Rotary Ultrasonic Drilling Research Articles

Research on Chip Removal Performance of Rotary Percussive Ultrasonic Drill for Planetary Rock Sampling

The objective of the kinematic model of rock chips is to examine the impact of the driving parameters of drilling tools on the effective chip removal speed, with a view to analyze the chip removal performance of rotary percussion ultrasonic drilling. The discrete element numerical simulation method, EDEM-2022 simulation software, was employed to establish a simulation model, match the simulation parameters, and conduct a simulation study of chip removal under the action of rotary percussion. This was performed to analyze the influence of the driving parameters on the chip conveying process. In order to ascertain the order of parameters affecting the degree of conveyance rate as well as the optimal driving parameters, orthogonal experiments were designed based on Taguchi’s experimental analysis method.

Deep learning-based temperature prediction during rotary ultrasonic bone drilling

Bone drilling is a common but critical medical procedure in orthopedic surgeries used to treat fractured bones. During this procedure, the temperature of the bone increases due to generation of frictional energy. Temperature control has been a major challenge in bone drilling since its foundation. If this temperature increases over 47°C for 1 min, then it can result in permanent bone damage. To control the temperature elevation this study proposes a deep learning-based robust predictive model which has been trained and tested on data from pig bones. Excessive in-house testing has been done on pig femur bones to gather data and verify the results. Rotary ultrasonic bone drilling was the machining process used for drilling. Four independent variables which were rotational speed, feed rate, abrasive grit size, and vibrational ultrasonic power were varied and the temperature for each set of values was recorded. Multiple deep learning models were made and were compared on different error metrics. It was found that convolutional neural network 1D gave the least error over other models. The error generated by deep learning models was less than mathematical and experimental models.

Processing parameter effect, formation mechanism and inhibition method of micro-hole exit defects in rotary ultrasonic pecking drilling of SiCf/SiC composites

High brittleness and anisotropy of ceramic matrix composites lead to great challenges for micro-hole machining. Micro-holes with large depth-to-diameter ratio (10:1) of SiCf/SiC composites were machined by rotary ultrasonic pecking drilling process. Based on the mechanical theory and structural characteristics of SiCf/SiC, a critical thrust force model was established. The effects of processing parameters on machining accuracy and machining quality of micro-hole exits were analyzed and parameters were optimized. The formation mechanism of exit defects includes interfacial debonding, fiber bending and matrix fracture. A method based on the surface morphology to inhibit exit defects by increasing the support stiffness of the material was proposed, under which the exit roundness all reached IT8 level and chipping factors decreased by 53 %–67 %, and only a small amount of chipping and micro-cracks was at the exit. The proactive control of micro-hole exit defects was realized, and a better machining quality was obtained.

Critical force of separation effect behaviors in rotary ultrasonic drilling for SiC

Critical force of separation effect behaviors in rotary ultrasonic drilling for SiC

Investigation on cutting temperature of CFRP in robotic rotary ultrasonic drilling with minimum quantity lubrication

Investigation on cutting temperature of CFRP in robotic rotary ultrasonic drilling with minimum quantity lubrication

Effects of fiber orientations on fracture mechanisms in rotary ultrasonic drilling of carbon fiber reinforced plastic laminates

The fracture mechanisms of the carbon fibers seriously depend on fiber orientations which significantly influence the surface quality of carbon fiber reinforced plastics (CFRPs). Rotary ultrasonic drilling (RUD), possessing some excellent characteristics including the superior sidewall quality and high cylindricity error, offers a possibility for the efficient drilling of the CFRP components. In contrast, the effects of fiber orientations on fiber fracture mechanisms are still not fully recognized in RUD of CFRP composites. Incorporated with kinematic characteristics of the abrasive, a novel theoretical model was developed to quantitatively describe the effective orientation of the fiber. Afterwards, the drilling experiments with and without ultrasonic were conducted under the same parameters. The surface topographies of the hole sidewalls at various orientations were comparatively characterized to explore the fiber fracture mechanisms. Subsequently, the influences of these mechanisms and the drilling parameters the surface qualities were also investigated. Moreover, the bending failure mechanisms of the carbon fibers were explored through theoretical analysis. As a result, another fiber fracture mechanism, bending failure, was identified with the smooth fracture and micro-fragmentation topographies at upwind and leeward parts of the fiber cross-section, respectively. Ultrasonic superimposition by means of the immense inertia force of the abrasive promoted the micro-fracture of the carbon fiber. The weaker sustainment from the back-up materials brought about the serious bending failure of fiber oriented at 135°, while the axial load component aggravated the tensile fracture of the carbon fiber with the effective orientation of 45°. The critical moment of the fiber bending failure was also established, by incorporating the beam theory and linear elastic fracture mechanics. The fundamental investigation provided a favorable foundation for further optimizing the parameters to improve the drilling quality and efficiency in formal RUD of CFRP composites.

Hole surface strengthening mechanism and riveting fatigue life of CFRP/aluminum stacks in robotic rotary ultrasonic drilling

Carbon fiber reinforced plastic (CFRP) and aluminum stacks are widely used in aviation industry due to light weight and high performance. Millions of rivet holes need to be drilled on body materials, and more than 80% of fatigue cracks occur at the connection holes, so the damage and residual stress of hole surface have crucial effect on the riveting fatigue life of CFRP/aluminum stacks and the flight performance. Recently, robotic rotary ultrasonic drilling (RRUD) technology is a promising method to machine the stacks. However, the hole surface strengthening mechanism in RRUD and the service performance of the riveting joint are not verified. Thus, in this paper, the hole surface strengthening mechanism of RRUD for CFRP/aluminum stacks is investigated, a theoretical residual stress model is established, and the fatigue life experiment of riveted joints is conducted. Firstly, analysis on residual stress in RRUD is carried out with consideration of strengthening force and cutting temperature. Residual stress model is established based on the calculation of elastic stress, plastic stress and stress release. Validation experiment results show that ultrasonic vibration changes residual stress from tensile stress to compressive stress. At the same time, comparative damage analysis of CFRP hole exit and hole surface in robotic conventional drilling (RCD) and RRUD is presented. Finally, fatigue strength experiments of riveted joints are conducted for performance verification. Experimental results indicate that fatigue life of single-hole riveted joints is increased by 68% with ultrasonic vibration, and four-hole riveted joint arranged according to aerospace design standards is increased by more than 86%.

Experimental Investigation and Statistical Modelling of Cutting Force and Torque During Rotary Ultrasonic Drilling of Polyetherimide Composite

Experimental Investigation and Statistical Modelling of Cutting Force and Torque During Rotary Ultrasonic Drilling of Polyetherimide Composite

Prediction of temperature elevation in rotary ultrasonic bone drilling using machine learning models: An in-vitro experimental study.

Bone drilling is frequently used during orthopaedic surgeries to treat the fractured part of the bone. A major concern for surgeons is the increase in temperature during real-time orthopaedic bone drilling. The temperature elevation at the bone-tool interface may cause permanent death of regenerative soft tissues and cause thermal osteonecrosis. A robust predictive machine-learning model is suggested in this in-vitro research for monitoring temperature rise during surgery. The objective of the present work is to introduce different machine learning algorithms for predicting temperature elevations in rotary ultrasonic bone drilling. Different machine-learning models were compared with the standard response surface methodology. The performance and accuracy of different predictive models were compared at different error metrics. It was witnessed that support vector machines performed the best for predicting the change in temperature in comparison to other predictive models. Moreover, the error metrics for statistical response surface methodology analysis were comparatively higher than the machine learning algorithms. By using machine learning models, it is possible to predict temperature rise during bone drilling.

Prediction of surface roughness and cutting force induced during rotary ultrasonic bone drilling via statistical and machine learning algorithms

The ultrasonic-assisted drilling of bone is gaining significant attention in orthopedic research and clinical applications due to the advantage of reducing thermal necrosis, cutting force, and microcracks. Mechanical and surface morphological damage due to cutting force and surface roughness rise during bone drilling may result in implant failure during osteosynthesis. It is difficult to predict and measure cutting force and surface irregularities during real-time medical orthopedic surgery. Therefore, the present work uses the application of different machine learning models to predict cutting force and surface roughness induced during bone drilling. The predictive results of machine learning models were compared with statistical analysis. During the study, rotary ultrasonic drilling is performed on the pig femur bone. The surface roughness and cutting forces are monitored using a surface roughness tester and a dynamometer respectively. Predictive models were developed by drilling parameters such as spindle rotational speed, abrasive girt size, and feed rate. Various machine learning algorithms such as ridge regression, lasso regression, support vector regression, multi-linear regression, and artificial neural networks were leveraged and compared at different error metrics to provide a robust predictive model. It was observed that ridge regression has the least error metrics compared to other machine learning algorithms during surface roughness prediction. Moreover, the most accurate model for predicting cutting force was support vector regression. The error metrics for statistical analysis were comparatively higher than the machine learning algorithms. Therefore, machine-learning algorithms are preferable for adequate prediction of surface roughness and cutting force induced during bone drilling compared to statistical analysis.

Influence of cutting force on temperature, microcracks and chip morphology during rotary ultrasonic bone drilling: An in-vitro study

Influence of cutting force on temperature, microcracks and chip morphology during rotary ultrasonic bone drilling: An in-vitro study

A mechanistic model for prediction of exit-chipping width in rotary ultrasonic drilling of sapphire

A mechanistic model for prediction of exit-chipping width in rotary ultrasonic drilling of sapphire

Experimental and Simulation Study on Breaking Rock under Coupled Static Loading and Ultrasonic Vibration

In recent years, ultrasonic vibration rock-breaking technology has aroused great interest in tunnel excavation and underground mineral. To apply this technology to practical engineering, it is necessary to compare the difference between cumulative damage and crack propagation of rock under static load and ultrahigh frequency alternating load. Numerical simulation and laboratory experimental methods were used in this paper to study the damage and fracture characteristics of rock under static loading and ultrasonic vibration. The variation laws of rock infrared temperature characteristics, porosity and compressive strength under different ultrasonic static loads were studied. The discrete element model of rock under ultrasonic vibration was established, and the numerical simulation was carried out by PFC2D software. We designed the ultrasonic rotary drilling device to verify the drilling effect. The process and mechanism of rock fragmentation under static load and ultrasonic vibration load were analyzed from the perspective of energy. Numerical simulation and experimental results showed that the combination of static load and ultrasonic vibration accelerates the failure speed of rock sample. The thermal infrared temperature characteristic test showed that the rock-breaking process under ultrasonic load and static load has three stages: stage I, elastic deformation and the temperature rises linearly; stage II, the development of microcrack and the temperature is further increased uniformly, and stage III, macrobreaking and rock chips falling off, and the temperature fluctuates sharply. There is a minimum threshold value for the promotion of static loading to break rock by ultrasonic vibration. Only when the static load is greater than 200 N, the crack propagation will occur in the rock sample. At this time, with the increase of static load, the crack propagation will further intensify, and the rock-breaking effect is more obvious. Under the same weight on bit (WOB), the penetration of rotary ultrasonic drilling can be increased by 13.93% ∼ 38.11% compared with conventional rotary drilling.

Experimental Investigations and Statistical Analysis in the Machining of Polyetherimide Composite Using Rotary Ultrasonic Drilling

Experimental Investigations and Statistical Analysis in the Machining of Polyetherimide Composite Using Rotary Ultrasonic Drilling

Thermal changes during drilling in human femur by rotary ultrasonic bone drilling machine: A histologic and ultrastructural study.

Undue heat production in surgical bone drilling leads to osteonecrosis and can be an important cause of failure of osteosynthesis, impaired healing, and loosening of implants following orthopedic surgery. The present work aims to minimize heat production below the critical temperature for thermal osteonecrosis (i.e., 47°C) and obviate thermal bone damage due to drilling. A total of 20 samples from the shaft of the human femur were obtained at autopsies and drilling was performed at room temperature by an operation theater (OT) compatible rotary ultrasonic bone drilling (RUBD) machine. K-type thermocouples were used to measure the temperature rise during drilling and the physical changes of the bone samples were observed by infrared gama camera. Light microscopic and transmission electron microscopic studies were performed to evaluate the bone cell damage. The maximum temperature recorded in RUBD (40.6 ± 1.3°C) was much below the critical temperature for thermal osteonecrosis (p < .05) at the rotational speed of 2000 rpm. Light microscopic and ultrastructural studies also revealed that there was no appreciable damage to the bone cells. Conventional bone drilling (CD) on the other hand recorded much higher temperature (66.6 ± 3.2°C), tissue burn and bone cell necrosis. Hence, RUBD machine has a potentiality for its use in orthopedic surgery and may provide better results.

Defect suppression mechanism and experimental study on longitudinal torsional coupled rotary ultrasonic assisted drilling of CFRPs

Longitudinal torsional coupled rotary ultrasonic assisted drilling (LTC-RUAD) technology is introduced to improve the surface roughness of the hole wall and solve the tear, burr and delamination of carbon fiber reinforced polymers (CFRPs) induced by large thrust force and torque during conventional drilling (CD) in this study. First, the defect suppression mechanism of CFRPs hole was proposed via the analysis of the types and forming mechanism of CFRPs hole defects using a tapered drill-reamer (TDR) in CD and the characteristics of LTC-RUAD. Then, the corresponding drilling experimental platform was built based on the novel designed LTC-RUAD vibration actuator, while drilling experiments involving T700S-12K/YP-H26 CFRPs specimens with different process parameters were performed by adopting the different ultrasonic vibration amplitude (UVA) in the longitudinal and torsional direction. The thrust force and torque, quality of the hole wall and holed defects obtained in both CD and LTC-RUAD were compared at the same process parameter. The experimental results show that compared with CD, the maximum average thrust force and torque can be reduced by approximately 30% and 40%, respectively. The surface roughness, defects at the exit of the drilled hole show a “concave” trend with the increase of UVA, and the burr factor, tear factor and delamination factor are reduced by 62.56%, 76.6%, 69.67% when the longitudinal UVA is approximately 7–9 μm, respectively. The forming mechanism of hole defects in CD and the defect suppression mechanism of CFRPs hole in LTC-RUAD are verified to be correct.

Developmental and Experimental Study of Rotary Ultrasonic drilling process

Abstract: The proper selection of machining conditions and machining parameter is an important aspect, before going to machine a brittle material by rotary ultrasonic drilling process Because these conditions will determine such important characteristics as; Material removal rate (MRR) and Surface roughness (SR). The purpose of this work is to determine the optimal values of machining parameters of rotary ultrasonic drilling process. The work has been based on the effect of three design factors: Tool feed rate, vibration frequency and grain size of abrasive particle on such characteristic like material removal rate (MRR). This work has been done by means of the technique of design of experiment (DOE), which provides us to perform the above-mentioned analysis with small number of experiments. In this work, a L9 orthogonal array is used to design the experiment. The adequate selection of machining parameters is very important in manufacturing system, because these parameters determine the surface quality and dimensional accuracy of the manufactured part. The optimal setting of the parameters are determined through experiments planned, conducted and analyzed using the Taguchi method. Keywords: RUSM, Material removal rate, Drilling, Taguchi method

Investigation into rotary mode ultrasonic drilling of bioceramic: an experimental study with PSO-TLBO based evolutionary optimization

PurposeThe purpose of this paper is to investigate experimentally the effect of several input process factors, namely, feed rate, spindle speed, ultrasonic power and coolant pressure, on hole quality measures (penetration rate [PR] and chipping diameter [CD]) in rotary mode ultrasonic drilling of macor bioceramic material.Design/methodology/approachThe main experiments were planned using the response surface methodology (RSM). Scanning electron microscopy was also used to examine and study the microstructure of machined samples. This study revealed the existence of dominant brittle fracture and little plastic flow that resulted in a material loss from the base work surface. Experiment findings have shown the dependability and adequacy of the proposed mathematical model.FindingsThe percentage of brittle mode deformation rises as the penetration depth of abrasives increases (at increasing levels of feed rate). This was due to the fact that at greater depths of indentation, material loss begins in the form of bigger chunks and develops inter-granular fractures. These stated causes have provided an additional advantage to increasing the CD over the machined rod of bioceramic. The desirability method was also used to optimize multi-response measured responses (PR and CD). The mathematical model created using the RSM method will be very useful in industrial revelation. Furthermore, the investigated answers’ particle swarm optimization (PSO) and teacher-learner-based optimization (TLBO) make the parametric analysis more relevant and productive for real-life industrial practices.Originality/valueMacor bioceramic has been widely recognized as one of the most highly demanded innovative dental ceramics, receiving expanded industry approval because of its outstanding and superior characteristics. However, effective and efficient processing remains a problem. Among the available contemporary machining methods introduced for processing typical and advanced materials, rotary mode ultrasonic machining has been identified as one of the best suitable candidates for precise processing of macor bioceramics, as this process produces thermal damage-free profiles, as well as high accuracy and an increased material removal rate. The optimized combined setting obtained using PSO is feed rate = 0.16 mm/s, spindle speed = 4,500 rpm, ultrasonic power = 60% and coolant pressure = 280 kPa with the value of fitness function is 0.0508. The optimized combined setting obtained using TLBO is feed rate = 0.06 mm/s, spindle speed = 2,500 rpm, ultrasonic power = 60% and coolant pressure = 280 kPa with the value of fitness function is 0.1703.

Experimental study on robotic rotary ultrasonic drilling of CFRP/aluminum stacks

In order to solve the problem of significant chatter vibration and large drilling force when drilling stacked materials by industrial robot, a new method is proposed. It combines rotary ultrasonic drilling with robotic machining to achieve high efficiency and low damage for CFRP/aluminum stacks. In this paper, comparative experiments of robotic rotary ultrasonic drilling (RRUD) and robotic conventional drilling (RCD) on drilling CFRP/aluminum stacks are carried out in a KUKA six-axis industrial robot. Drilling force, drilling chatter and aperture deviation are measured and analyzed. The experimental results illustrate that high-frequency vibration can not only reduce drilling force effectively, but also have a good inhibitory effect on robotic drilling flutter. In addition, the improvement effect of ultrasonic vibration on aperture deviation for CFRP is more significant than that for aluminium.

High-frequency vibration effects on the hole integrity in rotary ultrasonic drilling of carbon fiber-reinforced plastic composites

This investigation represented a fundamental research on the potential effects of the high-frequency vibration on the hole integrity involved in rotary ultrasonic drilling (RUD) of carbon fiber-reinforced plastic (CFRP) composites. It was found the increased thickness of the CFRP plate shrunk the flowing velocity of the coolant, which brought about the residual chippings gradually accumulated at the radial clearance between the tool and the material. Furthermore, the chipping accumulation at the clearance seriously increased the friction effects and the resultant thermal load, thus leading to the chipping adhesions on the tool surface and machined cylinder jamming at the central hole of the tool. The mutual constrain between two vertical bundles brought the delamination around the holes generated in conventional drilling (CD) process to a termination at the bundle interface. The ultrasonic superimposition reduced the thrust force of the diamond tool which provided inadequate energy for the delaminated fibers reaching the bundle interface. Moreover, hole position on the two-dimensional orthogonal fabrics significantly influenced the propagation of the delaminated fibers, which weakened the effects of the drilling parameters on the delamination dimensions. Additionally, superimposing an ultrasonic vibration prolonged the abrasive trajectories and increased their overlapping probability, and the induced smoothing effects resulted in the obvious reduction of the surface roughness. The tensile stress exerted on the margin of the machined surface was responsible for the initiation of the CD delamination. After the delaminated fibers reached the bundle interface, the further extrusion of tool brought about the margin suffered from the shear stress, thus leading to the collapse of the machined cylinder. Considering the thrust force of the diamond tool and the undrilled thickness of the machined surface, the critical conditions of the delamination initiation were developed, which revealing that the decreasing of the thrust force caused the reduction of the critical undrilled thickness.