Tool Wear Growth Research Articles

Multi-condition tool wear prediction for milling CFRP base on a novel hybrid monitoring method

In the carbon fiber-reinforced plastic milling process, the high abrasive property of carbon fiber will lead to the rapid growth of tool wear, resulting in poor surface quality of parts. However, due to the signal data distribution discrepancy under different working conditions, addressing the problem of local degradation and low prediction accuracy in tool wear monitoring model is a significant challenge. This paper proposes an entropy criterion deep conditional domain adaptation network, which effectively exploits domain invariant features of the signals and enhances the stability of model training. Furthermore, a novel unsupervised optimization method based on tool wear distribution is proposed, which refines the monitoring results of data-driven models. This approach reduces misclassification of tool wear conditions resulting from defects in data-driven models and interference from the manufacturing process, thereby enhancing the accuracy of the monitoring model. The experimental results show that the hybrid method provides assurance for the accurate construction of tool wear monitoring model under different working conditions.

Investigation on microstructure characteristics of tool wear and machined surface mechanisms while milling: kenaf vs glass fiber-reinforced composites

In composites' secondary/machining process, there is still a requirement for a comparative assessment of microstructure features of tool wear and machined surface mechanisms while machining natural fiber against glass fiber-based composites. This experimental study uniquely investigates the dry-end milling of two polypropylene (PP)-based composites made of 30 wt.% discontinuous reinforcements - kenaf and glass fibers (GF). Surprisingly, though, GF are much harder (GF:5.84 GPa > kenaf:0.15 GPa) and abrasive (silicon content, GF:24.16% > kenaf:0.57%) than kenaf inclusions, cutting GF/PP resulted in relatively lower tool wear (≈0.08 mm) but contrarily showed adverse machined surface finishes (>8 μm) depicting tearing-dragging mechanisms with fuzzy textures. This cautions on the appropriate consideration for the tool's life-determining criterion – i.e., whether it should be based on the tool wear or surface finish. While machining GF/PP material, the tool wear growth on the cutting edges was significantly restricted by the formations of continuous-robust microstructural transfer protective film (TPF) characterized by strong Si + O, Al + O, and Fe + O tribo-chemical reactions through the interesting wear mechanisms associated with tribological phenomena. However, thin-patch type microstructural TPFs consisting of weak Si + C bonds occurred on tool edge regions while machining kenaf/PP. Better mechanical properties and fiber-matrix adhesion of GF/PP influenced by fiber dimensions and their higher aspect ratios (GF:27.60 > kenaf:7.20) decisively seem to have a dominant effect on limiting the tool wear. Chip micrographs clarified the cutting of GF/PP and kenaf/PP occurred by predominant melt-extrusion and shearing respectively.

Study on machinability characteristics of novel additive manufactured titanium alloy (Ti-6Al-4V) fabricated by direct metal laser sintering

The pressing demand of Ti-6Al-4V (grade 5) in aerospace, medical, marine, and chemical processing industries has gained momentum in recent years due to its excellent properties such as high strength to weight ratio and corrosion resistance, bio-compatibility and a common material for additive manufacturing. Additive manufactured Ti-6Al-4V have higher mechanical properties as compared to wrought alloys due to difference in microstructure that negatively influences the machinability characteristics and also lacks ductility. The main limitation of fabricated additive manufactured (AMed) component is the poor surface quality, staircase effect and adhering of non-melted powder particles to the fabricated components. Again, fatigue life of components increases with decrease of surface roughness. Therefore the need of machining of AMed titanium alloys in recent years are gaining importance to eliminate these problems so that desired surface quality and tolerances can be achieved. Therefore the objective of the study is to develop additive manufactured Ti-6Al-4V through direct metal laser sintering process and investigate its machinability characteristics under flood cooling environment with respect to responses as tool wear, surface roughness, cutting temperature, and chip morphology. As most of the heat generated at the interfaces has been carried away through flood cooling, the rate of growth of tool wear, cutting temperature, surface roughness, and degree of serration decreases and thus makes the performance of AMed Ti alloys are comparable with wrought Ti alloys. The dominant tool wear mechanism during machining AMed Ti alloy have been found to be abrasion, chipping, adhesion, BUE, chemical interaction between titanium and cutting tool materials, coating delamination. Optimal parameters for multi-responses are 0.1 mm depth of cut, 0.1 mm/rev feed rate, and 70 m/min cutting speed and improved. Mathematical models are said to be significant and fitted well. Because of the improved machinability, AMed Ti alloys find itself suitable in industrial applications.

Roles of Eco-Friendly Non-Edible Vegetable Oils in Drilling Inconel 718 through Minimum Quantity Lubrication

Metal cutting fluids (MCFs) have played a principal role as coolants and lubricants in the machining industry. However, the wide use of mineral-based oil MCFs has contributed to an adverse effect on humans and the environment. Thus, to overcome the adverse effects of mineral-based oil MCFs, eco-friendly vegetable oil, which is non-edible oil, has been implemented to overcome the issues related to edible oil such as manufacturing costs and food shortages. This study investigated the performance of three different types of non-edible oil, namely castor, neem, and rice bran oils in drilling Inconel 718 using a coated titanium aluminum nitride (TiAlN) carbide drill towards tool life, tool wear, surface integrity, dimensional accuracy, and chip thickness. The MCFs were implemented under the minimum quantity lubrication (MQL) condition at a 50 mL/h flow rate using different cutting speeds (10, 20 m/min) and a constant feed (0.015 mm/rev). The results showed that castor oil minimizes the rapid growth of tool wear and prolongs the tool life by 50% at 10 m/min as compared to rice bran oil. At 20 m/min, castor oil obtained the lowest values of average surface roughness (1.455 µm) and chip thickness (0.220 mm). It was also found that different cutting speeds did not contribute to any significant trend towards hole diameter and roundness for all MCFs. The outstanding performance of castor oil proved that the oil is a potential alternative as an eco-friendly MCF for a cleaner machining environment. Castor oil was determined to be optimum in terms of tool life, tool wear, surface roughness, and chip thickness.

Experimental investigation of tool wear characteristics and analytical prediction of tool life using a modified tool wear rate model while machining 90 tungsten heavy alloys

Tungsten heavy alloys are widely used in the manufacturing of weights for aircraft, missiles, boats and race cars; penetrators; radiation shielding; and radioisotope containers. Manufacturing these components needs machining as a secondary operation. Since tungsten heavy alloys are difficult to machine, the in-depth analysis of tool wear growth and mechanism during machining of these alloys becomes essential. Hence, this work focuses on the experimental study of flank wear growth and its effect on other machining outputs for two different tool geometries (−5° and 2° rake angles) during turning of 90 tungsten heavy alloys. The predominant wear mechanism was identified as adhesion based on scanning electron microscopic analysis. Finally, three commonly used analytical tool wear rate models and one newly proposed model (modified Zhao model) were utilized for the prediction of flank wear growth and tool life. It was observed that the modified Zhao model could predict tool flank wear fairly well within error percentage of 4%–7% and thus could be used as a benchmark while machining difficult-to-cut alloys.

Effect of progressive tool wear on the functional performance of micro milling process of injection molding tool

In micro milling process, tool wear is one of the significant research area and tool behavior during machining is rather unpredictable. As tool wear progress, the cutting edge geometry change and leading to lower performance and failure of the machined surface integrity. This work investigate the influence of the progressive tool wear during micro end milling of a functional surface (micro ridges) on the injection molding tool with H13 tool steel material. In order to monitor the tool wear progress, five different TiAlN coated carbides micro end mills with 500 µm diameter were used to carry out the experiments in different cutting distances 64 cm to 320 cm. The chip formation, burr formation and surface quality in different tool wear conditions were evaluated. The burr form and size were affected by cutting edge wear and dissimilar results obtained at the end of cut. Moreover, the analysis of chip geometry in microscopic scale allows evaluating the chip morphology and cutting mechanisms in different tool wear conditions. The machined slots by the profile analysis and the surface quality of parts decreased as the tool wear growth. This work contribute to improved knowledge of cutting mechanisms with worn tools causing dissimilar material removal and surface integrity during machining process.

Roles of new bio-based nanolubricants towards eco-friendly and improved machinability of Inconel 718 alloys

Abstract The adverse effects of mineral oil-based metal cutting fluid on environmental sustainability have led to increased industrial concerns. Alternatively, biodegradable lubricants such as vegetable oil has a more positive impact with equivalent performance, but insufficient research on their benefits demands further exploration. This work features extensive experimental investigations on machining of Inconel 718 using novel formulations of coconut bio-based oil with enhanced nanoparticles and coco-amido-propyl-betaine. Bio-based with 0.8 wt% of Al2O3 managed to minimise the rapid growth of tool wear and prolong the tool life by 40.17%. Conversely, bio-based with 0.5 wt% of Al2O3 yielded lower values of cutting force (64.32 N), spindle power (2070 kW), specific cutting energy (6.55 W/mm3), and surface roughness (0.29 μm). The outstanding performance of bio-based nanolubricants contributed to superior machinability efficiency and eco-friendly machining environments.

Effect of metal cutting fluid (MCF) conditions on tool wear and thrust force in drilling Ti-6Al-4V using coated carbide tools

Titanium alloy (Ti-6Al-4V) is well known as difficult to cut material due to their low machinability rating. Machining Ti-6Al-4V generate high cutting temperature close to the cutting edge of the tool. The high cutting temperature, mostly during the deformation process and friction at the tool–chip and tool–workpiece interfaces. This circumstances will lead to the rapid tool wear. This study focuses on the growth of tool wear and development of the thrust force. Drilling tests were conducted using coated (TiAlN) carbide tool with diameter of 6 mm under two different condition of metal cutting fluid (MCF). The MCF used were minimum quantity lubrication (MQL) and minimum quantity cooling lubrication (MQCL). The outcomes of this study indicates MQL performed better coolant-lubricant effect during drilling Ti-6Al-4V as the results of thrust force development are consistent with the trends of tool wear growth.

Effects of Cutting Parameters on Tool Wear and Thrust Force in Drilling Nickel-Titanium (NiTi) Alloys Using Coated and Uncoated Carbide Tools

The difficulties of machining nickel-titanium alloys are due to their high ductility and super-elasticity, strong strain-hardening, and excellent wear resistance. These characteristics lead to poor chip breakability, high cutting forces, rapid and aggressive tool-wear, as well as excessive burr formation during mechanical machining processes. The present study addresses these issues by evaluating the effects of drilling parameters and drill bit coatings on the growth of tool wear and development of the drilling thrust force. The findings from this research indicate that the TiAlN coated carbide drill was found to significantly improve the wear resistance of the cutting tool. Likewise, the results of thrust force development are consistent with the trends of tool wear growth for all of the tested carbide drills.

PENGARUH GAYA POTONG PEMBUBUTAN TERHADAP KEAUSAN PAHAT KARBIDA COATED PADA BENDA KERJA BAJA AISI 4340

Cutting force and tool life is the important data in planning a machining process. The research is in order to describe about the influence of the cutting force to the tool wear on carbide coated cutting tools used the turning process of an alloy steel of AISI 4340. The research was conducted by observing the growth of tool wear on minutes 4.5, 9, 13.5, 18, 22.5 with the maximum value VB 0.3 mm, at the same time, the condition of other cutting such as the motion while the cutting, the depth and speed of the cutting movement was constant. The purpose of this experiment is to examine scientifically the influence cutting force to the growth of tool wear on carbide coated while the cutting process of alloy steel AISI 4340. The graphical method was used for the trial analysis, to see the cutting force comparison with the decrease of tool life of the carbide coated, and the correlation of the cutting movement with the cutting force. The mechanism decrease showed the adhesion decrease.

INTELLIGENT MACHINING: REAL-TIME TOOL CONDITION MONITORING AND INTELLIGENT ADAPTIVE CONTROL SYSTEMS

Unmanned manufacturing systems has recently gained great interest due to the ever increasing requirements of optimized machining for the realization of the fourth industrial revolution in manufacturing ‘Industry 4.0’. Real-time tool condition monitoring (TCM) and adaptive control (AC) machining system are essential technologies to achieve the required industrial competitive advantage, in terms of reducing cost, increasing productivity, improving quality, and preventing damage to the machined part. New AC systems aim at controlling the process parameters, based on estimating the effects of the sensed real-time machining load on the tool and part integrity. Such an aspect cannot be directly monitored during the machining operation in an industrial environment, which necessitates developing new intelligent model-based process controllers. The new generations of TCM systems target accurate detection of systematic tool wear growth, as well as the prediction of sudden tool failure before damage to the part takes place. This requires applying advanced signal processing techniques to multi-sensor feedback signals, in addition to using ultra-high speed controllers to facilitate robust online decision making within the very short time span (in the order of 10 ms) for high speed machining processes. The development of new generations of Intelligent AC and TCM systems involves developing robust and swift communication of such systems with the CNC machine controller. However, further research is needed to develop the industrial internet of things (IIOT) readiness of such systems, which provides a tremendous potential for increased process reliability, efficiency and sustainability.

Results if Machining by Tool of Self-Propelled Rotation Due to Wear

On the base of a well-known method of machining with disk-shaped rotating tool the self-propelled tool was designed. The principle is based on braking the tool rotation during machining, until the moment of determined wear criterion on the tool flank. As with the growth of tool wear the force of cutting resistance increases, it is possible to use it for automatic tool swinging into a new position by which a new part of cutting edge comes into engagement. The paper describes the tool design, theoretical analysis of Rz after machining and actual experimental machining results.

Performance studies of multilayer hard surface coatings (TiN/TiCN/Al2O3/TiN) of indexable carbide inserts in hard machining: Part-I (An experimental approach)

In recent years, hard machining using CBN and ceramic inserts became an emerging technology than traditional grinding and widely used manufacturing processes. However the relatively high cost factors associated with such tools has left a space to look for relatively low cost cutting tool materials to perform in an acceptable range. Multilayer coated carbide insert is the proposed alternative in the present study due to its low cost. Thus, an attempt has been made to have an extensive study on the machinability aspects such as flank wear, chip morphology, surface roughness in finish hard turning of AISI 4340 steel (HRC 47±1) using multilayer coated carbide (TiN/TiCN/Al2O3/TiN) insert under dry environment. Parametric influences on turning forces are also analyzed. From the machinability study, abrasion and chipping are found to be the dominant wear mechanism in hard turning. Multilayer TiN coated carbide inserts produced better surface quality and within recommendable range of 1.6μm i.e. comparable with cylindrical grinding. At extreme parametric conditions, the growth of tool wear was observed to be rapid thus surface quality affected adversely. The chip morphology study reveals a more favorable machining environment in dry machining using TiN coated carbide inserts. The cutting speed and feed are found to have the significant effect on the tool wear and surface roughness from ANOVA study. It is evident that, thrust force (Fy) is the largest component followed by tangential force (Fz) and the feed force (Fx) in finish hard turning. The observations yield the machining ability of multilayer TiN coated carbide inserts in hard turning of AISI 4340 steel even at higher cutting speeds.

Predictive model of tool wear in milling with coated tools integrated into a CAM system

The coated tool wear evolution in milling at constant cutting conditions can be described analytically based among other factors on the cutting edge entry impact duration. A tool wear predictive mathematical model for milling parts of complicated geometry was created employing this methodology and a commercial CAM system. Parameters of the developed model were determined based on experimental results. In this way, the expected tool wear growth during numerically controlled milling can be estimated, considering the cutting penetrations along the tool paths, the process up or down kinematic and other factors. The application of the introduced model is demonstrated through appropriate examples.

Experimental Study of Machinability of GFRP Composites by End Milling

This article describes an experimental investigation on end milling of glass fiber reinforced polymer (GFRP) composites using uncoated tungsten carbide tool. A series of experiments were carried out to evaluate the machinability of GFRP composites in terms of tool wear, tool useful life, machining quality, and machining forces. Machinability data were evaluated in the form of Taylor's equation in order to predict the tool performance while machining this composite material. The useful life of the cutting tool was found to be well described by the Taylor's equations. The cutting speed was identified as the key parameter in influencing the tool life followed by feed rate and fiber orientation. Machining force variations were constantly monitored during end milling tests, which are mainly attributed to the growth of tool wear and fiber orientation.

Growth of tool wear in turning of Ti-6Al-4V alloy under cryogenic cooling

Titanium alloys are readily machinable provided the cutting velocity is in the range of 30–60 m/min. To achieve higher productivity, if the cutting velocity is enhanced to 60–120 m/min and beyond, rapid tool wear takes place diminishing the available tool life. Tool wear in machining of titanium alloys is mainly due to high cutting zone temperature localised in the vicinity of the cutting edge and enhanced chemical reactivity of titanium with the tool material. Cryogenic cooling with its excellent cooling abilities and environmental friendliness is being investigated to control cutting zone temperature in machining of such alloys. In the present investigation, the tool wear and tool life of uncoated carbide cutting tool inserts in machining of Ti-6Al-4V alloy have been studied under dry, wet and cryogenic cooling environments. A substantial improvement in tool life was obtained under cryogenic cooling compared to dry and wet machining in all the machining trials undertaken. The scanning electron microscope (SEM) investigation of the used cutting tool inserts revealed adherent depositions of the titanium chip material on the inserts under all machining environments. Other than adhesion–dissolution–diffusion wear, attrition, micro and macro fracturing of the cutting edge and depression of the cutting edge also contributed significantly in rapid tool wear, especially at higher cutting velocities.

CRYOGENIC MACHINING OF KEVLAR COMPOSITES

ABSTRACT Previous attempts to machine Kevlar aramid fibre reinforced plastics (KFRP) with conventional cutting tools have proven to be extremely difficult. This has somewhat restricted the material's usage, often negating the advantages of its high strength to weight ratio and fatigue tolerance. The present paper describes a novel technique of machining KFRP under cryogenic conditions with remarkable results compared to those obtained at ambient temperatures. The investigation carried out with turning operation shows dramatic improvement of the tool performance and surface quality. The effects of various machining parameters such as workpiece temperature, cutting speed and tool geometry on the machinability of KFRP are presented and analyzed. It appears that care is necessary to judge the tool life as the typical tool wear growth and surface finish or cutting force may produce contradictory results. It is also suggested that, for KFRP, surface finish of the machined workpiece is a very good criterion to determine the tool life. To aid the understanding of the machining mechanics, a microscopic investigation of the cutting zone while actually machining a testpiece at ambient and cryogenic temperatures is also reported.

Flank Wear Characteristics of Cutting Tools in Different Types of Tests : Comparison between Results of Conventional Turning, Step Turning and Facing Tests

Although the performance of cutting tools has been evaluated by the tool-life values in the conventional turning tests, it is difficult to apply such data for the estimation of tool wear characteristics in different types of cutting tests. The purpose of this study is to clarify the relationships between various test results on flank wear. Three types of cutting tests, i.e., conventional turning, step turning and facing tests are performed on mild steel withsintered carbide tools. The tool wear growth curves of all tests are respectively formulated based on a few assumptions. The wear rate, which is defined by the wear land width per unit cutting length excepting the initial wear, is mainly used for analyzing the results. Thus, some relations are revealed between the results of above three tests ; a significant difference is recognized in the wear rate between facing test and the other two tests.