Tool Travel Research Articles

Optimization of Bobbin Tool Friction Stir Processing Parameters of AA1050 Using Response Surface Methodology.

The current research designed a statistical model for the bobbin tool friction stir processing (BT-FSP) of AA1050 aluminum alloy using the Response Surface Method (RSM). The analysis studied the influence of tool travel speeds of 100, 200, and 300 mm/min and different pin geometries (triangle, square, and cylindrical) at a constant tool rotation speed (RS) of 600 rpm on processing 8 mm thickness AA1050. The developed mathematical model optimizes the effect of the applied BT-FSP parameters on machine torque, processing zone (PZ) temperature, surface roughness, hardness values, and ultimate tensile strength (UTS). The experimental design is based on the Face Central Composite Design (FCCD), using linear and quadratic polynomial equations to develop the mathematical models. The results show that the proposed model adequately predicts the responses within the processing parameters, and the pin geometry is the most influential parameter during the BT-FSP of AA1050. The analysis of variance exhibit that the developed mathematical models can effectively predict the values of the machine torque, PZ temperature, surface roughness, hardness, and UTS with a confidence level of over 95% for the AA1050 BT-FSP. The optimization process shows that the optimum parameters to attain the highest mechanical properties in terms of hardness and tensile strength at the lowest surface roughness and machine torque are travel speed (TS) of 200 mm/min using cylindrical (Cy) pin geometry at the constant RS of 600 rpm. The PZ temperature of the processed specimens decreased with increasing TS at different pin geometries. Meanwhile, the surface roughness of the processed passes and machine torque increased with increasing the TS at different pin geometries. Increasing TS from 100 to 300 mm/min increases the hardness values of the processed materials using different pin geometries. The highest UTS of 79 MPa for the processed specimens was attained at the TS of 200 mm/min and RS of 600 rpm using the Cy pin geometry.

Investigation of machining characteristics during micro-hole fabrication in CFRP composite by ECDM process

Carbon fiber reinforced polymer (CFRP) composites have gained significant popularity in the field of aerospace, automotive, electronic, and sports due to its versatile properties. Although, fabrication of micro-holes in CFRP composite is troublesome by the conventional processes because of its anisotropic and abrasive behaviour. To overcome this difficulty, recently, an unconventional hybrid process such as electrochemical discharge machining (ECDM) is extensively used to machine such types of materials. This paper highlights the experimental and statistical analysis of machined micro-holes which was fabricated in CFRP composite using ECDM process. The experimentation was performed according to Taguchi’s L9 orthogonal array. The input parameters were (a) voltage, (b) tool rotation, (c) tool travel rate, and (d) duty cycle, each at three levels. Hole overcut and taper was measured as output responses. TOPSIS-Entropy based multi-response optimization technique was applied to optimize the chosen parameters. The hole overcut and taper was measured and analysed using SEM images. The parametric combination of 50 V, 360 RPM, 0.5 mm min−1, and 60% resulted minimum overcut and taper of 227 μm and 72 μm, respectively. The morphology of the machined hole exhibited better surface characteristics at a high tool travel rate and low duty cycle. Tool wear in terms of lateral wear and flank wear was observed during machining at high voltage and high duty cycle. From the TOPSIS Entropy analysis, the optimal condition for both overcut and taper was found as 50 V, 360 RPM, 0.5 mm min−1, and 60%.

A Simple Technique for the Precise Establishment of the Working Gap in an Electrochemical Discharge Machining Process and Some Experimental Results Thereof.

The working gap (Wg) between a tooltip and a substrate surface is a critical process parameter affecting the quality metrics and precision of microstructures fabricated using an electrochemical discharge machining (ECDM) process. Despite the extensive investigation carried out on ECDM processes for the last several years, only a few researchers have explicitly explained the technique used to establish the Wg. In the present work, the authors propose a simple, cost-effective technique using a commercially available metallic feeler gauge and a multimeter to precisely establish a Wg in an ECDM process. A systematic experimental investigation was carried out using the proposed method to study the influence of Wg on the quality metrics such as the depth, width, edge linearity, heat-affected zone, and surface finish of fabricated microstructures on a glass substrate. Experimental results revealed that even a 2 µm difference in Wg significantly influenced the quality and quantity metrics of an ECDM process. It was observed that no machining occurred beyond a Wg of 25 µm even when a TTR as low as 0.5 mm/min and an applied voltage greater than 44 V were used. A micro-channel with improved quality metrics was obtained using a tool travel rate (TTR) of 1 mm/min with an applied voltage of 33 V and a Wg of 2 µm while using 30% NaOH as an electrolyte. The proposed method would be helpful for researchers to fabricate precise micro-channels on glass substrates using ECDM processes.

Optimization of Friction Stir Welding Parameters in Hybrid Additive Manufacturing: Weldability of 3D-Printed Poly(methyl methacrylate) Plates

In this work, the expansion of friction stir welding (FSW) in parts made via material extrusion (MEX) 3D printing was investigated. Poly(methyl methacrylate) (PMMA) plates were joined in a full factorial experimental design. The effects of three FSW parameters (weld tool pin geometry, rotating speed, and travel speed) on the weld results were studied. The tensile strength was investigated using statistical modeling tools. A morphological characterization study was also conducted on the weld zone, with microscopy. The state of the material during the FSW process was monitored via real-time temperature measurements. The feasibility of the process was verified. The results show high industrial merit for the process. The highest tensile strength was reported for the sample welded with the frustum tool, at 1400 rpm and a 9 mm/min travel speed (the highest studied), with a welding efficiency > 1. This can be attributed to the reduced porosity of the weld area compared to the 3D printed structure, and indicates a high potential for joining 3D-printed PMMA sheets via the FSW process.

알루미늄 3003 합금의 마찰교반접합특성에 용접조건의 영향

Two-way factorial design method was applied to evaluate the joint strength of friction stir welded aluminum 3003 alloy in this study. The welding factors and levels were the tool rotation speeds of 1,300, 1,800, 2,300, and 2,800 rpm and the tool travel speeds of 150, 250, 350, and 450 mm/min under the shoulder diameter of 18 mm and pin diameter of 4 mm. The uniaxial tension tests were carried out for varience analysis of tensile strength of welded part, and micro-structure observations were also performed with hardness measurements at welded part. From the results, the variance analysis revealed that the contributions of welding factors on the tensile strength of the weld part were the rotation speed of 67.9% and the travel speed of 31.8%. The optimum condition for FSW was predicted the welding speed of 450 mm/min and rotating speed of 1,300 rpm, and the presumption range of tensile strength at optimal condition of reliability 95% was estimated to 135.53 ± 1.11 MPa. In addition, the lower the rotation speed and the higher the travel speed, the higher the tensile strength. Finally the hardness and grain size of optimal condition was higher and finer than that of lowest condition at weld part.

Risk-based methodology to optimize geotechnical site investigations in tunnel projects

The scope of geotechnical investigations in tunnel projects is generally driven by the allocated resources rather than the expected variability in the ground conditions. Uncertainties in ground conditions may lead to poor decisions in project planning and active risk management. This paper presents a systematic and rational methodology to identify priority locations of additional geotechnical investigations for soft ground tunneling applications based on tunnel risks, site conditions, and project-related constraints. The methodology is applied to the cutter tool wear risk and quantifies the uncertainty in soil abrasivity index (SAI), the relevant geotechnical parameter. Preliminary geotechnical investigation data and site conditions from an actual tunnel project in an urban environment are used to illustrate the proposed methodology and demonstrate its effectiveness. Pluri-Gaussian simulation and sequential Gaussian simulation are used to characterize the 3D spatial variability in soil units and soil abrasivity, respectively, along the tunnel alignment. The study integrates geospatial assessments of SAI uncertainty and consequences of tool wear to develop an R index map that delineates the impact of uncertainty in tool wear rate. Project constraints of drilling accessibility and budget are incorporated in the R index map to find locations of additional geotechnical investigations. The study simulates a virtual sampling of additional boreholes and quantifies the reduction in uncertainty in tool wear rate and tunnel boring machine (TBM) intervention locations. Additional investigation at priority locations is found to reduce cutterhead intervention location uncertainty by approximately 90 rings (160 m). Further, integrating the uncertainty in tool travel distance is found to influence the cutterhead intervention location uncertainty by approximately 40 rings.

Friction Stir Welding Optimization of 3D-Printed Acrylonitrile Butadiene Styrene in Hybrid Additive Manufacturing.

The feasibility of joining material extrusion (MEX) 3D-printed acrylonitrile butadiene styrene (ABS) plates with the friction stir welding (FSW) process was investigated herein as a promising topic of hybrid additive manufacturing (HAM). The influence of three process parameters on the mechanical strength of the joints was thoroughly examined and analyzed with a full factorial experimental design and statistical modeling. Hereto, the welding tool pin geometry, travel speed, and rotational speed were investigated. The joint’s efficiency and quality are evaluated through tensile tests and morphological characterization. More specifically, specimens’ areas of particular interest were investigated with stereoscopic, optical, and scanning electron microscopy. Throughout the FSW experimental course, the welding temperature was monitored to evaluate the state of the ABS material during the process. The majority of the welded specimens exhibited increased mechanical strength compared with the respective ones of non-welded 3D printed specimens of the same geometry. Statistical modeling proved that all processing parameters were significant. The feasibility of the FSW process in 3D printed ABS workpieces was confirmed, making the FSW a cost-effective process for joining 3D printing parts, further expanding the industrial merit of the approach.

Fabrication of Surface Metal Matrix composite of AA7075 using Friction Stir Processing

Friction stir processing (FSP), a process, derived from the friction stir welding (FSW) process, is an emerging novel, green and energy efficient processing technique to fabricate surface composite. In the present investigation, the FSP technique has been used for the fabrication of surface composites, usingAluminium Alloy 7075 as parent metal and Titanium Dioxide and Silicon Carbide powder particles as reinforcement. Aluminium Alloy 7075 has been selected as the matrix phase, as being widely used by the automotive and aerospace application and has the highest strength among all commercial Al alloys. In present work details about the fabrication of surface composites using various reinforcement combinations like AA7075-TiO2, AA7075-andAA7075-SiC,TiO2+SiC at constant tool rotation, tool travel speed and number of passes have been discussed. The same being intended to improve hardness. It is observed that the average hardness of friction stir processed surface composite was 4 higher than that of parent metal.

APPLICATION OF HYBRID SFLA AND ACO ALGORITHM TO OMEGA PLATE FOR DRILLING PROCESS PLANNING AND COST MANAGEMENT

<p>Tool traveling and tool switching time constitute almost seventy percent (70%) of the total time<br />consumed in drilling process. This fact that 70% of the total time is nonproductive and does not add any value to the job, grabs attention of the researchers and the industrialist for optimization. A literature on drilling process revealed that very few studies have been done on hybridization of metaheuristics for optimization of tool travel time. This research gap is the motivation of the present study. In this study, two metaheuristic approaches – the shuffled frog leaping algorithm (SFLA) and ant colony optimization (ACO) were hybridized. With respect to hybridization of SFLA and ACO, this study signifies its originality and novelty in which main objective is to minimize the tool travel time. The literature review also revealed that the shortest path generated through commercially available software is not optimal all the time. This aspect emphasizes the application of metaheuristic algorithms on the real-world industrial problems. In this study, the proposed hybrid algorithm was applied to drilling of omega plate which is used in automobile manufacturing industry. The results of the proposed hybrid algorithm were compared with those of manual drilling path and software generated path. The results obtained through proposed hybrid algorithm were improved by 11.1% when compared to results of manual drilling path. The results of proposed algorithm were also better than results of commercial software Creo 6.0 and Siemens NX by 5.9% each. This showed that hybrid algorithm outperformed the commercially available software. This not only validates the efficacy of proposed hybrid algorithm, but also indicates the significance of the metaheuristic algorithm applications in industrial optimization problems.</p>

Fabrication of Surface Metal Matrix Composite of AA7075 using Friction Stir Processing

Friction stir processing (FSP), derived from the friction stir welding (FSW) process, is an emerging novel, green and energy-efficient processing technique to fabricate surface composite. The FSP technique has been used in the present investigation to fabricate surface composites, using Aluminium Alloy 7075 as parent metal and Titanium Dioxide and Silicon Carbide powder particles as reinforcement. Aluminium Alloy 7075 has been selected as the matrix phase, as being widely used by the automotive and aerospace application and has the highest strength among all commercial Al alloys. The present work details the fabrication of surface composites using various reinforcement combinations like AA7075- TiO2, AA7075- and AA7075- SiC, TiO2+SiC at constant tool rotation, tool travel speed and the number of passes have been discussed. The same being intended to improve hardness and thereby wear resistance. The fabricated surface composites are examined for microstructure using an image analyzer and found friction stir processed zone with fine microstructure than the base material. It is also observed that the average hardness of friction stir processed surface composite was higher than that of parent metal. Wear Resistance is found to be improved compared to the parent metal. It is found that Tensile strength is also enhanced than the base material.

Influence of the Tool Wear on the Quality and Service Life of Gears for the Geared Turbofan Technology Machined by Five-Axis Milling

Abstract The geared turbofan technology is one essential way to reduce the fuel consumption, the environmental footprint, and the noise pollution of civil aircrafts. An added gearbox between the fan and the low-pressure compressor that reduces the fan speed, which allows higher bypass ratios, achieves the mentioned benefits of geared turbofans. To withstand the high mechanical loads, large double helical gears are used. Gear hobbing and gear grinding require large tool maneuvering spaces. This leads to a larger required space between the single gears of the double helical gear. As a result, the gears are larger and heavier, which lead to a reduced economy of the aircraft. The tool maneuvering space of five-axis milling with solid carbide end mills is much smaller. This enables the design of smaller, lighter, and more efficient aircraft engines. However, manufacturing these gears in tolerances better than IT5 is very challenging on five-axis milling machine tools. This paper presents investigations about finish machining of hardened gears on five-axis machine tools. In the investigations performed, varying tool substrates and tool coatings have been investigated together with tool travel paths in order to reduce the tool wear, which is key to achieve the demanded tolerances. Finally, the five-axis milled gears were compared to conventionally manufactured gears on test benches to enable statements regarding the expectable service lives of the manufactured gears.

Effect of processing parameters on the microstructure and tensile properties of a dual-phase Mg–Li alloy during friction stir processing

A dual-phase Mg–Li alloy LA103Z sheet was subjected to single pass submerged friction stir processing (FSP) at various of tool sizes, rotation rates and travel speeds. The relationships between processing parameters, frictional heat generation, microstructure, and the room-temperature tensile properties of LA103Z in the stir zone were systematically investigated. Both the α-Mg phase and the β-Li phase undergo complete dynamic recrystallization, the grains are significant refined and the texture is significantly weakened. The precipitation of the AlLi phase and the Li2MgAl phase are promoted by FSP. With the increase of the tool size and rotation rate, the average grain size of the FSPed LA103Z rises as well as the tensile strength, showing an inverse Hall–Petch relation. This is owing to the solid-solution strengthening effect and the reduction of the α/β phase boundaries caused by the dissolution of the α-Mg phase. After being processed by a 16 mm-diameter-shoulder stirring tool under the rotation rate of 800 rpm and the traverse speed of 100 mm/min, the ultimate tensile strength of the FSPed LA103Z is remarkably improved from 177.92 MPa (base metal, BM) to 268.04 MPa, showing the best mechanical property.

Influence of tool rotational speed on the evolution of microstructure and mechanical properties of precipitation-hardened Aluminium 6061 butt joint during friction stir welding

The present investigation aims to evaluate the influence of varying tool rotational speed (rotation per minute, rpm) on the mechanical properties and microstructural evolution within friction stir welded aluminium alloyAA6061-T6 joints. The effects of rpm underthe constant tool travel speedwere investigated by optical microscopy, field emission scanning electron microscopy (FESEM)and transmission electron microscopy (TEM)observation, tensile, fracture and micro-hardness test. Special attention was paid to the formation and evolution ofprecipitates.Results revealed that the tool rotational speedof 1300 rpmproduces highest hardness reaching to ∼69 HVN at the nugget zone (NZ), which could be attributed to the higher intensity of nano-sized re-precipitation. This specific tool rotational speed of 1300 rpm has been determined to be suitable to achieve the maximum joint efficiency of 70.6%. Significantly, the NZ is characterized with small equiaxed dynamically recrystallized grains. In a noteworthy findings, the NZ showed mostly either free from strengthening precipitate or trace of small tiny re-precipitates, while the thermo-mechanically affected zone (TMAZ) contains coarse precipitates with deformed and dynamically recovered grains. On the other hand, there was obvious grain growth with increasing rpm, substantiating more heat involvement with favourable thermal gradient. The experiment concludes thatthe rotational speed has an considerable effect on the precipitation characteristics, dislocation property and existence of finer second phase intermetallic compounds (IMC),which arethe predominant factors controlling the joint property.

Prediction of friction stir welding in aluminium 6061 – T6 using ANN

Neural networks are algorithms in series, which is like a human brain to identify the relationships between data. It is utilized for implementing ANN and ML for better prediction techniques for self-reacting friction stir welding (FSW) in Aluminium 6061-T6. It has an input, which gathers the data from outer sources and hidden layers that runs the data, and an output layer that provides data points based on the network function. Welding of different alloys like Mg (AZ91D) and Ti (Grade 2) during FSW is significantly challenging to study. ANN was used to explore the impact of Rotation speed (RPM), Bottom Diameter Tool Pins (mm), Travel Speed (mm/min) and Tool Profiles of Ti and Mg alloy during FSW, and ANOVA was used to determine the most optimal travel speed and feed rate affecting the responses. The primary and cooperative effects of information elements are investigated.

Software based analysis of angularity error for polygonal micro-cavities produced by die-sinking EDM

This paper aims to present the results of an investigation on the angularity error calculated for micro polygonal cavities i.e. triangular, square, pentagonal and hexagonal cavities. The investigation began by machining of micro polygonal shapes in series of three on steel sample using 400 µm tungsten carbide electrode in die-sinking EDM integrated with e-pulse supply and précised multi-axes electrode movement enabling micro-machining capabilities. After that the machined micro-cavities and their geometry were examined by an Olympus optical microscope and the accuracy of shapes has been evaluated after analyzing angularity error of these geometries by profile projector and olympus analysis five software. It was found that the average angularity error of triangular micro cavities is 4.34° while that for square, pentagonal and hexagonal micro cavities are 1.33°, 7.93° and 8.74° respectively. On the basis of obtained data, it is found that the square cavities have maximum angular accuracy as compared to others. It may be attributed to the fact that there is lesser presence of secondary discharge in case of square cavities and limited tool travel.

Optimization of wear characteristics on boron carbide/flyash reinforced aluminum alloy (7000 series) hybrid composites

In this research process, AA7475 was represented as a main material, boron carbide(B4C) along with flyash (FA) are utilized for reinforcements or additional elements to improve the wear behavior by using friction stir processing method(FSP).Al hybrid composites are made by FSP by change the level of the altered processing parameters such as Tool rotation speed TR (800,1000 & 1200 rpm), Tool travel speed TT (30, 40 &50 mm/min), groove width GW (1,1.5 & 2 mm) and % of reinforcements RS (B4C −5,7.5,10 wt% & fixed FA 5%). wear experimentations were conducted on POD apparatus. Taguchi orthogonal array (L9) have been selected for doing optimization process in which Signal to noise ratio (SN Ratio) helped to identify highest wear amount among the prepared samples.

Influence of tool travel direction on microhardness and tribological properties of AA2014/SiC-CNT hybrid surface composites produced by multi-pass friction stir processing

Friction Stir Processing (FSP) is a novel technique that is widely used to produce surface composites (SC). In FSP, the surface properties of the material can be altered as per the requirement and generally depends upon the type of reinforcement. In hybrid surface composites, two or more reinforcement particles (RP) are added to get the combined enhanced properties of the reinforcement and thus increase the overall properties of the surface composites. In this paper, FSP was employed on AA2014 aluminum alloy to produce the surface composite by using SiC-CNT hybrid reinforcement. Since the number of FSP pass plays an important role while deciding the properties of the produced surface composites, a total of 3 FSP passes were used in this paper. The direction of the FSP passes was changed after each pass. The produced surface composite was then measured for its microhardness, optical microscopy, wear resistance, and coefficient of friction (COF). It was observed that the alteration in FSP pass results in better uniformity of the microhardness and produces a uniform distribution of reinforcement in the surface composites.

Influence of tool offset on mechanical properties of solid-state-welded steel and AA7XXX joints

The objective of present work is to analyze the role of tool offset on mechanical properties of Friction Stir welded (dissimilar materials) AA7XXX and Steel joints. The major process parameters opted for current experimental study are, Tool Offset (T-OF), Tool Rotation Speed (TRS), and Tool Travel Speed (TTS). Tungsten Carbide (K-12) tool with cylindrical tapered pin is used to produce dissimilar butt welds. Steel plate is kept on advancing side and aluminum on retreating side during the joining process. Tensile, Impact, Bending and Hardness analysis are performed to assess the joint strength. Vickers Micro-hardness test was done along transverse direction of the joint to obtain hardness distribution at weld nugget. Experimental study divulge that, at tool rotational speed of 1400 rpm, tool travel speed of 16 mm/min and offset of +1 mm towards steel (advancing side) yields better results, i.e. around 23.3% improvement as compared to tool at zero offset.

Investigation of tool wear in alumina micromachining by multi-tip ECDM

ABSTRACT Experimental analysis of tool wear in alumina micromachining by multi-tip Electrochemical Discharge Machining (ECDM) technique is reported. Multi-tip tool electrodes having a tip size of 300 µm and length of 10 mm are created in stainless steel by wire-EDM. Experiments are conducted at different tool feed rates, i.e., 0.25 µm/s, 0.50 µm/s, 0.75 µm/s. Tool wear of 3 × 3 array electrode is categorized into three different zones, i.e., outer-most tip, outer-middle tip wear, and central-tip. The experimental results reveal that the outer-most tips are worn out rapidly compared to other tips due to the localization of higher current density and easier availability of fresh electrolytes. The tool wear is severe at a slower feed rate due to prolonged exposure to the higher temperature generated during the ECDM. However, at a higher tool feed rate (≥0.50 µm/s), the tool-tips are in physical contact with the alumina substrate. The central tip has a sideways bending beyond tool travel of 400 µm that would have led to the breakage of thin alumina substrate. The experimental results are useful in understanding the tool wear pattern in multi-tip electrodes during the ECDM process used in the micromachining of alumina and other non-conductive materials.

Influence of Friction Stir Welding Parameters on Joint Defects, Temperature and Hardness of AA6061-T6 and S27JR Mild Steel FSW Joint

The influence of welding parameters such as tool plunge depth, tool travel speed and tool tilt angle on welding temperature during friction stir welding of AA6061-T6 and S275JR mild steel was the focus of this research. Thermocouple placed in the aluminum alloy plate prior to welding was used to measure the temperature during the welding of joints under different set of parameter values. Joint appearance as well as defects occurring on the surface or within the joint was observed. Microhardness profiles were also taken by measuring microhardness values across the cross section of joints. Excessive flash, tunnel defects and insufficient welding were the type of weld defects observed on different joints with different parameters. Defects were attributed to the varied parameter values affecting the heat generation as well as the flow of the plasticized material. Highest temperature was recorded by the joint fabricated using the largest tool plunge depth, owing to the increased downwards pressure. Microhardness profiles were seen to be similar for all the welded joints. A “plateau” of low microhardness value was observed for all joints associated with the thermomechanically affected zone (TMAZ) and heat affected zone (HAZ). A wider plateau was observed for joints welded with higher tool plunge depth due to higher temperature.