Ultrasonic Assisted Machining Research Articles

Experimental investigation of micro-machining of borosilicate glass using an ultrasonic assisted rotary electrochemical discharge machining (UA-RECDM) process

Electrochemical discharge machining is an advanced micro-machining process for machining of conductive as well as non-conductive hard and brittle materials, e.g. glass, ceramics, silicon wafer, etc. The present work explores the machining of glass using an in-house developed novel ultrasonic assisted rotary electrochemical discharge machining setup. The setup has specialized features, such as using ultrasonic vibrations to tool the electrode and incorporating rotary motion for manipulating the workpiece. Experiments were conducted using a one factor at a time approach by varying the tool feed rate, the amplitude of the vibrations and the rotation of the workpiece as process parameters. The quality of the machining output was evaluated by observing two key parameters: the overcut and the circularity of the hole. It was observed that as the workpiece rotation speed increased from 40 rpm to 60 rpm, the overcut in the machined samples decreased from 181.378 μm to 163.564 μm. The rotary motion of the workpiece caused a seeping action of the electrolyte in the hydrodynamic regime, leading to the formation of a thin gas film and the stabilization of the discharging process. The morphology of the machined hole exhibits better circularity, low heat-affected zones, minimum micro-cracks and smooth edges at its periphery due to stable discharge formation.

Investigation of processing characteristics of PCD in ultrasonic-assisted graphene powder mixed EDM

Polycrystalline diamond is widely used in many fields including ultra-precise machining, optical material and semiconductor electronic devices due to its excellent physical properties. However, traditional mechanical processing methods of polycrystalline diamond leads to severe tool wear, low efficiency and high costs. Although electrical discharge machining can overcome some limitations, it usually exhibits a low material removal rate and poor surface quality. This study aims to explore the effect of graphene powder and ultrasonic vibration on polycrystalline diamond by electrical discharge machining. It was found that the synergistic effect of graphene powder and ultrasonic vibration can achieve a good surface quality. The results show that ultrasonic-assisted powder mixed electrical discharge machining can obtain the smallest surface roughness (1.98 μm) at low parameter and the biggest material removal rate (0.773 mg/min) at high parameter compared with ultrasonic assisted electrical discharge machining and powder mixed electrical discharge machining. In addition, after ultrasonic-assisted powder mixed electrical discharge machining, the minimum value (0.807) of ID/IG is obtained. For polycrystalline diamond, this study also proposes a removal mechanism that diamond converts into graphite and is peeled under tensile stress.

Grinding force model for ultrasonic assisted grinding of γ-TiAl intermetallic compounds and experimental validation

Abstract The introduction of ultrasonic vibration in the grinding process of γ-TiAl intermetallic compounds can significantly reduce its processing difficulty. It is of great significance to understand the grinding mechanism of γ-TiAl intermetallic compounds and improve the processing efficiency by studying the mechanism of ordinary grinding of abrasive grains. Based on this, this study proposes a grinding force prediction model based on single-grain ultrasonic assisted grinding (UAG) chip formation mechanism. First, the prediction model of grinding force is established based on the chip formation mechanism of abrasive sliding ordinary grinding and the theory of ultrasonic assisted machining, considering the plastic deformation and shear effect in the process of material processing. Second, the UAG experiment of γ-TiAl intermetallic compounds was carried out by using diamond grinding wheel, and the unknown coefficient in the model was determined. Finally, the predicted values and experimental values of grinding force under different parameters were compared to verify the rationality of the model. It was found that the maximum deviation between the predicted value of tangential force and the actual value is 23%, and the maximum deviation between the predicted value of normal force and the actual value is 21.7%. In addition, by changing the relevant parameters, the model can predict the grinding force of different metal materials under different processing parameters, which is helpful for optimizing the UAG parameters and improving the processing efficiency.

Characterization, quantitative evaluation, and formation mechanism of surface damage in ultrasonic vibration assisted scratching of Cf/SiC composites

Carbon fiber reinforced silicon carbide ceramic matrix composites (Cf/SiC composites) have a wide range of applications in aerospace, nuclear energy, braking systems owing to its excellent mechanical performance. Nevertheless, the hardness, brittleness, heterogeneity, and anisotropy of Cf/SiC composites give rise to difficulties in machining them. In addition, the characterization and formation mechanism of surface damage in the grinding of Cf/SiC composites have not been fully elucidated. The purpose of this paper is to provide a characterization method for surface damage of Cf/SiC composites and an evaluation index for surface edge chipping damage (SECD) through conventional scratching (CS) / ultrasonic vibration assisted scratching (UVAS) tests with single abrasive. Towards revealing the surface damage behavior of Cf/SiC composites during scratching, as well as the impact of fiber orientation on surface damage. The findings indicate that main forms of surface damage of Cf/SiC composites in single abrasive scratching are fiber breakage, fiber fracture-shedding, fiber fracture, fiber-matrix interface debonding, interface fragmentation, matrix cracking, and matrix microcracks. Further, ultrasonic vibration could help to suppress the SECD, and the SECD factor was smallest when scratching along the perpendicular fiber. Furthermore, the fiber orientation can significantly affect the scratching force and cross-sectional area of scratches on Cf/SiC composites via single abrasive scratching. The tangential scratching force was usually smaller as compared to the normal scratching force, and the cross-sectional area of scratches in UVAS is smaller than that in CS. Based on the above findings, this study elucidates the formation and evolution of surface damage after scratching under different fiber orientations, filling the research gap in surface damage under ultrasonic assisted machining of Cf/SiC composites and providing technical guidance for the machining.

Designing an Ultrasonic-Assisted Machining System by Using a Network Mapping Fusion–Convolutional Neuro-Fuzzy Network Model

Designing an Ultrasonic-Assisted Machining System by Using a Network Mapping Fusion–Convolutional Neuro-Fuzzy Network Model

Investigation of ultrasonic vibration assisted orthogonal turning under dry and minimum quantity lubrication conditions and performing sustainability analyses

Recently, increasing pressure on industries to innovate and adopt sustainable techniques has sparked investigations into machining strategies that have minimal carbon emissions, minimal energy consumption by machine tools, and low machining costs. The primary aim of this paper is to identify the machining conditions that can fulfill the criteria of clean production and sustainable chip forming for low-alloy steel which is extensively used in the many industrial field. To achieve this goal, experiments were done under both dry and Minimum Quantity Lubrication (MQL) conditions, aided by ultrasonic vibration assisted hybrid machining conditions at various cutting speeds (100 and 140 m/min) and uncut chip thicknesses (0.1, 0.14, and 0.18 mm). The study was conducted in two stages. In the first part, machining experiments were performed afterward, cutting forces, cutting temperature, chip morphology, surface roughness, and texture were examined. The second part of this study evaluates the sustainability of various machining parameters and cutting environments. The analysis of economic feasibility or rather the total machining costs were estimated by evaluating the costs incurred due to investment of machine tools, lubricant/coolant delivery systems and ultrasonic vibration system costs, waste processing and management costs, cutting tool and labor costs, cost of cutting fluid and energy consumed. On the other hand, environmental viability was evaluated by estimating the carbon emissions (CE) due to the power consumed, material utilization (i.e., the cutting tool and cutting fluid), and the waste processing and management (i.e., disposal of cutting tool, cutting fluid and chip recycling). Results indicate that both dry and MQL ultrasonic-assisted machining processes resulted in improved chip breakability, and produced short-comma chips. Additionally, it reduced cutting force by 28% and the cutting temperature was lowered by 30 %. Besides, Minimum Quantity Lubrication + Ultrasonic Vibration Assisted Machining (MQL + UVAM) hybrid method prevented surface defects and reduced average surface roughness by 24%–35% compared to dry conditions. While utilizing the MQL + UVAM method, the overall machining cost decreased in the range of about 20–30 % as compared to dry and dry + UVAM conditions. From an environmental standpoint, the MQL + UVAM hybrid machining process was found to be a significant contribution to the overall CE due to use of cutting fluids and increased machine tool utilization. This paper contributed to the understanding of sustainability and cleaner production to mitigate CO2 emissions by using the MQL + UVAM hybrid method.

Research on ultrasonic assisted press-fit assembly of small interference fits

Interference fits are widely used in aerospace, precision instruments and other fields. Press-fit assembly is one of the traditional assembly methods for interference fitting parts. Wear during assembly will affect the performance of interference components and the service life of marine equipment. Ultrasonic assisted press-fit can significantly reduce the press-mounting force of an interference fit. However, its effect on connection quality is rarely studied. The mechanism of ultrasonic assisted press-fit is unclear. In this paper, ultrasonic assisted press-fit was simulated and experimentally studied. The effects of ultrasonic vibration on heat generation, press-mounting force, connection strength, and interface wear were analyzed and discussed. Through analogy analysis with similar ultrasonic assisted machining processes, the mechanism of ultrasonic assisted press-fit was revealed. The results show that the superimposed ultrasonic vibration can effectively reduce the joining force (up to 33.5%), and increase the connection coefficient from 10% to 40%. This is due to stress superposition, friction reduction and acoustic softening that reduces interface wear. The increase of the interface roughness Rz from 3.681 to 4.586 μm confirms this analysis. Furthermore, the ultrasonic vibration can effectively reduce the material plastic flow of contact interface. This study reveals the significant advantages of ultrasonic assisted press-fit assembly (UAPA) method and provided a basis to understand the underlying mechanisms of UAPA.

Research on the machining mechanism of AISI 304 ultrasonic vibration assisted grinding

Compared with conventional grinding (CG), ultrasonic vibration assisted grinding (UVAG) has more prospects and competitiveness in processing AISI 304. Due to the change of strength of materials, when the vibration is superimposed on the workpiece, the mechanism of ultrasonic assisted machining is different from that of tool ultrasonic assisted machining. Therefore, this article proposes a workpiece vibration grinding device suitable for UVAG to study the corresponding grinding mechanism. The vibration characteristics of workpiece ultrasonic generator were discussed based on finite element simulation and the vibration situation of the device was tested with instruments to verify the accuracy of the simulation. Meanwhile, the machining mechanism of workpiece ultrasonic vibration was studied through grinding comparative experiments. The experiment showed that the displacement curve of the output end of the ultrasonic vibration of AISI 304 with time could be approximated to a sine wave and there was no other clutter. As the amplitude percentage of the ultrasonic generator increased, the output amplitude of the transducer showed an increasing trend. The ultrasonic amplitude and the amplitude percentage of ultrasonic generator approximately follow a linear relationship. The grinding force decreased with the increase of spindle speed and amplitude, and increased with the increase of feed rate and grinding depth. Compared with conventional grinding force, the grinding force of tangential ultrasonic vibration assisted grinding (TUVAG) decreased by about 29 %, while the grinding force of radial ultrasonic vibration assisted grinding (RUVAG) decreased by about 28 %. Under the action of ultrasound, the workpiece obtained better surface morphology. Under processing conditions of vw = 25 mm/min, ap = 0.01 mm, n = 2000r/min, A = 8 μm, f = 20000 Hz, the minimum surface roughness Ra of TUVAG is 0.51, followed by RUVAG with Ra = 1.02, while the surface roughness Ra of CG is the worst at 1.56 due to grinding burns.

EFFECTS OF VIBRATION CONDITIONS ON MACHINABILITY OF AISI 52100 BEARING STEEL

This study focused on determining the effects of the cooling condition in the conventional and ultrasonic-assisted turning of AISI 52100 steel. AISI 52100 steel has been widely used in the bearing, mold, and automotive industries because of its superior wear resistance and mechanical properties. However, its high wear resistance caused poor machinability in conventional machining methods. Low surface quality, rapid tool wear, high cutting temperature, and high cutting force are the main difficulties in the conventional machining of AISI 52100 steel. On the other hand, ultrasonic-assisted machining has become widely used in the past decades for the machining of materials that have low machinability in conventional methods. Conventional turning and ultrasonic-assisted turning were selected as machining methods. Ultrasonic-assisted turning experiments were conducted under 20 and 30 kHz vibration frequencies. Cubic Boron Nitride (CBN) cutting tools were used in machining experiments. In machining operations 50, 100, and 150 m/min cutting speeds were selected, and feed rate (0.1 mm/rev) and depth of cut (0.5 mm) were kept constant in experiments. Minimum quantity lubrication technique which used 1% Al2O3 nanoparticle additives cutting fluid and dry cooling methods were used. CBN insert was used as a cutting tool. The effects of cutting speed, cutting method, and cooling condition on surface quality, cutting force, cutting zone temperature, and cutting tool wear were studied experimentally. Analysis of Variance (ANOVA) was carried out to determine the significance of the effects of input variables on process outputs. As a result of this study, it is determined that combined UAT and nanoMQL have significant effects on the process outputs.

Experimental investigation of ultrasonic vibration-assisted cryogenic minimum quantity lubrication for milling of Ti-6Al-4V and grinding of Zerodur

Increasing demands on component properties are leading to the development of high-performance materials for which conventional production methods are reaching their limits from an economic and ecological point of view. In recent years, two technologies have been developed that show great potential compared to conventional machining processes, particularly in machining high-performance materials such as the titanium alloy Ti-6Al-4V. Ultrasonic-assisted machining leads to reduced cutting forces and increased tool life. Cryogenic minimum quantity lubrication prevents the occurrence of high machining temperatures and allows higher material removal rates without a negative impact on tool life. This paper shows the influence of ultrasonic-assisted milling and grinding processes in combination with cryogenic minimum quantity lubrication on the machinability of the high-strength materials Ti-6Al-4V and Zerodur. The investigation addressed cutting forces, tool wear, and surface roughness. The superposition of the technologies resulted in longer tool life and lower tool wear for both milling and grinding. However, the surface roughness was consistently higher due to the ultrasonic superposition. Nevertheless, machining with ultrasonic vibration-assisted cryogenic minimum quantity lubrication has great potential for difficult-to-machine materials, especially due to the reduction in tool wear.

Overview of Electric Discharge Machining of MachineTooled Ceramics and Ceramic-Based Composites

Accordingly, many engineering designers have improved the wear friction performance of such materials. Also, the use of polymers as reinforcements in their endeavors has been done to improve intrinsic performance. Intrinsic properties played an important role in intrinsic polymer orientations, improving the cohesion of some reinforcement while at the same time worsening those Effects Woven glass, carbon and amethyst polymeric composites Inter-laminar shear strength and abrasion composites samples. Wear properties are calculated using machine and testing machine in computer aided universal testing. Fracture of composites showed surface modifications for Group bonding. The mechanical properties of basalt are better than glass reinforced composites the result of the study confirms the applicability of basalt as a reinforcing agent in polymer composites. Hybrid Mechanical Processes Ultrasonic assisted laser/water jet machining processes are used to solve machining problems related to insulating ceramics such as ultrasonic assisted discharge machining, discharge milling, electro-chemical discharge machining and powder hybrid discharge machining and discharge diamond grinding. Processes can create complex patterns in spark discharges. An attempt has been made here to compare the convex stability with the above cast iron and polymer impregnated mechanical properties.

Ultrasonic Assisted Machining Overview: Accessing Feasibility and Overcoming Challenges for Milling Applications

Machinability, along with its associated facets, is a critical parameter that ultimately determines the cost of machining. Its optimization, however, is inherently limited by the current technology. To surmount such limitations, novel alternative machining technologies, such as Ultrasonic Assisted Machining (UAM), have emerged. The present study introduces UAM, the technology’s underlying principles, and general considerations for vibration application (harmonic waves, eigenfrequencies, resonance). The influence of ultrasonic application on the key parameters of conventional machining processes is studied and relevant research data are presented to support UAM benefits. Following, a comprehensive kinematic examination of vibration application to the milling process is conducted, accounting for various possible vibration modes. A detailed analysis of the requisite system components and their technical specifications is presented, followed by identifying common issues within such systems. Solutions for the identified limitations are proposed, acting as design guidelines for future technological advancements. Finally, based on the conducted research, conclusions are drawn and future directions for UAM are suggested.

Modeling of acoustic field dependent tensile property for metal materials

Acoustic softening is a physical phenomenon with important application significance. Whether for ultrasonic-assisted metal processing or metal materials serving in the acoustic field environment, quantitative characterization of the impact of the acoustic field on material strength have important technological and engineering values. However, there are few reports on theoretical characterization models that can reveal the evolution of metal material strength with acoustic field. Based on the Force-Heat Equivalence Energy Density Principle, considering the equivalent relationship between acoustic energy and elastic deformation energy, the acoustic field dependent yield strength model of metal materials without fitting parameters is developed; considering the equivalent relationship between acoustic energy and elastoplastic strain energy, the acoustic field dependent ultimate tensile strength model considering strain hardening behavior is developed, and only the fitting parameters introduced in the constitutive equation are included in this model. The predicted results of both models are in good agreement with the experimental results. The quantitative effects of strength coefficient and strain hardening index on ultimate tensile strength under different acoustic fields is analyzed. The critical acoustic energy density is proposed to describe the point of abrupt change of ultimate tensile strength. Further, quantitative comparison of the influence on strain hardening effect and yield strength in different acoustic fields is conducted to explain the rapid decline of ultimate tensile strength. Finally, based on the above conclusions, some useful suggestions for safe use of metal materials under acoustic fields and ultrasonic-assisted machining are put forward.

Tool–workpiece separation characteristic and surface generation in ultrasonic assisted milling

Ultrasonic assisted machining is an eco-friendly surface texture fabrication method with low machining cost, high-accuracy precision, and efficiency. This study analyzes the surface texture formation in feed direction ultrasonic vibration assisted milling (FUVAM) and elliptical ultrasonic vibration assisted milling (EUVAM). The trajectories of the single and adjacent tool tips in FUVAM are analyzed. Furthermore, the tool–workpiece separation mechanism in EUVAM is discussed. Moreover, a 3D surface topography model of EUVAM is applied to study the influences of machining parameters on the ultrasonic machining topography. The experiments of conventional milling (CM) and EUVAM are carried out and different types of surface textures are successfully fabricated on Ti-6Al-4V using EUVAM. The results of the response surface indicate that the surface roughness shows an increasing trend with higher spindle speed, but decreases with improved feed speed and cutting depth. Compared with CM, the chips generated in EUVAM have the characteristics of small width and low bending degree. This work is expected to provide some guidance for the selection of machining and vibration parameters during ultrasonic assisted milling.

Hybrid simultaneous laser- and ultrasonic-assisted machining of Ti-6Al-4V alloy

The machinability of Ti-6Al-4V alloy has been a constant challenge in the industry, although the material is widely used in the aerospace and medical industries due to its mechanical properties, particularly its strength-to-weight ratio. The current research presents a hybrid laser- and ultrasonic-assisted machining (LUAM) technique to improve the machinability of Ti-6Al-4V alloy in a turning process. This is compared with ultrasonic-assisted machining (UAM), laser-assisted machining (LAM), and convectional turning (CT). The results reveal that UAM and LAM can reduce the cutting forces and surface roughness (Ra) compared to the CT. However, these are achieved mainly at the lowest range of cutting speeds. The hybrid LUAM process demonstrates process improvement with wider range of cutting speeds and depths of cut, which is achieved due to the combined force reduction and thermal softening effect by the hybrid process.

Micro-machining and process optimization of ultrasonic assisted rotary µ-electrochemical discharge machining using TOPSIS method

Glass is a substance that is gaining numerous applications in many industries, such as biomedical, nuclear, etc., due to its hard, transparent, and inert nature. The main challenge is to machine glass due to its brittle nature. Electrochemical Discharge Machining (ECDM) is a novel process that is being used to machine such hard and electrically non-conductive materials. Over the years, researchers tried to incorporate many other processes into the ECDM process in order to increase the process capabilities. In this research, Ultrasonic assisted Rotary µ- ECDM process was used to drill holes in glass workpiece. In this process, the rotary motion was provided to the workpiece rather than to the tool to observe the results of this process. Experiments were performed using Taguchi’s L9 orthogonal array taking amplitude of vibrations, rotational speed, and tool feed rate as the input parameters and overcut and circularity as the response characteristics. In addition to this, multi-response process optimization was carried out using TOPSIS (Technique for Order Preference by Similarity to Ideal Solution) method to optimize the process.

Theoretical and experimental investigations of surface generation induced by ultrasonic assisted grinding

Ultrasonic assisted machining has been proved to have good performance for difficult to cut materials. Due to the complex contact between abrasives and workpiece, in-depth insight of material removal process of ultrasonic assisted grinding (UAG) is still challenging. In this investigation, ultrasonic surface texture is studied considering the effects of the grinding wheel topography, brittle-ductile transition behavior and ultrasonic vibration. A novel theoretical model of the grinding wheel topography is reconstructed considering the shape, size and random arrangement of abrasives. Based on this, surface topography prediction is conducted by the numerical method. The simulation analysis demonstrated that interference and self-interference of abrasive grits induced by ultrasonic vibration are the primary patterns, which explains the material removal mechanism in the UAG process. Furthermore, the grinding damages of the brittle and ductile grinding are parameterized based on different brittle and hard nature. Surface topography and surface roughness are predicted and analyzed by comparisons of simulation and experimental results. Those models proposed in this paper have potential for in-depth understanding the material removal process and optimizing the process parameters of the UAG process.

Experimental investigations into ultrasonic assisted magnetic abrasive flow machining process

ABSTRACT In the present study, an advanced variant of abrasive flow machining (AFM) is developed. Ultrasonic assistance and magnetic field assistance with rotating effect have been designed, fabricated, and simultaneously used to develop ultrasonic-assisted magnetic abrasive flow machining (UAMAFM) process. The ultrasonic horn and electromagnets were designed based on the simu modified by adding iron particles to make abrasive media respond effectively under the applied magnetic field. The effects of the external assistances, machine, and media-based parameters were explored on the amount of material removed (MR) and percentage improvement in the surface roughness (% ΔRa) for pure titanium (Grade II). The influence of input parameters was investigated using analysis of variance (ANOVA) by analyzing the process responses. Quadratic regression models showing the effect of input parameters and their interaction were developed for each response. The influence of individual parameters on process outcomes and response surface plots for significant interactions have also been discussed. The maximum MR of 26.62 mg and ΔRa of 54.42% were achieved at the optimized setting of process parameters. The predicted values of MR and % ΔRa from developed statistical models agreed with the experimental results.

Surface analysis in rotary ultrasonic-assisted milling of CFRP and titanium

Nowadays, tools with the ability to machine advanced materials is very much needed by industries. Therefore, design and manufacture of a rotary ultrasonic assisted machining tool is carried out in this study. In order to evaluate this tool, the milling process is conducted on the carbon fiber reinforced polymer composite and titanium materials where cutting forces, surface roughness, and fiber pull-out are selected as key factors for analysis. As a result, it is seen that the manufactured tool has a good performance in milling of advanced material. In particular, it is shown that fiber pull-out is eliminated when the ultrasonic tool is used in milling of CFRP. In addition, surface roughness is reduced about 15 %. Meanwhile, micro-texture can be generated on the surface of titanium workpiece by using harmonic movement of end mill.

Numerical study of the synergistic effect of cavitation and micro-abrasive particles

In ultrasonic-assisted machining, the synergistic effect of the cavitation effect and micro-abrasive particles plays a crucial role. Studies have focused on the investigation of the micro-abrasive particles, cavitation micro-jets, and cavitation shock waves either individually or in pairs. To investigate the synergy of shock waves and micro-jets generated by cavitation with micro-abrasive particles in ultrasonic-assisted machining, the continuous control equations of a cavitation bubble, shock wave, micro-jet, and micro-abrasive particle influenced by the dimensionless amount (R/R0), a particle size-velocity–pressure model of the micro-abrasive particle was established. The effects of ultrasonic frequency, sound pressure amplitude, and changes in particle size on micro-abrasive particle velocity and pressure were numerically simulated. At an ultrasonic frequency of 20 kHz and ultrasonic sound pressure of 0.1125 MPa, a smooth spherical SiO2 micro-abrasive particle (size = 5 µm) was obtained, with a maximum velocity of 190.3–209.4 m/s and pressure of 79.69–89.41 MPa. The results show that in the range of 5–50 μm, smaller particle sizes of the micro-abrasive particles led to greater velocity and pressure. The shock waves, micro-jets, and micro-abrasive particles were all positively affected by the dimensionless amount (R/R0) of cavitation bubble collapse, the larger the dimensionless quantity, the faster their velocity and the higher their pressure.