Grinding Device Research Articles

Feasibility of Novel Grinding Device With Forward-Looking Intravascular Ultrasound Transducer in Coronary Rotational Atherectomy

Feasibility of Novel Grinding Device With Forward-Looking Intravascular Ultrasound Transducer in Coronary Rotational Atherectomy

Research on an Accurate Simulation Modeling and Charge Motion Quantitative Evaluation Method for Ball Mill in Confined Space

A ball mill is a type of complex grinding device. Having knowledge of its charge-load behavior is key to determining the operating conditions that provide the optimum mill throughput. An elaborate description of the charge movement inside the ball mill is essential. This study focuses on a laboratory-scale ball mill and utilizes a discrete element simulation model to investigate the impact of mill speed and ball filling on charge-load behavior. Initially, the EDEM 2.7 (Engineering Discrete Element Method) software contact parameters were calibrated through heap-angle experiments. Subsequently, four charge-motion characteristic parameters were defined and analyzed based on Powell’s theory to understand the variations in charge-load behavior. This research proposes a theoretical calculation model for predicting power in a ball mill, highlighting the significance of the CoC (Center of Circulation) and CoM (Center of Mass) in reflecting changes in charge-load behavior. The theoretical model for mill-power prediction is effective and aligns well with the EDEM simulation and experimental results, providing valuable insights for optimizing large-scale ball mill structures and controlling charge motion during production.

Integrating 3D Printed Grinding Tools and Closed‐Loop Temperature Management for Optimal Surgical Outcomes

AbstractGrinding is a commonly employed surgical technique for the partial removal of bone. However, the grinding process often generates excessive heat at the interface, leading to localized temperature raise. This can result in irreversible damage to not only the bone but also surrounding tissues, such as nerves. Existing devices rely on the continuous application of coolant to mitigate temperature rise. With the rate and location of coolant deposition being primarily empirical, the current process brings potential risks to patients. In this study, a novel grinding device capable of continuously monitoring grinding temperatures and applying coolant precisely when needed is designed. Utilizing additive manufacturing techniques, a customized grinding tool head equipped with embedded temperature sensors and coolant channels is successfully created. This innovation has enabled the development of an intelligent closed‐loop device that provides precise temperature control during surgery. The device effectively maintains the grinding surface temperature within the user‐defined range, with a latency of less than 1 s. Furthermore, the design ensures that the coolant spray outlets remain unobstructed by debris during grinding and effectively removes debris at the interface, reducing the risk of potential complications, such as bone hyperplasia.

Theoretical research of the parameters of the biters that distribute feed to the grinding rotor

Justifying the diameter of the distribution biters and the number of rotations of the device that grinds the pressed feed to the level required by zootechnical standards is the primary goal of the study. The press feed distribution biters’ plan and its working principle are presented. It is necessary to scientifically justify the number of shovels of the proposed distribution biters and the width of the slits between them. During crushing the feed collected by the press, it should ensure the transfer of specified amounts without being stuck in the rotor of the device. The output of the pressed feed grinding device should be 500-600 kg/h in the main time, 400 kg/h during its use, and the length of the crushed feed should be for cattle. 30-50 mm, for sheep it should be 30-40 mm. Based on this, we accept the productivity of 600 kg/hour, the cutting length of 30 mm. In this instance, it was found that in order to maintain the device’s stated productivity of 500–600 kg/h, the biter revolutions should be between 250 and 300 r/min.

Effects of processing parameters and grinding direction on the material removal mechanism of (100) surface single crystal diamond in self-rotating mechanical grinding

The current commonly used method for diamond processing is mechanical polishing using the cast iron grinding wheel (Scaife). However, this method is challenging to meet the processing requirements of semiconductor applications. This study proposes a more efficient grinding method that employs a high-speed self-rotating grinding device, coupled with a bonded abrasive diamond grinding wheel with high self-sharpening properties, to achieve high precision grinding of single crystal diamonds. Different cutting depths, grit sizes, and linear velocities are employed in the processing, and the material removal mechanism is studied through morphology characterization, element content, and other detection methods. The experimental results indicate that the material removal method of diamond (100) crystal surface is influenced by the cutting depth. It is a collaborative removal process in the 〈110〉 and 〈100〉 directions, and the brittle-ductile transition in the <110> direction significantly affects the machining quality. Surface fractures and subsurface cracks primarily occur through cleavage along the (111) plane, so a method to distinguish the orientation of the (100) crystal plane is proposed. Additionally, this study demonstrates the influence of different processing directions on the surface of the diamond within the same plane. By using this method, the surface roughness of the 7 × 7 mm as-grown crystal can be reduced to Ra 0.523 nm within 10 min, with a material removal rate of 32.4 μm/h.

Feasibility Analysis of Novel Grinding Device With PVDF Sensor in Coronary Rotational Atherectomy

Feasibility Analysis of Novel Grinding Device With PVDF Sensor in Coronary Rotational Atherectomy

Design and Experiment of Ultrasonic Assistant Grinding Device of Spiral Bevel Gear

The precisely ground tooth surface of the spiral bevel gear still shows the thermal crack, and its micromorphology is the cause of high-frequency noise. The ultrasonic assistant grinding (RUAG) technology has the unique advantage of solving these problems. Therefore, this paper designed the split-type rotary device in which the disc grinder and amplitude horn are core components and bolted together. A deformation coefficient was proposed to calculate the strain stress of the disc grinder. Combined with the stepped horn resonant theory, the theoretical model of a multi-step rotating body can be used to calculate the frequency and amplitude of the grinder and horn. The harmonic response simulation was adopted to verify the theoretical results. The experiment proved that the device’s frequency, node, and amplitude are reasonable. The comparison results showed that the simulated frequency and amplitude were closer to the practical one. Moreover, the difference between them increased with the dimension of the device.

Developing a novel radial ultrasonic vibration-assisted grinding device and evaluating its performance in machining PTMCs

Particle-reinforcing titanium matrix composites (PTMCs) exhibit the sharp raising applications in modern industries owing to its extraordinary physical and mechanical properties. However, the poor grindability and unstable grinding processes due to the existence of TiC particles and TiB short fibres inside PTMCs, leading to the sudden grinding burn and low material removal rate. In this work, a novel radial ultrasonic vibration-assisted grinding (RUVAG) device with a special cross structure was developed to improve machining efficiency and avoid grinding burns. Meanwhile, the resonant modal and transient dynamic characteristics of radial ultrasonic vibration system were discussed. Comparative grinding performance experiments were then conducted under the conventional grinding (CG) and RUVAG using mono-layer cubic boron nitride abrasive wheels, in views of the grinding forces and force ratio, grinding temperature, and ground surface morphology. Results show that the ultrasonic vibration direction can be transformed effectively using the special cross structure of vibration converter, and better vibration homogeneity can be obtained. RUVAG has a smaller tangential grinding force by 5.0%–17.2% than that of CG, but a higher normal grinding force of 6.5%–14.9%, owing to the periodic impact of grinding wheels. In addition, RUVAG possesses a remarkable lower grinding temperature in range of 24.2%–51.8% and a higher material removal rate by 2.8 times compared with CG, resulting from the intermittent cutting behavior between the grinding wheel and workpiece. In this case, the sudden burn can be avoided during high-speed grinding processes. Moreover, the proportion of micro-fracture defects on machined surface is slightly increased once the ultrasonic vibration mode is employed because of the periodic impact on reinforced particles, whereas the pull-out defects of reinforced particles are reduced significantly.

Theoretical determination of the speed and number of revolutions of the grain grinder hammer propeller

A mini grain grinder device was created for small farms, which is used to prepare feed by grinding grains. The main working organ of the grain grinder is a propeller with a hammer, and the grinding of grains during the work process depends on the rotation speed of the hammer and the number of revolutions of the propeller. Because when the propeller rotates, the speed of the hammer attached to it must be sufficient to crush the grains. With this in mind, theoretical studies were conducted and the rotation speed and number of rotations of the hammer propeller of the grinding device needed to grind the grains were determined. According to the research, the speed of the propeller hammer should be at least 40.2 m/s for grain crushing in the device, and this speed is ensured when the number of rotations of the hammer propeller reaches 1785 rev/min when the radius of the hammer propeller is r = 0.215 m. For rapid grinding of nutritious grains in the grinding machine, the speed of the hammer should be higher than 40.2 m/s and the number of propeller revolutions should be higher than 1785 rev/min.

Development of Horizontal Vibration-type Synthetic Electric Field Measurement Prototype

At present, field grinding measurement devices are mainly adopted for DC synthetic electric field measurement. The sensor unit of the device is of a rotating blade structure, and the surface wind generated by rotation causes ion flow distortion, making it difficult to ensure the accuracy of measurement data. In order to optimize the sensing structure of measuring equipment, the vibration-type synthetic field sensing mode was obtained through selection analysis, the horizontal vibration sensor structure and data acquisition hardware circuit structure were proposed, and a vibration-type synthetic field measuring prototype was developed. Through the simulation comparison of the influence of vibration type and field grinding type on the electric field, it can be known that the internal field intensity of the upper and lower 1 mm planes of the equipment shell is basically uniform, and the field intensity of the square and the corner position of the equipment shell are distorted. The electric field distortion of the upper surface of the field grinding device and vibration device is 2.36-8.55 and 1.9-6.84, respectively. The higher the device is, the greater the distortion of the field intensity near the shell, and the distortion of the field grinding type is larger than that of the vibration type. Vibration equipment has less influence on the background field intensity when measuring the ground composite field intensity.

Development, design and methodology for calculating the structural and technological characteristics of a screw grinder of root crops

The design of the auger grinder of root crops for cattle has been developed, which will make it possible to obtain ready-made feed in accordance with zootechnical requirements with minimal specific energy consumption by reducing the speed characteristic of the auger and regulated placement of flat knives in the knife grate. The expressions obtained analytically reflect the influence of the main design and operating parameters of the grinding device, as well as some physical and mechanical properties of the crushed root crops (friction coefficients, bulk density) on productivity, power an specific energy consumption. Keywords: design, screw grinder, calculation. aleksei_brusenkov@mail.ru, kdn1979dom@mail.ru

Constant Force Control of Centrifugal Pump Housing Robot Grinding Based on Pneumatic Servo System

In order to solve the problem of constant force control in the robot grinding process of a centrifugal pump housing a circular inner surface, this study used the force–position hybrid control mode based on a pneumatic servo system to realize the constant control of grinding force. In this process, the manipulator realizes the position and pose control of the end grinding device, and the end grinding device realizes the constant force control in the grinding process. The mathematical model of the pneumatic system is established and linearized by using the gas balance state equation, the adiabatic equation of the isentropic process, and the Sanville flow equation. The balance equation of the cylinder piston was established by using Newton’s second law, the transfer function of the contact force between the grinding device and workpiece was obtained, and the stability of the pneumatic control system was determined by the Hurwitz criterion. The PID algorithm was used to improve the displacement response speed of the system and eliminate the impact and oscillation in the force response. The feasibility, stability, and robustness of the system were verified by simulation experiments. This method has the advantages of simple control, a small amount of calculation, and a fast response, as well as providing a feasible scheme for the popularization and application of robot grinding technology.

Petrological footprints of the millstones of Megara Hyblaea (Sicily Island, Italy) highlight the human interactions with Mediterranean volcanoes

A petrographic and geochemical study of several volcanic millstones, representative of 119 artifacts found in the ancient Greek colony of Megara Hyblaea (Sicily Island) and recording the grinding device evolution from the Archaic to the Hellenistic period, unravelled the volcanoes involved as quarrying and production areas. This was possible also through the comparison with available petrographic and geochemical literature data of ancient volcanic millstones found in the whole Mediterranean. Saddle querns, hopper-rubber, rotary Morgantina- and Delian-type millstones of Megara Hyblaea consist of lithotypes belonging to five magmatic series: Tholeiitic, Na-Alkaline, Tholeiitic Transitional, Calcalkaline and High-K Alkaline. A provenance from the Eastern Sicily, i.e. mugearites from Etna and basalts and basaltic andesites from the Hyblaean Mountains were recognized for all the four investigated grinding devices. By contrast, a sea-trade is involved for several saddle querns made of calcalkaline basaltic andesites and andesites lavas (Aegean Islands) and two Morgantina-type millstones consisting of a calcalkaline rhyodacite ignimbrite from the quarrying site of Mulargia (Sardinia). A wide millstone trade, both local (Eastern Sicily) or maritime (Central-Eastern Mediterranean) was thus constrained through six centuries, from the foundation of the Greek colony up to the destruction of the settlement at the end of third century BCE. Finally, Vulture Volcano (southern Italian peninsula) is the most probable candidate for the only leucite- and haüyne-bearing phonolite of the High-K Alkaline Series.

EMD-based time–frequency denoising algorithm for the self-sensing of vibration signals in ultrasonic-assisted grinding

An empirical mode decomposition (EMD)-based time–frequency denoising algorithm is derived in this paper to accomplish the extraction of active ingredients for multi-frequency mixed signals, and then the self-sensing of vibration signals is realized without additional sensors for an ultrasonic-assisted grinding device. EMD is employed to accomplish the signal decomposition, and multiple intrinsic mode function components and the residual are obtained. Then, the weighted factors used for signal reconstruction are obtained based on innovation statistical distance, which is selected as a criterion to evaluate the time–frequency domain correlation between decomposition results and the original signal. Next, the maximum correntropy criterion-based similarity detection method is designed to adaptively modify the weighted factors, and the signal is reconstructed on the foundation of the modified weighted factors. Finally, numerical simulations and a self-sensing experiment are conducted to verify the denoising performance of the proposed algorithm. The self-sensing of the 4.59 dB vibration signal is realized for an ultrasonic-assisted grinding device.

Construction of Functional Model of Grinding Device of Rail Milling and Grinding Vehicle Based on Functional Backstepping Analysis

Construction of Functional Model of Grinding Device of Rail Milling and Grinding Vehicle Based on Functional Backstepping Analysis

Development of a grinding device for producing coal powder-raw materials of coal-water fuel

Development of a grinding device for producing coal powder-raw materials of coal-water fuel

Design of Underwater Grinding Device for Nuclear Power Plant

In order to solve the problems of difficulty in cleaning the inner wall of the hammer-shaped component in the RIC system of the nuclear power plant and the low surface accuracy after cleaning, a profiling cleaning system was designed. First, the working principle of profiling cleaning is introduced to ensure that the surface accuracy after cleaning meets the installation requirements. Secondly, in order to ensure the normal operation of the profiling airbag, a mechanical model between the air supply volume of the air pump and the force on the conical inner wall is derived. Finally, in order to accurately control the output torque of the motor, the PID method is used to control the output torque of the motor. The system can increase the success rate of cleaning the inner wall of the hammer-shaped component in the RIC system and improve the efficiency of nuclear power plants.

The ‘Assyrian mill’. A case study on food processing technology and innovation in the Near East during the Neo-Assyrian period (c. 900–600 BC)

Assyrian mills are innovative grinding tools that were introduced during the Neo-Assyrian period (c. 900–600 BC) in northern Mesopotamia, and which continued to be attested throughout the Neo-Babylonian, Achaemenid and Hellenistic periods. This paper focuses on the Assyrian mills’ morphological characteristics and archaeological contexts, as well as their geographic and chronological distributions, in order to cast light on the possible reasons behind their spread and final demise. Despite being characteristic of the Neo-Assyrian period, these devices did not spread uniformly across the Neo-Assyrian Empire. It will be argued, therefore, that their spread should be seen as being mainly connected with agricultural policies implemented by the Assyrians in some areas of their empire. Following the Neo-Assyrian period, the use of Assyrian mills drastically dropped: one of the possible reasons behind their final demise is the introduction of the Olynthus mill, a competitive grinding device which became predominant during the Hellenistic period.

Potential Applications of a Novel Ballast Water Pretreatment Device: Grinding Device

To investigate the removal efficiency of the grinding device (GD) as a potential replacement for the pretreatment filtration device of ballast water, solid grinding and viability experiment were conducted according to a treatment flow rate of 5 tons (Pilot test, PT), and 200 tons (Full-scale test, FST) per h. The solid grinding effect was observed in the particle size of ≥25 μm. Under the high-turbidity conditions (&gt;300 mg L−1), no change in pressure (0.98 kgf/cm2) or stoppage in the GD were observed. The removal efficiency of the GD for &gt;100 μm organism was determined to be 100% in both PT and FST, whereas the removal efficiency was determined to be 93% and 87% in the PT and FST, respectively, for the &lt;100 μm organism. There was no statistically significant change in the removal efficiency stored within 2 h after passing through the GD, while the removal efficiency was determined to be ≥99% in the sample stored for 120 h. Future study is necessary to determine the additional removal efficiency according to the storage period after passing through the GD, but the GD might be utilized as the pretreatment device for the ballast water management system.

Mechanism and Experiment Study of Non-Contact Ultrasonic Assisted Grinding

Ultrasonic-assisted grinding processing can effectively reduce the surface roughness and enhance the processing efficiency in the processing of hard and brittle materials. However, the most common ultrasonic assisted grinding is a type of contact ultrasonic grinding where the grinding tool directly contacts the workpiece, which means that it is necessary to accurately control the pre-pressure of the grinding tool on the workpiece. The control of pre-pressure will inevitably increase the complexity of the grinding device, and it is easy to wear the workpiece because of improper pre-pressure control. In this paper, a non-contact ultrasonic grinding method is proposed and the machining mechanism of non-contact ultrasonic grinding is revealed. The resonant frequency of the ultrasonic vibration system and vibration amplitude of the grinding tool working face were simulated and experimentally tested, respectively. Then, the experiment of non-contact ultrasonic grinding of a sapphire wafer was carried out. The result showed that non-contact ultrasonic grinding of the sapphire wafer could reduce the surface roughness by 48.6%. Compared with traditional contact grinding of sapphire wafer under certain pre-pressure conditions, the experimental results show that non-contact ultrasonic grinding has better effects in reducing surface roughness, improving processing efficiency, and improving the quality uniformity of the workpiece machining surface.