---

The spring-back of a work-piece during machining operation causes dimensional error of the work-piece. In the present study, the spring-back of work-piece in ultrasonic-vibration assisted turning and conventional turning has been modeled. It is illustrated that the reaction of the work-piece in high frequency vibration cutting is similar to a static behavior, whereas the spring-back in this process is theoretically and experimentally smaller than the conventional cutting leading to smaller error. A method has also been proposed to obtain the errors caused by rigid assumption of the spindle assembly used for correction of the results.

---

One directional and elliptical vibration cutting of IN738 at ultrasonic frequency has been investigated both experimentally and by FEM in the present study. The influence of each process on the cutting force was studied. The FEM modeling was carried out by using MSC-MARC. The results were compared with the experimental findings of the conventional cutting. The ultrasonic vibration was applied to a rigid cutting tool along the cutting velocity in one directional vibration cutting. In elliptical vibration cutting the vibration was applied both along the cutting velocity and in the chip flow direction. The experiments were carried out on an ultra precision CNC lathe with single crystal diamond tools. The same effects were confirmed in the machining practice and by FEM. It was quite feasible when machining IN738 to obtain the advantages of elliptical vibration cutting already reported for some other materials such as copper, aluminum, tungsten and super alloys.

---

In tube hydroforming process, due to friction condition, uniform wall thickness, as well as sharp corners may not be achieved. Use of ultrasonic vibration can improve the contact conditions at the tube-die interface. The current work studies the effect of applying ultrasonic vibration on wall thickness and corner filling of hydroformed tubes. Firstly, a numerical model based on geometric relationships and stress-strain state has been established by which wall thickness and corner radius of hydroformed tubes can be obtained. In this model, the ultrasonic vibrations affect the nonlinear friction conditions at the tube-die interface. By comparing the FEM models of tubes in two cases of with vibration and without vibration, it is possible to investigate the effects of vibration on wall thickness and corner filling. The results indicate superimposing ultrasonic vibrations to the process will increase corner filling ratio of the tube significantly, and more uniform tube wall thickness will be achieved.

---

In this paper an innovative vibration rotary tool was designed and manufactured. Vibration turning tool is a compound of turning rotary tool and ultrasonic assistant turning. In this tool, an ultrasonic wave generator with power equal to 20 KHz transducer that has a rotational motion during the process was used. For tool vibration, a stainless horn with resonance frequency equal to 20618 Hz, were designed and manufactured. Round insert with 10 millimeter diameter were used. One of the most important key points in this setup is that the simultaneous rotation and vibration has to be achieved. For rotational motion a motor power and a rack and pinion were used. Also a structure with ability to mount on turning machine were designed and manufactured. Cutting force and surface roughness for each experiment were measured and compared with data collected from conventional rotary tool on 7075 aluminum material. Results shows that ultrasonic vibration cause decreasing in cutting tools and surface roughness, tremendously.

---

In tube hydroforming process, due to friction condition, uniform wall thickness, as well as sharp corners may not be achieved. Use of ultrasonic vibration can improve the contact conditions at the tube-die interface. The current work studies the effect of applying ultrasonic vibration on wall thickness and corner radius of hydroformed tubes. By comparing the FEM models of tubes in two cases of with vibration and without vibration, it is possible to investigate the effects of vibration on process. In addition, the finite element analysis, as the modal and harmonic analysis, are used to design a set of ultrasonic tube hydroforming. A simple mechanism introduced in this paper is used to form the tube. The results indicate superimposing ultrasonic vibrations to the process will improve formability and spring back of the, and more uniform tube wall thickness will be achieved.

---

The problem of bone fracture in medicine due to an accident, aging or diseases, has existed from times when humans started to work and activity. The process of bone drilling is an essential part of internal immobilization in orthopaedic and trauma surgery. The force required to chip formation in drilling process, resulting in heat generation in drill site that leads to the occurrence of thermal necrosis. This research experimentally investigates the effect of ultrasonic vibration on thrust force in drilling of bovine femur bone. This method induces high-frequency and law-amplitude vibration in the feed direction during cutting, and has the potential to spread tiny cracks in bone and decrease friction leading to reduce of cutting forces and also increase the speed of chip disposal leading to reduction of machining forces, totally. Experimental results demonstrate that ultrasonic assisted drilling of bone produces fewer thrust force than conventional drilling and rotational speed of 1000 rpm is the optimal speed to achieve at minimum thrust force for all feed rates. Moreover, this method is due to the force independence of the feed rate in the rotational speed of 1000 rpm, is applicable in orthopedic surgery.

---

Incremental Sheet Metal Forming (ISMF) is based on localized plastic deformation. In this process, a hemispherical-head tool, controlled by a CNC milling machine, shapes a sheet metal according to a defined path. Study of the forming force is one of the most important topics in this process. Increasing of vertical step size, tool diameter, wall angle and sheet thickness together with using of high strength sheet metals and lightweight alloys, leads to an increase in the forming force. In this paper, the performance of a novel forming process, named Ultrasonic Vibration assisted Incremental Sheet Metal Forming (UVaISMF) has been investigated. The procedure of design, manufacture and test of vibratory forming tool, is presented. The occurrence of longitudinal mode and resonance phenomenon has been confirmed by the results of modal analysis and experimental test. Furthermore, the effect of ultrasonic vibration on the vertical component of forming force and spring-back has been studied. Aluminium sheet of grade Al 1050-O is used as a work material. Experimental results obtained from straight groove test, indicate that ultrasonic excitation of forming tool, will reduce the average of vertical component of forming force and spring-back in comparison to conventional process.

---

Incremental sheet metal forming process is considered as one of methods which able manufacturer to produce parts without dedicated die in low and rapid prototype production, and many researches have been done to improve it. Using of ultrasonic vibration is one of the modern approaches in forming processes which reduce friction and forming force. The purpose of this study is to investigate the effect of ultrasonic vibration applied to the tool in single point incremental sheet metal forming process. For this, first theory of single point incremental forming has been studied; its principle has been investigated and analytical relations have been modified then analytical relations in the case of applying ultrasonic are derived from those. To practical evaluation of applying ultrasonic to this process a set can be installed to the head of CNC milling machine is designed and manufactured. According to results of analytic compared to experimental results a reasonable approximation of forming force variation in normal single point incremental forming process and applying ultrasonic can be offered. Based on tests results forming force in applying ultrasonic compare to normal mode reduces between 33 to 63.5 percent depend on test circumstances.

---

When two bodies slide on each other, friction is created. By superposing ultrasonic oscillation to one of the bodies, the friction force is reduced .This phenomenon is widely used in metal forming and metal cutting. For the production and transmission of ultrasonic vibrations to a target it is required to use an ultrasonic system the components of which are a generators, a transducers and a horn. Horn constitutes an important part of the Ultrasonic systems. The main task of the horn is to transmit the ultrasonic vibrations and amplify the ultrasonic vibration amplitude at the output. In this study, an Aluminum horn was designed in cylindrical-conical-cylindrical shape geometry and was analyzed by the finite-element method(FEM) using the Abaqus software was manufactured. The resonance frequency obtained in Abaqus was equal to 19976 Hz. The resonance frequency obtained from the generator was equal to 19920 Hz. Hence there is a very good agreement between the experimental result and the FEM simulation. The difference between the finite element simulation results and the experimental ones is less than one percent. Moreover, a horn –workpiece assembly for applying the ultrasonic sliding friction was designed and manufactured. Then the fixture and the tool holder clamp were designed for the vibrating tool so that it can be installed on a milling machine and the friction force measurement is possible while the ultrasonic vibrations are applied.

---

In the current work, a modified method of friction stir process (FSP) based on ultrasonic vibration and modified FSP tool design was developed to disperse multi-walled carbon nano-tube (MWCNT) throughout nylon 6 matrix. To this end, Field emission scanning electron microscopy, X-ray diffraction, Vickers’ micro-hardness, and visual inspection were used to evaluate the fabricated nano-composites. Also, a modified design of FSP tool together with ultrasonic vibration were used to improve the impact and efficiency of FSP. Several experiments were conducted to approach an optimum range of FSP parameters (rotational speed and traverse speed). The scanning electron microscopy observations and X-ray diffraction patterns (XRD) declare that MWCNT was dispersed homogeneously throughout nylon 6 matrix. Micro-hardness results illustrate that homogeneous dispersion of MWCNT throughout nylon 6 matrix results in 33% increase of micro-hardness. In general, the obtained results declare that ultrasonic vibration causes an increase in traverse speed and production speed of nano-composite without affecting the homogeneous dispersion and hardness of nano-particles throughout the matrix. Also, it is clear that ultrasonic vibrations did not noticeably affect superficial form of nano-composites due to low traverse speeds used in ultrasonic assisted friction stir process.

---

When two bodies slide on each other the asperities are engaged and friction is created. By superposing ultrasonic vibrations to one of the bodies, the friction force is reduced .This phenomenon is widely used in metal forming and metal cutting. In this research, experimental study of the effect of ultrasonic vibrations has been on sliding friction force in longitudinal direction. For this purpose, set-up was designed and fabricated. The main components of the set-up, including generators, transducers, first engaged body and second engaged body. The Set-up was installed on the machine lathe for investigation of the effect of ultrasonic vibrations on sliding friction force in longitudinal direction. The experiments were performed for eight different performance conditions. Next, the effect of each parameter ultrasonic wave velocity, roughness and material of contact surfaces were studied on the reduction of the friction force due to addition of ultrasonic vibrations. The result show that range of reduction friction force due to addition of ultrasonic vibrations in longitudinal direction is between 40 to 100% for the different performance conditions also friction force significantly reduced by increasing ultrasonic wave velocity so that friction force can be brought to zero by significant increase in ultrasonic wave velocity. The results also show that friction force has a more reduction for the surface has a less roughness. Aluminum-aluminum surfaces can be more reduction friction force from aluminum – steel surfaces.

---

Electrical discharge machining is one of the usual and widely used machining processes for machining hard metals and alloys which has low machinability by traditional machining methods. Due to the thermoelectric nature of this process, changes in metallurgical and mechanical properties of machined surface and development of residual stresses in components are inevitable. In this research machining of Ti-6Al-4V titanium alloy is conducted by ultrasonic assisted electrical discharge machining process and the effects of ultrasonic vibration of tool on the machining efficiency, surface integrity such as surface micro-cracks, residual stress and surface hardness has been evaluated. Machined surface were imaged by scanning electron microscopy imaging to study the size and distribution of surface micro-cracks. Residual stresses along the depth of the machined surface, evaluated using Nano indentation technique and hardness of discharged surface is measured using a micro hardness measuring instrument. The results show that applying ultrasonic vibration increases electrical discharge machining process efficiency (about 90%), reduces the amount and size of surface micro-cracks, changes residual stress distribution and decreases the amount of it (average 17%); Increases of surface hardness caused by ultrasonic assisted electrical discharge machining process is 13% more than the traditional electrical discharge machining process.

---

Metal forming is a conventional manufacturing process that a material with simple form is subjected to plastic deformation and emerged to industrial end products. Reduction of forming forces and improving of products quality have been a promising object for investigators and artisans. To accede this purpose, primary methods such as increasing material temperature and modern methods such as use of high power low amplitude ultrasonic vibrations were introduced. In ultrasonic assisted forming, high power ultrasonic transducer produces low amplitude high frequency mechanical vibrations which transmitted to material subjected to deformation and contacting surfaces of tool/workpiece. Results show reduction of forming forces and tool wear as well as improving surface integrity and dimensional stability that lead to increasing production rate and process efficiency. By regarding to importance and capability of ultrasonic assisted metal forming, this paper is concerned with application of ultrasonic vibration on metal forming processes. To this purpose, fundamental and mechanisms of application of high power ultrasonic were introduces and discussed. Also, industrial future of this technology as well as its advantages, range of application and its restriction were mentioned.

---

Ultrasonic Assisted Magnetic Abrasive Finishing (UAMAF) is the combination of magnetic abrasive finishing (MAF) and ultrasonic vibrations to finish the surfaces in nanometer scale. In this work, the experimental setup for UAMAF was prepared to finish inner surface of tube workpiec. By using experimental setup, the effect of experimental parameters such as ultrasonic vibrations, mesh number, the type of abrasives (SiC and diamond) and finishing time has been investigated on the changes in the surface roughness of AL6061 tube workpiece. The experimental results showed that the use of ultrasonic vibrations has a significant effect on reducing the surface roughness. The changes in surface roughness increases with the mesh number from 90 to 800 and finishing time from 30s to 5 min. Among two types of abrasives, diamond showed the best performance in finishing. Optical microscopy images showed that the dominant finishing mechanism in MAF for coarse grains (with mesh size of 90 and 120) is two body and for fine grains (with mesh size of 220, 400 and 800) is three body. In UAMAF for both of the coarse and fine grains the dominant finishing mechanism is three body.

---

Electric discharge machining is one of the most widely used non-traditional machining techniques which use thermal energy for machining in small dimensions, machining complex shapes and machining hard materials with high strength such as ceramics and heat-treated steels. In this study the ultrasonic vibrations and magnetic field assisted EDM process as a new hybrid process was introduced and used for machining of AISI H13 too steel, to solve the EDM process limitations such as low material removal rate. In this investigation, several experiments were designed and performed based on full factorial method by selecting pulse current and pulse duration as most effective parameters of EDM process in order to study the effects of applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of EDM process, simultaneously, on material removal rate and tool wear rate. According the results, applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of EDM process, simultaneously, despite the increases of tool wear rate, increases the material removal rate as compared with EDM (60%), ultrasonic vibrations assisted EDM (40%) and magnetic field assisted EDM processes (55%) in all pulse durations and pulse currents except in pulse current of 32 A. In pulse current of 32 A, because of the interference of the influences of applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance, the material removal rate and tool wear ratio are decreased.

---

Despite the unique usage of electrical discharge machining process at machining in small dimensions, machining complex shapes and machining of high-strength parts such as ceramics and heat treated steels, which can’t be machined by traditional machining methods, low machined surface integrity achieved by electrical discharge machining process is one of the most important limitations of this process. In this investigation the machined surface integrity will be improved by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of electrical discharge machining process, simultaneously. So several experiments were designed and performed based on full factorial method by selecting pulse current and pulse duration as the most important input parameters, in order to study the effects of pulse current and duration on surface integrity of workpiec machined by this hybrid process and to investigate the effects of tools ultrasonic vibrations and external magnetic field on machined surface roughness and integrity of machined surface. According the results, machined surfaces roughness is increased by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance of electrical discharge machining process, simultaneously, while the SEM pictures of machined surfaces showed that the, amount of created surface cracks, blowholes, globules and beads of debris are decreased and integrity of machined surfaces by EDM process is improved by applying ultrasonic vibrations to tool electrode and external magnetic field around gap distance, simultaneously.

---

Vibration waves with frequencies greater than 20 kHz, known as ultrasonic vibrations, are used in many manufacturing and engineering processes. This paper studies the occurrence of acoustic softening in steel specimens with three different microstructures. For this purpose, specimens with bainite and martensitic microstructures were created by Austempering and Quench heat treatments. The final dimensions of these specimens were obtained with Modal finite element analysis using ANSYS software so that the resonance frequency of the specimen is equal to the resonance frequency of transducer. Given that ultrasonic vibration induces a tension called vibrational stress to the crystal, this stress causes movement of dislocations and reduces the yield strength of specimens. In this paper 55 w / cm2 ultrasonic vibration, 18%, 12% and 8% yield strengths of specimens are reduced with ferrite- perlite, bainite and martensitic microstructure. Due to the absorption of vibrational energy by dislocation, the metal forming of these materials takes place with less energy. Also, in this paper, a numerical model for acoustic softening was investigated and it was found that there is a good correlation between numerical modeling and experimental e results.

---

The main purpose of this paper is to reveal the volume effect of ultrasonic vibrations on the plastic behavior of S355J2 steel specimens with different grain sizes and investigate the decrease in the Yield strength and ultimate strength of these steel specimens. For this study, samples of grain size of 10, 35 and 60 microns were created by performing various cycles of normalization and annealing heat treatments. An experimental setup was designed and developed for the tensile test with ultrasonic vibration. The tensile test was carried out at a room temperature and constant speed of 1 mm /min and it was found that by applying 390 watts of vibrations, the yield strength reduction of steel specimens with a grain size of 10, 35 and 60 microns was 8%, 18% and 27%, respectively. . The grain boundary length in fine-grain specimens is greater than the largest-grain specimens, therefore, the sound energy is distributed over the boundary. Therefore, the effect of applying ultrasonic vibrations on fine-grain specimens is less than that of largest grains and the yield strength and ultimate strength of fine-grain specimens showed a lower reduction

---

---