Rolling Cutter Research Articles

Research on Fatigue Stress Reconstruction of Major Equipment Based on Neural Network

Abstract This article first proposes a stress/strain reconstruction method based on neural networks. The construction of the dataset and the setting of the network structure are introduced around this method. Standard component strain reconstruction experiments are carried out to verify the method, and the error between the reconstructed values and the measured values is within 15%. This article further takes the tunnel boring machine (TBM) disk cutter shaft as the research object, extracts the coordinate load stress dataset of dangerous positions through finite element method, trains and tests the stress reconstruction model, and the error between the reconstruction value and the simulation value is within 10%. Finally, this article utilized a stress reconstruction model to reconstruct the stress time history of the dangerous position of the TBM rolling cutter shaft and evaluated the fatigue life of the cutter shaft based on various life criteria.

Vibration analysis of rock breaking by TBM rolling cutter assisted with various depth kerfs

Kerfing on the tunnel working face is one of effective ways to promote the performance of tunnel boring machines (TBMs) in hard rock masses, since the rock mass integrity is reduced. When TBM cutter cuts along the midline of two kerfs, the lateral cracks generated from the cutter tip could propagate to the bottom of adjacent kerfs, thus improving the cutting efficiency. However, the cutter vibration under such circumstance was rarely investigated. To analyze the impacts of kerf depth and cutter penetration on the cutter vibration, a series of full-scale linear cutting tests were conducted on two granite samples with high strength. Kerfs of different depths were processed by the saw before each cutting on one sample, while conventional cuttings without kerfs were performed on the other one to make a comparison. A vibration monitoring system was installed in the cutter holder, three axial accelerations and forces of the cutter were recorded during the tests. Rock mucks were collected and sieved to obtain the muck mass and coarseness index. It was found the intense cutter vibration induced by the intact rock cutting could be alleviated by kerfs. The most severe vibration was found in the cutter normal direction thus needed to be focused on. A greater cutter penetration depth made the vibration more intense. The kerf depth had quadratic correlations with various vibration parameters, indicating there was a critical depth beyond the which the vibration could be greatly alleviated, while the higher rock breaking efficiency could be also guaranteed. The critical depth obtained was about 6–9 mm within the range of experimental design. Variational mode decomposition (VMD) was introduced to extract two main subbands and their central frequencies in the frequency domain. The central frequency of the lower frequency band had a bell-shaped correlation with the kerf depth, the critical depth was still found at 6 mm. The findings are conducive to the design of the kerf-assisted TBM tunnelling and the prolongation of cutter life.

Geometric modeling of drilling bit rolling cutters by generalized Hermitian splines

The effective algorithms for calculating the theoretical profiles of the gauge surfaces of various bits have been developed, which reproduce such profiles using spline functions with precision up to the resolution of graphic devices on modern computers. Execution of the profile of gauge surface close to the theoretical one (especially for large-diameter bits with displaced axes of rolling cutters) can increase tool life by reducing the loss of diameter during bit processing. The proposed algorithm allows, based on well-known and rather routine method of calculating the elements of the gear armament, to develop automatic algorithm for calculating the cutting structure of crown, requiring the designer only to fill in a particle of initial data and then visually evaluate the displayed results.

Experimental study on the optimal profile and spacing of a rolling cutter with spherical inserted -tooth

The rolling cutter with spherical inserted-tooth has been an effective tool for mechanical excavation. Significant research has been conducted on the optimization of the tooth shape parameters, tooth spacing, and row spacing of the alloy teeth on the cutter to improve the efficiency of mechanical tunneling and reduce the construction cost. In this study, three spherical teeth with different diameters were designed to perform indentation tests on Beishan granite under various penetration and spacing conditions. The rock fragmentation mechanisms of spherical teeth was analyzed through the fluorescence method, to optimally design the spherical inserted-tooth roller cutter. For Beishan granite, when the tooth spacing and row spacing were about 30 mm and 35 mm respectively, the spherical tooth with a radius of 16 mm gained the highest rock breaking efficiency. Research results provide a guidance for the design of the inserted-tooth roller cutter and the force estimation of cutter head.

Results of the experimental bits bench test, equipped with the compound built-up layers

The article shows the results of performance laboratory studies of compound built-up layers, as well as benches of the pilot tests of the drilling bit rolling cutters, equipped on the bit gage surface of the compound built-up layer; the hardening layers were located along the gage teeth contour. The cast tungsten carbide building-up welding on experimental bits was carried out using a gas-flame method. The induction method of building-up welding was implemented on the rolling cutters of the serial bits. The article shows the results of comparative indicators of serial and experimental bits when their processing on the bench. It was found that experimental bits were more efficient than the serial ones. The estimation of the performance laboratory tests results was confirmed by tests on the bench under pilot conditions of the rolling cutter bits drilling, equipped on the bit gage surface by the compound built-up layer.

Development and testing of rolling cutter bit with a new arrangement of teeth on the balls

Research has found that the axial load applied to the bit is distributed unevenly along the crowns of the balls. The middle crowns are the busiest. The value of the axial force perceived by a separate ring is associated with the deformation of the details of the ball joint. You can reduce the uneven loading of crowns by shifting them along the ball along the radius of the bit, placing them so that the vertical line passing through the center of the lower ball of the lock bearing passes through the middle of the gap between the crowns of neighboring balls. The bits with the new option of placing the teeth on the balls were tested on the stand and in industrial conditions. For the bits of this design, the axial load was distributed more evenly over the crowns, which allowed increasing the efficiency of their work.

Experimental Study of the Mechanism of TBM Disk Cutter Penetration in Mixed-Faced Grounds under Confining Pressure

Abstract In this article, the effects of tunnel boring machine (TBM) disk cutter penetrations on rock fragmentation are experimentally investigated. In these tests, the tested sample is composed of Beishan granite and Chongqing sandstone. The effects of five sets of TBM disk cutter penetrations are investigated under confining pressure of 10 MPa, and 3-D forces acting on the rolling cutter and the forming rock chips are analyzed. It is found from the experimental results that in the mixed-faced ground, for granite, the boreability of the TBM disk cutter increases slowly with increasing penetration, while for sandstone, the boreability of the TBM disk cutter almost linearly decreases. At the same penetration, the average normal force and rolling force in granite are larger than those in sandstone, and cutter vibration becomes obvious when the disk cutter rolls through the interface of the composite rocks. Moreover, the optimizing penetration, which is equal to 2 mm in the mixed-faced ground composed of granite and sandstone under confining stress of 10 MPa, is provided to guide the TBM operation and to predict rock fragmentation in TBM tunneling.

Application of cryo-treatment for improving machining characteristics and reduce manufacturing cost

With the improvement of super-hard materials (intrinsic compounds and extrinsic compounds) the cutting of these materials turns into a matter of worry as far as their quality and quantity. So as to cut such tough materials assortment of inserts are being applied at contemporary.Concentrate on cryo-treatment which is otherwise called a method forever expanding cure for enlightening the properties of the various cutting tools. Examination of impact of profound cryo-treatment at ‘−185 °C’ on P.V.D treated and C.V.D coated tungsten carbide (WC) supplements (inserts) has been appeared in the investigation, which has been trailed by different microstructural and mechanical investigation, for example, Flank Wear test, Hardness test, Scanning Electron Microscopy (SEM) and Energy-dispersive X-ray Spectroscopy (EDS) examination and so on. The examinations was done on both untreated and treated supplements. With SEM examination impact of cryogenic treatment on the microstructure was identified and EDS investigation was used to identify chemical portrayal.Cryogenically treated supplements (inserts) were executed on Rolling shaper and D2 Roll at Ludhiana. With the application of cryogenic cured supplements (inserts) in the industry, it has been seen that the life of Rolling Cutter machining increased by 19 percent and 50 percent of life increased in D2 Roll machining and complete benefits after usage was seen Rs. 90,360 every year.

Simulation of stresses and contact surfaces of disk rolling cutters with the rock when sinking in mixed soils

In this paper, we consider the crack propagation in the rocks during sinking depending on the distance between the cutters. Under the same conditions, the hard and soft rocks form various fracture networks that leads to uneven sinking and decrease in the efficiency of the tunneling machine. In order to study this issue, four ranges of distance between the contact surfaces and various incidence angles of the contact surface were selected. The study includes a system that is a mountain mass layout with a disk cutter the only parameter of which is the tip width or the contact width of the disk cutter with the end-type rock. Simulation of research conditions and finding a solution to the problem were performed using the Autodesk Inventor Nastran 3D simulation software.

MODELING OF IMPACT OF CENTRIFUGAL REINFORCEMENT MODES ON WEAR OF CUTTER TEETH OF DRILL BITS

A study was performed to improve the performance of drill bits. It is noted the main work item are cones, equipped with serrated arms, made in the form of solid or false teeth. It is noted reinforcement of cutters during destruction of rocks is subjected to intensive wear under the action of high loads at the bottom, significant temperature differences, in the presence of abrasive particles, changes in the rock hardness. To reduce the impact of these factors on the wear of rock-destruction weapons, comprehensive design and technological measures are proposed to create a rock-destructive tool and, in particular, its reinforcement. The efficiency criterion of such events is proposed to choose resistance of rock-cutting elements to various types of wear. For implementation of the proposed approach to creating effective reinforcement, a critical analysis of the design of the cutter teeth of drill bits equipped with teeth of various designs and technologies for their manufacture was performed, and rolling cutters with plug-in teeth made by centrifugal reinforcement were selected as the object of research as the most optimal. The design of such teeth, implemented by a centrifugal casting process, provides for location of the rock-breaking hard alloy in the tooth head. The tooth root, pressed into the cutter housing, is made of steel. A mathematical model of the process of centrifugal reinforcement of cutter teeth of drill bits was developed to study the impact of process conditions on their resistance to impact-abrasive wear. As independent variables, otherwise the factors determining the technological process modes of centrifugal reinforcement were selected X1, X2, X3, X4, their main level and intervals of variation, the upper and lower levels were established. A full factor experiment 24 was used in the research. An experimental plan was drawn up. In accordance with the chosen plan, 16 active experiments were performed; each experiment was repeated three times. Then, a mathematical model and its describing regression equation were developed. The impact degree of process factors on the value of shock-abrasive wear of teeth and their optimum values were determined.

Studying load of the cutting structure of rolling cutter bit depending on the errors of its manufacture

The article deals with the results of experimental studies of the load of the cutting structure of rolling cutter bit depending on the errors of its manufacture. The results of field studies of bits indicate a significant decrease in the resistance of the supports of the rollers, the elements of the cutting structure and sinking on the bit with an increase in the height of the rollers. One of the reasons for reducing the resistance of supports and cutting structure in this case is the uneven distribution of the axial load in the sections. We have tested a batch of bits to establish quantitative regularities between the accuracy of bit production and the load of the cutting structure. The difference in height of chosen bits is varied from 0,34 to 1,28 mm. We have carried out the tests on a special stand, which allowed us to determine the value of the axial force acting on the individual crowns of each cutter bit. It is established that with an unfavorable combination of the mutual position of the rollers, even within the tolerance of the difference in height, the axial load acting on one roller can change almost twice. The results of studies allow investigating the appointment of indicators of accuracy of bit production more reasonable.

Theoretical research of process of separating tobacco leaf from stem

The article is devoted to tobacco leaves harvesting in per leaf way, using a roller-type separating device acting on object of harvesting with rolling cutter having cutting flanges forming leaf–separating cells in working area.The subject of these studies is highly specialized and relates to field of agricultural engineering. Tobacco plants were chosen as an object of processing. The aim of research was theoretical substantiation of the interaction of tobacco stems with leaf–separating device in process of harvesting.The article has a research character, which is expressed in fact that theoretical analysis of interaction of tobacco plant with leaf–separating of cutter–roller type in process of harvesting is carried out. In result of research there were obtained dependences that allow to determine constructive and technological parameters of separating device for separating tobacco leaf. Conclusions set out the main results achieved so far.

Применение детонационных покрытий для упрочнения опор шарошечных буровых долот

Применение детонационных покрытий для упрочнения опор шарошечных буровых долот

Совершенствование конструкций опор шарошечного бурового инструмента

Совершенствование конструкций опор шарошечного бурового инструмента

Kinematics of Large-Diameter Multiple Rolling-Cutter Rock Drilling Bits Under the Conditions of Reactive Turbo-Drilling

Special features of the kinematics of large-diameter multiple rolling-cutter rock drilling bits under the conditions of reactive turbo-drilling are considered. An analysis of the kinematics of the rolling cutters of drilling bits functioning with slippage of the cutting structures along the well bottom is undertaken. Factors that influence the magnitude and direction of slippage of the teeth of the cutting structures along the well bottom are determined. Shortcomings of the geometry of the cutting structures of rolling-cutter drilling bits designed for full-diameter drilling when used in reactive turbo-drilling units are identified. On the basis of these studies, it is concluded that fabrication of drilling bits of increased diameter with the use of sections of standard box-type drills is not an efficient approach for full-diameter drilling, since the geometry of the cutting structures of conventional drilling bits does not take into account the specific features that arise in the interaction of the teeth of the cutting structures with the well bottom surface under the conditions of reactive turbo-drilling.

Совершенствование вооружения шарошечного бурового долота

Совершенствование вооружения шарошечного бурового долота

Обеспечение качества соединения твердосплавных зубцов в шарошках буровых долот

Обеспечение качества соединения твердосплавных зубцов в шарошках буровых долот

Method of assessing deviation from the flute’s circularity of rolling tenon of a rolling cutter bit

Method of assessing deviation from the flute’s circularity of rolling tenon of a rolling cutter bit

Effect of microrelief on the contact shakedown of fixed joints

Under the conditions of cyclic loading at fixed joints, the repeated mutual slip of the contacting surfaces is observed in the contact zone, fretting appears, and the wear and destruction of the assembly elements occurs. The existing methods for overcoming fretting are aimed at reducing its intensity. The finite element analysis of fixed joints of smooth contact surfaces and surfaces with relief under the conditions of cyclic loading of junctions makes it possible to reveal the regions of mutual slip and, to determine the parameters of the microrelief, which contribute the most to the onset of contact shakedown. The method for improving the resistance to fretting in friction units based on achieving the conditions for the onset of contact shakedown using microrelief is implemented for fixed joints of a hard-alloy cutter pick and a drilling bit rolling cutter, as well as for an abutting joint of the rotor impeller shrouds of a universal gas distributor.

Control by technological mode parameters with an intellectual automated system

The scheme of functional correlation of input and output parameters of the "drilling rig - rolling cutter bit - rock" system is proposed. The necessity to apply drilling rigs of the automated intellectual system with the adaptive element for a quick time response of the investigated system on the change of physical and mechanical rock properties and the maintenance of the adjusted operating parameters of the technical system in an optimal ratio.