Ultrasonic Vibration-assisted Drilling Research Articles

Experimental study on ultrasonic vibration‐assisted drilling performance of carbon fiber polyetherketoneketone laminate

AbstractParts made from carbon fiber reinforced polyetherketoneketone (CF/PEKK) primarily use mechanical connections during assembly, where the quality of hole processing directly impacts the connection strength. However, defects like delamination, burrs, and fiber pull‐out frequently occur during drilling. While existing research focuses on optimizing conventional drilling (CD) and helical milling (HM), ultrasonic vibration‐assisted drilling (UVAD) shows superior performance in reducing thrust force and defects. This study experimentally evaluates the hole‐making performance of CF/PEKK using the UVAD method. It examines the effects of ultrasonic vibration on thrust force, drilling temperature, processing damage, chip morphology, and surface microstructure, and discusses the damage suppression mechanism. The results show that the UVAD method significantly reduces thrust force and drilling temperature compared to the CD method, with similar trends in delamination and burr damage. This study demonstrates that using the UVAD method for drilling CF/PEKK laminates effectively reduces thrust force, drilling temperature, and machining damage, thereby significantly improving processing quality. The material removal mechanism of UVAD was analyzed, offering substantial insights and practical guidance for the efficient drilling of CF/PEKK laminates.Highlights The drilling performance of CF/PEKK was studied. The drilling quality of UVAD and CD is compared by experiments. UVAD has a lower thrust force and drilling temperature. UVAD can reduce machining damage and improve machining quality.

Hole-exit defect formation during traditional and ultrasonic vibration-assisted drilling of C/SiC composites

Hole-exit defect formation during traditional and ultrasonic vibration-assisted drilling of C/SiC composites

Machinability of submillimeter holes in ceramic matrix composites by high-frequency ultrasonic vibration-assisted drilling

Ceramic matrix composites (CMCs) are highly promising for the hot components of the high thrust-to-weight ratio aeroengines because of their excellent high-temperature resistance and lightweight. Submillimeter cooling holes are necessary cooling structures for the extremely high working temperature of a CMCs hot component. However, CMCs are hard, brittle, and poorly conductive. Current machining is trapped in severe tool wear, poor hole quality, and low efficiency in machining such small size holes. This paper proposes high-frequency ultrasonic vibration-assisted drilling (UAD) to machine submillimeter holes of CMCs. It reveals that increasing vibration frequency during machining can enlarge the cutting edge's effective rake angle and reduce drilling forces. Correspondingly, the tool life and hole quality are improved. The machinability of high-frequency UAD is rationalized by both theoretical analysis and experiments. Results show that compared with low-frequency UAD and Conventional drilling (CD), the drilling force in high-frequency UAD is reduced by 47 % and 81 %, the tool life is more than three times, and the hole quality is improved by 12 % and 35 %, respectively. Therefore, the study paved the way for the machining of submillimeter cooling holes in CMCs, which is important to the industrial application of CMCs.

Understanding the mechanism of ultrasonic vibration-assisted drilling (UVAD) for micro-hole formation on silicon wafers using numerical and analytical techniques

Understanding the mechanism of ultrasonic vibration-assisted drilling (UVAD) for micro-hole formation on silicon wafers using numerical and analytical techniques

Enhancing engagement behavior in small-diameter deep drilling through ultrasonic vibration-assisted drilling and quantitative evaluation of hole dimensions

Enhancing engagement behavior in small-diameter deep drilling through ultrasonic vibration-assisted drilling and quantitative evaluation of hole dimensions

Mechanical drilling force model for longitudinal ultrasonic vibration-assisted drilling of unidirectional CFRP

Mechanical drilling force model for longitudinal ultrasonic vibration-assisted drilling of unidirectional CFRP

Experimental Research of High-Quality Drilling Based on Ultrasonic Vibration-Assisted Machining.

Micro-hole is widely used in various fields, and common machining methods of micro-hole in factories are drilling and electrical discharge machining (EDM), but because of low machining efficiency, these methods cannot meet requirements. Therefore, it is urgent to investigate a high efficient micro-hole machining technology to meet the demands of micro-hole machining in factory. Over past few decades, ultrasonic machining technology has developed rapidly and achieved good results in solving many critical machining problems in field of difficult-to-cut materials. Therefore, this paper builds an ultrasonic vibration-assisted drilling (UAD) experiments platform to combine micro-fine small hole drilling with ultrasonic machining technology for micro-hole multi-factor experimental research. Results show that UAD machining of micro-hole below diameter 0.5 mm is comparable to conventional drilling machining because of its high-frequency pulse intermittent cutting process, stable change in machining diameter, good stability of parameters such as shape tolerance roundness and cylindricity, small cutting force during cutting, small tool wear, and small surface roughness of inner wall of micro-hole. Compared with EDM, UAD has high efficiency and good stability of parameters such as diameter and roundness of shape tolerance. Comprehensive analysis of UAD can be used as an alternative technology solution for machining small holes in non-special requirements of metal materials in factory and has technical feasibility of stable batch production.

Towards understanding the cutting temperature in ultrasonic vibration-assisted drilling based on the dynamic contact characteristics between the cutting edge and workpiece

Compared with conventional drilling (CD), ultrasonic vibration-assisted drilling(UVAD) is experimentally proven a promising method to reduce the cutting temperature. But sometimes cutting temperature also becomes higher in UVAD than in CD. To further make clear the cutting temperature mechanisms in UVAD, this study aims to study the effect of tool’s ultrasonic vibration on the cutting heat generation and heat dissipation at a relatively micro level. Firstly, drilling experiments are designed to explore the variations of cutting heat under different ultrasonic vibrations. Then, to analyze the influence of ultrasonic vibration on the cutting heat theoretically, a kinematic model is developed to describe the dynamic contact between the cutting edge and workpiece in UVAD. Besides, a cutting heat analysis model based on the contact characteristics in UVAD is proposed to study and compare the variations of cutting heat generation. The effect of ultrasonic vibration on the cutting heat generation, heat dispassion, and the resultant cutting temperature under different machining in UVAD conditions are discussed. It is indicated from the theoretical analysis that more cutting heat tends to be produced due to the significantly increased sliding velocity on the cutting edge-workpiece interface when the ultrasonic vibration is applied. The analysis agrees with the experimental results that the cutting temperature in dry UVAD is higher than in dry CD. But on the other hand, ultrasonic vibration can also improve the lubrication and cooling effect under appropriate machining conditions, which is beneficial to the reduction in cutting temperature. The investigation shows the multifaceted influences of ultrasonic vibration on the cutting temperature in the drilling process in detail, which provides a reference for UVAD parameter optimization.

Investigation of force modeling in ultrasonic vibration-assisted drilling SiCf/SiC ceramic matrix composites

Due to their exceptional high-temperature and rust resilience, SiCf/SiC ceramic matrix composites have been regarded as potential high-temperature components. For application, to overcome issues resulting from the high hardness and brittleness, the ultrasonic vibration-assisted machining technique is primarily adopted in the machining of SiCf/SiC ceramic matrix composites. It is essential to develop a force model for a better understanding of the material removal and cutting processes by applying ultrasonic vibration. As a result, studies on force modeling during ultrasonic vibration-assisted drilling of SiCf/SiC ceramic matrix composites have been conducted in this study, taking into account the trajectory of the drilling tool, the tool-workpiece contact state, and the material removal mode. Based on the coefficient calibration experiment and least square method, the irregular coefficient of abrasive grains, the crack growth parameters of materials, and the mechanical parameters that are difficult to be measured were determined. After that, the drilling parameters and vibration parameters were merged to build the analytical force model, and the parameter influence rules on the force was also studied. The suggested drilling force model concurred well with tests under the highest relative error of 17.34 %, according to the findings of the confirmation experiments.

Investigation of transient machining in the cortical bone drilling process by conventional and axial vibration-assisted drilling methods.

A temperature exceeding the safety threshold and excessive drilling force occurring during bone drilling may lead to irreversible damage to bone tissue and postoperative complications. Previous studies have shown that vibration-assisted drilling methods could have lower temperatures and drilling forces than those of the conventional drilling method; we hypothesized that the main reason for these reductions stems from the differences in the transient machining processes between conventional and vibration-assisted drilling methods. To investigate these differences, comparative experiments and two-dimensional finite element models were performed and developed. The differences in the transient machining processes were verified by experimentation and clearly exhibited by the finite element models. Compared with the steady cutting process that produced continuous-spiral chips in the conventional drilling method, transient machining in the low-frequency vibration-assisted drilling method was a periodically dynamic cutting-separation process that produced uniform petal chips with specific settings of drilling and vibration parameters. Moreover, the transient machining process in the ultrasonic vibration-assisted drilling method was transformed into a combined action with high-speed impact and negative rake angle cutting processes; this action produced a large proportion of powdery chips. Therefore, it could be concluded that the superposed axial vibration significantly changed the transient machining process and radically changed the mechanical state and thermal environment; these changes were the main reason for the apparent differences in the drilling performance levels.

A novel model of vibration plowing effect for longitudinal ultrasonic vibration-assisted drilling

A novel model of the vibration plowing effect (VPE) is proposed for the first time to reveal hitherto not well-understood ultrasonic cutting mechanics and provide a theoretical basis for controlling the tool wear and machining quality of longitudinal ultrasonic vibration-assisted drilling (LUAD). The new model includes a condition model to judge the occurrence of the VPE on the whole flank of the drill and a volume model to calculate the vibration plowing force caused by the VPE of LUAD. For one thing, a condition model is proposed to distinguish the plowing effect of conventional machining and the VPE of LUAD by comprehensively analyzing the relationship between the clearance angle of the main cutting edge and the drill's path. For another, an analytical model of the vibration plowing volume (VPV) of LUAD is derived by integrating the plowing volume of the main cutting-edge element to improve the tool wear and machining quality. Finally, a series of comparative experiments between conventional drilling (CD) and LUAD is carried out. The validity of the proposed VPE's condition model and the VPV's analytical model is verified by the chip's micromorphology and the specific plowing force of the workpiece, respectively. The experimental results show that the fine and regular textures caused by the VPE can be observed on the chip surface and side micromorphology of LUAD. However, the coarse and irregular textures are displayed in CD, which shows that the proposed conditional model is adequate. Moreover, it is calculated by the deduced VPV's analytical model that when the ultrasonic amplitude is 3.8 and 8.3 μm, the average value of the specific plowing force of Al 6061-T6 determined in this paper is 1.399 × 105 N/mm3 and 1.274 × 105 N/mm3, respectively. These results agree with the value reported in other literature, that is 1.31 × 105 N/mm3, which proves the validity of the proposed model of the VPV. The validated analysis model is then used to conduct predictive analysis on the VPE and vibration plowing force of LUAD under a series of process parameters. The above research results clarify the mechanism of vibration plowing under ultrasonic action and provide a theoretical basis for controlling the tool wear and machining quality of LUAD.

Experimental research on new hole-making method assisted with asynchronous mixed frequency vibration in TiBw/TC4 composites

With the gradual promotion and the application of difficult-to-machine materials such as titanium matrix composites in the aerospace field, high-quality hole-making technology has become a major demand in aviation manufacturing. In order to improve the hole-making quality of TiBw/TC4 composites, asynchronous mixed frequency vibration-assisted hole-making (AMFVAHM) method is proposed. The process consists of two steps: ultrasonic vibration-assisted drilling (UVAD) base hole and low-frequency torsional vibration-assisted helical milling (LFTVAHM) target hole. Based on this process, the cutting trajectory modeling is established, and the hole-making experiment on TiBw/TC4 composites is conducted. The experimental data show that during the hole expansion stage, the maximum XY-plane average milling force decreases by 30.96% and the maximum axial average milling force decreases by 24.49% compared with conventional helical milling (HM) when the torsional vibration frequency and the milling frequency are the same in LFTVAHM. The hole-making experiment shows that AMFVAHM can reduce the chip size, tool wear, and some other defects such as entrance/exit burrs, scratches, and fractures of the hole wall. Comparing with HM and UVAD, the verticality of hole wall increases by 71.43% and 86.21%, the inlet damage decreases by 27.98% and 31.60%, the outlet damage decreases by 2.80% and 14.47%, the hole wall roughness (Ra) decreases by 36.29% and 63.43%, and the maximum white layer thickness decreases by 19.99% and 67.66%. Meanwhile, AMFVAHM process not only reduces the cutting force and cutting temperature but also improves the hole-making quality due to the fretting friction effect of LFTVAHM in secondary hole expansion, which meets the need for high-quality hole-making of difficult-to-machine materials in practical engineering applications.

Interaction between Micro-Amplitude Vibration and Thrust Force in Ultrasonic-Vibration-Assisted Drilling of Glass-Fiber-Reinforced Plastics

This research intends to investigate the effect and potential of the ultrasonic vibration of tools for drilling glass-fiber-reinforced plastics (GFRPs), especially with the aim of minimizing the thrust force. As an important parameter to characterize the vibration intensity, the vibration amplitude has a significant effect on the thrust force in the ultrasonic-vibration-assisted drilling (UVD) of GFRPs. It has been observed that the thrust force also influences the vibration amplitude, which may eventually result in a failure of the vibration. In this study, a method for the in-process measurement of the vibration amplitude was introduced to enable the investigation of the interaction between the thrust force and vibration amplitude in UVD. It was investigated how variations of the thrust force and vibration amplitude influence each other from holistic and individual perspectives. The critical condition was identified to ensure a sufficient ultrasonic vibration effect during drilling. Additionally, UVD experiments with different vibration amplitudes were carried out. The interaction between thrust force and vibration amplitude in UVD was revealed. It can be concluded that the combination of a moderate thrust force, low vibration amplitude reduction ratio, and high vibration amplitude increases the thrust force reduction ratio and secondly that an excessive thrust force undermines the effect of ultrasonic vibration. This provides an in-depth understanding of the interaction between vibration and thrust force in UVD, and helps to further improve the effect of ultrasonic vibration.

Defect suppression mechanism of ultrasonic vibration-assisted drilling carbon fiber/bismaleimide composite

Ultrasonic vibration-assisted drilling (UVAD) has recently been successfully applied in the drilling of carbon fiber reinforced polymer/plastic (CFRP) due to its high reliability. Multiple defects have been observed in the CFRP drilling process which negatively affects the quality of the hole. The carbon fiber/bismaleimide (BMI) composites is an advanced kind of CFRPs with greater strength and heat resistance, having been rapidly applied in lightweight and high temperature resistant structures in the aerospace field. To suppress the defect during the drilling of carbon fiber/BMI composites, it is necessary to comprehensively understand the defect formation and suppression mechanism at different positions. In this study, the defects formation in both conventional drilling (CD) and UVAD were observed and analyzed. The variation trend in the defect factor and thrust force with the spindle speed and feed rate were acquired. The results revealed that the UVAD could significantly enhance the hole’s quality with no delamination and burr. Meanwhile, the defect suppression mechanism and thrust force in UVAD were analyzed and verified, where the method of rod chip removal affected the exit defect formation. In summary, UVAD can be considered a promising and competitive technique for drilling carbon fiber/BMI composites.

Elucidation of Drilling Behavior on Workpiece Superimposed with Ultrasonic Vibration

This study quantitatively and theoretically clarifies the machining characteristics of the chisel engagement and the cutting-edge wear behavior in drilling in a workpiece superimposed with ultrasonic vibration. The machining phenomenon of drilling by this method considers being the same as drilling by ultrasonic vibration spindle from the viewpoint of the relative motion of the cutting edge and workpiece. However, the details have not been clarified yet. The chisel engagement behavior experiment at the initial stage of the drilling and cutting-edge wear experiment were carried out in this study. The chisel engagement behavior experiment revealed lower axial relative velocity results in a minor effect. In the cutting-edge life experiment, when the cutting fluid and the supply method were changed, the minimal oil with mist supply showed the same result as water-soluble with jet supply without breaking the drill. However, considerable wear was generated at the cutting edge in the initial drilling stage. When suitable ultrasonic vibration-assisted drilling was applied, initial wear decreased by 40% but could not be suppressed entirely. As a result of theoretical elucidation on this initial wear, it was proven that the flank face of the cutting edge contacted the workpiece when critical amplitude was exceeded. In the experiment to prove the validity of this theory, the initial wear occurred when the critical amplitude was exceeded. The cutting-edge wears increased in proportion to the working relief angle.

Tool wear prediction in ultrasonic vibration-assisted drilling of CFRP: A hybrid data-driven physics model-based framework

Accurate tool wear prediction is the key to evaluating tool usability and ensuring drilling quality. Recently, fusion prediction methods have attracted great attentions. However, no similar work has been reported yet in ultrasonic vibration-assisted drilling (UVAD) of carbon fiber reinforced polymer (CFRP). To fill this gap, a hybrid data-driven physics model-based framework for predicting tool wear is proposed. The physics model builds a mathematical description of the tool wear degradation process. The data-driven model predicts tool wear based on multilayer perceptron (MLP). The fusion method fuses the results of both models based on particle filter to obtain the final tool wear. Results indicate that the hybrid model performs better than any of individual models, with the lowest prediction errors.

Modeling Evolution of Cutting Force in Ultrasonically Assisted Drilling of Carbon Fiber Reinforced Plastics.

In this study, the effects of process parameters (feed rate, spindle speed, and ultrasonic power level) on the cutting force and delamination in the ultrasonic vibration-assisted drilling of carbon fiber-reinforced plastics (CFRPs) have been investigated. A series of drilling tests under various conditions defined by the design of experiment technique were conducted. The evolution of the cutting force during drilling cycles was measured and analyzed. Experimental analysis results based on the Taguchi method and analysis of variance show that the spindle speed is an influential factor affecting the cutting force with a contribution of 75.36%, and the feed rate significantly affects the delamination damage with a contribution of 46.57%. In addition, the cutting force was found to increase with drilling cycles at different rates, which depends on the process parameters used in drilling. The evolution behavior of cutting force was well fitted based on the process parameters by proposed regression models. Experimental validation indicates that the predicted forces show reasonable agreement with measured values under different conditions and reveal good prediction performances, with a root mean square error of 5.6 and a mean absolute percentage error of 5.8%. In drilling tests with variable cutting conditions, the evolution of the cutting forces predicted based on the selected parameters was successfully verified when compared with the measured results, with RMSE and MAPE values of 7.55 and 5.61%, respectively. As a conclusion, this predictive model provides an effective basis for selecting appropriate drilling parameters to suppress the cutting force on CFRP composites.

Study on exit damage characteristics of ultrasonic vibration assisted drilling of CFRP

In order to solve the disadvantage of tearing and burr damage in axial drilling of carbon fiber reinforced plastics (CFRP), the stiffness at the exit is increased by applying different drilling speed in ultrasonic vibration assisted drilling (UVAD) Firstly, compared with conventional drilling (CD), ultrasonic assisted vibration drilling can realize the separation of axial tool and tool/chip; Secondly, the cutting speed characteristics of ultrasonic assisted drilling at different speeds are analyzed, and the change of cutting speed characteristics of ultrasonic assisted drilling at low speed is obvious; Finally, the change trend of contact rate at different speeds is analyzed. The experimental results show that the stiffness of ultrasonic assisted vibration drilling is significant. Taking the speed of n = 100 r/min as an example, the stiffness of ultrasonic assisted drilling is about twice as high as that of rotary speed n = 2400 r/min, which is about 8% higher than that of ordinary drilling when n = 100 r/min; Hole exit quality of low-speed drilling: compared with CD, the tearing factor of ultrasonic assisted vibration drilling is lower. Therefore, this method provides a way to improve the hole quality of CFRP.

Numerical simulation and experimental study for ultrasonic vibration-assisted drilling of SiCp/AL6063.

Thrust force and metal chips are essential focuses in SiCp/AL6063 drilling operations. Compared with conventional drilling (CD), the ultrasonic vibration-assisted drilling (UVAD) has attractive advantages: for instance, short chips, small cutting forces, etc. However, the mechanism of UVAD is still inadequate, especially in the thrust force prediction model and numerical simulation. In this study, a mathematical prediction model considering the ultrasonic vibration of the drill is established to calculate the thrust force of UVAD. A 3D finite element model (FEM) for the thrust force and chip morphology analysis is subsequently researched based on ABAQUS software. Finally, experiments of CD and UVAD of SiCp/Al6063 are performed. The results show that when the feed rate reaches 151.6 mm/min, the thrust force of UVAD decreases to 66.1 N, and width of the chip decreases to 228 um. As a result, the errors of the mathematical prediction and 3D FEM model of UVAD are about 12.1 and 17.4% for the thrust force, and the errors of the CD and UVAD of SiCp/Al6063 are 3.5 and 11.4% for the chip width, respectively. Compared with the CD, UVAD could reduce the thrust force and improve chip evacuation effectively.

Experimental study on the effect of tool parameters on the vibrational characteristic of ultrasonic vibration-assisted drilling system

In ultrasonic vibration-assisted drilling (UVAD), the processing stability is strongly influenced by the ultrasonic vibration system's vibrational characteristics. The effect of tool parameters on UVAD's vibrational characteristic was experimentally studied and theoretically analyzed in this paper. Firstly, a measurement experiment was designed to assess the above effect in three various tools under different loads. The relationship between the ultrasonic power and amplitude was used to indirectly monitor the ultrasonic amplitude variation, which was corroborated by the UVAD test results. The ultrasonic amplitude and power were mainly controlled by the stiffness coefficient, while the damping coefficient effect could be ignored. Furthermore, the tool vibration frequency exhibited an increasing trend with the load value. Finally, the effects of the stiffness coefficient and damping coefficient on the vibrational characteristics were theoretically substantiated. The results of this study are considered instrumental in selecting tool and process parameters in ultrasonic machining.