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The swaging quality of self-lubricating spherical plain bearings (SSPBs) has an important influence on the safety of the aircraft. The roller swaging process has an edge on other swaging processes in low swaging load and high swaging quality. The 3D elastic–plastic finite element model of roller swaging and push-out test were developed, and the influence of the roller swaging process loading parameters, such as the swaging time, the swaging load and the rotation speed of the roller tool on the push-out load, the gap between the flanging lip of the V-groove and the housing chamfer, and the radial displacement (the inner surface of the outer ring) after roller swaging were studied. Finally, the roller swaging test was conducted, and the test results were compared with the simulation results. The research shows that the test results are consistent with the results of the simulation model, and with the increase of the swaging time, swaging load, and rotation speed of the roller tool, the gap will be increased as well, resulting in an increase in the push-out load. However, the excessive swaging load and rotation speed of the roller tool will increase the radial displacement, which will result in a reduction in the rotation flexibility of the bearing. Under the conditions of reasonable swaging time and swaging load, a good swaging quality can be obtained by controlling reasonable rotation speed of the roller tool.

For decades, attentions have been paid to metal cutting processes, especially for the critical components in aerospace, marine, medical industries, etc. Scholars investigated the influence of cutting parameters, tool geometry, lubricant, pursuing a deeper understanding of process signatures, better tool performance, and more superior surface integrity. Edge microgeometry is proved to be an essential factor that significantly influences the tool-workpiece-chip contact, plastic deformation, and heat generation, which in turn affects the cutting phenomena. This paper aims to provide an insight and scientific overview of the role of edge microgeometries in metal cutting, with special attention on material flow state, cutting mechanics, tool performance, as well as the surface integrity. The characterization of edge microgeometries includes edge types (honed, chamfered, mixed), size parameters (edge radius, form-factor K, chamfer angle, chamfer length), and edge preparation techniques (grinding, drag finishing, brushing, micro-blasting, etc.). The researches on the influence of edge microgeometries on material flow state and cutting mechanics are reviewed, mainly focusing on analytical modeling and finite element method to explain how the edge microgeometries affect cutting processes. Then, the researches on the influence of edge microgeometries on tool performance and surface integrity are well organized to present the various findings in these topics. From the current perspective, many scholars have noticed the importance of edge microgeometries in metal cutting and have done numerous researches on this topic. Summary and future suggestions are given based on their state-of-the-art contributions in the last section.

Researches on the modeling of machining difficult-to-cut metals are important for optimization of the processing parameters, in which the force modeling is essential due to its significant influence on the performance of tools and the quality of parts. A semi-analytical method for force prediction in orthogonal cutting with chamfered tools considering both edge and size effect is proposed in this paper. The plastic deformation in the shear band was investigated using a parallel shear zone model and unequal division shear zone model. The influence of size effect on cutting force was discussed and a simplified expression of improvement factor is introduced to describe the sharp increase of shear stress under the condition of low feed rate. Simulations of orthogonal cutting with different chamfer lengths are conducted to analyze the variation of cutting force with respect to chamfer length, which reveals that the influence of chamfer length on cutting force is determined by the ratio of chamfer length to uncut chip thickness. A modified function considering the trend of material flow condition is proposed, which treats the total cutting force as a combination of cutting forces caused by chamfered edge and rake face. The calibration of constants in the proposed method is achieved using particle swarm optimization (PSO), a meta-heuristic algorithm for complicated non-linear models. The experiments show that the method works well on both fitting and predicting modules in orthogonal cutting of AISI 304 using cemented carbide tools with 15° chamfer angle or 25° chamfer angle.

Taking advantage of the superior cutter axial stiffness, plunge milling provides a higher material removal rate in rough milling for components with deep cavities. Tool wear depending on cutting parameters of radial cutting width, axial cutting depth, step interval, feedrate, and spindle speed has been studied by several researchers. For a more comprehensive understanding of the wear mechanism, this study investigates the influences of tool engagement angle and tool geometry on tool wear based on multiple sets of machining tests. The development of tool wear during plunge milling is monitored. Results show that tool wear of insert with large engagement angle mainly exists on minor edge, which is caused by increased tool deflection. When the radial distance equals to tool radius, optimal engagement angle can be achieved while considering both tool life and machining efficiency. The experimental results show that tool life of insert with rake angle of 22° is 6.5% higher than rake angle of 15°. Smaller corner radius has positive influences on tool life improvement. Surprisingly, tool life of insert without cutting edge chamfer is 3.6 times than insert with cutting edge chamfer. The best tool geometric parameters of plunge insert can then be identified among a variety of inserts. This work is useful for cutting tool producers and manufacturers to optimize tool geometry and machining parameters.

Owing to the relevance of the turning operation to the metal working industry, intensive research is constantly undertaken in order to improve the quality of manufactured products, optimise production time, and reduce costs. Among the investigated topics, texturing of the cutting tool rake face has received increasing attention since it can affect tool life, process forces, and cutting temperature. The contribution of the present work resides in depicting the procedure for laser texturing the cutting edge chamfer of uncoated tungsten carbide inserts aiming at weakening the stability of the seizure region. Moreover, the performance of textured and non-textured tools was assessed when turning grey cast iron. Two parallel columns of dimples with an average diameter of 40 μm and variable distance between rows of dimples (60, 100, and 200 μm) were produced and the turning experiments were carried out dry and with the application of minimal quantity lubrication (MQL). The findings indicated that the lowest values for the turning force components were obtained when cutting with textured tools possessing dimples 100 μm apart and using MQL. Texturing did not affect tool life in dry turning; however, when cutting with MQL, the longest tool lives were obtained using the tools textured with dimples 60 and 100 μm apart. Finally, machined surface roughness was not affected by tool texturing and decreased slightly with the application of MQL.

When drilling holes, burrs are created in particular on the exit surface. Existing deburring tools and methods enable the deburring of plane exit surfaces or slightly curved cross-drilled holes. However, these tools do not meet practical requirements for deburring in the machining industry where component geometries are often complex. This paper presents a numerical method, which enables deburring of complex-shaped drilling intersections with ball-end cutters. First, the particular intersection is analysed as it defines the maximum tool diameter of the ball-end cutter. Subsequently, a three-axis tool path for ball-end cutters is generated to correlate with the intersection geometry thus enabling constant chamfering and avoiding tool collisions. The model is verified by an experiment using the material AlSi7Mg and measuring secondary burr heights and chamfer widths. Subsequently, the functionality of the model for further geometry variants is investigated.

This paper presents a novel grinding enabled texture, ‘V’ shaped texture (VST), on flank face. To implement the texture on a cutting performance, a set of chamfering experiments of stainless steel materials used as 3C product shell usually are presented. Cutting forces, surface qualities, and tool wear are measured and compared, of which results show that both smallest surface roughness and longest tool life are achieved by using a 30° VST chamfer tool. By comparing the results, a clear conclusion can be drawn that texture types and angles are not independent factors to cutting performance; therefore, a suitable combination of texture types and texture angles can provide a significant improvement of tool life and surface quality.

Electric upsetting process is used to prepare a preform before proceeding to a hot forging process of a long aspect ratio part (L/D > 40), such as an axial shaft and engine valve. Many researchers have been studied and investigated the effect of process parameters on the forming defects by experiments and simulations. The examples of the defects are surface burnt and buckling at the surface due to high electrical current and high compressive load, respectively. The “surface dimple” contacted at the anvil surface is another defect which is normally occurred during the production and has not been investigated a possible cause. This defect is a major cause of the underfilled for later the hot forging process. The objective of this paper is to investigate the cause of this defect by viscoplastic finite element modeling. It is found that the shifting of the high-temperature location comes from the chamfer. The non-chamfered workpiece will have the high temperature occurring around the middle of the anvil and the gripper which makes the high amount of the material rollover to the anvil caused of the high degree of the dimple when comparing to its with the chamfered workpiece.

A new approach of plastic joining two thin-walled tubes by compression instability was investigated in this work. Numerical simulation of the whole deformation process of the plastic joining was performed. Experiments of plastic joining by compression were conducted. The influence of some geometrical parameters on the joint mode was discussed in detail. The force-displacement response of the tubes subjected to axial compression was analyzed. The main deformation characteristic of each stage was described. The strength of the joint under uniaxial tension was assessed by simulation. The formability of the tube joining by plastic instability was assessed from three aspects. The results showed that there were three joint modes in tube joining processes, immature joint, qualified joint, and unqualified joint, which was dependent on the ratio of the free length with radius. The chamfer angle of the tube ends played an important role in the plastic deformation amount of the tubes. The formability of the tube plastic joining by compression instability could be assessed by geometrical parameters of the tubes, the compatibility of two wrinkles induced by compression and the plastic deformation amount of the tubes. The strength of the joint was highly dependent on the wrinkles’ geometry.

The present work aims to investigate the performance of recently designed chamfered inserts in high-feed turning of Ti-6Al-4V which is considered as the mainstream alloy for aerospace applications. So far, extensive experimental data has been published while turning this alloy using square-, round-, and rhombic-shaped inserts despite certain limitations associated with each insert design. Recently, a novel chamfer insert has been developed with an intention of combining the geometric benefits of aforementioned individual inserts into a single tool. The present work evaluates wear behavior and machining performance of this newly designed insert while turning Ti-6Al-4V without coolant under constant depth of cut of 1 mm at four levels of feed rate (0.14, 0.337, 0.45, 0.562 mm/rev) and three levels of cutting speed (55, 85, 110 m/min). For output responses of tool life and workpiece surface roughness, the novel chamfer inserts not only outperformed the conventional shaped tooling but more interestingly, they were seen to compete with much expensive PCD inserts. Flank wear was observed as the principle wear mode without any signs of crater formation. Chipping was evident at the lowest cutting speed (55 m/min) and low feed rate combinations (0.14 and 0.337 mm/rev). On the other hand, fracture was encountered when operated either at an intermediate cutting speed (85 m/min) with highest feed rate (0.562 mm/rev) or highest cutting speed (110 m/min) and medium to high feed rates (values ranging from 0.337 to 0.562 mm/rev). Workpiece surface roughness (Ra) values were within the range of 0.51 to 3.91 μm over the investigated regime of operating parameters. Strain-hardened layer that deepened up to 150 μm from the machined surface was observed without any microstructural damage.

Tool life is a significant issue for the application of micro mills. Optimizing cutting edge geometries of micro mill is an effective way to improve tool life. This paper investigates the effects of different chamfered cutting edges of micro mill on the tool cutting performance. A series of slot milling experiments are conducted on aluminum alloy 7075 by using micro mills with various cutting edge chamfer lengths, and the tool wear and surface roughness are measured. The results show that the cutting edge chamfer of micro mill can improve the tool life. For the micro mill fabricated with sharp cutting edge, the fracture of cutting edge easily occurs resulting in the tool early broken. As the cutting edge chamfer length is bigger, the tool life becomes longer, but the tool flank wear width increases due to the higher stress in cutting region. However, the effects of various cutting edge chamfer lengths on surface roughness are not obviously found.

A lightweight reliable joint is required for the self-lubricating spherical plain bearing which is widely used in aerospace as a key flexible connection. And the roller swaging is a promising process for obtaining the lightweight reliable joint by the plastic deformation. The experimental setup of the roller swaging assembly process and the push-out load inspection tooling were designed and fabricated in this paper. Moreover, the 2D elastic-plastic FE models of roller swaging and push-out test were developed under the Abaqus/Explicit environment for obtaining the metal flow and equivalent strain distribution during the processes. The good agreements of joint condition and push-out load are highlights between the FE simulation and experiment. Based on the results, the optimum designs of the housing chamfer height a and angle α and roller feed distance h were carried out with a typical roller angle β(60°). It can be found that the little chamfer height and angle are beneficial to obtain a good joint condition. However, compared with 45 and 60°, the load-carrying capacity of chamfer angle 30° is reduced by 30% at least. And the inward displacement of the outer race inner surface for chamfer height 0.7H is more than 50% larger than the ones of 1.0H and 1.2H. What is more, the larger roller reduction will enhance the load-carrying capacity and improve the joint condition, but result in a heavily inward metal flow.

This paper proposes a self-piercing riveting (SPR) method which uses a flange pipe rivet. This joining technology can solve the problems of oblique rivet and incorrect rivet position which are usually found in the SPR with a pipe rivet. The lap shear strength of the joint with a flange pipe rivet is higher than that of a joint with a conventional rivet. In this research, a flange pipe rivet was placed between two sheets with a force applied to the top sheet by a punch riveting machine. The flange pipe rivet moved downward along with the top sheet to induce appropriate bending and form a mechanical interlock in both sheets. Finite element (FE) analysis of the SPR with a flange pipe rivet was done by DEFORM software. The simulated joint cross-section shapes were observed, and the influence of the flange pipe rivet parameters on joint quality was analyzed. Simultaneously, some riveting experiments on joining aluminum sheets were conducted taking into consideration different rivet heights and chamfer angles. The results show that the joining surface is smooth and the simulated joint cross-section shapes are in good agreement with the experimental results. The joining property with a chamfer angle of 45° and a rivet height of 5 mm is found to be the best in joining the Al6063 aluminum alloy sheets with a thickness of 2.4 mm by using the SPR with a flange pipe rivet.

Time, cost, and life span are three major concerns that are needed to manufacture a new hot embossing stamp in the industry. The aim of this study is to develop a rapid and low-cost method for fabricating new hot embossing stamps with a long life span. Based on the results of ANSYS simulations, the maximum stresses can be reduced when the round and chamfer were applied at the junction of groove and sprue in the backing plate. Experimental results found that the fracture locations were found to be in reasonable agreement with the simulation results using ANSYS software. The hot embossing stamp can be used for batch production and evaluation in the research and development stage of a new optical element when the junction of groove and sprue in the backing plate were rounded with a radius more than 2 mm or chamfered with a width more than 3 mm.

Geometry of cutting edge has great influence on performance and reliability of modern precision cutting tools. In this study, two-dimensional finite element model of orthogonal cutting of Fe–Cr–Ni stainless steel has been built to optimize the geometric parameters of chamfered edge. A method to measure the chip curl radius has been proposed. The effect of cutting edge geometric parameters on tool stress and chip curl radius has been analyzed. Then, the chamfered edge parameters have been optimized based on numerical simulation results. It finds that, keeping the equal material removal rate, the optimal geometric parameters of chamfered edge for rough machining Fe–Cr–Ni stainless steel are that the rake angle is from 16° to 17°, and the chamfer length is from 60 to 70 μm. Small (large) rake angle combined with small (large) chamfer length is more reasonable to reduce the tool stress. When the length of land is approximately equal to undeformed chip thickness and the rake angle is larger than 15°, the chip curl radius is minimal. The groove type with large radio of width to depth should be used in the chip breaking based on the optimization results.

The performance of cutting tools can be drastically affected by cutting edge preparation i.e. the presence of a radius and/or a chamfer and their dimensions can alter cutting forces and temperature and, consequently, tool life as well as the surface quality of the machined component. The aim of this work is to investigate the machinability of AISI 4140 steel hardened to 40 HRC and 50 HRC when turning with coated tungsten carbide inserts with various microgeometries (brushed edges with distinct slopes). The following aspects were considered: cutting force components, cutting temperature and machined surface roughness. In comparison with the published literature, the novelty of the present work is related to the investigation of the machinability of a hardened steel by applying a large variety of customized non-commercial cutting edge geometries. Differently from other studies, the paper presents experimental results for temperature in the contact zone employing different cutting edge geometries. Moreover, in order to explain the results, an analysis of tool-workpiece contact zone is carried out for each edge geometry. The results indicated that cutting edge microgeometry affects mainly the feed and passive force components, while the cutting force, specific energy and cutting temperature are not drastically altered. Finally, no clear relationship between microgeometry and machined surface roughness was noticed, although irregular marks on the roughness profile were found when sharp edges were used (suggesting edge chipping) and evidence of side flow was noted when rounded edges were tested.

This study analyzed the effects of geometric size and grain size on the forming characteristics of a phosphor bronze thin sheet during micro bead forming processes. Specimens with different thicknesses were first heated at various temperatures for obtaining objective grain sizes. A tensile test was conducted to determine the mechanical properties of the specimens. A bead forming machine was used to conduct a bead forming test to measure and analyze curled angles, springback, and forming load; the measurement and analysis were conducted for investigating the geometric size and grain size effects in addition to the chamfer and lubrication effects during bead forming. The geometric size effect showed that the springback decreased with the thickness decreasing, and the grain size effect indicated that the springback increased with an increase in the grain size. Incorporating chamfers into the specimens enabled the specimens to be curled effectively, thus rendering chamfers the essential parameters for ensuring successful bead forming.

An optimization concept of the various machining parameters for the plasma arc cutting procedures on AISI 316 stainless steel conducting a hybrid optimization method has been carried out. A new composition of response surface methodology and grey relational analysis coupled with principal component analysis has been proposed to evaluate and estimate the effect of machining parameters on the responses. The major responses selected for these analyses are kerf, chamfer, dross, surface roughness and material removal rate, and the corresponding machining parameters concentrated for this study are feed rate, current, voltage and torch height. Thirty experiments were conducted on AISI 316 stainless steel workpiece materials based on a face-centered central composite design. The experimental results obtained are applied in grey relational analysis, and the weights of the responses were evaluated by the principal component analysis and further evaluated using response surface method. The results show that the grey relational grade was significantly affected by the machining parameters directly as well as with some interactions. This method is straightforward with easy operability, and the results have also been established by running confirmation tests. The premise attributes beneficial knowledge for managing the machining parameters to enhance the preciseness of machined parts by plasma arc cutting.

This article presents the results from a traverse internal cylindrical grinding process conducted using grinding wheels with sol–gel alumina abrasive grains and varying volumes of glass–ceramic vitrified bond. The aim was to determine how changing the bond volume within the range of V b = 11.5–14.5 % influenced the wear phenomenon of the microcrystalline sintered corundum abrasive grains and the ceramic bond bridges with glass-crystalline structure. The paper presents grinding wheels with conic chamfer and the most important wear phenomena of the grinding wheel components occurring in the area of contact between the tool and the workpiece material. The work includes the methodology of the experimental tests on the traverse internal cylindrical grinding of bearing rings made from steel 100Cr6 (62 ± 2 HRC). A wide range of test results were analyzed, including machined surface roughness parameters (Ra, Rz, Sm, Δa), grinding power, grinding wheel volumetric wear V s , material removal V w , G-ratio, root-mean–square roundness deviation from mean circle (Δ, rms), grinding wheel edge wear, grinding wheel microtopography parameters (Sa, St, Sdr, Sds), and SEM images of the wear marks on the grinding wheel active surface. The dominant wear phenomena of the grinding wheels with conic chamfer and the influence of the bond volume share on its intensity were experimentally determined. The results show that the decrease in bond volume from V b = 14.5 to 11.5 % increases the grinding wheel life by twofold. This was due to a decrease in abrasive wear and plastic flow phenomena and to a greater fracture wear (mostly fatigue and thermal-fatigue). These events led to a periodic shedding of the oxide layer and the plastically deformed grain layer and also revealed the crystals’ sharp edges, located below the plastically deformed surface layer.

The longevity of hard alloy indexable cutting inserts used to cut metal parts is significantly related to their proper geometric design. Such a relationship is outstanding in an intermittent cutting scenario. One solution is to use a strengthened cutting insert with a negative chamfered edge. This method has proven to be effective in avoiding chipping and brittle fractures. However, it does have other effects, like a larger cutting force and a higher cutting heat. In the present research, a set of intermittent cutting experiments were conducted through combinations of two grades of hard alloy indexable inserts and multiple geometric parameters of cutting edges. A three-dimensional dynamometer and a high-speed camera were used to monitor and collect data on the impact and cutting force during the process. A study over the strengthening mechanism of the negative chamfer to the cutting insert was conducted using statistical analysis, which revealed the influence of those geometric parameters of cutting edges on the insert’s lifetime. Further, it gave a quantified relationship between the negative chamfer parameter and the feed. This conclusion serves as both data and technical support for the design enhancement of hard alloy indexable inserts.