Coated Carbide Drills Research Articles

Multi objective optimization of process variables using grey relational analysis for drilling of hybrid composites (LM6/B4C/fly ash)

Aluminium alloys continue to be an effective material for the aviation and automotive sectors in spite of the development of composites and other lightweight materials because of their sophisticated manufacturing techniques, strong durability against fatigue fracture propagation, and excellent impact endurance. As numerous holes are needed for creating rivets, drilling is the most difficult of all the machining operations. The primary problems with drilling these aluminium alloys are represented by a low hole quality, which increases the risk of airframe construction defects and lowers reliability. As a result, parts get discarded throughout the process of assembling, which affects the overall cost of production. To satisfy the needs of machined parts, the selection of Feed rate (F), Spindle Speed (S), Drill Material (D) and percentage of reinforcements (R) as well as drilling equipment, is necessary. The objective of this research work is to study the impact of cutting parameters on surface roughness (SR) and thrust force (TF) during drilling Hybrid MMCs, which were prepared by stir casting. The reinforcements used for fabrication were fly ash and boron carbide. A computer numerical control VMC with a cutting tool dynamometer for measuring TF was used for the experiments. The investigations used the L18 orthogonal array as their base of operation. The multi response optimization considering TF and SR was carried out using grey relational analysis (GRA) and the optimal level of cutting parameters like ‘F’, ‘S’, ‘D’ and ‘R’ were identified to obtain low TF and SR. The optimal machining parameters which give low TF and low SR are at 6 % reinforcement, coated carbide drill, S 3000 rpm and F 50 mm/min. Feed Rate (67.20 %) has the most significance on GRG trailed by S (15.88 %), Drill Material (6.39 %) and reinforcement percentage (3.65 %). Confirmation experiments demonstrated that grey relational analysis precisely optimized the process variables in drilling of hybrid MMCs.

Optimization of stir casting and drilling process parameters of hybrid composites

AA2219 alloy is widely used in aerospace and automobile applications, wherein the properties can be enhanced with 15% wt. of B4C reinforcement particles. Assembly task in aerospace application requires drilling millions of holes, and it is often challenging to obtain good-quality drilled holes due to the presence of hard B4C particle reinforcements. The self-lubricating capability of molybdenum disulfide (MoS2) and Graphene (Gr) materials was used as secondary reinforcements to improve the drilled hole quality characteristics. The stir-casting route fabricates the hybrid composites (AA2219 alloy/B4C/Gr/MoS2). The hardness and wear resistance properties of hybrid composites are affected by the influencing process variables such as percent reinforcement of Gr and MoS2, stirring speed, and pouring temperature. Taguchi L9 matrix is used for experimentation and performs statistical analysis. All stir-casting variables are found to make significant contributions toward hardness and wear resistance. The limitation of the Taguchi method to solve multiple objective optimizations is solved by applying Data Envelopment Analysis Ranking (DEAR) method. A DEAR method determined optimal conditions (Gr and MoS2: 1.5 wt%, stir speed: 400 rpm, and pouring temperature: 760 °C) resulted in a reduced wear rate of 1.65 × 10−3 mm3/min and 128 HV hardness in hybrid composites. The hybrid composites were prepared for the determined optimal stir casting conditions. Drilling experiments were carried out to analyze the variables such as feed rate (FR), drilling speed (DS), and drill tool material (DM): high-speed steel: HSS, carbide: C, and coated carbide: CC that affect the hybrid composite hole quality characteristics such as burr height: BH, material removal rate: MRR, and thrust force: TF. A DEAR method determined optimal drilling conditions (FR: 0.25 mm/rev; DS: 20 m/min; DM: coated carbide drill tool) resulted in 645 mm3/min of MRR, 2.95 kN for TF, and 0.16 mm for BH, respectively. The self-lubricating capability of Gr and MoS2 reinforcement particles in hybrid composites ensures excellent composite properties and drilled-hole quality characteristics. Taguchi and DEAR methods employ simple mathematical steps which can be used by novice industry personnel to perform optimization for other output characteristics.

Experimental Study on the Dry Drilling Nickel-Based Superalloy of CrAlYN Coated Carbide Bit.

Nickel-based superalloy is regarded as one of the materials with the poorest cutting and drilling performance. Additionally, there is much less research on the drilling of it. This paper aims to study the drilling performance of dry drilling nickel-based superalloy with uncoated and CrAlYN coated carbide bit. First of all, the primary and secondary factors influencing the machining performance of dry drilling nickel-base superalloy uncoated carbide bit were explored through an orthogonal test. Secondly, the self-prepared CrAlYN coated carbide drills, and uncoated drills were compared and analyzed from perspectives of service life, drilling force, drilling temperature, drill surface topography, failure mechanism, and machining surface quality. The research results are as follows: the drilling temperature is the primary factor affecting the drilling performance under dry drilling conditions. CrAlYN coating can obviously prolong the service life of tools, reduce the drilling force and drilling temperature, and improve the machining surface quality at lower rotational speeds. Moreover, the coated cemented carbide bit has a similar failure mode to the uncoated cemented carbide bit after the CrAlYN coating falls off in the wear zone of cemented carbide bit, which is mainly bonding wear on the rear tool surface and the front tool surface.

Parametric analysis on drilling of aluminium alloy hybrid composites reinforced with SIC/WC

Aluminium alloy (Al7075) based hybrid metal matrix composites reinforced with Silicon carbide (SiC) and Tungsten carbide (WC), at 5 wt% each are considered for this investigation, which are developed by stir casting methodology. Material characteristic analysis both at micro and macro (Tensile strength and micro hardness) level were performed. This investigation is further progressed with drilling of the composites using titanium aluminium nitride coated carbide drill (5mm diameter) for varied point angle, feed rate and drill speed. The responses such as thrust force, surface roughness and roundness error were investigated by adopting Response Surface Methodology (RSM). Multiple linear regression (MLR) is developed along with Artificial Neural Networks (ANN) model for predicting the outputs. Scanning Electron Microscope (SEM) image reveals the uniform distribution of ceramic particles in matrix which ascertains enhanced mechanical properties. The parameters such as feed rate and point angle are found to have significant influence during drilling process. The roundness error is found higher with higher point angle which is due to the wider cutting edges in the drill bit. For unconstrained multi-objective optimization, the optimal condition obtained are 128°- point angle, 0.05 mm rev−1 feed rate and 1000 rpm drill speed. For constrained optimization (roundness error ≤0.05 mm), optimal conditions are 118° point angle, 0.05 mm rev−1 feed rate and 1000 rpm drill speed.

The influence of tool quality on the machining of additive manufactured and powder metallurgy titanium alloys.

This study was carried out to investigate the impact the quality of the drill bits has on the machining behavior of additive manufacturing (AM) and powder metallurgy (PM) titanium alloys. Therefore, commercially available drill bits which typically reflect two extremes of drill bit quality were selected. The performance of coated carbide twist drills, typically recommended for the drilling of wrought titanium alloys was compared with that of high-speed steel (HSS) drills. The average torque value, specific cutting energy (SCE), and tool wear were used to evaluate the drilling performance of AM and PM titanium alloys. The results of drilling tests revealed the application of the coated carbide drill resulted in lower torque and SCE values, less flank wear, and lower build-up-edge (BUE) compared with the uncoated HSS drill bits for AM fabricated titanium alloys. However, the carbide drill appeared to offer negligible improvement over the uncoated HSS drill when employed with the PM fabricated titanium alloy. In spite of the improvement in the drilling performance offered by the carbide drills for the AM titanium alloy, TiB intermetallic particles (part of the AM titanium microstructure) contributed to the damage of the coated carbide drill which would limit the drill lifetime.

Comparative analysis of thrust force, roughness and roundness error in drilling of aluminium composites using RSM, ANN and fuzzy logic

Making holes without any defect in a solid product made of hybrid Aluminium composite material, is a difficult job in assembly industries. Hybrid composite of Aluminium 7075 reinforced with ceramic materials like silicon carbide, boron carbide, graphite and mica are used in automobile and structural industries due to their excellent mechanical properties. Thrust force developed during drilling, Error in the circularity and poor surface finish of the drilled holes are some of the common problems faced in the drilling process. Hence, to optimise the quality of drilling, analysing these responses under various conditions of drilling by varying the drilling factor become essential. This study discusses the development of various models to predict the thrust force developed, roughness and circularity error in the holes drilled on a hybrid metal matrix composite. Testing of drilling is conducted in CNC vertical machining centre using Titanium aluminium nitride (TiAlN) coated carbide drill tool of 5 mm diameter. Various drilling factors considered in our study are point angle of the drill tool, drilling speed and feed rate. Multiple regression equations using RSM, Artificial neural network (ANN) and Fuzzy Logic algorithms are used to develop the prediction models. The predicted values of thrust force, surface roughness and circularity error from these models are found to be matching with the observed experimental values.

Procena i višekriterijumska optimizacija hrapavosti površine, odstupanja od tačnosti dimenzija i greške zaobljenosti u bušenju CFRP/Ti6Al4 naslaga

In this study, machinability tests were carried out to investigate the effects of control factors (cutting tool geometry, cutting speed, and feed rate) on the surface roughness (Ra), deviation from dimensional accuracy (Da_dev), roundness error (Re) in drilling CFRP/Ti6Al4V mixed metallic stack and to determine the optimum levels of drilling parameters. The effects of each control factor and their interactions on three quality characteristics were analyzed, and their levels were single-objectively optimized for each component material by the Taguchi method. The material has components (CFRP and Ti6Al4V) with essentially different properties (mechanical, physical, machinability). Single-objective optimization has limited usability as the drilling must be performed in one through both layers. Therefore, in an additional step, the optimum levels of the control factors were determined by optimizing multi-objective with the Additive Ratio Assessment (ARAS) method. Higher Ra, Da_dev, and Re values were obtained on the CFRP component compared to the Ti6Al4V component. The CFRP/Ti6Al4V stack should be drilled with a nano fire coated carbide drill (T3) at medium cutting speed and high feed rate to achieve minimum Ra, Da_dev, and Re values in one go.

Experimental investigation on the machinability characteristics in drilling of syntactic foams

Syntactic foams (SFs) finds its application in automobiles, aircrafts and underwater vehicles. Drilling is most frequently used machining operation for assembly of these composite structures. In the present investigation, an effort is made to analyse the effect of cutting speed (Cs ), feed rate (fr ), drill diameter (D) and filler content (F) on machinability characteristics in drilling glass microballoon (GMB) reinforced epoxy SFs. Machinability characteristics analyzed includes thrust force (Tf ) and surface roughness (Sr ). SFs are fabricated by dispersing 25, 35 and 45 vol.% of GMBs in epoxy resin. Experiments are carried out based on full factorial design (FFD) using TiAlN coated carbide drills. Experimental results show that Tf and Sr increases with increasing Cs . As fr increases, Tf increases but decreases the Sr . Increasing GMB content significantly reduces the Tf and Sr of developed SFs.

Influence of drilling parameters on thrust force and burr on fiber metal laminate (Al 2024-T3/glass fiber reinforced epoxy)

In the present work a fiber metal laminate (FML) of three aluminum sheets interspersed with eight layers of glass fiber reinforced epoxy was used. The processes were carried out using 4000 and 8000 rpm and a 0.05; 0.10 and 0.20 feed in mm/rev with a coated carbide drills (TiAlN) with Ø4.8mm. With the found results, it could be stated that the thrust force was affected significantly by the feed with 99.75% of contribution, the burrs thickness was influenced by spindle speed and feed (27.59% and 63.14% respectively), and burrs height by feed and interaction between factors (21.33% and 75.76%).

Performance Analysis of Multi-Spindle Drilling of Al2024 with TiN and TiCN Coated Drills Using Experimental and Artificial Neural Networks Technique

Multi-spindle drilling simultaneously produces multiple holes to save time and increase productivity. The assessment of hole quality is important in any drilling process and is influenced by characteristics of the cutting tool, drilling parameters and machine capacity. This study investigates the drilling performance of uncoated carbide, and coated carbide (TiN and TiCN) drills when machining Al2024 aluminium alloy. Thrust force and characteristics of hole quality, such as the presence of burrs and surface roughness, were evaluated. The results show that the uncoated carbide drills performed better than the TiN and TiCN coated tools at low spindle speeds, while TiCN coated drills produced better hole quality at higher spindle speeds. The TiN coated drills gave the highest thrust force and poorest hole quality when compared with the uncoated carbide and TiCN coated carbide drills. Additionally, a multi-layer perceptron neural network model was developed, which could be useful for industries and manufacturing engineers for predicting the surface roughness in multi-hole simultaneous drilling processes.

An experimental study of drilling parameters and determination of ovality during the drilling of grade 5 titanium alloy with TiN coated carbide drill tools

Titanium is particularly a hard to cut element. Alloys of Titanium are also regarded as hard-to-machine materials. Out of many machining operations on Titanium, drilling is treated as very important operation as it is crucial in many applications. Drilling is normally considered among the final steps of fabrication of parts and has critical economic importance. Hence it is desirable to develop an economical and feasible drilling process for Titanium alloy and improve the effectiveness of current methods since even a small mistake in the drilling operation can lead to throwing away the entire part and having to replace the entire part. On account of above facts, an experimental trial has been made to study the machining aspects during drilling of the Ti-6Al-4V alloy. The primary aim of this research paper is to study various issues in drilling holes on grade 5 Titanium alloy with Titanium Nitride (TiN) coated carbide tool. Drill bits are selected in varying diameters and drilling procedure is carried out under different feed rates and speed. The output responses measured are temperature, thrust force and torque which are analyzed and studied. Also, the hole quality is studied by measuring the Hole Ovality on a profile projector. FESEM of drill bits is carried out to analyze the pattern of wear occurred on drill bits while drilling.

Evaluation of minimum quantity lubrication and minimum quantity cooling lubrication performance in hard drilling of Hardox 500 steel using Al2O3 nanofluid

The work in this study presents an experimental evaluation on minimum quantity cooling lubrication based on the Ranque–Hilsch vortex tube and minimum quantity lubrication performance in hard drilling of Hardox 500 steel (49–50 HRC) using coated carbide drills. Al2O3 nanoparticles are suspended in the based fluids including water-based emulsion and rice bran oil to enhance the cooling and lubricating effects. The response variables, consisting of drilling thrust force, surface roughness, surface profile and microstructure, and tool wear, are studied, and the analysis of variance is used for evaluating the input machining parameters under minimum quantity lubrication and minimum quantity cooling lubrication conditions. The results of this article indicate that minimum quantity cooling lubrication using Al2O3 nanofluid provides the better machining performance and gives out better surface quality and lower thrust force compared to minimum quantity lubrication with/without nanofluid and minimum quantity cooling lubrication with pure fluid. Also, based on the optimization results, the validation experiments are conducted to study more on drilling thrust force, chip morphology, and tool wear.

Experimental investigation and analysis of drilling in Grade 5 Titanium alloy (Ti-6Al-4V)

Titanium is one of the hardest elements in the world and it has superior properties. Some of the highlighted properties of Titanium which makes it suitable for various critical applications are its corrosion resistance and the highest strength-to-density ratio to any metallic element. Amongst all Titanium machining operations, drilling (or hole making) is very important and is considered difficult as Titanium is a very hard element. Hence in this paper an attempt is made to perform drilling on Titanium alloy and study the machining parameters during the dry drilling of the Grade 5 (Ti-6Al-4V) alloy with coated carbide drills.

Effects of minimal quantity lubricants reinforced with nano-particles on the performance of carbide drills for drilling nickel-titanium alloys

Abstract Drilling of NiTi alloys under two lubricant-coolant strategies; namely flood and minimal quantity nanolubricant; two types of carbides drills, and three cutting speeds was investigated. Progressive tool wear, tool-life, drilling thrust force, surface finish quality, and dimensional accuracy were considered. Experimental results suggest that the application of minimal quantity nanolubrications with coated carbide drills outperformed the flood lubrications with uncoated carbide drills. These results were pronounced for cutting speed of 10–20 m/min, whereas, accelerated tool wear, high thrust force, and low tool life were experienced for 30 m/min cutting speed. Despite of some promising results obtained from the supply of minimal quantity nanolubricants, this approach was found to be ineffective towards improving surface roughness and hole diameter accuracy.

Chip Deformation Mechanism during Drilling of Nickel-based Superalloy FGH97

Nickel-based superalloy is widely used in aviation, aerospace, shipping and petrochemical industry. An experimental investigation was conducted to analyze the effects of cutting parameters on chip deformation during drilling process of nickel-based superalloy FGH97. Drilling experiments have been carried by means of a machining center YCM-V116B and TiN/TiAlN coated carbide drill bit SECO made SD203-8.0-27-8R1. The chip root is obtained by means of ourselves-made device. The chip deformation decreases with the increasing of cutting speed during drilling process of Ni-based superalloy. The larger the feed rate, the less the chip deformation is. When cutting speed is from 6 m/min to 12 m/min, the shear angle of drilling changes from 14.8 degrees to 19.9 degrees. When feed rate speed is from 0.03mm per tooth to 0.06mm per tooth, the shear angle of drilling changes from 13.7 degrees to 17.4 degrees.

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.

Dry and minimum quantity lubrication high-throughput drilling of compacted graphite iron

ABSTRACTThis research studies the sustainable and high-throughput drilling of compacted graphite iron (CGI), a high strength, lightweight material for automotive powertrain applications. CGI drilling experiments were conducted using a 4 mm diameter coated carbide drill at 26.5 mm/s feed rate. In two repeated tests under three lubrication conditions: dry, dry with through-the-drill compressed air, and through-the-drill minimum quantity lubrication (MQL), the drills were able to produce a maximum of 1,740, 3,150 and 2,948 holes, respectively, before the breakage of the drill. The Joule–Thomson effect due to the expansion of high pressure air from through-the-drill holes at the drill tip, chip shape, chip size and chip speed are investigated. Flank wear of the drill cutting edge is measured and results are correlated to drill life. Results indicate that dry machining of CGI is technically feasible. Chip evacuation and advanced tool cooling are important factors that affect drill life for high-throughput sustainable dry drilling of CGI.

Online monitoring of delamination mechanisms in drilling of Mwcnts reinforced Gfrp nanocomposites by acoustic emission

Among various unconventional Non-Destructive testing (NDT) methods, Acoustic Emission (AE) referred as the most suitable NDT method for detection and characterization of material defects during machining on nanocomposites. AE technique can also be applied for dynamic machining operation called drilling for better understanding of different drilling events from start to the end of the process. The present paper mainly focuses on on-line monitoring of drilling-induced delamination of multi-walled carbon nanotubes (MWCNTs) reinforced glass fiber reinforced plastic (GFRP) nanocomposites laminates through AE technique. A 4 mm thickness of 0.3wt% MWCNTs reinforced GFRP laminates were fabricated by 16 layers of glass fabric cloth with modified epoxy resins for drilling experimentation and trails were conducted on these laminates with uncoated, TiCN and TiAlN coated 6mm diameter carbide twist drills. Design of experiments were planned based on Taguchi L9 orthogonal array and speed, feed were considered as input process parameters. The AE output response parameters such as Root Mean Square (RMS) voltage, AE rise, energy, peak amplitude, hits, AE count, duration and counts to peak were helped to analyse the delamination mechanisms as well as cutting force generation during drilling on nanocomposites. From the experimental results, it was concluded that low feed rate (0.02 mm/rev) and high spindle speed (1500 RPM) with TiCN coated carbide drill gives the reduced delamination factor and thrust force values. Additionally, AE parameters were also highly influenced by the cutting parameters as well as delamination mechanisms. Out of all AE parameters AE-RMS voltage designated as the important parameter to analyse the delamination factor and increased RMS voltage observed with higher feed rate and cutting forces. The other AE parameters were very closely associated to the RMS voltage. Finally, it was confirmed that AE is most suitable NDT technique for on-line monitoring of drilling induced delamination for production of defect free holes on GFRP-MWCNTs composites laminates.

Experimental investigation and optimization of multiple performance characteristics of Al-Mica-B4C hybrid reinforced composite in drilling operation

Machining of composite is critical task and many parameters are needed to study in order to evaluate the performance of composite. In present study, performance characteristics of Al- mica-B4C composite are evaluated and optimized with Taguchi-grey relational analysis in drilling of B4C and mica reinforced hybrid aluminium matrix composites (AMCs) manufactured by powder metallurgy process. HSS, TiAlN coated carbide drill bits and uncoated cementide carbide drills bits were used under dry cutting conditions. The drilling parameters such as feed rate, spindle speed, drill tool material and material parameters like wt. % of B4C as well as Mica particles were optimized based on multiple performance characteristics including thrust force, drilling torque and surface roughness. Experiments were conducted on a computerised numerically controlled vertical machining centre. Drilling tool dynamometer is used to measure the thrust force and drilling torque. Also, to measure the surface roughness of drilled hole portable surface roughness tester is used which shows the readings in microns. Microstructure of composites and surface morphology of drilled hole is studied by using optical microscopy. Finally, it is concluded that, among the drilling tools used, TiAlN coated carbide drill bit shows the better result than other drill bits used. Composites manufactured in present study shows better strength for all levels of reinforcement. Also, it is found that the drilling feed rate affects on the drilling process significantly.

Diamond tools wear in drilling of SiCp/Al matrix composites containing Copper

Although SiCp/Al matrix composites possess numerous excellent physical and mechanical properties, high hardness and high wear resistance characteristics of SiC reinforcement lead to low tool life and resultant poor machined surface quality in cutting. The aim of this paper is to investigate the micromechanism underlying the macro-scale wear of diamond tools in drilling of high volume fraction SiCp/Al composites. To achieve this, the worn morphologies and possible crystal structure evolution of diamond tools after drilled 10 holes were examined using Laser Scanning Microscope and Raman spectroscopy, respectively. Additionally, based on drilling forces and hole quality, the machinability assessment of SiCp/Al6063 composites was carried out. The results indicate that the mechanically induced abrasion and thermodynamically activated chemical graphitization is the dominant and common wear mechanisms for PCD and CVD diamond coated tools in drilling of 65vol% SiCp/Al6063 composites containing copper. The reciprocating actions of thin graphite layer formed by oxidizing hydrogen chemisorbed on diamond surface by Copper oxides and graphite removal due to SiC particulates’ high-frequency scrape lead to continual and significant occurrence of diamond graphitization. In air atmosphere, the thermodynamic conditions of diamond-graphite transformation in machining of SiCp/Al6063 composites containing Copper are investigated. The coupled abrasive-chemical wear model is formulated based on analytical description of diamond wear mechanisms above. In terms of machinability of high volume fraction SiCp/Al composites, CVD diamond coated carbide drill is preferred, due to its stable cutting force, less wear and its ability to produce acceptable machined quality with increasing hole number.