbide tools with diameter 0.381 mm. Previous experiments were performed in order to choose the most appropriate cutting conditions for the evaluation of tool wear. The tools were examined before and after each experiment using a scanning electron microscope. The results show that the major forms of wear encountered during machining are nose and flank face wear, with adhesion being the most clearly observed wear mechanism. The wear land as a function of machined length showed similar behavior to macro machining operations with three defined regions of wear. Taylor's tool life equation was obtained and the resultant coefficients are similar to results from literature for macro machining operations.

Rock mass‐scale factors with an influence on tool wear in the mechanised tunnelling process in hard rock

AbstractWear to the tools used for excavate the rock mass has a significant relevance for the cost and performance of tunnel drives in hard rock. This applies in particular to mechanised tunnelling processes, where the effect of wear is an important factor for system availability. At the moment, laboratory tests and derived abrasiveness indices like the Cerchar Abrasiveness Index (CAI) or the Rock Abrasivity Index (RAI) provide the basis for evaluation of tool wear. It should however be noted that such index values can only take into account influential factors on the scale of the intact rock. Influential factors on the scale of the rock mass, for example mixed‐face conditions, unstable face conditions, blockiness or the primary and secondary stress states at the face, can also be significant for the tool wear that is actually experienced. The possible consequences of such disadvantageous effects, which for example can cause catastrophic failure of tools, can represent many times the abrasiveness of the intact rock.

Improvement of boring quality of CFRP and evaluation of tool wear by inclined planetary milling

In recent years, CFRP is widely used as an alternative structural material to improve fuel consumption with high strength and light weight comparing to conventional aluminum alloy.CFRP is also expected to be the structural material for next generation automobiles - especially electric vehicles - in order improve fuel and/or electric power efficiency. However, CFRP is categorized as one of the difficult-to-cut material and burrs and delamination could occur with conventional drilling and cutting ways due to their severe cutting tool wear. For above mentioned reasons, in order to improve the machinability of CFRP drilling situations, the authors have proposed the inclined planetary milling process as a novel high quality boring technique for CFRP.According to our past experiments, the effectiveness for reduction of burrs and delamination of CFRP boring by the inclined planetary milling has been demonstrated. However, demands for higher speed and wear resistance of cutting tools are rising in the industrial field. The objective of the study is to achieve shorter processing time of CFRP boring and reduction of tool wear with maintaining high bore quality. The authors have carried a set of experiments for evaluating the relationship between feed rate variations and bore quality transition. The workpiece materials were unidirectional and fabric CFRP stack plates and the cutting tool shape was corner radius end-mill. From the experimental results, it was confirmed that the feed rate per one cutting edge strongly affected the generation of cross-sectional profile of the bore. This was also theoretically confirmed by our developed kinematic cutting model of the inclined planetary milling theoretically.In the article, the optimal cutting conditions of the inclined planetary milling for CFRP boring and factorial effect of feed rate to the bore quality are reported.

An investigation on measurement and evaluation of tool wear based on 3D topography

Tool wear and its service life have great influence on machining quality, production efficiency and cost. Tool wear is a three-dimensional phenomenon accompanied by physical and chemical factors. However, the tool wear model and evaluation standard characterised by two dimension are still widely used today. In order to explore the use of three-dimensional topography to track the tool wear trend and measure the tool wear condition, relatively high speed cutting experiments were done for cutting three kinds of materials. Laser scanning confocal microscope was used to measure the worn tool topography at different cutting times. After that, the deficiency of two-dimensional indicators and validity of three-dimensional topography in evaluating tool wear were analysed. Besides, some improved tool wear evaluation methods were proposed. [Submitted 19 December 2016; Accepted 24 October 2017]

Can A Low Cost Sensing System Be Exploited For High Precision Machining?

The aim of the present study is the assessment of the integration of a low cost optical measurement device into a high-precision machine tool for micro manufacturing applications. The measurement system can be effectively integrated into the working volume of different types of machines allowing both tool and workpiece measurements and avoiding its disassembly from the machine stage for off-line measurements and, consequently, reference losses. The fast measurements of tool and workpiece during the machining contribute to increase the accuracy and reduce the overall machining-measurement iterations. The assessment is achieved by a test case where a low cost USB microscope is applied to a micro-EDM machine. The low cost device has been applied for tool electrode measurements and tool wear evaluation after an accuracy enhanced calibration procedure and high performance image processing algorithms, which effectively reduce the lack of the hardware performance. The measurement performance gives a feedback on the deviations of the machined features from nominal geometry and allows their compensations by an adequate machining strategy.

An investigation on measurement and evaluation of tool wear based on 3D topography

Tool wear and its service life have great influence on machining quality, production efficiency and cost. Tool wear is a three-dimensional phenomenon accompanied by physical and chemical factors. However, the tool wear model and evaluation standard characterised by two dimension are still widely used today. In order to explore the use of three-dimensional topography to track the tool wear trend and measure the tool wear condition, relatively high speed cutting experiments were done for cutting three kinds of materials. Laser scanning confocal microscope was used to measure the worn tool topography at different cutting times. After that, the deficiency of two-dimensional indicators and validity of three-dimensional topography in evaluating tool wear were analysed. Besides, some improved tool wear evaluation methods were proposed. [Submitted 19 December 2016; Accepted 24 October 2017]

Wpływ zużycia narzędzia na jakość połączeń zakładkowych blach ze stopu Aluminium 7075 T6 wykonanych metodą FSW

The article concerns the issues of tool wear effect on the quality of a friction stir welding joint quality. The experiment used aluminum alloy 7075 T6 sheet metal, which is used primarily in the aerospace industry. 1.0mm and 0.8mm thick lap joints were tested. Tool wear was determined based on multiple readings on a multisensory machine. The tool wear evaluation was done on the basis of a static tensile strength test and metallographic sections of the joints. The pin of the tool works in more demanding conditions and is more exposed to friction. This results from tooling operations performed at full depth dive in the jointed material. When also considering the small dimensions of the pin such as the diameter and the great forces occurring in this process, it is easy to see why this element is most susceptible to tool wear. The welding process causes the tool to undergo friction wear, which is the cause of reduced tool dive depth in the jointed material. As a result, it is paramount to constantly control the tool extension to achieve the desired quality parameters of the joint. After creating 200m of joints, a decrease in the strength of joints was observed as well as the repeatability of the results connected to a change in the stirring conditions in the material. The change in joint strength and tool wear is also confirmed in the metallographic analysis, which states that the continued degradation of the tool makes it subject to a decrease in size of the characteristic sizes of the thermoplastic zone that is the main determining factor of the joint strength.

Application of an interval wear analysis method to cutting tools used in tunneling shields in soft ground

The replacement of cutting tools is important when shield tunneling in abrasive soils. The task is performed based on an assessment of the degree of cutting tool wear. The wear of cutting tools is influenced by many factors, such as the soil abrasiveness, shield machine operational parameters, and tool sliding distance. The representation of the uncertainty in these factors is the primary problem in the evaluation of tool wear. Instead of real variables, interval variables are employed to represent the uncertainty in the influencing factors, and the interval of the tool wear amount is attained based on interval arithmetic operations. With the calculated interval for the amount of tool wear and the dimensionless indices η and ξ, the feasibility of completing shield tunnel construction with tool wear within a predefined tolerance is quantitatively evaluated. Measures and countermeasures can be implemented based on the results of the evaluation. A five-step process for conducting an evaluation is described and explained using an example application. The suggested methodology can help realize active tool replacement and obtain cost-effective and less-disruptive solutions for shield cutting tool wear in tunnel construction.