Bucket Teeth Research Articles

Causes of accelerated failure of excavator bucket teeth crowns when operating in Arctic regions

Causes of accelerated failure of excavator bucket teeth crowns when operating in Arctic regions

The effect of manganese and carbon on the mechanical properties of the welded layer of the bucket teeth of the Hadfield steel excavator

The paper investigates the effect of the surfacing composition’s chemical structure (the manganese and carbon concentrations’ ratio) on the mechanical properties of the surfacing layer on Hadfield steel for increasing the durability of the products made from it, namely the excavator bucket’s teeth. Two criteria, namely the impact toughness and wear resistance of the coating, were chosen as optimization parameters. The assessment of the impact strength of the deposited coating was carried out on the Sharpie samples on the pendulum copra, and the wear test was carried out according to the Brinly-Haworth scheme in the conditions of samples’ abrasion with quartz sand. Wear resistance of Hadfield steel, containing 1.1% C and 13% Mn, was taken as a unit of wear resistance in these experiments. To determine the optimal coating modes, the active experiment with the application of mathematical planning methods was conducted. The obtained response surfaces and graphs of equal output lines make it possible to establish the level of studied factors’ influence on the optimization parameter. In order to analyze the influence of given factors on the optimization criteria, scatter plots with histograms were constructed, which make it possible to determine the rational values ​​of the selected optimization criteria graphically - impact toughness and wear resistance of the coating

Finite element analysis & topology optimization of excavator bucket teeth for optimal performance

In the realm of heavy-duty machinery, excavators hold pivotal roles in construction, mining, and various large-scale projects. The excavator's efficacy relies significantly on its bucket teeth, crafted from robust materials like steel, crucial for soil and rock excavation. However, inadequacies in tooth shape and composition can lead to wear which in turn leads to diminished productivity. Employing finite element analysis, the present research delves into the influence of cantilever profile on TATA Hitachi Ex70 and JCB JS81 bucket teeth, using AISI 4340 and AISI 4140 materials, respectively. Analysing von Mises stress and deformation through Altair HyperMesh, subsequent Altair OptiStruct facilitates topology optimisation aims to reduce tooth mass. It appears that Tooth I (TATA Hitachi Ex70) experienced a decrease in mass, yet an elevation in von Mises stress compared to its initial mass of 2.81 kg and stress level of 1.74 E + 02 MPa. Similarly, Tooth II (JCB JS81) showcased a reduction in mass and a rise in von Mises stress from its original mass of 2.03 kg and stress of 1.038 E + 02 MPa. Validation of optimised designs through the graphs depicting the Factor of Safety (FOS) for both teeth ensures compliance with specified requirements, confirming that optimised excavator bucket teeth designs are safe.

A model-based framework to prevent excavator induced damage in operations on natural gas pipelines

Despite the presence of numerous safety precautions, the primary cause of damage to underground pipes is often attributed to external interference from excavators during their operations. To address this issue, this paper introduces a model-based approach that incorporates both static and dynamic contact in assessing the damage caused by excavators on pipes. The objective of this method is to offer a practical tool that can assist in determining the appropriate excavator size for buried gas pipes. By identifying the maximum safe excavator size, the aim is to minimize the potential risks of mechanical damage to the pipe, to prevent hazards for operators and to protect the integrity of the pipeline. For this purpose, a comprehensive excavator model is constructed. Following this, a suitable damage model for the pipe is selected and the interaction between the bucket tooth and the pipe is modelled. To enhance accuracy, the excavator and pipe are interconnected through the solution of damped contact equations, which take into account the stiffnesses of both the pipe and excavator, as well as the damping effect resulting from pipe deformation. Results provide valuable insight into the potential damage caused to the pipe, which can be attributed to either static or dynamic contacts, depending on which excavator is being used. Failure is addressed by plastic dent, that can be avoided by selecting the most suitable excavator size. Moreover, the analysis of dent depth caused by various excavators on different pipes for gas transmission, opens to the possibility of mitigating the risk of failures by limiting the excavator workspace.

Підвищення тріщиностійкості чавунів з кулястим графітом та їх термічна обробка при виготовленні зносостійких виробів

Methods of achieving the maximum values of crack resistance of Spheroidal graphite cast irons (SGCI) due to the combination of strength of bainite with high plasticity of residual austenite (in the amount of 30-35%) are considered. The results of such studies are suitable for use, in particular, in the manufacture of teeth or crowns of buckets of excavators and other working bodies of mining, earthmoving or earth-moving machinery, as well as parts that function in extreme conditions. These data are comparable to the known results of work on increasing the wear resistance of SGCI for variable parts of agricultural machinery and transport. In addition to crack and wear resistance, the long-term performance and efficiency of the working organs depends on maintaining their pointed part or blade in a sharp condition. The creation of functional-gradient materials, which are characterized by the effect of self-sharpening during their operation and wear, is considered. This effect is proposed to be implemented through the use of gradient heat dissipation in the material of the sand mold, increasing these values by introducing a refrigerant near a specific surface of the casting to accelerate its cooling. For this, casting molds made of loose sand were used in the Lost Foam casting (LFC) process. The method of manufacturing metal working bodies is described on the example of casting by the LFC method of an excavator bucket tooth, it is proposed to obtain its gradient structure according to the regime of heat treatment of castings in a foundry mold due to intensive cooling of its given surface to increase its hardness. At the same time, such conditions were used for the construction and formation of the pattern cluster in the sand, which cause the cooling of the opposite surface to slow down with its lower hardness, which corresponds to the conditions of self-sharpening of the tooth under its operating conditions. Keywords: Spheroidal graphite cast iron, austempering, heat treatment, castings, austenite, Lost Foam casting, bainite.

DESIGN AND ANALYSIS OF THE KOMATSU PC400 EXCAVATOR'S TOOTH BUCKET THICKNESS USING THE FINITE ELEMENT METHOD

Bucket teeth are an important component of an excavator that functions as a material penetrator or digger. This part is prone to failure because it is in direct contact with the ground. This study aims to determine the value of stress, strain, deformation, and safety factors that occur in the Komatsu PC400 excavator bucket teeth against thickness variations of 2.5 mm, 5 mm, 7.5 mm, and 10 mm. This study uses a computer with specifications: processor: Intel (R) Celeron (R) N4000 CPU @ 1.10 GHz, memory: 8 GB. Windows 10 Home Single Language 64-bit Operating System. This computer is equipped with Autodesk Inventor Professional 2023 and ANSYS Workbench R1 2023 software. The method used in this research is a testing method using ANSYS software with a finite element method approach, namely static structural. The simulation results of bucket teeth show the maximum deformation values are 0.16382 mm, 0.13832 mm, 0.1249 mm, and 0.11619 mm, respectively. Furthermore, the maximum equivalent stress values are 108.6 Mpa, 79.712 Mpa, 80.338 Mpa, and 79.992 Mpa, respectively. For the equivalent elastic strain maximum, 0.00052993, 0.00038899, 0.000392, and 0.00039029 were obtained. Then the safety factor value is obtained 3.8214, 5.2062, 5.1657, and 5.188. This shows that the thicker the thickness variation, the better the strength value.

Comparison of Backhoe Loader Bucket Teeth Produced by Welded and Casting Methods Using Finite Element Analysis

Comparison of Backhoe Loader Bucket Teeth Produced by Welded and Casting Methods Using Finite Element Analysis

Abrasive Wear Properties of Wear-Resistant Coating on Bucket Teeth Assessed Using a Dry Sand Rubber Wheel Tester.

Ni60-WC coatings with different WC contents on the bucket tooth substrates were pre- pared using laser cladding technology. Their abrasive wear properties were assessed using the dry sand rubber wheel test system. The substrate and the hard-facing layer were tested for comparison. The results showed that the hardness of the Ni60-WC coatings increased with the increase in WC content. The wear resistance of the bucket tooth substrate was greatly improved by hard-facing and laser cladding Ni60-WC coatings. The wear rate of the hard-facing layer was reduced to 1/6 of that of the tooth substrate. The wear rate of the laser cladding coatings with 20-40 wt.% WC was similar to that of the hard-facing layer. It is worth mentioning that the wear rate of the coatings with 60-80 wt.% WC was only 1/4 of that of the hard-facing layer. Micro-cutting with surface plastic deformation was the main wear mechanism of the substrate to form narrow and deep furrows. The wear mechanism of the hard-facing layer was mainly plastic deformation with a wide groove, and the surface cracks promoted the removal of the material. The removal of the binder phase caused by micro-cutting was the main wear mechanism of the laser cladding Ni60-WC coatings. However, the hard phase of WC hinders micro-cutting and plastic deformation, which improves the wear resistance of the coating.

Dynamic digging force modeling and comparative analysis of backhoe hydraulic excavators

The evaluation of excavator performance relies heavily on digging force, which serves as a crucial indicator. However, the accuracy of performance assessment is hindered by the absence of a suitable method to characterize the dynamic digging capacity of excavators. This study addresses this limitation by proposing an approach to establish a set of solution-limited inequalities for dynamic digging force. The approach incorporates D’Alembert’s principle and composite digging, while considering the influence of inertia force. Furthermore, to mitigate the issue of bucket tooth tip trajectory shaking caused by discontinuous posture during excavation, an amount of measurement data from a 20-ton machine is utilized to construct a consistent theoretical digging trajectory. The theoretical trajectory is subjected to numerical verification to determine the dynamic digging force along the trajectory. A comparative analysis is then conducted, contrasting the obtained dynamic digging force with different theoretical digging forces and measured resistances. Additionally, the dynamic digging forces within the selected digging area of the machine are characterized, without accounting for attitude continuity. The findings demonstrate that the dynamic digging force effectively captures the excavator’s performance along the trajectory, and it also provides an excellent characterization of the digging force at discrete digging spots.

THE EFFECT OF HARD FACING PROCESS ON THE HARDNESS AND MICROSTRUCTURE OF BUCKET TOOTH FOR DIFFERENT MANGANESE CONTENT

High hardness and wear resistance of bucket tooth are required in the face of abrasion and impact. High manganese steel is hard and ductile, making it more suitable for bucket tooth materials. Bucket tooth can wear out and need to be returned to their original size, so that bucket tooth that have been eroded must be coated with a hard material, using a hard facing process. In this study, the hard facing process was carried out in bucket tooth containing 10.4%, 11.60%, 12.70%, 13.60%, and 14.60% men (manganese) elements, using hard facing electrodes of the AWS A5.13 (JIS Z 3251). Hard facing process was using SMAW welding with an average heat input of 1087.43 J/mm. The hard facing process shown that the hardness of weld metal was always lower than of HAZ (Heat Affected Zone) and base metal. The hardness of the weld metal was almost the same for all types of bucket tooth, which was about 233.478 HVN.

Research on the motion control strategy of autonomous excavator based on online compensation

The motion control accuracy of the excavator manipulator is the primary guarantee for autonomous excavators to complete work tasks. This paper studies the motion control strategy of the manipulator of a certain autonomous excavator. By establishing a dynamic model of a 3-degree of freedom of excavator manipulator, the gravity term, inertia term, and centripetal force term in the model are equivalent to external disturbances for online compensation, which improves the motion control accuracy of the excavator manipulator. Based on the dynamic model, a control method of the bucket tooth tip trajectory of an autonomous excavator is proposed. The simulation and test results show that the maximum tracking errors of the joint angles of the boom, the bucket, and the bucket are reduced by 43.14, 26.56, and 51.05% respectively, and the average errors of the whole trajectory are reduced by 56.41, 61.33, and 64.26% respectively. The simulation and test results show that the proposed motion control strategy improves the operation accuracy of the excavator, and can effectively improve the operation accuracy and efficiency of the autonomous excavator.

Sensor-fused simulation-based decision support system for earthmoving projects

Discrete Event Simulation (DES) is an effective method to study cyclic and uncertain projects at the operation level. However, qualified DES results highly depend on the input data quality. This paper describes a simulation-enabled context-aware Decision Support System (DSS) based on sensor fusion to model earthwork operations realistically. The DSS backbone is a DES continually updated using real-time data. The information on earthmoving operations is exchanged between reality and DES using GPS and equipment-mounted cameras. The equipment spatiotemporal data and shovel-mounted cameras enhance the DES quality (i.e., locational and contextual awareness) by providing timely information about task durations, load types, and bucket teeth status. Sensor data is fused and fed into the DES model to replicate the earthmoving project. The proposed method is successfully implemented and validated in a large-scale earthmoving case study. The developed DES is proven promising as a reliable DSS for enhancing resource allocation and time-cost reduction.

Excavating Trajectory Planning of a Mining Rope Shovel Based on Material Surface Perception.

The mining rope shovel (MRS) is one of the core pieces of equipment for open-pit mining, and is currently moving towards intelligent and unmanned transformation, replacing traditional manual operations with intelligent mining. Aiming at the demand for online planning of an intelligent shovel excavation trajectory, an MRS excavating trajectory planning method based on material surface perception is proposed here. First, point cloud data of the material stacking surface are obtained through laser radar to perceive the excavation environment and these point cloud data are horizontally calibrated and filtered to reconstruct the surface morphology of the material surface to provide a material surface model for calculation of the mining volume in the subsequent trajectory planning. Second, kinematics and dynamics analysis of the MRS excavation device are carried out using the Product of Exponentials (PoE) and Lagrange equation, providing a theoretical basis for calculating the excavation energy consumption in trajectory planning. Then, the trajectory model of the bucket tooth tip is established by the method of sixth-order polynomial interpolation. The unit mass excavation energy consumption and unit mass excavation time are taken as the objective function, and the motor performance and the geometric size of the MRS are taken as constraints. The grey wolf optimizer is used for iterative optimization to realize efficient and energy-saving excavation trajectory planning of the MRS. Finally, trajectory planning is carried out for material surfaces with four different shapes (typical, convex, concave, and convex-concave). The results of experimental validation show that the actual hoist and crowd forces are essentially consistent with the planned hoist and crowd forces in terms of the peak value and trend variations, verifying the accuracy of the calculation model and confirming that the full bucket rate and various parameters meet the constraints. Therefore, the trajectory planning method based on material surface perception are feasible for application to different excavation conditions.

Hardening of bucket teeth made from creusabro 8000 steel by using the induction hardening method

Excavators are often used in mining projects such as for penetrating, excavating, dredging, gouging, and crushing mineral rocks. Bucket teeth are an excavator component that is often being replaced due to failure. The most common failure mode that occurred in bucket teeth was wear on the tip or front section of it. To reduce the wear of the bucket teeth material then its hardness should be increased. As the hardness value increases, the resistance to wear increases. The bucket teeth were made of Creusabro 8000 steel and a hardening process was then carried out on the front section of the bucket teeth components by using an induction furnace. The power used in the induction furnace varies from 28, 35, 42 and 49 kW (kilowatts) and the holding time varies between 3 and 5 minutes. The heat treatment process used oil as a cooling medium. The analysis was carried out to determine the area that experienced an increase in hardness and its occurred microstructure. Microstructure examination was carried out with an optical microscope, and hardness test by using a Vickers microscopy. It can be concluded from the result of the analysis that the large area experienced an hardness increase is directly proportional to the electric current magnitude and holding time. The microstructure has changed from fine pearlite to martensite thus hardness of Bucket Teeth can be increased up to 100% of the initial hardness.

PROSES PENGECORAN ADAPTOR PADA BUCKET TEETH UNTUK EXCAVATOR DENGAN MENGGUNAKAN METODE PEMBUATAN CETAKAN FURAN

The following paper was made to understand the process, and defects from metal casting of Low Carbon Steel GS-25 CrMo 4 Bucket Teeth Adaptor for Excavator with furan molding method and how the results of the Chill Test on the product. Metal casting process of making objects by melting metal and pouring it into a mold cavity. Metal casting has been discovered and continues to be developed, one of which is Sand Casting, where there are various types of methods in making molds including the Furan, Disamatic, and Jolt Squeeze methods. The method used in this research is the Furan method which can be used to make objects with complex shapes such as the Adaptor component used in the Bucket Teeth for Excavators. The casting material used in this casting is GS-25 CrMo 4 steel which has strong and tough properties. All manufacturing processes are carried out through several stages, namely; design, model and core making, mold making, smelting, pouring, fettling and finishing, and quality control. From the results of the research that has been carried out, it can be seen that several rejections from these products include: cold shut, missrun, inoculant inclusion, slag inclusion, and sand inclusion.

Review of the Modeling Methods of Bucket Tooth Wear for Construction Machinery

Construction machinery, which is widely used in infrastructure construction, is growing rapidly all over the word. However, the complex working conditions of construction machinery lead to serious wear, particularly the wear of the bucket teeth on construction machinery. To control the wear procedure, it is essential to understand the wear mechanism and identify the wear form under variable working conditions. The modeling methods of bucket tooth wear with different wear mechanisms were reviewed. The modeling methods were divided into the analytical method and the numerical simulation method. The numerical simulation method included the discrete element method, finite element method, SPH method, and so on, which were used to simulate the bucket digging process and analyze the interaction between the material and bucket teeth during the working process. This enabled a force analysis of the bucket digging process and the identification of the location of maximum wear. By establishing a wear model, it is possible to better understand and address the wear problem in construction machinery. This article aims to summarize research methods concerning the wear of wear parts in construction machinery. It provides a theoretical foundation for future investigations in this area and aims to address challenges such as lengthy wear life testing, numerous interfering factors, and the difficulty of data collection pertaining to wear parts.

Single-layer hardfacing of excavator bucket teeth

Single-layer hardfacing of excavator bucket teeth

Studies of stress and strain in bucket teeth of earth-moving machines

This paper aims to analyze the existing designs of bucket teeth in earth-moving machines with the purpose of selecting an optimal design in a scientifically grounded manner. The research objects included six design models of teeth of earth-moving machines made of alloyed manganese steel 110G13L. Teeth models were built using the KOMPAS-3D software. Lateral elastic internal stresses and elastic strains in the teeth models were determined using the COMSOL Multiphysics software. Lateral elastic internal stresses and elastic strains were calculated for the applied load of 9 kN in soft soil and 90 kN in rocky soil. Optimal teeth designs were determined for soils of various hardness. In soft soils, a ripper tooth and a combined curved tooth with an extra ripper tooth showed the optimum combination of efficiency and strength. Thus, provided that the elastic strain of a standard tooth in soft soils equals 100% and depending on the initial state, a ripper tooth and a combined curved tooth with an extra ripper tooth showed the strain values of 30–50% and 32–35%, respectively. In hard soils, a combined curved tooth with an extra ripper tooth and a regular curved tooth showed the optimum combination of efficiency and strength. Thus, provided that the elastic strain of a standard tooth in hard soil equals 100% and depending on the initial state, a combined curved tooth with an extra ripper tooth and a curved tooth showed the strain values of 18–20% and 42–45%, respectively. The feasibility of using buckets with combined teeth of optimal design in earth-moving machines was scientifically substantiated. Future research will investigate various bucket designs of earth-moving machines to find their optimal modifications for soils of various hardness.

The Influence of Microstructure Quality on the Efficiency of Bucket Teeth of Career Excavators

The mining industry is the main base of the country's industrial potential, a significant part of which is the development and production of various rocks and minerals. The main type of machines used in open pit mining are powerful excavators, who make up the bulk of the equipment fleet of mining enterprises. Operating enterprises incur large losses due to wear and destruction of excavator bucket teeth, therefore, improving the quality of the tooth material is an urgent task. This article discusses the influence of the casting quality, including the cast structure of the material, on the performance of the excavator teeth. The object of research was the teeth of the buckets of Cat-391 and VOLVO-350 mining excavators made of 30Cr2Si2MnMo steel after long-term operation. The actual condition of the bucket teeth of mining excavators after operation was examined and microstructure, hardness and worn surfaces of the teeth was analyzed. The study showed that the efficiency of excavator bucket teeth is determined by the level of unevenness of the microstructure and microhardness and the presence of defects, hot and cold cracks. It has been established that the main reason for the accelerated failure of the teeth of open-pit excavator buckets is the superposition of various microstructural defects connected with unevenness of the metal microstructure and imperfection of the casting process. Main directions of increasing efficiency of mining excavators’ teeth bucket were identified.

Determining rational parameters for the impeller of a hydraulic excavator with a crowding mechanism

Introduction. The rationale for the research is conditioned by the need to improve the efficiency of hydraulic excavators which affect the prime cost of mining significantly. Research objective is to improve the design of hydraulic excavator impeller and develop the methods of determining impeller’s rational parameters ensuring its weight reduction. Methods of research. A model of hydraulic excavator with an impeller including a boom, a dipper arm, bucket, and hydraulic slewing cylinders for a boom, a dipper arm, and a bucket. For a front shovel hydraulic excavator, a new design has been developed that excludes hydraulic cylinders for a beam which are used in a base model of hydraulic excavator; a pressure rod is used for boom travel. In the developed scheme of the impeller, a superstructure is installed on the slewing ring, a crowding mechanism for the pressure rod extension is installed in the upper part of the superstructure. The pressure rod is connected to the fore boom and runs inside the saddle bearing. Such scheme allows excluding boom slewing cylinders, reduce the bending moment that has effect on the boom, which is going to reduce the boom cross section and therefore its mass. A mathematical calculation model for excavation coordinates and forces has been developed, as well as an algorithm and software on the Visual Basic language for applications, allowing to determine possible forces in the impeller elements within the limits of the working area. The force values are used when optimizing according to the mass criterion to select the cross section of a boom and dipper arm and for cylinders’ location. The mass criterion application and a restriction in a form of the required technological parameters implementation when operating in the preset mining and technological conditions will allow selecting rational parameters for the impeller’s elements. Results. Changes in the arrangement of elements (elimination of boom slewing hydraulic cylinders and the arrangement of the crowding mechanism on the rotation axis) makes it possible to improve the bucket tonnage, and therefore, the excavator’s capacity. The developed methods of determining the excavator design parameters also ensures the working zone construction and bucket teeth forces calculation within its limits in order to prove the possibility of implementing the operating functions of the new model designed.