High Speed Steel Twist Drills Research Articles

Study of Machinability in Drilling Operation of Enset–Sisal Hybrid Polyester Composite

Due to their light weight, low density, high-specificity strength, and ease of fiber surface treatment, natural-fiber-reinforced composites are recognized as the most suitable materials for interior part applications. Moreover, natural fibers are widely accessible and environmentally friendly. The fabricated parts are assembled predominantly by fastening using drilled holes, which makes drilling operations common machining processes for the composite parts. Damage occurs at the entry and exit surfaces of drilled holes. In this study, hand layup procedures are used to create unidirectional and woven forms of 1:1 ratio enset (false banana)/sisal hybrid polyester composites that have been treated with 5% NaOH. The drill operation was performed using a computer numerical control (CNC) drill machine with high-speed steel twist drill. A Taguchi design tool was used to complete the analysis. The experiments were conducted at different levels of drilling speeds: 600, 1200, and 1800 rpm. Feed rates of 0.1, 0.2, and 0.3 mm/rev and drill bit diameters of 6, 9, and 12 mm were used. These were determined to be the study parameters that influenced the delamination factors (Fd) and surface roughness (SR) of the hybrid composite drilled parts. Delamination occurred at the entry and exit surfaces of the drilled holes, and surface roughness occurred at the inner surface of the sectioned drilled hole. The quality of the drilled holes was compared based on the delamination factor and the surface roughness, as analyzed by the 3D optical surface profiles.

Thermal Investigation on Coated and Uncoated HSS Twist Drill using ANSYS Software

Abstract: In drilling, a cylindrical hole is produced in workpiece, removing the material inside the workpiece. The cutting tool used in drilling operation is called ‘Twist Drill’; it rotates and allows the material to be removed from the workpiece in the form of chips and thus drill the hole. Cutting fluids or coolants are used to perform this operation smoothly. The coating on the drill bits helps to reduce friction in the cut and the heat buildup in the drill bit. Coating also helps in protecting against corrosion. The present work focuses on the features of uncoated High Speed Steel (HSS) Twist Drill bit and Titanium Nitride (TiN) and Titanium Aluminium Nitride (TiAlN) coated on HSS Drills. The workpiece material was Mild Steel and the drilling operation was done using normal machining condition i.e. in presence of coolant. The cutting parameters used are cutting speed (35.5 m / min), spindle speed (1500 rpm), feed rate (0.2 mm / rev.), depth of cut (10 mm). These parameters were kept constant. Temperatures were measured with the help of thermal imaging camera and with the help of ANSYS software thermal analysis were done. Experimental results showed that the average rise in temperature of uncoated HSS tool was higher as compared to TiN coated and TiAlN coated HSS tools. TiAlN coated drills showed the least average rise in temperature. Keywords: High Speed Steel (HSS) Drill, TiN and TiAlN Coated HSS Twist Drill, Mild Steel (MS), Thermal Analysis, ANSYS Software.

RESEARCH AND REVIEW OF CLAY AND GLASS FIBER REINFORCED POLYESTER NANOCOMPOSITE MATERIALS USING OPTIMIZATION TECHNIQUES

Drilling process plays a vital role in the development of polymer clay nanocomposites. The effects of various parameters, such as tool, feed rate and speed to generate the impact on tangential force, thrust force and delamination factor acting on the material in production are studied during drilling operations in the aerospace and automotive industries. The input variable settings to adjust the speed and feed rate to show the outcomes of tangential force, thrust force and delamination factor of the material according to the consumption of the parts in the next stage of manufacturing are calculated by efficient feed rate optimization. A series of tests are performed by changing tools such as High speed steel (HSS), end mill (HEM), High speed steel (HSS), twist drill (HTD) and carbide twist drill (CTD) on various materials to evaluate the influence on the feed rate and speed. Based on the experimental analysis, mathematical modeling is implemented to study the properties of glass fiber reinforced polyester nanocomposite (GFRPNC; 3[Formula: see text]wt.%). Using the desirability approach, the optimum operating conditions of the selected process variables are considered to minimize delamination. A full factorial experiment design is adopted using the two fundamental concepts of replication and randomization of experimental design to research the relationship between the variables. Based on the analysis of variance (ANOVA), the process model is formulated using the [Formula: see text] statistical kit. It is inferred that the delamination factor is minimal for all tools (CTD, HTD and HEM) at 0.1[Formula: see text]mm/rev feed rate and speed at 852[Formula: see text]rpm.

Chisel edge wear measurement of high-speed steel twist drills based on machine vision

Tool wear is usually the most relevant parameter of tool performance detection, which directly affects the product quality and tool life. Online tool condition monitoring can effectively reduce workpiece scrap and machine failure. Chisel edge wear is one of the main wear forms in high-speed steel (HSS) twist drill. A machine vision method for chisel edge wear measurement is proposed in this paper to improve measure accuracy and reduce testing costs. Firstly, Otsu segmentation based on Laplacian edge information is proposed for tool image segmentation. A morphology-based Canny operator is developed to perform edge detection and image registration for rough positioning of the tool wear area. Zernike moment-based sub-pixel edge detection is proposed to improve the measurement accuracy. Finally, principal curve is employed to fit sub-pixel edge points to obtain smooth edge curve of the tool wear. Finally, the chisel edge wear can be detected and measured effectively based on the proposed method. In the real machining process, the test results show that the proposed system shows high response speed and inspecting accuracy, which is more convenient and efficient than manual measurement with an electron microscope. This system can be effectively applied to the real-time monitoring of tool wear in industry.

Optimization Drilling Parameters of Aluminum Alloy Based on Taguchi Method

This paper focuses on the optimization of drilling parameters by utilizing “Taguchi method” to obtain the minimum surface roughness. Nine drilling experiments were performed on Al 5050 alloy using high speed steel twist drills. Three drilling parameters (feed rates, cutting speeds, and cutting tools) were used as control factors, and L9 (33) “orthogonal array” was specified for the experimental trials. Signal to Noise (S/N) Ratio and “Analysis of Variance” (ANOVA) were utilized to set the optimum control factors which minimized the surface roughness. The results were tested with the aid of statistical software package MINITAB-17. After the experimental trails, the tool diameter was found as the most important factor that has effect on the surface roughness. The optimal drilling factors that minimized the surface roughness are (20mm/min cutting speed, 0.2 mm/rev feed rate, and 10mm tool diameter).

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

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

Detecting Safety Zone Drill Process Parameters for Uncoated HSS Twist Drill in Machining GFRP Composites by Integrating Wear Rate and Wear Transition Mapping

The previous research investigations informed that the tool wear of any machining operation could be minimized by controlling the machining factors such as speed, feed, geometry, and type of cutting tool. Hence the present research paper aims at controlling the process parameters to minimize the drill tool wear, during the machining of Glass Fiber Reinforced Polymer (GFRP) composites. Experiments were carried out to find the tool wear rate and a wear mechanism map of uncoated High Speed Steel (HSS) drill of 10 mm diameter was developed for the drilling of GFRP composite laminates. The surface micrograph images on the drill land surface displayed dominant wear mechanisms induced on HSS drill during machining of GFRP and they were found to be adhesive wear, adhesive and abrasive wear, abrasive wear, and diffusion and fatigue wear. A “safety wear zone” was identified on the wear mechanism map, where the minimum tool wear of the HSS drill occurs. From the safety zone boundaries, it was inferred that the drill spindle speed should be set between 1200 and 1590 rpm and feed rate must be set within a range of 0.10–0.16 mm/rev for GFRP work and HSS tool combination to enhance the service life of 10 mm HSS drills and to minimize the tool wear.

A Damage-Free Machining Method for CFRP Without Feedback Control Systems

A damage-free cutting method called the constant- load feeding method is proposed as a high-precision machining method in carbon-fiber-reinforced plastic (CFRP) cutting. The constant-load feeding method can minimize cutting defects such as burrs and scuffing during diamond-saw cutting. In addition, there was no apparent cutting damage to the cutting surface from drilling with a high-speed steel twist drill. The cutting resistance was kept at a constant value during the entire process. The constant-load feeding can self-regulate the optimal tool feed rate to realize damage-free machining of CFRP composites without any feedback control systems based on the cutting-force.

Effects of drilling parameters and aspect ratios on delamination and surface roughness of lignocellulosic HFRP composite laminates

ABSTRACTHemp fibre‐reinforced polycaprolactone (HFRP) composite has inherent good mechanical properties and benefits which include remarkably high specific strength and modulus, low density, and renewability. No doubt, these properties have attracted wider applications of HFRP composite in engineering applications. This paper presents an investigation on the influence of drilling parameters and fibre aspect ratios, AR (0, 19, 26, 30, and 38) on delamination damage factor and surface roughness of HFRP composite laminates utilising high speed steel twist drills under dry machining condition. Taguchi's technique was used in the design of experiment. The results obtained show that increase in cutting speed reduces delamination factor and surface roughness of drilled holes, whereas increase in feed rate causes increase in both delamination factor and surface roughness. Feed rate and cutting speed had the greatest influence on delamination and surface roughness respectively when compared with aspect ratio, while an increase in fibre aspect ratios leads to a significant increase in both delamination factor and surface roughness. The optimum results occurred at cutting speed and feed rate (drilling parameters) of 20 mm/min and 0.10 mm/rev, respectively, when drilling sample of AR 19. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 42879.

Response Surface Methodology Modeling of Drill Exiting Damage Factor in High Speed Drilling of GFRP Using HSS Twist Drill Bit

This paper presents a research on experimental and response surface methodology (RSM) approach in evaluating the damage factor of the drilled holes in high speed drilling of glass fiber reinforced polymer (GFRP). From the experiment, the influences of drilling parameters toward damage factor are more prominent in thicker GFRP; where high speed drilling using high speed steel twist drill bit produces lower damage factor in thicker GFRP. Lastly an optimized set of drilling parameters was generated for the use of high speed steel twist drill bit in high speed drilling.

Study of the Wear of Drills in Dry Drilling of NM360 Steels

According to the characteristics of NM360, a contrast experiment for drilling performance in YG8 cemented carbide twist drill, high-speed steel twist drill and factories used in coating the ordinary high-speed steel twist drill has been done. Using microscope to observe tool wear, we found that the flank wear and chisel edge wear are the main wear of the drill. The carbide tools has a better ability of resistance to plastic deformation, abrasive wear and adhesive wear than high-speed steel cutting tools. The coating tools are better to resist abrasive wear and adhesive wear than uncoated tools.Deformation of carbide cutting tools, abrasive wear, ability than high-speed steel cutting tools.

Study of the Damage of Drills in Dry Drilling of NM360 Steels

According to the characteristics of NM360, a contrast experiment for drilling performance in YG8 cemented carbide twist drill, high-speed steel twist drill and factories used in coating the ordinary high-speed steel twist drill has been done. Using microscope to observe the damage of drills, we found that form this experiment some causation in tool invalidation that tool breakage is main factor for the high-speed steel drill bits, brittle fracture is main factor for carbide drill bits. Brittle carbide cutting tools, feed speed too much impact load is too large, causing the blade fracture. As the tool edge wedge angle is too small, poor edge strength, easy chipping, edge wedge angle can not be too small.

Machinability of AISI 316 Austenitic Stainless Steel With Cryogenically Treated M35 High-Speed Steel Twist Drills

In this paper, machinability of AISI 316 austenitic stainless steel was investigated using cryogenically treated and untreated high-speed steel (HSS) twist drills. Machinability of AISI 316 austenitic stainless steel was evaluated in terms of thrust force, tool life, surface roughness, and hole quality of the drilled holes. Experimental results showed from 14% to 218% improvements for treated tool lives. Thrust force, surface roughness, and hole quality are better with treated drills when compared with untreated drills. These improvements were mainly attributed to formation of fine and homogeneous carbide particles and transformation of retained austenite to martensite. Microhardness and microstructure observations verified these formations.

Research on Cutting Performance of Graphite-Like Carbon Coated Tools in Dry Drilling of Ferrous Metal

The graphite-like carbon (GLC) coating was deposited onto high-speed steel (HSS) twist drills by magnetron sputter ion plating technique. The drilling tests were performed on the ferrous metal under dry cutting conditions. By the analysis and comparison of the flank wear and the drilling forces on drills, the cutting performance of GLC coated HSS tools was researched. The results show that GLC coating with high hardness and low friction coefficient, due to its good adhesion and match with HSS substrate, can significantly improve the cutting performance of HSS twist drills, prolong the tool life, decrease the drilling forces in drilling the ferrous metal. And its cutting performance is better than the hard coated drills in the lower speed, but its thermal stability is inferior to the hard coated drills in the higher speed.

Magneto-abrasive machining for the mechanical preparation of high-speed steel twist drills

In this paper investigations of the influence of magneto-abrasive machining (MAM) on the micro-geometry of the tool cutting edges and the surface quality of high-speed steel (HSS) twist drills are presented. It is shown that MAM makes it possible to reproduce defined radii of the cutting edges and corner edges of the drills and improves the tool surface quality. The optimally rounded cutting corner edge of the drill makes it possible to avoid the run-in period of the drill and increases the stability of the cutting edge substantially. This results in an improved wear behaviour and higher tool life of the drill.

Study on the Complex Tools Coating Technology by EDM

A kind of new complex tools coating technology by EDM (Electrical Discharge Machining) is studied in this paper. Firstly the principle of this technology is discussed. In order to meet the coating requirement of the high-speed steel twist drill, milling cutter or other complex tools, a set of coating device is designed and fabricated secondly, and the tools with different dimension are coated successfully by this device. Finally the performance evaluation of coated twist drills is carried out through the drilling test.

Efficiency of the laser texturing on the adhesion of the coated twist drills

The coating adhesion is an important property of cutting tools. High speed steel twist drills coated with TiN have proved that cutting speeds can be 2.5–4 times higher and feed velocity also can be 3–5 times higher than those speeds used when uncoated tools are utilized. However, a suitable adhesion is very important, because the coated tool with poor adhesion between the substrate and the coating presents a worse performance than the uncoated tool. The formation of hard and abrasives particles, resulting from the premature destruction of the coating, accelerates the wear of the surfaces which have sliding contact. A new technique to clean and texturing the surfaces using a laser beam, previous to the coating deposition was applied to a set of drills and its performance compared with another set of coated drills without texturing. In the texturing process, a laser of short pulses and high repetition rate generates a surface texturing due to the formation of small liquid drops of the material. After the solidification, nanostructures are formed which allow a better coating retention. The comparison between these two sets of drills was carried out in drilling tests of the ABNT 304 steel, in three different cutting speeds. The evaluation parameters were: the number of holes drilled by each drill, feed force, thrust moment and flank wear. The results showed a large increase of the tool life when texturing of the substrate was made.

The Performance of Small Diameter Twist Drills in Deep-Hole Drilling

This paper investigates the performance of small diameter high-speed steel twist drills drilling boreholes with a depth of ten times the diameter into carbon steel AISI 1045 using minimum quantity lubrication. The performance of small twist drills is determined, first, by their deep-hole drilling capability, i.e., in how far the cutting forces can be kept at a noncritical level by maintaining the chip disposal, and, second, by their tool life. This work shows that both the deep-hole drilling capability and tool life of small drills are strongly dependent on their geometry, in particular the size of the chip flutes, and the flute surface topography.

Effect of MQL on the tool life of small twist drills in deep-hole drilling

Drilling of deep and small boreholes using twist drills has to be considered as one of the most difficult metal cutting operations. There are many reasons for this, one of them being that the cutting fluid has to be supplied externally. This research work investigates in how far the manner of supplying and the type of minimum quantity lubricant have an effect on the tool life of coated and uncoated high-speed steel twist drills of 1.5 mm diameter. Deep-hole drilling is performed as the holes, drilled into plain carbon steel, had a depth of 10 times the diameter. The feasibility of dry machining as an appropriate alternative to MQL in deep-hole drilling has also been investigated. This work shows that, compared to a continuous supply of the minimum quantity lubricant, a discontinuous supply brings about a significant reduction in tool life, especially in the case of heat-sensitive drills. With respect to the type of minimum quantity lubricant, a low-viscous type with a high cooling-capability gave rise to a notably prolonged tool life. It is also shown that dry drilling is associated with strongly accelerated tool wear for most of the twist drills tested, resulting in a significant reduction in tool life.

A study of the wear mechanisms of Ti 1− xAl xN and Ti 1− x− yAl xCr yN coated high-speed steel twist drills under dry machining conditions

Recent advances in cutting tool materials and PVD surface coatings are making high-speed dry machining an increasingly viable machining operation in commercial manufacturing sectors. High oxidation resistant coatings, such as TiAlN, are used extensively in global manufacturing for reducing production costs and improving productivity in such aggressive metal-cutting operations. In this investigation, the performance of TiN, Ti 1− x Al x N and Ti 1− x− y Al x Cr y N coatings was assessed on Co-HSS twist drills used to machine an automotive grade grey cast iron. As part of the study, two experimental methods were used to characterise the performance of the twist drills, namely, by an audible ‘screech’ and measurement of the progression of outer corner flank wear lands. Both techniques showed that a single layer TiN coating failed to outperform even uncoated twist drills when dry machining grey cast iron under aggressive machining conditions. However, using the measurement of outer corner flank wear technique, the average tool life of uncoated twist drills was increased by factors of 4.5, 6.5 and 6.9 by Ti 0.59Al 0.41N, Ti 0.27Al 0.19Cr 0.54N and Ti 0.21Al 0.14Cr 0.65N coatings, respectively. In the case of ‘screech’ failure, the average tool life of uncoated twist drills was increased by factors of 3.9, 7.3 and 10.8 by Ti 0.59Al 0.41N, Ti 0.27Al 0.19Cr 0.54N and Ti 0.21Al 0.14Cr 0.65N coatings, respectively. The performance of twist drills was also assessed using a number of quantitative techniques, namely, measurement of thrust and torque, hole diameter and drill wear. The latter was also observed using scanning electron microscopy (SEM) which showed an early onset of workpiece material transfer at the margins of the uncoated drills. In the case of the PVD coated drills, an improvement in the tribological interaction between the coatings and the grey cast iron workpiece resulted in a significant reduction in material transfer at the drill margins. The above results are discussed in terms of their affect on hole diameter and cutting forces.