Friction Drilling Research Articles

EFFECT OF COATING TYPE ON TRIBOLOGICAL RESPONSE OF H13 TOOL STEEL

Tribology is the study of friction, wear and lubrication. This work aims to study the effect of coatings on the wear behavior of H13 tool steel. Liquid nitriding, plasma nitriding, PVD TiN coating and DLC were utilized on H13 tool steel for increasing the tool life, quality of drilled holes and to reduce the cost of tool material. The wear behavior of H13 was evaluated using pin on disc wear test. Microstructural and scanning electron microscope analysis of wear surface of tool was carried out to identify the best coating and wear mechanism. This study reveals that PVD-TiN-coated H13 tool exhibited the best wear response and least coefficient of friction hence can be selected for friction drilling process.

Investigation of the Mechanical Properties of Friction Drilling with 6082-T6 Aluminium Alloy.

Friction drilling is a non-conventional hole-making process suitable for thin-section, ductile metals. During friction drilling, heat is generated due to tool rotation and the resulting flow of metal creates a bushing on the exit side of the hole. The bushing offers a longer engagement length for any subsequent thread making process. The threaded holes in this study were created by friction drilling and thread forming in 6082-T6 aluminium alloy. Four scenarios of the threaded holes were created with four levels of rotation rates of friction drilling processes (2000 rpm to 4000 rpm) and the mechanical properties of the threaded holes were compared. It was shown that 3000–3500 rpm is the optimum range of the rotation rate that achieved the higher load-bearing capacities (i.e., resistance to thread stripping) of 5.0–5.5 kN. In addition, the regions close to the thread surfaces in all scenarios were found to have experienced localised hardening to a hardness from 113 HV to around 125 HV.

Dimension-based failure analysis of formed internal threads in AlSi10Mg cast profiles using coupled DT/NDT testing methods

The production of detachable joints in lightweight components using friction drilling and internal thread forming processes could be considered as a lightweight design strategy, which can reduce material and time consumption and enhance the thread strength by imposing a further work-hardening into the subsurface of the formed threads. Pre-study indicated that oversizing the friction drilled bores as a pilot bore can hinder the complete deformation of the thread profiles during the thread forming process. This work investigates the effect of process parameters in the friction drilling process (friction drill speeds and diameter) on the quality of the drilled bores and following formed threads. Computed tomography was chosen to measure the dimension deviation of manufactured bores and threads. Comparing the deviation with the measured static and dynamic strengths declared that increasing the tool diameter by 0.1 mm increased the inner volume of the friction drilled bore, which led to an incomplete deformation of the thread profiles and decreased static and cyclic strength accordingly. Although the friction drilling with an adaptive speed reduced the oversizing of the created bore in comparison to the friction drilled bores with a constant speed, measuring the volume of the formed threads into mentioned bores indicated an opposite trend. While the formed M6-threads into the friction drilled bores with constant speed showed a better strength by subjecting to a quasi-static load, manufactured threads with an adaptive speed indicated a higher dynamic strength. The fatigue tests were monitored through NDT methods by measuring the change in deformation-induced temperature and ACPD potential. The measured results were correlated to plastic strain up to failure corresponding to occurring softening, hardening, or possible crack initiation and propagation in thread profiles.

Minimum quantity lubrication and heat-assisted friction drilling of AA7075-T6 aluminum alloy

In this study, friction drilling was performed for AA7075 - T6 alloy under dry, minimum quantity lubrication (MQL), heat, and heat + MQL process environments. The aim is to achieve the optimum bushing profile by increasing the productivity of friction drilling in different process environments. Friction drilling experiments were carried out at constant speed and feed rate; the effects of the drilling environment on thrust force, temperature, hole bushing profile geometric properties, hole surface quality, thread stripping strength, and micro hardness values were investigated. The test results revealed that the drilling environment directly affects the formation of heat and thrust forces during the process. The best surface roughness (Ra) value was achieved in the heat environment with 2.61 µm. Thread stripping experiments showed that the heating process improved the thread stripping strength of AA7075-T6 by 14.65% when compared with the dry environment. The results revealed that the main damage mechanism occurred in the transition zone from the heat-affected zone (HAZ) to the base material (BM) in the tensile strength test on the heat process environment specimen, while the roots of threads were affected in other process environments. The different microhardness values were measured in the thermo-mechanically affected zone (TMAZ), HAZ, and BM formed during the process.

An Experimental Study on Copper Plates Using Friction Drilling.

Abstract: Friction drilling is a novel hole-making method that can be performed on thin-walled sheets. In recent years of study, the thrust force and torque under numerous process conditions were performed to demonstrate the benefits. In recent years of study, the thrust force and torque under various process conditions were performed to demonstrate the benefits. Our objective is to review the behavior of the material with the use of friction drilling by variation of thickness, Spindle speed, and feed rate. Our objective is to study the behavior of the material with the use of friction drilling by variation of thickness, Spindle speed, and feed rate. The friction between a rapid rotating conical tool and a sheet metal workpiece generates heat to soften and displace the metal to form a whole. Friction drilling is a non-traditional hole-making process in which a conical rotating tool is applied to penetrate the workpiece and make the outlet in a single step, without generating chips. the process relies on the heat generated thanks to the resistance force between tool and workpiece, to soften, penetrate and deform the work material into a bushing shape. Generally, friction drilling is applied to thin-walled materials owing to increasing connection length and clamping strength. The generated resistance heat cause softening piece of work material, increase its ductility, and providing it to flow, that extruded onto both the front and back sides of the holes. Keywords: Friction Drilling, Conical Tool, Material Displace, Temperature, Hardness & Thickness.

INFLUENCE OF PROCESS PARAMETERS IN FRICTION DRILLING OF TITANIUM TI-6AL-4V ALLOY

Friction drilling is a process of using the friction between the rotating conical tool and the workpiece to generate heat and deform the work piece’s material and penetrate the hole. The softened material is pushed sideward and downward to make the bushing. This paper aimed to study the influence of friction drilling parameters. Thrust forces and torque forces were analysed. Experiments were carried out with a friction drill tool made of tungsten carbide on titanium grade Ti-6Al-4V. The parameters used in this study were spindle speed and feed rate. It was found that the thrust force and torque decreased with increased spindle speed and with decrease of feed parameters. The microstructure reveals that deformed grains at hole’s surface relate to hardness on the cross-section of workpiece. The highest value of microhardness was 813.2 HV and reduced to the original hardness of the matrix material.

Finite Element and Finite Volume Modelling of Friction Drilling HSLA Steel under Experimental Comparison.

Friction drilling is a widely used process to produce bushings in sheet materials, which are processed further by thread forming to create a connection port. Previous studies focused on the process parameters and did not pay detailed attention to the material flow of the bushing. In order to describe the material behaviour during a friction drilling process realistically, a detailed material characterisation was carried out. Temperature, strain rate, and rolling direction dependent tensile tests were performed. The results were used to parametrise the Johnson–Cook hardening and failure model. With the material data, numerical models of the friction drilling were created using the finite element method in 3D as well as 2D, and the finite volume method in 3D. Furthermore, friction drilling tests were carried out and analysed. The experimental results were compared with the numerical findings to evaluate which modelling method could describe the friction drilling process best. Highest imaging quality to reality was shown by the finite volume method in comparison to the experiments regarding the material flow and the geometry of the bushing.

Effect of Pre-hole Diameter on Bushing Dimensions for Friction Drilling Process of A6063-T6 Aluminum Alloy

Friction drilling is a non-conventional method for hole making in thin sheet metals. It depends on many parameters regarding the tool conical angle, process conditions and material parameters. In this work, the effect of process conditions and pre-drill diameter on temperature, drilling force, bushing height and bushing thickness of A6063-T6 aluminum alloy were studied. It was found that adding a pre-hole to the plate helps in obtaining uniform bushing thickness and reduces the heat and force required to perform the process.

Influence of pre-drilling on hardness and tensile failure of formed internal threads in thin-walled AZ91 cast alloys

This study investigates the influence of pre-drilling diameter on hardness and tensile failure of the formed internal threads (M6), manufactured perpendicular to the profile thickness of thin-walled AZ91 magnesium casting alloys. Previous investigations have shown that providing a pre-drilling before friction drilling prevents the failure of the bore’s outer wall during the friction drilling process. Considering the oversizing of core bore (friction drilled bore) as an effective factor that can contribute to an incomplete formation of the threads profile through thread forming process, the influence of the pre-drilling diameter was investigated on the hardness and tensile failure of the formed M6 threads. Computed tomography of the friction drilled bores indicated an increase in oversizing of the friction drilled bore with increasing the pre-drilling diameter. Metallographic investigations of the manufactured samples by friction drilling and thread forming process revealed a rhombus-shaped deformation region around the manufactured thread, which provides an enhanced hardness especially at the subsurface of threads profile. The resulting hardness was decreased insignificantly in thickness direction with an increase in pre-drilling diameter. The failure mode of the M6 threads was analysed by means of quasistatic tensile tests. Due to incomplete formation of the threads profile, variation of the pre-drilling diameter did not declare a concrete trend in measured tensile strengths. Fractographic failure analysis by scanning electron microscopy on threads before and after tensile tests showed that the cold-formed threads were mostly sheared off in load direction (thread stripping) by tensile tests implying an internal thread failure caused by shear stresses because of the incomplete formed threads profile, especially along the cross section corresponding profile thickness direction.

Development of software to calculate of friction process parameters used in friction drilling process

Friction drilling processes are used frequently in hot forming operations. This process is similar to drilling processes but it has not chips and used to join of thin-walled metal components. The created frictional heat plasticizes the material and allows the punch type tool to enter the material surface, thus creating additional heat by friction. By the feeding tool pressure, it is advancing into the material surface while creating a hole. An analytic model and software was developed to calculate the friction drilling process parameters as torque and axial power, heat transfer coefficient for friction drilling process in this study.

Experimental investigation on friction drill joining of difficult-to-machine materials: a new methodology for joining of similar and dissimilar materials

ABSTRACT Friction drill joining is a one-sided thermo-mechanical joining process to connect similar and dissimilar materials. Due to the excellent potential for multi-material joining and wide application in designing the lightweight and modern vehicle, special attention has been paid to this approach of the friction drilling process. However, the most challenging issue in this process is the joint quality. This paper focuses on the effect of process parameters on joint quality and tool performance. A modification method to improve the joint quality is also provided. The quality of the formed joint is analysed, by applying the tensile shear test. Moreover, the microstructural alteration of the formed joint is characterized. The main contribution of this work is presenting a new approach of friction drilling for the joining of sheet metals. The findings reveal that optimum process parameters, in terms of maximum joint quality and tool performance, are spindle speed 3000 rpm and feed rate 120 mm/min. It is found that the hardness near the formed hole is greater than the base material. The findings also contribute to providing an enhanced microstructural characterization of sheets, which identifies the material behaviour and shows how it affects the joint quality.

Studying the distribution of hardness values in friction drilled 7075 Al-alloy sheets at different conditions

The thickness of sheet metal parts can be locally increased by friction drilling technology via forming of a hole with a bush by a special drilling tool. Here, a 7075 Al-alloy was drilled by friction using tool cone angles with values of 40, 45 and 50° under different feed rates (100, 200 and 315 mm/min) and rotational speeds (1000, 1250 and 1600 rpm). The present study investigates the hardness distribution in the thermally-formed bush and in the heat-affected zone around the bush. It was found that the hardness of the bush was slightly increased with increasing of the tool cone angle and reduction of the tool rotational speed. However, the hardness of the thermally-induced bush showed values lower than the parent metal. The hardness near the drilling surface was approximately 65±10 HV, while it recorded hardness values of 75±10 HV at 5 mm away from the drilling surface. In addition, the microstructure of the friction drilled specimens showed a very fine structure in the drilling zone due to crushing of the original structure during the friction drilling process.

Friction drilling: a review

Friction drilling: a review

Ultrasonic-assisted friction drilling process of aerospace aluminum alloy (AA7075): FEA and experimental study

Joining sheets and plates in the industry is of high importance. In the automotive and aerospace industry, using friction drilling technique is developing. In order to improve this method, different techniques have been used. In this research, applying ultrasonic vibration on the tool will be investigated. In this regard, a special tool was designed. Axial force and surface hardness were measured in friction drilling and ultrasonic assisted friction drilling. Higher rotational speed and lower feed rate induce lower axial force and higher surface hardness. In addition, ultrasonic vibration causes the surface to be harder with lower axial force. The results show that increasing the rotational speed and decreasing the feed rate in lathe machine causes axial force reduction and surface hardness increase in heat affect zone and thermomechanical region. Moreover, finite element method was carried out which indicated lower axial force occurs in ultrasonic assisted friction drilling comparing to conventional condition. Equivalent plastic strain was used to examine hardness value numerically. The obtained numerical and experiment results were in good agreement.

Thread-stripping test procedures leading to factors of safety data for friction-drilled holes in thin-section aluminium alloy

Friction drilling is a hole-making process suitable for thin sections of ductile metal. A rotating tool is plunged into the workpiece to form the pilot hole. The hole is then threaded in a follow-up process. A bushing forms on the exit side of the hole, which allows for longer engagement lengths in threaded assemblies. For comparison purposes, four combinations of threaded-hole processes were applied to 1.5 mm-section, 6082-T6 aluminium alloy. The processes involved were friction and twist drilling followed by thread forming or cutting. Vickers hardness and microstructural analyses were used to assess the condition of the material. An in-house test method was developed to measure the axial load–deflection response. Progressive failure occurred by thread stripping. Friction drilling followed by thread forming gave peak loads 35% higher than conventionally drilled and tapped holes. Also, hardness increased from 111HV in the parent metal to 125HV (with an increase in hardness to depths of 0.5 mm) due to work hardening. Evidence of precipitate dissolution was negligible which suggests that the friction drilling process operated below the solvus temperature. A novel approach for determining reliably-based, thread-stripping Factors of Safety (FoS) is presented. FoS in the range 3.61 to 4.38 gave a reliability of 95% to 99.9% against thread stripping in friction-drilled, thread formed joints.

Friction drilling of AA7075-T6 and AZ31B alloys under dry and oil containing ceramic particulates

This study investigates the friction drilling behaviors of AA7075-T6 aluminum and AZ31B magnesium alloys containing ceramic powders of B4C, SiC, and Al2O3 under dry and minimum quantity lubrication (MQL). The aim is to create a composite structure while applying the pressure of a drilling tool on the hole surface when adding ceramic powders into the cutting oil during frictional drilling. Friction drilling tests are performed at a constant spindle speed and feed speed, and the effects of dry and cutting oil mixtures containing ceramic particulates on the thrust force, temperature, hole surface quality, bushing profile, and thread stripping strength of the specimens are investigated. The results revealed that ceramic particles penetrated through the hole and created a composite structure on the surface. The dry friction drilling of AA7075-T6 and AZ31B yielded acceptable surface quality. However, the surface quality worsened considerably during the friction drilling of AA7075-T6 using the oil mixture, whereas the surface roughness and hole bushing of AZ31B magnesium alloys are not negatively affected by the ceramic containing oil mixtures. Petal formation and cracks appeared in the hole profiles of the AA7075-T6 aluminum alloy. Thread stripping tests indicate that the ceramic-particle- containing oil mixtures enhanced the thread shear strength of AA7075-T6 by 19.2 %, and the highest shear strength of 56.78 kN is achieved using the Al2O3 containing an oil mixture. The oil mixture-containing B4C ceramic particles improved the thread shear strength of AZ31B by 7.7 %.

Effect of Friction Drilling on Metallurgical and Mechanical Properties of Composite Materials: A Review

The objective of this study is to carry out a literature review on the effect of friction drilling parameters on the mechanical and metallurgical properties of materials. The friction drilling process uses heat generated by friction between the workpiece and the tool. In a single step, tool penetrates into the work material, forming a circular hole and forms bushing without generating chips. Bushing acts as a structural scaffold and guide to assemble sheet metal parts without the need for separate threaded parts. This review focuses on the basics of friction drilling, advantages, applications, metallurgical and mechanical properties of the tool and materials. Tools reviewed in this research are high speed steel (HSS) and AISI H13 chromium hot work steel. The study observes that coated friction drilling tool life is more than uncoated friction drilling tool. At higher spindle speed and feed rate, good quality hole is produced with maximum bushing height and better surface finish.

Experimental investigation and dimensional analysis of friction drilled hole on 6082 aluminium pipe using hardened M2 centre drill

The main aim of this research is to investigate the form drilling parameters using Buckingham Pi-Theorem and identifying the most effective parameters for effective heat generation. It is important to identify the most effective parameters which give a cylindrical shaped bushing without significant radial fracture or petal formation. To produce better results, the parameters of friction drilling are optimized by dimensional analysis. Effect of work piece temperature, spindle speed, and feed rate in experimentally measured along with torque. The designed and developed high speed steel M2 tool is used for friction drilling of Al 6082 work piece. The present research develops theoretical analysis of the various friction drilling parameters by conducting the experiments on friction drilling process over aluminium tubing material of AL 6082. The presented work also attempts the application of Buckingham pi-theorem to find what parameters are influencing the friction drilling process and using dimensionless parameters.

Highlights of Non-traditional friction drilling process A review

Frictions drilling a hole making process were hole is produced in sheet metal lesser than 4 mm thickness. In 90% of the manufacturing industry adopts drilling process. Apart from traditional methods non-traditional method of hole making process is adopted for producing hole in sheet metal. Friction drilling is a chip less hole making method, were chips formed as bosh and bush into front and bottom of the plate. Bushing height is produced three times the thickness of work piece thickness. The tool is plunged into the hole due to the heat generated in-between tool and work piece. The temperature developed in the tool and material is very high, due to this the chances of getting damage in tool and material is also high. In this review the highlights of friction drilling process has been covered. The key factors is the way of hole making process. Frictions drilling a chip less method, metal melt to form as a bushing shape. To avoid material as well as tool damages factors like input parameter, material thickness, adopting coating thickness etc. In the observation section the key issues are highlighted and in further how the friction drilling tool can be designed to avoid material damages.

Experimental investigation and optimization of surface treated and coated friction drilling tool for AZ31B magnesium alloy

Abstract Friction drilling is recently innovated technique, which is having more benefit than any other techniques. Friction drilling is applicable for material which is