Tool Wear In Drilling Research Articles

Steady and periodical heat-mass transfer behavior of mixed convection nanofluid with reduced gravity, radiation and activation energy effects

Significance of this study is to explore Arrhenius activation energy, microgravity, chemical reaction and porous medium effects on Darcy nanofluid over a stretching sheet with nonlinear thermal radiations. Purpose of this study is to enhance the lubrication efficiency, excessive heat reduction, surface roughness and tool wear in drilling, milling, grinding and cutting tools of machining procedures. Use of Brownian and thermophoretic nanoparticles in base liquid is very effective to reduce friction in tool-chip and tool-work interfaces, tool life ability and cooling ability through nanofluid minimum quantity lubrication in machining operations. A refined mathematical model is solved using dimensionless variables; oscillatory stokes conditions and primitive variables. The implicit form of finite difference method is applied for numerical results using Gaussian elimination approach. The numerical and physical outputs are secured using Gaussian elimination methodology in FORTRAN tool and TecPlot-360. Graphs are displayed by using numerical data in Tecplot-360 program. Impact of activation energy (AE), solar radiation (Rd), microgravity (RG), porosity (Ω), thermophoresis (NT), chemical reaction (Kr), Prandtl (Pr) and Schmidt factor (Sc) on oscillating frequency of heat and mass transport is depicted. Amplitude in fluid velocity, surface temperature and volume of concentration is enhanced as radiation, microgravity and activation energy increases. It is noted that the increasing amplitude in fluid velocity, temperature and fluid concentration is found with activation energy, radiation and buoyancy force effects. Steady behavior of skin friction and mass transport decreases as Darcy porous medium and reaction rate decreases. Frequency of oscillating skin friction and oscillating heat transfer increases as Schmidt and Prandtl coefficient increases. Fluctuations and amplitude in the frequency of heat and mass transport enhances as thermophoretic nanoparticle enhances.

Progressive Weakening of Granite by Piezoelectric Excitation of Quartz with Alternating Current

A promising solution to reduce energy usage and mitigate the wear of drilling and comminution tools during mining operations involves inducing vibrations within the piezoelectric phases dispersed in the structure of rocks using alternating current (AC). This paper presents experimental evidence of AC-induced weakening of Kuru granite, manifested as improvements in rock drillability and reductions of strength. Sievers’ J-miniature drill tests were used to assess surface drillability. The impact of AC treatment on the quasi-static strength of granite was assessed via three-point bending and indirect tension Brazilian disk tests. The influence of AC treatment on the dynamic tensile strength of the rock was determined using split Hopkinson bar tests, with the fragmentation process captured using in situ ultra-fast synchrotron X-ray phase contrast imaging. The quasi-static tests revealed no reduction in rock strength after the AC treatment. In contrast, reductions of 25% in hardness and 18% in dynamic tensile strength were observed. Fragmentation patterns differed between treated and non-treated rocks, with treated specimens exhibiting reduced macrocrack formation during loading.

Evaluation of data augmentation and loss functions in semantic image segmentation for drilling tool wear detection

Evaluation of data augmentation and loss functions in semantic image segmentation for drilling tool wear detection

A New Architecture Paradigm for Tool Wear Prediction during AISI 9840 Drilling Operation

In conventional machining processes based on the chip removal mechanism, the progressive wear of the tool determines a change of the geometric characteristics of the cutting edge. Tool wear is a complex phenomenon and related tool life depends on several factors, such as cutting parameters, lubrication, and tool-workpiece relative trajectories. Tool wear progression affects the quality of the machined parts, making the tool replacement necessary even before its breakage. Moreover, in industrial practice, tool replacement cannot depend on the subjectivity of the operator, thus, the definition of an optimized strategy for cutting tool wear monitoring before tool failure is mandatory. This work compares Random Forest and Neural Network models for predicting tool wear in drilling. For the development of predictive models, tool life tests were performed by drilling through holes on AISI 9840 steel parts, with a coated tungsten carbide drill of 8 mm of diameter and by using constant cutting parameters. Flank wear of the tool was monitored. A set of statistical features computed from the vibration signals, the acoustic emission signals, the power signals and the torque signals constitute the input of the algorithms. The classification accuracy was 88% and 91% for Neural Network and Random Forest models respectively. In order to correctly define the tool replacement policy during production, the developed Random Forest model has been implemented in an industry, through production management software, achieving promising results.

Determination of Tool Wear Drilling Process of Aluminum 6061 and Brass C3604 by using CNC Robodrill Machine

Hole making process is a stimulating process as it impacts the drilling tool’s performance and wear. The main objective of this paper is to determine the drilling tool wear by using step-by-step drilling approaches used by most of the manufacturing companies. Two types of materials involved; Aluminum 6061 & Brass C3604. Firstly, the raw material grade was confirmed by testing it using an Oxford Spectrometer. Four types of drilling tools are used; center drill diameter 3.00 mm; drill diameter 10.00, 13.00 and 14.50 mm. The drilling tool material used is High-Speed Steel (HSS). The cutting parameter used is stated in detail in the methodology section. Two approach are used to determine the tool life; measuring the holes diameter produced by using Vernier caliper; graphical form with the help of the camera. The major finding of this research is the understanding on how the cutting process react with the drilling tool during the cutting process as discussed in the results and discussions. The tool life of a center drill, drilling tool diameter 10.00 mm, 13.00 mm and 14.50 mm in drilling Aluminum 6061 is 476, 250, 485 and 499 holes while for Brass C3604 is 360, 190, 360 and 375 holes.

Comparative Analysis of Friction and Wear Properties of Titanium Alloy Drill Pipe and Steel Drill Pipe

During the drilling process of complex structural wells such as horizontal wells, the wear, and tear of the drill pipe can lead to its weakened strength, which is one of the important reasons for the damage accidents of the drill pipe. Titanium alloy drill pipes are widely used in major oil fields as a new type of lightweight drill pipe with high fatigue life. To compare the wear performance of titanium alloy drill pipe with wear-resistant zones and traditional S135 steel drill pipe, this article tested and analyzed the chemical composition, hardness, and metallographic structure of these two drill rod materials and established models for these two materials. In the experiment, the wear morphology and wear rate before and after the experiment were analyzed and compared. Finally, based on the experimental results, an in-depth analysis was conducted on the wear mechanism of the drill pipe, and anti-wear measures were proposed. The results show that the hardness of the two materials decreases from the wear-resistant belt to the inner wall, and the microhardness of the S135 drill pipe is about half of that of titanium alloy drill pipe with wear-resistant belt drill pipe; the wear test shows that the wear loss of the S135 drill pipe is 0.1667 g, the wear rate is 0.042 g/h; through measurement, it was found that the wear loss of titanium alloy drill pipe reached 0.0055 g, and the wear rate is 0.0063 g/h. The wear rate of S135 steel drill pipe under the same conditions is 6.7 times that of titanium alloy drill pipe. Through analysis, it is shown that under the same conditions, titanium alloy wear-resistant belts have excellent wear resistance, which can effectively protect the inner matrix and prevent excessive wear of drill pipes. The research results of this article can provide theoretical references for the on-site use of titanium alloy drill pipe and experimental research on drilling tool wear resistance.

Prediction of TiAlN- and TiN-coated carbide tool wear in drilling of bidirectional CFRP laminates using wavelet packets of thrust–torque signatures

Prediction of TiAlN- and TiN-coated carbide tool wear in drilling of bidirectional CFRP laminates using wavelet packets of thrust–torque signatures

Comparison of TiAlN DLC and PCD Tool Wear in CFRP Drilling

Comparison of TiAlN DLC and PCD Tool Wear in CFRP Drilling

In-situ investigation of drilling performance and bit wear on an electrical drill hammer

Estimation of drillability is very important in rock drilling. Drilling performance and tool wear are two indispensable parameters for time and cost evaluation of an operation. In this article, by using an electrical drill hammer and two types of drill bits, in-situ drilling tests were conducted on three rock types to estimate the drilling performance and tool wear. Experimental results showed that the highest performance and the greatest bit wear occur in drilling sandstone, while the lowest values of penetration rate and wear are observed in amphibolite and basalt. Moreover, the penetration rate of drilling is related to rock mechanical properties. Regression analysis indicated that the correlation of performance with uniaxial compressive strength, Brazilian tensile strength and point load index, respectively, is significant and reliable. Regarding to the tool wear, equivalent quartz content showed a reasonable correlation with bit wear, compared to Cerchar abrasivity index and LCPC abrasivity coefficient.

On-Line Monitoring Method of Carbon Fiber Composite Drilling Tool Wear Driven by Digital Twin

Aiming at the problems of not being able to directly monitor the wear state of drill bit during vibration drilling and not being able to collect relevant dynamic data online during machining, a digital twin-driven online monitoring method for vibration drilling bit wear was proposed. Firstly, feature extraction of multi-source signals in drilling process is carried out by wavelet analysis, and a double neural network model for bit wear recognition is established. Based on this, an online monitoring method for bit wear is proposed. The digital twinning system for bit wear is implemented, and the dynamic data in drilling process is collected online, and the simulation of bit wear process is realized synchronously. Finally, the proposed prediction method is compared with Support vector machine (SVM) recognition method. The results show that the proposed method can effectively predict the tool wear condition and realize the real-time identification of tool wear degree in machining process.

The influence of extremely abrasive rock on the drilling velocity and tool wear in bored piles

The significance of the excavatability for the successful completion of constructional projects has been recognized in recent years, but little attention has been paid specifically to rotary pile boring. Given the quantity of geological parameters alone which need to be taken into account, it is apparent that the estimation of the drilling rate is difficult. Based on a case study in extremely abrasive tertiary silcretes (quartzite), the engineering geological influences on the drillability are examined. A minutely detailed documentation of the drilling process was produced, and laboratory testing was conducted to gain a better understanding of the correlation between significant rock properties and wear on drilling tools. The examined silcretes (quartzite) show CERCHAR abrasivity indices (CAI) up to a value of more than 6. It comes as no surprise that this highly abrasive rock causes extensive wear on piling equipment and an extremely high consumption of wear parts. In combination with the drilling velocity of both the drill tools and the casing shoe remaining well below 10 cm/min, it is obvious that the drilling performance is significantly impacted in more than one way. A correlation between the lifespan of the wear parts and the net drilling velocity is developed, allowing for a more reliable performance prediction for bored piles.

Delamination and tool wear in drilling of carbon fabric reinforced epoxy composite laminate

In the present work, drilling experiments were performed on carbon fiber reinforced epoxy composites, fabricated by compression molding. The effect of various process parameters on delamination and tool wear during drilling were investigated. The laminate, after fabrication, was tested to find the elastic modulus, fiber volume fraction and tensile strength. A full factorial experiment with process parameters at three levels each were performed initially to find the optimum cutting condition which was used in the second experiment to compare the performance of four different drill bits with varying geometry. Analysis of delamination and tool wear revealed that the tool with point angle 90°, helix angle 35° was the best tool for drilling carbon fiber reinforced epoxy composites as it resulted in the least delamination and showed no significant tool wear. Tool with point angle 140°, helix angle 30° also performed well while TiAlN coated tool performed poorly due to the erosion of the coating at the cutting edges resulting in increased cutting forces and higher delamination. Delamination and tool wear was observed to be the highest in tool with a point angle of 118°and helix angle 30°.

Assessment of drilling-induced delamination and tool wear in carbon fibre reinforced laminates

A highly accurate X-ray damage characterization technique was used in this study to investigate the correlation between hole damage, tool wear and thrust force in drilling of carbon fibre reinforced laminates. Woven carbon/epoxy panels were drilled with a twist tool for 592 holes and the internal damage induced by drilling was investigated by high-resolution penetrant-enhanced X-radiography for comparison with damage evaluated by visual inspection. The study shows that the dominant damage mode induced by drilling is delamination and that tool wear has a significant effect on the size of the delaminated area. The analyses also show that the delaminated areas estimated by visual inspection are much smaller than those identified by X-radiography. This finding indicates that visual observation techniques may provide dangerously unconservative indications and should be used in association with more reliable damage evaluation methods to assess the hole quality of drilled carbon fibre reinforced composites.

Tool wear analysis in high-frequency vibration-assisted drilling of additive manufactured Ti6Al4V alloy

Drilling of Additive Manufactured (AM) Ti6Al4V alloy parts represents a necessary operation in the prosthetics manufacturing to guarantee tight tolerances and acceptable surface finishing. However, due to the AM process, the parts are characterized by a different microstructure if compare to the wrought material of the same chemical compositions and thus a different machinability. In this research, an innovative system of high-frequency Vibration-Assisted Drilling (VAD) was implemented to investigate the tool wear and holes quality in drilling of Ti6Al4V parts fabricated through Laser Powder Bed Fusion (LPBF). AM cylindrical samples were manufactured and holes with a diameter of 1.6 mm were produced using both Conventional Drilling (CD) and VAD for which the values of frequency and amplitude were determined by analytical modelling. Tool wear was evaluated during subsequent drilling cycles and related to the hole quality. The results showed that VAD not only preserved tool life, but it also improved the overall holes quality. The reasons for these improvements were ascribed to the VAD kinematics, characterized by an interrupted cut mechanism favoring the chip removal and evacuation. In summary, the impulsive separation between the drill bit and hole surface in VAD was proved to favour the machinability of AM alloys.

Integrated analysis of drilling tool wear

The integrated analysis of wear of drilling tools is performed. The wear pattern is analyzed versus the build of the acting faces of drilling tools. It is found that a cooling lubricant containing a surface active substance (SAS) has influence on the axial load of the tool and on the drilling capacity. The correlation between wear and current roughness of acting faces of tools is revealed. The additive technology developed and validated for feeding cooling lubricants enables higher competitive capability of allmetal tool owing special grooves made in the drill body by 3D printing to ensure SAS inlet to the rock–drilling tool contact. The comparative study of wear of tools under vibro-percussive loading with regard to the loading condition is carried out. We studied three tools made of steel grades 65S2VA, 5KHNM and of hard alloy VK-8. An attempt is made to utilize hidden capacities of spring steel in manufacture of tool capable to operate under superposition of vibrations. For such rocks as sandstone, limestone, shale, iron ore, clay, etc., having strength categories from IV to X on the Protodyakonov scale, it is possible to use tools made of spring or structural steel, which enables considerable reduction in the cost of drilling. Structural steels used to manufacture drilling tools for hard rock drilling under superposition of vibrations sometimes can efficiently replace expensive tools made of hard alloys. Another beneficial factor is high brittle fracture resistance of instrument steels as against hard-alloy tools. The study reveals the dependence of tool durability on the tool geometry. Preliminary observations show that geometry is an essential factor for tools made of structural and instrumental steels. It is suggested that wear of instrumental steel tool insignificantly differs from hard-alloy wear. In some cases, well-hardened instrumental steel successively competes with hard alloy.

A smart tool wear prediction model in drilling of woven composites

Undetected tool wear during drilling of woven composites can cause laminate damage and fiber pull-out and fuzzing, causing subsurface damage. This diminishes the life of the produced part under fatigue loads. Thus, the producing of proper and reliable holes in woven composites requires accurate monitoring of the cutting tool wear level to safeguard the machined parts and increase process productivity and profitability. Available tool condition monitoring (TCM) systems mainly require long development lead time and extensive experimental efforts to predict the tool wear within predefined values of cutting conditions. The changes in these values require system relearning. Therefore, developing of a smart generalized TCM system that can accurately predict tool wear based on unlearned data during drilling of woven composite plates is crucial. In this work, an attempt was presented and discussed to predict the tool wear in drilling of woven composite plates at different and wide range of cutting conditions based on the drilling forces using biased learning data. A generalized heuristic model was proposed to accurately predict tool wear value. The performance of the proposed model was benchmarked with respect to four machine learning techniques namely regression tree, support vector machine (SVM), Gaussian process regression (GPR), and artificial neural network (ANN). Extensive experimental validation tests have showed that the GPR model has offered the lowest prediction error based on a reduced biased learning dataset, which represents 50% reduction in learning efforts compared with available literature. However, the developed heuristic model showed a comparable accuracy using significantly less learning efforts.

Tool Wear and Material Removal Predictions in Micro-EDM Drilling: Advantages of Data-Driven Approaches

In micro electrical discharge drilling, regression models are commonly used for predicting the material removal rate (MRR) and tool wear rate (TWR) from the applied processing parameters. However, these models can be inaccurate since the processing parameters might not always be representative of the actual machining conditions, which depend on several other factors such as the tool length or gap flushing efficiency. In order to increase the prediction accuracy, the present work investigates the capability of data-driven regression models for tool wear and material removal prediction. The errors in predicting the MRR and TWR are shown to decrease of about 65% and 85% respectively when using data collected through process monitoring as input of the regression models. Data-driven approaches for in-process tool wear prediction have also been implemented in drilling experiments, demonstrating that a more accurate control of the hole depth (50% average reduction of the depth error) can be achieved by using data-driven predictive models.

Numerical simulation of tool wear in drilling Inconel 718 under flood and cryogenic cooling conditions

This paper aims to model and simulate tool wear in drilling of Inconel 718 under two different cooling conditions, using an innovative numerical procedure. Although tool wear models can be implemented in most of finite element analysis (FEA) software to calculate the tool wear rate, there is a great limit due to the inability of all these software to update the geometry of the worn tool. In order to overcome this limitation, a subroutine able to modify the tool geometry based on a given tool wear model was developed and implemented in DEFORM 3D, an implicit FEA software. Experimental tests were performed to measure tool wear in drilling using conventional metal working fluids (MWF) and liquid nitrogen (LN2) cooling. Experimental data were used to calibrate the tool wear model and to validate the drilling models. A comparison between simulated and measured results demonstrated the suitability of the developed drilling model to predict tool wear under both MWF and LN2 cooling conditions. Therefore, the developed model can be efficiently used to evaluate the influence of the cutting conditions (including cooling conditions) on tool wear, minimizing the number of expensive and time-consuming tool wear tests.

High throughput deep-hole drilling of Inconel 718 using PCBN gun drill

Overcoming the myriad challenges in the high-speed machining of Inconel 718, especially for deep-hole drilling (DHD), has been a long-standing area of research for several manufacturers and researchers. Owning to the difficult-to-machine characteristics of Inconel 718, the traditional carbide-tipped gun drills often get worn at an accelerated pace and require repetitive re-sharpening or replacement. This lowers productivity and increases costs. Furthermore, it is also a challenging task to meet the stringent hole-straightness requirement of 1/1000 mm for DHD of such difficult-to-machine materials, especially using those carbide gun drills. Hence, this study presents a development of polycrystalline cubic boron nitride (PCBN)-tipped gun drill to address the rapid tool degradation and poor hole-straightness issues. The developed PCBN-tipped gun drill has a layer of PCBN on its cutting tip and bearing pads. Several gun drilling tests on Inconel 718 have been performed at high drilling speed conditions to assess the performance of developed gun drill. In contrast to traditional carbide-tipped gun drills, the developed PCBN-tipped gun drill has the capability of not only performing in the higher cutting speeds but also reducing drilling forces, drilling torques, and tool wear. Furthermore, the surface quality of drilled holes is also much better than those drilled by traditional carbide gun drills. With these results, it further validates the credibility of the developed PCBN gun drill in enhancing the deep-hole drilling process with high throughput productivity and superior quality of drilled holes, especially for difficult-to-machine materials.

Effect of dipped cryogenic approach on thrust force, temperature, tool wear and chip formation in drilling of AZ31 magnesium alloy

Magnesium alloys tend to have inflammable nature and chip self-ignition at high cutting speeds under dry machining condition, although they can be easily machined with good surface quality. In the drilling process, cooling and lubrication have a critical impact as it controls heat generation, tool wear, surface quality, and cutting force. In the present study, drilling tests on AZ31 magnesium alloy were performed with dry and cryogenic conditions at various feed rates and cutting speeds. The effect of dipped cryogenic application during drilling on thrust force, temperature, tool wear, and chip formation were investigated. The results showed that the applied cryogenic drilling method provided less tool wear, smaller chips and reduced amount of adhesions. Drilling tests performed in the cryogenic environment increase the thrust forces by 32 %–39 % compared to dry cutting. Spark and chip ignition were not observed even at high cutting speeds during dry cutting.