Rotary Ultrasonic Machining Research Articles

Investigation of Process Responses in Rotary Ultrasonic Machining of Al/SiC Composite Through Designed Experiments

Abstract In production-based trades, Al/SiC composite is vastly required owing to its outstanding possessions. Though, the problems in its machining confine the application and attractiveness of this material. Present study focused on different experimental conditions (spindle speed, rate of feed, and ultrasonic power) on responses of interest like surface roughness (SR), material removal rate (MRR), and chipping thickness in rotary ultrasonic machining of Al/SiC composite. Microstructure scrutiny of the processed samples has been employed to illustrate the chipping size and thickness over the end-edge through SEM process. The experimental results showed that rate of feed was the most significant variable for MRR and SR.

Parametric Optimization of Rotary Ultrasonic Drilling using Grey Relational Analysis

Abstract The present article targets to investigate the effects of machining variables on the performance of rotary ultrasonic machining of BK-7 glass and concurrent optimization of output measures through Grey relational analysis. Taguchi approach has been employed for framing the experimental matrix. Machining variables - Feed rate, tool rotational speed and ultrasonic power - have been picked after pilot experimentation to investigate their influence on output measures namely - material removal rate and surface roughness. Thereafter, experimental data was tested using “analysis of variance” for recognizing the significant factors and their relative percentage contribution on the output measures. Then Taguchi approach was integrated with Grey relational analysis for individual as well as concurrent optimization of performance attributes. Feed was found to influence the MRR and SR on a large scale followed by tool rotation speed that has a substantial impact on SR. All the predicted optimal settings were found to be well tuned with experimental results

Delamination formation and suppression during rotary ultrasonic elliptical machining of CFRP

As a superior hole manufacturing process, rotary ultrasonic elliptical machining (RUEM) has been successfully employed for drilling carbon fiber reinforced plastics (CFRPs) recently. The delamination of CFRP during drilling is generally considered as the most undesirable form of damage and the most challenging failure mode. In order to reduce the delamination in this novel process, it is important to understand the formation and suppression mechanisms during RUEM of CFRP. In this study, the delamination formation in both core drilling (CD) and RUEM was observed and analyzed. The variation trend of delamination factor with feed speed as well as cutting speed was obtained. The experimental results show that, compared with CD, RUEM method can effectively reduce hole exit delamination by 5.4%–19.3% between 1/2 plies and 0.7%–8.4% between 2/3 plies at the feed rates from 50 to 100 μm/rev. Moreover, the delamination suppression mechanism in RUEM was fully analyzed and verified. In a word, in the industry practice, RUEM can be considered as a competitive and promising technique to drill CFRP compared to other delamination suppression techniques.

Effects of tool vibration on surface integrity in rotary ultrasonic elliptical end milling of Ti–6Al–4V

Titanium alloys have been applied in aerospace, biomedical, and chemical industries due to their superior mechanical properties. As a novel machining method, rotary ultrasonic elliptical machining has been successfully introduced into high-speed side milling of Ti–6Al–4V recently. However, the surface integrity in end milling of titanium alloy using this method is still unclear. In this study, a comprehensive experiment on surface integrity in rotary ultrasonic elliptical end milling of Ti–6Al–4V was conducted at various vibration amplitudes and cutting speeds. Results show that regular substantial micro-vibration textures in the form of separated ridges are obtained on the machined surfaces in RUEEM. Surface roughness values rise from Ra 0.160 μm to Ra 0.758 μm with the increasing cutting speed and vibration amplitude. Both the thickness of subsurface deformed layer and the value of surface micro-hardness increase with rising amplitude at low cutting speeds, while the hardening effect gradually weakens as the cutting speed increases to 160 m/min. Besides, the values of surface compressive residual stress gradually decrease with vibration amplitudes at low cutting speeds, while opposite trends show at the high cutting speed (160 m/min). This study can provide a new method for the effective control of the surface integrity for high-speed end milling of titanium alloy.

Rotary ultrasonic machining of SiCp/Al composites: An experimental study on cutting force and machinability

To improve the processing quality and reduce the cost of SiCp/Al composites has become a key problem for its application. Rotary ultrasonic machining is highly suitable for machining of SiCp/Al composites with a medium or high volume fraction of reinforced phase, and the processing quality and efficiency could be improved greatly. In this article, the rotary ultrasonic machining experiments were performed for the SiCp/Al composites reinforced with 45% volume fraction, and the effects of processing parameters on the cutting force of face and flank machining were studied. The cutting force values reduce significantly, and the grinding force ratios Fn/ Ft of face and flank machining are 2.843 and 1.336, respectively, which indicate that better machinability can be achieved for SiCp/Al composites using rotary ultrasonic machining.

Advances in rotary ultrasonic machining system for hard and brittle materials

Rotary ultrasonic machining has been widely used for machining of hard and brittle materials due to the advantages of low cutting force, high machining accuracy, and high surface integrity. Focusing on the development of specialized rotary ultrasonic machining systems, this article summarizes the advances in the functional components and key technologies of rotary ultrasonic machining systems for hard and brittle materials, including the ultrasonic generator, power transfer structure, transducer, ultrasonic horn, and cutting tool. Developments on the automatic frequency tracking method, the establishment of an electrical compensation model for power transfer, the energy conversion characteristics of piezoelectric materials and giant magnetostrictive materials, and the design methods for the ultrasonic horn and cutting tool were elaborated. The principle of magnetostrictive energy conversion, output amplitude characteristics of a giant magnetostrictive transducer, and high-power giant magnetostrictive rotary ultrasonic machining systems were also presented. Future research and developments of rotary ultrasonic machining systems regarding the ultrasonic generator, amplitude stability, energy conversion efficiency, vibration mode, and system integration were finally discussed.

Experimental investigations and statistical modeling of cutting force and torque in rotary ultrasonic bone drilling of human cadaver bone.

Cutting force and torque are important factors in the success of the bone drilling process. In the recent past, many attempts have been made to reduce the cutting force and torque in the bone drilling process. In this work, drilling on human cadaver bones has been performed using rotary ultrasonic bone drilling process to investigate the effect of drilling parameters on cutting force and torque. The experimental work was carried on a recently developed rotary ultrasonic bone drilling machine for surgical operations. The experimental work was performed in two phases. The first phase includes a comparative study between rotary ultrasonic bone drilling and conventional surgical bone drilling, to study the influence of various drilling parameters (rotational speed, drill diameter, and drilling tool feed rate) on the cutting force and torque. The results revealed that the cutting force and torque produced during drilling operations in rotary ultrasonic bone drilling were lesser (30%-40%) than conventional surgical bone drilling. In the second phase, response surface methodology was used to perform the statistical modeling of cutting force and torque in rotary ultrasonic bone drilling process. Analysis of variance was performed at a confidence interval of 95% to analyze the significant contribution (p < 0.05) of process parameters (drilling speed, feed rate, drill diameter, and abrasive particle size) on the responses (cutting force and torque). The confirmatory experiments were performed to validate the developed statistical models. It was found that both cutting force and torque decrease with increase in drilling speed and increases with the increasing drill diameter, feed rate, and abrasive particle size.

Effect of parameters and optimization of Rotary Ultrasonic Drilling through desirability and PSO

In this paper, an attempt has been made to drill 'BK-7' using rotary ultrasonic machining (RUM). The effects of machining parameters namely feed, spindle speed and ultrasonic power were investigated on material removal rate (MRR) and chipping thickness (CT). Response surface methodology (RSM) was utilised for developing regression equations for output responses. The response observations were tested through analysis of variance (ANOVA) for recognising the significant input variables. The selected responses were found to be highly influenced by feed and exhibited opposite variation with increase in feed. Furthermore, the study also targets to improve the machining efficacy by optimising the machining parameters using desirability and particle swarm optimisation (PSO) approaches. Both the approaches were found to be equally viable. However, PSO exhibited an ease in obtaining the optimised solution with lesser time to cope up with industrial needs. [Submitted 15 April 2018; Accepted 23 December 2018]

Borealis and ADNOC sign Memorandum of Understanding to explore strategic opportunities in the polyolefin industry

Detail discussion on various advanced machining processes utilizing mechanical energy namely, Ultrasonic machining (USM), Abrasive jet machining (AJM), Water jet machining (WJM), and Ion beam machining (IBM) have been included. The fundamentals, material removal mechanism and related modeling, setup details, effects of process parameters on different outcomes, advantages and limitations of these processes have been presented in this chapter. The stationary ultrasonic machining (USM) as well as rotary ultrasonic machining (RUM) processes are applied for machining of hard and brittle materials like glass and ceramics with high accuracy those are highlighted. Rotary ultrasonic machining (RUM) is the recent development in USM which has higher machining rate and accuracy as rotary and ultrasonically vibratory abrasive bonded tool is used for machining. The abrasive jet machining (AJM) is applied for drilling, cutting, grooving and finishing operations on difficult to machine materials like glass and ceramics. In depth discussions on abrasive jet machining process have also been included. Water Jet Machining (WJM) process has been discussed in details which is utilized for cutting and drilling operation of various hazardous materials such as coal, rocks, asbestos, bones etc. for different field of applications such as mining, construction, mechanical and biomedical engineering. Ion beam machining (IBM) is one of the most advanced machining processes which utilize focused beam of ions to bombard and eject atoms from the workpiece surface by elastic collisions to crate desired shapes. IBM becomes attractive for fabrication of intricate structures especially in micro and nano range with high resolution. Recent advancements considering the latest research findings of all the advanced machining processes have also been highlighted.

The Influence of Loading Force on Ultrasonic Drilling Garnet Ferrite

In order to achieve high precision microholes of garnet ferrite, the rotary ultrasonic assisted machining and the tool load matching system were employed. An ultrasonic precise microholes technology experiment platform was built to machine garnet ferrite materials. A series of drilling experiments to machine garnet ferrite were presented in this paper, which were used to explore the influence of cutting force on tool wear. And the holes’ exit aperture and wall surface roughness were applied to be evaluation parameters to explore the effect of loading force on machining quality. As a result, tool wear is aggravates as cutting force increases. And loading force shows different influence tendency on exit aperture size precision and wall surface roughness, the selection of proper loading force does good to control exit aperture size and hole wall surface roughness effictively.

Parametric optimization in Rotary Ultrasonic Drilling of BK7 through RSM based PSO

This paper aims to establish the rotary ultrasonic machining as a pragmatic solution to tackle the machinability issues with brittle materials. In the present article, drilling variant of rotary ultrasonic has been used to machine the optical glass BK7 owing to its numerous applications in manufacturing sector. Experimental matrix has been designed by utilizing the response surface methodology after scrutinizing the machining variables (feed rate, spindle speed and ultrasonic power) through single variable at a time approach. Material removal rate (MRR) and surface roughness (SR) have been chosen as responses for assessing drilling performance. Thereafter ANOVA analysis was done at 95 % confidence level for figuring out the significant model terms (linear, interaction and square) that affect the responses of interest. Feed rate was found to have profound impact over the machining performance. Thereafter, desirability approach and particle swarm optimization (PSO) were used for yielding the right combination of input factors for concurrent optimization of responses. In comparison to desirability, particle swarm optimization (PSO) provided the instant optimal solutions to meet the industrial requirements. Further, confirmation experiments validated the accuracy of desirability and PSO to predict the optimal solution with little errors.

Evaluation and optimization of machining performance for rotary ultrasonic machining of Al/SiC composite material

In manufacturing industries, Al/SiC composite material is highly demanded due to its excellent properties. However, the difficulties in its machining restrict the application and competitiveness of this material. This investigation is aimed at studying the impact of different experimental conditions (feed rate, spindle speed, and ultrasonic power) on responses of interest (material removal rate, surface roughness, and chipping thickness) in rotary ultrasonic machining of Al/SiC composite material. The experiments have been planned by using full factorial design. Analysis of variance (ANOVA) is also employed to identify the significant factors and the optimized process settings for the different responses. The experimental results showed that feed rate was the most significant factor for material removal rate and surface roughness. However, all the factors were found to be insignificant for chipping thickness. From the surface topography analysis of the machined surface, no surface damage in the form of micro-cracks etc. was visible.

Mechanistic prediction for cutting force in rotary ultrasonic machining of BK7 glass based on probability statistics

Material removal in rotary ultrasonic machining (RUM) of hard-brittle material is an abnormal complicated process, which involves the combination effects of the numerous abrasive grains with the random distributions in the dimensions and penetration depths. These stochastic characteristics result in the evident differences in the extrusion loading between the material and each individual grain, and their aggregate effects serve to significantly affect the cutting force of the diamond tool. However, few mechanistic prediction models of the cutting force have incorporated in the random distribution features of the abrasive grains, restricting the current optimization methods for the reduction of the cutting force during the formal RUM process. Giving consideration to the abrasive processing kinematics and their distribution features on the tool end-face, the number of the effective grains together with their penetration depths was calculated utilizing the probability statistics. Subsequently, the novel theoretical model of the cutting force was established by incorporating the gaussian distribution characteristics of the grain size and their penetration depths. Afterward, the confirmatory experiments were performed for the validation of the proposed cutting force model, revealing that the predicted results were accordant well with the experimental measurements. Furthermore, it was found that the number of the active abrasive grains accounted for 2.972% of the total number on the tool end-face at the specific processing parameters. Additionally, the mechanistic predictions of the developed model represented that the cutting force depicting an irregular decreasing trend with the grain dimension increasing, which was attributed to the coupling effects between the grain size and their number.

An amplitude prediction model for a giant magnetostrictive ultrasonic transducer

Rotary ultrasonic machining (RUM) is widely used in the processing of brittle and hard materials. The application of giant magnetostrictive ultrasonic transducers (GMUT) with effective vibration performance is an increasingly popular field of research within RUM. A generalized amplitude prediction model for GMUT is obtained in this paper by first providing an equivalent kinetics model of the GMUT. Considering the influence on interaction force between Terfenol-D and the external mechanical mechanism, the prestress mechanism of Terfenol-D and the joint face of the horn are determined as equivalent to two spring-damping systems in series, and a general GMUT vibration equation is established. The equivalent stiffness of the prestress mechanism is then identified, and the mechanical quality factor of the vibration system is calculated by impedance analysis. The influence of the joint face of the horn and the prestress mechanism on the amplitude is then studied by nonlinear least square fitting. Based on a magnetostriction and magnetization model, an odd power amplitude prediction model with mechanical quality factor, excitation current amplitude, and excitation frequency is proposed. The experimental results demonstrate that the proposed model can effectively predict the output amplitude of the GMUT with different mechanical quality factors for different excitation signals, providing a method for system design and optimization of the GMUT.

An output amplitude model of a giant magnetostrictive rotary ultrasonic machining system considering load effect

The load effect is a key factor influencing the amplitude stability of an ultrasonic machining system during processing. To explore the influence of the load, a giant magnetostrictive rotary ultrasonic machining system was designed and fabricated by utilizing giant magnetostrictive materials. Based on the single-degree-of-freedom vibration characteristics of the ultrasonic oscillator, an output amplitude model that considers the load effect was proposed for the system. In order to validate the model, a rotary ultrasonic drilling experiment of quartz glass was performed. A critical cutting ability parameter on the basis of cutting depth for a single abrasive grain was put forward to differentiate between acceptable and unacceptable ultrasonic performance. The actual ultrasonic amplitude in the machining process obtained from the model was explored. The experimental results indicate that the load has a significant effect on the resonant frequency, resulting in a decrease in the actual ultrasonic amplitude. Moreover, the amplitude characteristics can be considerably improved by tuning. The process parameters of the giant magnetostrictive rotary ultrasonic machining system can be optimized by using the proposed model. The results of this study provide reference data for research and development of rotary ultrasonic machining equipment.

Rotary ultrasonic machining of carbon fiber–reinforced plastic composites: effects of ultrasonic frequency

Rotary ultrasonic machining (RUM) is effective and efficient in cutting carbon fiber–reinforced plastic (CFRP) composites. With ultrasonic vibration assistance, both machining efficiency and machining effectiveness can be improved. Ultrasonic vibration has two major variables (including ultrasonic amplitude and ultrasonic frequency), which play important roles in RUM processes. Other intermediate variables, such as ultrasonic power and indentation depth, are directly related to these two variables. Effects of ultrasonic vibration amplitude have been extensively investigated in RUM hole making and surface machining processes. However, the effects of ultrasonic frequency in RUM have not been reported. The effects of ultrasonic frequency under different combinations of tool rotation speed, feed rate, and depth of cut on output variables, including cutting forces, surface roughness, and machined surface characteristics, are investigated, for the first time, in this study. The critical frequency is analyzed for the RUM process. Three different levels of ultrasonic frequencies are generated and applied to the RUM process. The kinematic motions of abrasive grains in RUM with different frequencies are analyzed and discussed. The results show that RUM with higher frequency of ultrasonic vibration is a more effective machining process, leading to cutting force reduction and the machined surface quality improvement.

Rotary ultrasonic machining: effects of tool natural frequency on ultrasonic vibration amplitude

Rotary ultrasonic machining (RUM) is a hybrid machining process that combines the material removal mechanisms of grinding and ultrasonic machining. RUM has been applied to hole-making for a wide range of materials. It is known that ultrasonic vibration amplitude has significant effects on cutting force, torque, and surface finish in RUM. One experimental observation that has been reported in the literature multiple times states that different tools show different vibration amplitudes on the same ultrasonic power level. However, no analyses can be found in the literature to explain this observation. The existence of this knowledge gap makes it difficult to explain some experimentally obtained trends or to conduct more realistic physics-based modeling work. The objectives of this research are to understand the effects of tool natural frequency on ultrasonic vibration amplitude in RUM, to provide an explanation to the observation and verification of measurement methods, and also to guide tool design and selection in RUM. Ultrasonic vibration amplitudes of tools are measured by three methods and compared. It is found that tool natural frequency significantly affects ultrasonic vibration amplitude. The tool with its natural frequency closest to that of the ultrasonic power supply (20 kHz) generates the highest ultrasonic vibration amplitude on every ultrasonic power level tested.

A cutting force model based on kinematic analysis in longitudinal and torsional ultrasonic vibration drilling

The longitudinal and torsional ultrasonic machining (LTUM) is an emerging ultrasonic vibration machining method, which is an innovation method based on rotary ultrasonic machining (RUM). Compared with one-dimensional longitudinal ultrasonic machining (LUM), LTUM has better performances and promising applicability. In this research, the machining mechanism and a drilling force model in longitudinal and torsional ultrasonic vibration drilling is proposed based on kinematic analysis. Besides, the kinematic model and track model in LTUM are established. In addition, the dynamic characteristics and cutting characteristics of the abrasive grains in LTUM are analyzed. Meanwhile, the material removal model for fracture material based on the indentation fracture theory in LTUM is considered. Based on the kinematic analysis and material removal model in the longitudinal and torsional ultrasonic vibration drilling, the cutting force model is developed and the relationship of cutting force with processing parameters and material parameters is investigated. Eventually, the verification experiment is carried out on carbon fiber-reinforced polymer (CFRP)-T700. The experimental result shows that the developed cutting force model predicts the cutting force accurately and the deviation is less than 10% in CFRP drilling. Additionally, the drilling experiment of LTUM, LUM, and conventional drilling (CD) are carried out respectively, and drilling force in the three processes are compared. The comparative analysis results show LTUM is superior to LUM and CD with lower drilling force and better performance.

Machinability study of biolox forte ceramic by milling microchannels using rotary ultrasonic machining

Rotary ultrasonic machining (RUM) shows capabilities in several manufacturing applications specifically for fabrication of high-quality features on ceramic materials. However, surface fracturing and edge chipping are the persistent issues during the RUM of ceramic materials. This research reports an experimental investigation to analyze the machinability of the biolox forte ceramic by milling microchannels using RUM. Machinability is studied by analyzing the performance measures such as the surface roughness, surface morphology, edge chipping and tool wear. The effects of the five major RUM input parameters including spindle speed, feed rate, depth of cut, vibration amplitude, and vibration frequency are taken into consideration on the machinability of the biolox forte material. An attempt has been made to characterize the material removal behaviour within the microchannels. The results reveal more brittle fracturing and deep pits on the channel bed as compared to the channel sidewall due to the difference in the cutting action of the RUM tool. Furthermore, it is observed that the channel sidewalls always show a coarse machined region near the top edge and a relatively smooth machined region up to the channel bed. The energy dispersive spectroscopy (EDS) analysis reveals that no change in the composition of the biolox forte occurs and no traces of tool material are observed in the microchannels. The scanning electron microscopy (SEM) analysis of the tool shows that the plastics deformation, attritious wear, and the tool edge rounding and chipping are the primary tool wear mechanisms. By selecting the appropriate RUM parameters, microchannels with good surface finish (Ra =0.21 μm), smoothed morphology and minimal edge chipping (16.3 μm) can be milled on the biolox forte material.

Parameter Optimization of Rotary Ultrasonic Machining on Quartz Glass Using Response Surface Methodology (RSM)

In the current research, rotary ultrasonic machining was used to drill holes in quartz material. The effect of different RUM parameters namely tool feed rate, tool rotational speed and ultrasonic power on material removal rate and surface roughness has been studied experimentally. The response surface methodology with central composite design has been used to design the experiments. From the desirability approach, the optimum setting of the rotary ultrasonic machining parameters was found to be the tool rotational speed of 4968 rpm, feed rate of 0.55 mm/min, and ultrasonic power of 80% for achieving the maximum MRR of 0.2135 mm3/s and minimum SR of 0.3685 μm. Microstructure analysis of the machined surface was performed by using scanning electron microscopy in order to study the mechanisms of material removal under the different settings of RUM parameters. It was observed that at very low feed (0.08 mm/min) and high rpm (5681) the material is predominantly removed by plastic deformation whereas at high feed (0.92 mm/min) and low rpm (2318) the material is removed by brittle fracture.