Influence Of Tool Geometry Research Articles

Friction stir processing of AA6061-T6/graphene nanocomposites: Unraveling the influence of tool geometry, rotation, and advancing speed on microstructure and mechanical properties

This research investigated the effect of tool geometry, rotation, and advancing speed on the microstructure and mechanical properties of aluminum AA6061-T6/graphene nanocomposites fabricated by friction stir processing (FSP) using three conical tools with the pin cone angles (PCAs) of 2, 2.5, and 3°. In the first step of the study, the process was performed with and without graphene nanoplatelets (GNPs) at different rotations (710, 1120, and 1400 rpm) and advancing speeds (80, 125, and 160 mm/min). The yield strength, tensile strength, and microhardness of all the samples were lower than those of the base metal. In the second step of the study, the heat input was controlled by reducing rotations (112, 180, and 280 rpm) and advancing speeds (31.5, 25, and 20 mm/min). The mechanical properties of processed samples were studied by tensile tests and microhardness measurements. Microstructural evolution in samples was analyzed by means of a field emission scanning electron microscope (FESEM) equipped with an X-ray energy dispersive spectrometer (EDS) and electron back-scattered diffraction (EBSD) detector. The results indicated that the mechanical properties were improved in the second step with the increase in the advance per revolution (APR) and the PCA. This was linked to the microstructure evolution in the processed samples affected by process parameters and regulated heat input. The effect of each input variable on the mechanical properties was evaluated by statistical analysis and was validated by analysis of variance (ANOVA). The optimal processing was attained by utilization of PCA, tool rotation, and advancing speed.

Use of threaded cylindrical pin tools to reduce macroscopic defects in dissimilar welded joints of AA7075-T6 and AZ31B alloys by the FSW process

The continued increase in greenhouse gas emissions has had dire consequences for the global climate. In order to reduce such emissions, several efforts have been made by researchers in the transport sector, such as the development of electric motorization, the development of hybrid engines, the use of biofuels and the use of light alloys. The use of light alloys such as aluminum and magnesium in vehicles can reduce the emission per kilogram of vehicles drastically, however, it is still necessary to develop effective and more agile methods of the dissimilar joints of these materials. Some authors have studied the friction stir welding of AZ31B magnesium alloys and AA7075-T6 aluminum alloys in order to determine better process parameters to enable this bond, however, few articles have been published in order to evaluate the influence of tool geometry on such properties. In this sense, this article aims to evaluate the influence of friction welding tool pin geometry as smooth cylindrical pin, threaded cylindrical pin, conical and hexagonal pin configurations in the formation of the mixed zone of welds manufactured by the FSW process. For this purpose, AZ31B and AA7075-T6 alloys were welded by FSW with welding speed of 75 mm/min, tool rotation speed of 565 rpm, offset of 0.5mm and inclination of the tool geometry in relation to the plates to be welded of 3º, the joints were evaluated for their macro and microstructures and Vickers hardness with a load of 100 gf. It was possible to observe that the joints welded with the threaded cylindrical pin tool presented stir zones free of macroscopic defects, similar hardness values for the four tools studied and the presence of a thin layer of intermetallics between TMAZ and SZ on the AZ31B side.

Identification of dynamic coefficient matrix for drilling process simulations from measured tool geometry, axial force and torque

This paper aims to quantitatively analyze the relationship between forces acting on the tool tip and tool movement during drilling operations. The study encompasses axial and lateral vibrations superimposed on the nominal tool movement, arising from rigid body motion (rotational and axial velocities). Specifically, only forces attributed to the cutting process are considered, excluding considerations of indentation forces around the chisel edge. The research adopts a generalized approach, spanning from tool measurements to establishing the force model. The investigation involves measuring cutting forces and correlating them with the varying rake and inclination angles of the drill’s cutting edges. An analytical model is proposed to describe the distribution of all local force components along drill edges, considering the evolution of forces and geometry. The dynamic coefficient matrix is evaluated by using the identified cutting coefficient and tool geometry. Validation of the proposed methodology is demonstrated through drilling experiments on Ti6Al4V alloy, utilizing three solid carbide drills with distinct geometries. The proposed procedure allows complete identification of the dynamic characteristics from the measurements taken at the entrance stage of hole drilling operation. Moreover, the influence of tool geometry on cutting coefficients and dynamic coefficient matrices are discussed.

Nonlinear chatter and reliability analysis of milling Ti-6Al-4V with slender ball-end milling cutter

Slender ball-end milling cutters with high length/diameter ratio can offer increased accessibility in the deep cavity machining of parts in the aviation industry. In this paper, a comprehensive nonlinear machining dynamics model for milling Ti-6Al-4V with the slender ball-end milling cutter is proposed to predict and understand on cutting stability, vibration characteristics and dynamic reliability. The tool tip dynamics model of the slender ball-end milling cutter is established including the structural nonlinearity of bearing joints, the contact flexibility of joint interfaces and the influence of tool geometry. Generated nonlinear dynamic cutting force is calculated considering the multiple regenerative effect, the nonlinearity of tool away from cutting and the run-out of tool. The effect of process damping is included in the nonlinear time-delayed differential equation of the machining dynamics model. Furthermore, the reliability evaluation method for the dynamic accuracy of milling Ti-6Al-4V workpieces is established with the application of Monte Carlo method and active learning Kriging model. Some milling experiments on Ti-6Al-4V workpiece are designed to validate the proposed model by comparing the predicted and measured results. The milling stability, vibration characteristics and dynamic accuracy reliability of milling Ti-6Al-4V with the slender ball-end milling cutter are discussed. The increase in the fractal dimension of joint interfaces can lead to the improvement of milling stability, and increased fractal roughness results in reduced milling stability. The reliability in the dynamic accuracy of milling Ti-6Al-4V workpiece is 99.26 %, and the distribution parameters in the fractal dimension of joint interfaces have the greatest influence on the reliability of dynamic accuracy.

Influence of tool geometry on mechanical and microstructural characteristics of friction stir welded cast alloys

Abstract Cast alloys find suitable applicability in aerospace sector owing to low porosity, high specific strength, corrosion resistance, fluidity and good machinability. The investigation focuses on friction stir welding (FSW) of cast A356 and A2014 alloys with varied range of process parameters, namely tool pin shape (cylinder, threaded cylinder, square, and conical), tool rotation speed (1800–2100 rpm) and welding speed (10–25 mm × min−1). Experimentation on stirwelding was performed based on selected tool pin shape between varied tool rotation and welding speed. The output responses, namely Ultimate tensile strength (UTS) and micro hardness, have been evaluated to study the effect of each tool. The microstructural characteristics of the weld samples were analyzed using optical microscope and scanning electron microscope (SEM) technique. The microstructural observation unveiled that complete fusion prevails between the parent alloys devoid of micro porosities and segregations. The re-crystallization effect resulted in the finer grains. The cylinder-shaped tool with a thread and square shaped tool rendered better strength and hardness properties of 136.6 MPa and 109.4 HV, respectively.

Влияние геометрии инструмента на формирование сварного соединения при сварке трением с перемешиванием алюминиевого сплава АМг5

One of the important parameters influencing the formation of a weld during friction stir welding is the tool geometry, which affects the processes of heat generation and stirring of metals in their connection zone. These processes influence the formation of a high quality and strength welded joint without continuity defects. In this regard, it is relevant to analyze the influence of tool geometry on the welding mode parameters, at which the welded joint is formed without continuity defects, as well as on the welded joint strength under static tension. The work considers the influence of the cylindrical and conical shapes of the tool pin, as well as the conical shape of the pin with a thread on its outer surface and a spiral groove on the end surface of the tool shoulder on the welding mode parameters, at which the welded joint is formed without continuity defects. The study shows that changing the shape of the pin working surface from cylindrical to a conical one had no effect on the range of welding mode parameters, at which the welded joint is formed without continuity defects. It has been found that the presence of a thread on the pin outer surface and a groove on the end surface of a tool shoulder allows producing welded joints without continuity defects in a wider range of welding mode parameters compared to a simpler tool geometry. The macrostructure of the resulting welded joints was considered. It has been found that the studied tool geometry has almost no influence on the maximum strength values of welded joints produced by friction stir welding and reaches 95 % of the strength of the base metal.

Influence of Tool Geometry on the Stress–Strain State of Cylindrical Parts in Reversible Surface Plastic Deformation

Influence of Tool Geometry on the Stress–Strain State of Cylindrical Parts in Reversible Surface Plastic Deformation

Influence of tool geometry on reaction forces and strength of an inseparable joint produced on a prototype stand with the use of jaws

The present article describes a new and innovative method of producing an inseparable joint with the use of expansion jaws. The effect of jaw tool geometry on the reaction forces and ultimate strength of an inseparable joint formed on a prototype stand was analyzed. The results are also compared of joints produced by jaws with single movement method and with complex movement method. The tool responds with bending and pressing one part into the other, which results in their permanent connection. In the tests, differentiation was introduced with regard to the height of the applied force to the collar of the connection pipe. A novelty is also a solution based on a complex, parameterized trajectory of the stamp movement consisting of horizontal and vertical displacements. This paper presents the tests of the joints formed at the stand. The new approach described in this article has resulted in a joint strength increase of approximately 30% using the innovative complex jaw movement of the biaxial clinching process. A joint tensile strength close to 1000 N was achieved.

The Influence of Tool Geometry on the Mechanical Properties and the Microstructure of AA6061-T6 Aluminum Alloy Friction Stir Spot Welding.

In this work, the influence of the tool geometry on friction stir spot welding (FSSW) was studied on sheets made of AA6061-T6 aluminum alloy. Four different AISI H13 tools with simple cylindrical and conical pin profiles and 12 mm and 16 mm shoulder diameters were used to perform the FSSW joints. Sheets of 1.8 mm thickness were used during the experimental work to prepare the lap-shear specimens. The FSSW joints were performed at room temperature. For each joining condition, four specimens were carried out. Three specimens were used to find the value of the average tensile shear failure load (TSFL), while the fourth one was used to examine the micro-Vickers hardness profile and to observe the microstructure of the cross-section of the FSSW joints. The investigation concluded that higher mechanical properties corresponding to the finer microstructure were obtained by the conical pin profile and the higher shoulder diameter compared with the specimens performed using the cylindrical pin tool and lower shoulder diameter due to the higher strain hardening and the higher frictional heat generation, respectively.

Simulation of a Power Skiving Gear Cutting Process

Abstract The results of the computer simulation of the cutting process of gears by the power skiving method are presented. Following the kinematics of the process, a method for generating 3D geometric models of undeformed sheared layers were developed, and their parameters were analyzed. The influence of tool geometry and technological parameters on cutting conditions is investigated. The simulation results and calculation of the tangential force and torque on the tool axis and their influence on the error due to angular elastic deformation of the tool are given.

Analysis of the effect of tool geometry on the cutting process of polycrystalline Fe-Cr-W alloy based on molecular dynamics simulation

In order to study the influence of tool geometry on the machining mechanism of alloy tool steel in the process of ultra precision turning, the polycrystalline molecular dynamics model of alloy tool steel is established with Fe, Cr and W, and the molecular dynamics model of tool is established with B and N. Four potential energy functions, Tersoff, EAM, Morse and L-J, are used to characterize the interaction between atoms in the model. The effects of tool geometry on hydrostatic stress, cutting force, cutting temperature and amorphous atoms in the turning process are analyzed. Research indicates:(1) Hydrostatic stress is mainly concentrated in the contact position between the tool tip and the workpiece, and it is compressive stress; (2) Cutting forces fluctuate and are significantly affected by tool geometry; (3) The cutting heat of about 1000K is concentrated in the chip, and the tool clearance angle has a great influence on the cutting temperature. (4) Amorphous atoms are formed at the chip location and the machined surface, and eventually turn into chips and the metamorphic layer of the machined surface.

Investigation of tensile property and strain distribution of drilled carbon fiber reinforced polyetheretherkrtone composites

Tool geometry can significantly influence hole quality during drilling of CFRP laminates, which has impact on mechanical properties. In this paper, drilling experiments with different drill bit geometries (twist, brad and dagger drill) are carried out on carbon fiber reinforced polyetheretherketone (CF/PEEK) composites. The influence of tool geometry on drilling temperature, thrust force, and hole-making quality are analyzed. The effect of machining-induced damage on the tensile properties of CF/PEEK composites with machined hole are investigated. The strain distributions around the holes were measured using digital image correlation (DIC). The results indicate that PEEK is softened by heat, the matrix is plastically deformed, and the edge burrs of the hole are curled and agglomerated. The best hole-making quality is obtained by brad drill. Compared to the tensile strength of undrilled laminates, the tensile strength of the laminates drilled with brad, dagger and twist drills decreases by 51.47%, 53.99% and 56.09%, respectively. The strain distribution of open-hole laminates with different machining-induced damage shows obvious difference. The fracture mode of matrix cracking, fiber splitting, delamination, fiber pull-out and debonding are mainly observed. The research results in this paper can provide reference for the optimization of CF/PEEK composites drilling process.

Surface roughness analysis for improving punching tools performance of 5754 aluminium alloy

The use of lightweight materials in the automotive industry, as a key element in fuel economy, is a growing trend to meet the global emissions reduction agreement. Aluminium, in the form of stamped sheet, has the potential to be used extensively in vehicle as a high-specification structural and skin parts. However, compared to steel, aluminium is more difficult to stamp, thus the optimized techniques and manufacture strategies learned in steel stamping are not adequate given the complex processability of aluminium alloys. To achieve the quality standards, it is necessary to optimize aluminium stamping processes by developing specific techniques, geometries, and functional surfaces on tooling. In this work, the influence of tool geometry and surface roughness, as well as the use of lubricant during the punching process of 5754 aluminium sheets have been evaluated in a pilot plant under similar industrial conditions. Before the pilot plant test, different tool surface roughness qualities were evaluated at lab scale using a ball on disc test. Subsequently, performance of coated tools was evaluated through “coated ball” on “5754 aluminium disc” tests. The best combination between lubricant and coating was used to perform the aluminium punching process in the pilot plant, where two types of geometry and roughness of tool were analysed. Results were expressed in terms of aluminium adhesion on tool surface. Polished surface before coating deposition and geometry punches were the key factor to improve the process.

Bone Abrasive Machining: Influence of Tool Geometry and Cortical Bone Anisotropic Structure on Crack Propagation.

The abrasive machining of cortical tissue is used in many arthroplasties and craniofacial surgery procedures. However, this method requires further research due to the processes’ complexity and the tissue’s composite structure. Therefore, studies were carried out to assess the impact of grid geometry and the anisotropic structure of bone tissue on the cutting process and crack propagation. The analysis was performed based on an orthogonal cutting in three directions. The grain shape has been simplified, and the cutting forces, crack path and surface quality were monitored. The results indicate that a depth of cut at 100–25 µm allows the most accurate cutting control. A transverse cutting direction results in the greatest surface irregularity: Iz = 17.7%, Vvc = 3.29 mL/m2 and df = 5.22 µm and generates the most uncontrolled cracks. Maximum fracture force values of FF > 80 N were generated for d = 175 µm. For d < 5 µm, no cracks or only slight penetration occurs. A positive γ provides greater repeatability and crack control. Negative γ generates penetrating cracks and uncontrolled material damage. The individual types of cracks have a characteristic course of changes in Fx. The clearance angle did not affect the crack propagation.

Evaluation of milling parameters on the surface integrity of welded inconel 625

Nickel-based alloys are used widely in aerospace components and the oil and gas industry, operating in an extremely adverse environment. These alloys are characterized as difficult-to-machine materials due to their high hardening rate, low thermal conductivity, and superior hot hardness. Since the material and its machining are very expensive, it is important to evaluate how the machining processes deteriorate the surface integrity to prolong the service life of the Inconel components as long as possible. In order to reach this goal, the influence of tool geometry, feed rate, and cutting speed on surface integrity was evaluated for the milling process of Inconel 625 cladding. Qualitative and quantitative mechanical and metallurgical analyses on the surface and subsurface were performed using 3D optical microscopy, scanning electron microscopy (SEM), instrumented indentation, X-ray diffraction for residual stress measurements, and corrosion tests. The results indicate that cutting speed has the greatest influence on specific cutting pressure. The cutting speed and feed rate were the main factors that affected the thickness of the deformed layer. The results suggest that surface and subsurface alterations after machining are driven by mechanical-thermal loadings and cause beneficial results related to corrosion resistance and compressive residual stress.

Comparative Studies on Influence of Tool Geometry on Heat Generation in Friction Stir Welding Process

Friction Stir (FS) welding offers a number of advantages over the conventional fusion welding process, and it is used to join aluminum alloys that are difficult to weld by fusion welding processes. It has compatibility to any alloy composition, and produces the welded joints by eliminating the defects with improved mechanical properties. The weld quality is mainly influenced by the heat generated and material flow pattern that takes place during the friction stir welding process which depends on the above mentioned parameters. The mechanical and micro structural properties are highly influenced by the heat generation and material flow patterns. The tool geometry plays a vital role in the heat generation and material flow. The aim of the research is to study the influence of tool geometry on heat generation and temperature during friction stir welding process. A comparative study has been done based on the results obtained from numerical analysis and experimentation. It was found that the dissimilar FS welded joints fabricated using hexagonal tool pin profile generates optimum heat generation and temperature required for formation of quality weld irrespective of other process parameter.

Importance of Finite Element Analysis for Verification of Technological Parameters of Seamless Tubes Production Obtained by Experiment

Experimental research on the process of cold tubes drawing was performed in order to obtain important information about the behaviour of the tube material in the drawing tool during the drawing to the required outer diameter of Ø12 mm. The DEFORM-3D simulation software was an important tool for verifying the plastic flow of material in the drawing tool (i.e. drawing die), as well as for optimizing the technological parameters of cold tubes drawing. In the finite element (FE) analysis, emphasis was placed on determining the influence of tool geometry, strain degree, drawing speed and friction on the size of the drawing force and the quality of production of drawn tubes. The paper points out the importance of simulation software for common comparison of results obtained from laboratory experiment and FE analysis of the process of tubes drawing. By comparing the results, the reliability of the used simulation software was proved, as the results were identical for all monitored technological parameters. Computer simulation brings valuable knowledge that is important for the correct design of the drawing tool as well as for the technology of production of tubes with precise dimensions.

Investigation of residual stresses and workpiece distortion during high-feed milling of slender stainless steel components

In high-feed milling, the workpiece surface is subjected to high thermo-mechanical loads, which leads to excessive changes in residual stresses and thus affects the quality of the product. In this work, the influence of tool geometry and cutting speed on the residual stress state and the resulting workpiece distortion was investigated. Machining tests were performed by face milling of slender parts made of low sulfur stainless steel X2CrNiMo17-12-2. The results showed that the macro-geometry of the tool has a major influence on the surface topography and residual stresses. The cutting edge radii have barely any influence on the residual stresses under the conditions investigated.

Influence of tool geometry on cutting zone temperature during turning of aluminium alloy AA2219

Machining of aluminium alloys is considered to be highly important owing to their wide spectrum of applications. Analysis of machinability with respect to the cutting zone temperature decides the behaviour of the material when used in various functional areas. Current research aims to investigate the cutting zone temperature during the turning of aluminium alloy using cemented carbide inserts. From the results, it could be noted that the feed and nose radius were the most dominant factors which influenced the cutting zone temperature. A regression model was developed by using the Taguchi’s full factorial design of experiment. Cutting zone temperature regression model exhibited least deviation when compared with the actual response within the range of considered turning process parameters. The adequacy and accuracy of the regression equation was justified by using a comparative study. It was found that the optimal combinations of machining parameters to minimize the temperature were 0.4 mm nose radius, 0.1 mm/rev of feed rate, 1500 rpm speed and 0.3 mm depth of cut.

Mechanical and Microstructural Evolution of Friction stir welded joint of AA2014 alloys

The solidification cracking phenomenon restricts the use of fusion welding process to join aluminum and its alloy. Friction stir welding (FSW) process can be used in joining of aluminium alloys which is not or less susceptible to form welded voids, induced distortions, solidification cracking. In the present work an investigation of mechanical and microstructural changes after FSW is presented during the similar joining of AA2014 aluminium alloys. The influences of tool geometry during FSW is analysed and compared among the joint made by triangular, pedal and pentagonal pin. Based on the obtained mechanical properties of the joint metallurgical investigation is performed. Optical micrographs are used to reveal the phases present in the fusion zone. EBSD investigation of the selected sample is done to analyse the mis-orientaion angle and grain size etc. Pedal pin profile tool exhibit better mechanical properties in comparison to pentagonal pin and triangular pin. Obtained ultimate tensile strength and percentage elongation are 345MPa and 13.5 % respectively. Micro-hardness and impact energy are obtained as 125HV0.2 and 4.6 J of F pedal sample. Obtained joint efficiency of Fpedal sample is 74%, which is higher among joint efficiency of Fpentagonal and Ftringular samples.