Performance Of Cutter Research Articles

Characterizing Rock-Breaking Performance of PDC Cutters via Stability Metrics and Energy consumption in FDEM Simulations

As oil production increasingly transitions from shallow to deep formation, the need for efficient PDC cutters to drill through deep hard rock becomes paramount. Currently, there is a lack of effective methods for optimizing cutter shapes and their cutting parameters. This study addresses this gap by developing a rock-breaking mechanism model for PDC cutters and proposing a Stability Index (SI) based on cutting force variations during the cutting process. Using the FDEM method, we simulated the rock-breaking processes of planar, stinger, and machete cutters under various cutting depths and angles. SI and Mechanical Specific Energy (MSE) were employed as evaluation metrics to analyze the rock-breaking characteristics and determine the optimal cutting parameters for each cutter type. The results indicate that at shallow cutting depths, cutting force changes are minimal, predominantly causing plastic damage to the rock, resulting in lower stress and reduced wear on the PDC cutters. Conversely, at greater cutting depths, significant fluctuations in cutting force occur, leading to brittle failure and the generation of large cuttings. This sudden increase in cutting force can accelerate rock breaking but also increases the risk of cutter wear. Our findings suggest that the planar cutter offers stable performance with high cutting force requirements, optimal at a cutting depth of 1.5 mm and an angle of less than 20°. The stinger cutter, requiring lower cutting forces, performs best at a cutting depth of 2 mm and an angle of 20°. The machete cutter exhibits characteristics similar to the stinger cutter at shallow depths and the planar cutter at deeper depths, making it suitable for drilling at a depth of 2 mm and an angle of less than 10°. By balancing SI and MSE, this study provides a comprehensive approach to optimizing PDC cutter performance, enhancing drilling efficiency while minimizing cutter wear.

Assessing cutter-rock interaction during TBM tunnelling in granite: Large-scale standing rotary cutting tests and 3D DEM simulations

The widespread utilisation of tunnel boring machines (TBMs) in underground construction engineering requires a detailed investigation of the cutter-rock interaction. In this paper, we conduct a series of large-scale standing rotary cutting tests on granite in conjunction with high-fidelity numerical simulations based on a particle-type discrete element method (DEM) to explore the effects of key cutting parameters on the TBM cutter performance and the distribution of cutter-rock contact stresses. The assessment results of cutter performance obtained from the cutting tests and numerical simulations reveal similar dependencies on the key cutting parameters. More specifically, the normal and rolling forces exhibit a positive correlation with penetration but are slightly influenced by the cutting radius. In contrast, the side force decreases as the cutting radius increases. Additionally, the side force shows a positive relationship with the penetration for smaller cutting radii but tends to become negative as the cutting radius increases. The cutter's relative effectiveness in rock breaking is significantly impacted by the penetration but shows little dependency on the cutting radius. Consequently, an optimal penetration is identified, leading to a low boreability index and specific energy. A combined Hertz-Weibull function is developed to fit the cutter-rock contact stress distribution obtained in DEM simulations, whereby an improved CSM (Colorado School of Mines) model is proposed by replacing the original monotonic cutting force distribution with this combined Hertz-Weibull model. The proposed model outperforms the original CSM model as demonstrated by a comparison of the estimated cutting forces with those from the tests/simulations. The findings from this work that advance our understanding of TBM cutter performance have important implications for improving the efficiency and reliability of TBM tunnelling in granite.

Comparison of the specific energies of sinusoidal VCS cutter rings and CCS cutter rings in breaking rock-like materials based on the FEM.

Disc cutters are essential for full-section hard-rock tunnel boring machines. The performance of these devices directly affects tunnel engineering costs and duration. This paper proposes a sinusoidal variable cross-section (VCS) cutter ring and design method and establishes a digital model. Rock-like materials are simulated with a finite element model, and the model validity is verified via rock simulation mechanics tests. A disc cutter rolling rock simulation model for a linear cutting machine is also established, and simulation tests are performed for single- and three-cutter rolling using sinusoidal VCSs and constant cross-section (CCS) cutter models, respectively. The stress and energy changes for the cutters and rock-like material damage area were compared via simulation, confirming that some sinusoidal VCS cutter rings do less work on rock-like materials and cause larger crushing areas under the same engineering parameters; therefore, these cutter rings have smaller specific energies. The sinusoidal VCS cutter ring performance is 7% greater than that of CCS on average under single-cutter simulation, and the intermediate cutter performance of the intermediate cutter is 9% greater than that of CCS on average under three-cutter simulation. Thus, sinusoidal VCS cutter rings offer improved rock damage performance, and further research and application of this technology will improve the working efficiency of tunnel boring machines.

Research on Mechanical Characteristics of TBM Cutter Bearing Based on DEM-MBD Coupled Simulation

Introduction: The cutter is a crucial excavation tool employed by Tunnel Boring Machines (TBM) for tunneling underground passages. During operation, it undergoes intense impact loads, which are transmitted to the bearings, thus posing a risk of bearing failure. Method: This paper combines the Discrete Element Method (DEM) and Multibody Dynamics (MBD) by establishing a coupled simulation patent model of the cutter and surrounding rock, various methods of cutter load profiles are compared. The study investigates the variation patterns of multi-directional rock-breaking loads on the cutter and validates the findings through wire-cutting experiments. Result: The research findings indicate that the discrepancies between the simulated and experimental mean values of the cutter's normal force and rolling force are 6.26% and 35.20%, respectively. The efficiency of cutter load transmission to the outer ring of the bearing is 99.10%, leading to the characterization of the vibration characteristics curve of the bearing's outer ring. Simultaneously, the mean square error of the cutter load obtained through the coupled method and traditional method is 78.50 kN and 76.10 kN, respectively. In comparison, the experimental load's mean square error is 99.20 kN, indicating that the coupled method better aligns with actual conditions. Conclusion: This research approach serves as a reference for TBM cutter performance analysis and bearing fatigue analysis.

Comparative Evaluation of Developed Onion Stem and Root Cutter CumSorting Machine with Manual Cutting Method

In India, manual cutting of onion stem and root is still a practice. This is very labour intensive, drudgery prone and time consuming operation. For this reason, an onion stem and root cutter cum sorting machine that can be easily adapted in farmer’s field was developed. In this study, comparative evaluation and analysis of a developed onion stem and root cutter cum sorting machine with manual cutting method was performed. Major objective was to assess the performance, labor requirements and economic benefits of using the onion stem and root cutter over the manual cutting technique. The developed onion stem and root cutter cum sorting machine was designed to efficiently stem and root cut and separate grade onion bulbs from the onion crop with minimizing damage. The study was conducted in an onion field, comparing the cutter performance with the manual cutting method commonly employed in the region. The cost of the machine is found as 61190.00 Rs. with breakeven point was calculated as 139.79 h/year and payback period was found to be 3.38years taking profit as 20%. The newly developed machine saves 70.37% cost and 92.59% labour as compared to traditional sickle and 46.07 % cost and 82.60 % labour as compared to battery operated onion stem and root cutter at desired stem length.

Comparative Study of the Rock-breaking Mechanism of a Disc Cutter and Wedge Tooth Cutter by Discrete Element Modelling

The operation of a shield tunnel boring machine (TBM) in a high-strength hard rock stratum results in significant cutter damage, adversely affecting the thrust and torque of the cutter head. Therefore, it is very important to carry out the research on the stress characteristics and optimize the cutter parameters of cutters break high-strength hard rock. In this paper, the rock-breaking performance of cutters in an andesite stratum in the tunnel of Qingdao Metro Line No. 8 was investigated using the discrete element method and theoretical analysis. The rock-breaking processes of a disc cutter and wedge tooth cutter were simulated by software particle flow code PFC3D, and the rock-breaking degree, stress of the cutter, and rock-breaking specific energy were analyzed. The rock damage caused by the cutter in a specific section was divided into three stages: the advanced influence, crushing, and stabilizing stages. The rock-breaking degree and the tangential and normal forces of the wedge tooth cutter are larger than that of the disc cutter under the same conditions. The disc cutter (wedge tooth cutter) has the highest rock-breaking efficiency at a cutter spacing of 100 mm (110 mm) and a penetration depth of 8 mm (10 mm), and the rock-breaking specific energy is 11.48 MJ/m3 (12.05 MJ/m3). Therefore, two types of cutters with different penetration depths or cutter spacing should be considered. The number of teeth of wedge tooth cutters can be increased in hard strata to improve the rock-breaking efficiency of the shield. The research results provide a reference for shield cutterhead selection and cutter layout in similar projects.

Prediction of Chatter Stability in Bull-Nose End Milling of Thin-Walled Cylindrical Parts Using Layered Cutting Force Coefficients

During the bull-nose end milling operations of thin-walled structures, chatter usually occurs and adversely affects cutter performance, finished surface quality, and production efficiency. To accurately predict chatter stability, a suitable dynamic model with effective system parameters is required. In this article, a three-degree-of-freedom (3-DOF) dynamic model is developed to analyze the milling stability of the thin-walled cylinders, in which the dynamics of the bull-nose end mill along the x-axis and y-axis directions and the dynamic of the workpiece along the z-axis direction are taken into account. Then, the cutter-workpiece engagement (CWE) is extracted by employing a slice-intersection-based approach. And the layered cutting force coefficients are identified by considering the influences of varying cutter diameters on the cutting speed. Thereafter, the semi-discretization method (SDM) is adopted to compute the stability lobe diagram (SLD). In the end, a group of milling tests are carried out on a thin-walled cylinder to validate the accuracy and reliability of the proposed model, and the results show that the model predictions agree well with the experimental data.

Performances of a Stinger PDC cutter breaking granite: Cutting force and mechanical specific energy in single cutter tests

The Stinger PDC cutter has high rock-breaking efficiency and excellent impact and wear resistance, which can significantly increase the rate of penetration (ROP) and extend PDC bit life for drilling hard and abrasive formation. The knowledge of force response and mechanical specific energy (MSE) for the Stinger PDC cutter is of great importance for improving the cutter's performance and optimizing the hybrid PDC bit design. In this paper, 87 single cutter tests were conducted on the granite. A new method for precisely obtaining the rock broken volume was proposed. The influences of cutting depth, cutting angle, and cutting speed on cutting force and MSE were analyzed. Besides, a phenomenological cutting force model of the Stinger PDC cutter was established by regression of experimental data. Moreover, the surface topography and fracture morphology of the cutting groove and large size cuttings were measured by a 3D profilometer and a scanning electron microscope (SEM). Finally, the rock-breaking mechanism of the Stinger PDC cutter was illustrated. The results indicated that the cutting depth has the greatest influence on the cutting force and MSE, while the cutting speed has no obvious effects, especially at low cutting speeds. As the increase of cutting depth, the cutting force increases linearly, and MSE reduces with a quadratic polynomial relationship. When the cutting angle raises from 10° to 30°, the cutting force increases linearly, and the MSE firstly decreases and then increases. The optimal cutting angle for breaking rock is approximately 20°. The Stinger PDC cutter breaks granite mainly by high concentrated point loading and tensile failure, which can observably improve the rock breaking efficiency. The key findings of this work will help to reveal the rock-breaking mechanisms and optimize the cutter arrangement for the Stinger PDC cutter.

Study on the distribution and variation of temperature field in the rock breaking process of TBM disc cutter

When the disc cutter crushes the rock, it will generate a large amount of cutting heat, which will increase the temperature of the cutter ring, accelerate the failure, and seriously affect the service life. In order to study the temperature effect in the rock breaking process of the disc cutter, a heat source model and a finite element model in the rock breaking process were established to determine the temperature field of the disc cutter in a single cutting and the temperature of the disc cutter for a long time was predicted. Finally, temperature evolution was verified by a multifunctional cutter performance experimental system and infrared thermal imaging technology. The results show that the heat flux and the temperature of the disc cutter rise with the increase of penetration, cutting speed, and rock compressive strength. The highest temperature occurs at θ/φ (The ratio of included angle from any point on the contact surface to the deepest point of rock breaking and contact angle) = 0.64–0.73. When the disc cutter cuts the rock in a short time, the temperature rises rapidly and then begins to decline and approach the ambient temperature. The temperature of the disc cutter for a long time presents a rapid rise and steady rise state. When cutting granite, the maximum temperature can reach 492.5 °C, and the maximum heat flux can reach 3570 kW/m2. The overall average error of the highest temperature of the disc cutter obtained by simulation and experiment is less than 20%, which proved the correctness of the heat source model and the numerical simulation model.

Design of surface micro texture in the cutter-chip contact area of a cemented carbide cutter

Placing micro textures on a cutter surface can enhance the cutter-chip and cutter-workpiece contact, improving the cutter performance and machined surface quality. However, both the proper placement of micro textures and careful modeling of their density function are required for optimizing the cutting performance. In this study, a ball end milling cutter was utilized to demonstrate how these can be achieved. Initially, the theoretical cutter-chip contact length of the was calculated based on the chip curl theory and the theoretical cutter-chip contact area was obtained by combining the theories of cutter contact area and micro texture placement. Then, a mathematical model describing the micro texture distribution was established using a uniform density function, which allowed the determination of the specific distribution model for the micro textures. Finally, both simulations and experiments were used to validate the accuracy of the theoretical solution for the cutter-chip contact area and the uniformity of the micro texture density function. The results showed that the theoretical cutter-chip contact area and the uniform micro texture density mathematical model are consistent with the simulation and experimental results. The results reported in this paper provide a theoretical basis for the accurate preparation of micro textures.

Experimental Setup and Study of Solar Operated Chaff Cutter

Solar energy is a renewable energy. Earth continuously intercepts solar power of about 1.78 x 1011 MW. By using solar energy converging devices solar energy may be converted into other form of energy. Use of solar energy in agricultural field is essential now-a-days. Solar photovoltaic system converts solar energy directly into electrical energy using solar photovoltaic cell [3]. Increasing wind velocity improved the power generated by solar panel [6]. The main aim of this paper is experimental study and testing of solar operated chaff cutter. A solar operated agricultural chaff cutter uses solar panel to absorb the spectrum of solar energy is quite wide and its intensity and that energy converted into electric energy via solar PV system. Experimental model of solar operated chaff cutter is taken into consideration in this investigation. In this paper we also considered losses in solar panel, angle of solar panel with horizontal, performance of cutter.

Rock-cutting and wear performance of a novel TBM disc cutter with spiral grooves

Tunnel boring machines (TBMs) require a large thrust and suffer from extensive cutter wear when tunneling in hard rock stratum. Controlling the cutter-rock contact by using an appropriate contact surface design can potentially improve the cutting performance of TBM cutters. This paper proposes a design scheme of disc cutters with surface grooves and uses a hybrid discrete element model and a reduced-scale rock-cutting experiment to evaluate the cutting performance of the proposed cutter. The results show that at the same penetration depth, the cutting force required by the grooved cutters is lower than that of the conventional flat-top cutter, and the rock chip volume decrease is not significant. Thus, the rock-cutting specific energy is reduced. The grooved cutter has a discontinuous contact area with the rock, reducing the volume of the crushed zone and the rock powder; thus, less energy is required for rock cutting. Wear experiments are performed to evaluate the durability of the proposed cutter. The results indicate that the tooth tips of the spiral groove cutter suffer plastic deformation in the first several hundred cycles, leading to a larger diameter decrease than that of the flat-top cutter. However, the two cutters have similar wear rates after the run-in period, and adhesive wear is the dominant wear mechanism of both cutters. This study demonstrates the feasibility of improving the cutter performance by changing the surface structure, providing a new strategy for increasing the driving speed of TBMs in a hard rock stratum.

Numerical study of rock-breaking performance of cutters in heterogeneous sand cobble ground

Numerical study of rock-breaking performance of cutters in heterogeneous sand cobble ground

Investigation of the Effect of Rope Cutter on Water Flow behind Ship Propellers Based on CFD Analysis

Small vessels operating in coastal waters are susceptible to propeller failure because of the entanglement of marine debris. Secondary accidents such as the injury of divers may also occur when removing entangling material. Rope cutters are devices used to prevent marine litter from entangling the propeller of small ships. However, installing rope cutters on propeller shafts might affect the working of the propeller. In this study, three-dimensional simulations were performed to investigate the effect of a rope cutter on flow characteristics behind the propeller. The Computational fluid dynamics (CFD) models were validated by particle image velocimetry (PIV) experiments performed in a rope cutter performance testing tank. The study results showed that the installation of a rope cutter on the propeller shaft led to an insignificant reduction in water flow velocity magnitude behind the propeller. Additionally, the effects of the rope cutter on the reductions of thrust (0.87%) and torque (0.76%) of the propeller were also negligible. However, it is very interesting to note that rope cutter installation resulted in a lower vortex formation, leading to a significant reduction in the turbulence intensity behind the propeller by 27.12%, 37.50%, and 47.29% at 100, 150, and 200 rpm propeller speed, respectively. Based on the study results, it can be concluded that rope cutters help to reduce propeller entanglements without significantly affecting the propeller’s working.

Effects of surface grooves on rock cutting performance and contact behavior of a TBM disc cutter

Tunnel boring machines (TMBs) have a slow tunneling speed and low energy utilization rate in hard rock strata. A potential method to improve the cutting performance of cutters is the control of the contact state between the cutter and the rock using a specific geometric design of the contact surface. This paper discusses a design scheme of a TBM disc cutter with surface spiral grooves. Discrete element modeling, finite element modeling, and a scaled experiment are used to evaluate the rock cutting performance and contact behavior of the proposed cutter design. The results show that at the same penetration depth, the cutting force required by the spiral groove cutter is significantly lower than that of the traditional constant cross-section flat-top cutter. Moreover, the rock chip volume is slightly lower, and the rock cutting specific energy is lower. The reason is that the discontinuous contact area between the cutter and rock reduces the degree of rock fragmentation due to the presence of grooves, reducing the energy consumption for rock breaking. In addition, the grooves do not cause severe internal stress concentration inside the cutter, and the contact stress on the cutter’s tooth surfaces is randomly distributed. This study confirms that the cutter shape is directly related to the cutter performance, indicating that a suitable cutter design improves the tunneling efficiency of a TBM.

Rock cutting mechanism of special-shaped PDC cutter in heterogeneous granite formation

Special-shaped Polycrystalline Diamond Compact (PDC) cutters show the superiority for improving rate of penetration (ROP) in hard abrasive formation drilling. However, few attentions have been paid on its geometric design and rock cutting mechanism. To deepen the understanding of special-shaped PDC (SPDC) cutter's rock-breaking mechanisms and provide a certain reference for the selection and application of SPDC cutters in the specific target formation, this paper firstly proposes two new principles (loading performance (LP) and cutting performance (CP)) as well as their evaluation indexes for evaluating the cutting process of cutters from the relationship between geometry, aggressiveness, stress state, working life, and rock cutting efficiency of SPDC cutters. Then, using gray-white granite as the research object, the finite element heterogeneous granite model, whose relative percentage error of all calibration quantities with experiment are less than 7%, based on Voronoi tessellation and the granite cutting model of 10 types cutters under confining pressure are established. Finally, the cutting results are discussed, and the CP of all cutters are evaluated. It's found that the ductile-brittle failure mode in the removal area and the influence region of cutting process determine the rock failure mode of SPDC cutters. The confining pressure has an inhibitory effect on rock cutting efficiency, it's because the high confining pressure leads to ductile dominated failure mode in removal area. The confining pressure weakens the LP and CP of cutters, but has no obvious effect on their stress distribution state. With the increasing of confining pressure, “ductile-plastic stick-slip cutting” effect is produced in the removal area. The conical-shaped cutter (whose CP coefficient is 4.3 × 10 −3 - 5.4 × 10 −3 N −1 ) and saddle-shaped cutter (whose CP coefficient is 3.4 × 10 −3 - 4.8 × 10 −3 N −1 ) are the optimal selection for heterogeneous granite formation. On the contrary, the three-blade cutter and cusp-shaped cutter are unsuitable for heterogeneous granite formation. This research leads to an enhanced understanding of rock-breaking mechanisms of SPDC cutters, and provides the basis to select of SPDC cutters for the specific target formation. • A heterogeneous granite generation method based on Voronoi tessellation using finite element method. • The rock-cutting mechanisms and differences of 10 kinds of PDC cutters. • A new ideas and methods for parameter optimization and performance evaluation of special-shaped PDC cutter using FEM.

Prediction of straight tooth milling of Scots pine wood by shank cutter based on neural net computations and regression analysis

Regression models and a neural net approach were used to predict the cutting performance during milling of Scots pine (Pinus sylvestris L.) by shank cutter. The influence of rake angle, spindle speed, and milling depth on surface roughness of the workpiece, as well as the connection between the milling force and the surface roughness, were thoroughly considered. Four approaches were used to predict the workpiece’s surface roughness based on the experimental data: Back Propagation Neural Network (BPNN), Radial Basis Function Neural Network (RBFNN), Support Vector Machines (SVM), and multiple linear regression. The comparative analysis of the predictive models showed that Neural Network (NN) had preferable performance for prediction of machined surface roughness, with an R2 of 0.98. The SVM had certain fluctuations and the R2 of the multiple linear regression was just 0.87, indicating that they did not fit well for prediction machined surface roughness. In summary, the effective trend of milling parameters on the machined surface roughness of Scots pine was similar to multiple nonlinear regression, and the accurate prediction by BPNN model can provide technical support for the surface roughness of the Scots Pine and enhance shank cutter performance.

Full‐Scale Laboratory Test of Cutting Large‐Diameter Piles Directly by Shield Cutterhead

Based on the TBM tunnel of Red Line of Tel Aviv in Israel, this paper carried out laboratory tests of shield cutting concrete and reinforced concrete piles and investigated cutting performance of cutter, failure model of rebars, length of damaged rebars, and cutter vibration. The results indicate that under the condition of low tunneling speed and rotating speed, vibration of the cutterhead is small, and vibration of the center cutterhead is more obvious in the radial direction of the cutterhead. Cross sections of broken rebars mainly consist of shear section, tensile‐shear section, tensile‐compressive section, and bending section. Considering the tunnel status, it is recommended to adopt excavation speed of 3∼5 mm/min, and rotating speed of 1.0∼1.3 r/min. While cutting RC piles, the principle of “low excavation speed, high rotating speed, and less disturbance” is recommended. Cutting with disc cutters is efficient and the torque of which is stable but the length of the rebars got from cutting varies a lot. It is recommended that majorities of the cutters shall be disc cutters and supplemented with drag bits and tear cutters.

Identifying the causes of residual stress in polycrystalline diamond compact (PDC) cutters by X-Ray diffraction technique

An attempt was made to identify the sources of residual stress in polycrystalline diamond compact (PDC) cutters by X-ray diffraction (XRD) technique. PDC retains residual stress after sintering and this residual stress plays an important role for cutter performance. X-ray diffraction method of residual stress measurement is very common because it is nondestructive. Residual stress was measured in a finished 16 mm PDC cutter and changes in residual stress were observed as the substrate was removed by grinding. Residual stress was also measured after full removal of cobalt from the diamond table by leaching. Comparison was made between the as-pressed PDC cutter, after removing the substrate, and after removing the cobalt to understand the relative contribution of geometry and cobalt binder to overall residual stress. An additional measurement was made under High Pressure High Temperature (HPHT) compacted diamond powder in the absence of cobalt to evaluate the contribution of high temperature deformation of diamond particle on residual stress.

Research on cutting performance in high-speed milling of TC11 titanium alloy using self-propelled rotary milling cutters

Titanium alloys are widely used in many areas, such as aerospace, biomedical, and automotive industries, due to their excellent chemical and physical properties. However, its difficult-to-machine characteristic causes various problems in the machining process, such as serious tool wear and elastic deformation of workpieces. To achieve high efficiency and quality of machining titanium alloy materials, this paper conducted an experimental research on the high-speed milling of TC11 titanium alloy with self-propelled rotary milling cutters. In this paper, the wear mechanism of self-propelled rotary milling cutters was explored; the influence of milling velocity was analyzed on cutting process, and the variation laws with the change in milling length were obtained of milling forces, chip morphology, and machined surface quality. The calculation method of self-propelled rotary velocity was proposed, based on the experimental research. The results showed that in the early and middle stages of milling, the insert coating peeled off evenly under the joint action of abrasive and adhesive wear mechanisms. As the milling length increased, the dense notches occurred on the cutting edge of the cutter, the wear mechanism converted gradually into fatigue wear, and furthermore, coating started peeling off the cutting edge with the occurrence of thermal fatigue cracks on the insert. As the milling length was further extended, the milling forces tended to intensify, the chip deformation worsened, and the obvious cracks occurred at the bottom of chips. The increase in milling velocity intensified the friction between chips and self-propelled rotary milling cutters, and decreased the ratio of self-propelled rotary velocity to milling velocity. This caused the drop in cutting performance of cutters and the growth in tool wear rate.