The iron roughneck is an automated piece of equipment utilized for the connection and removal of drilling tools. This paper presents the design of an integrated iron roughneck, providing a detailed ...introduction to its clamp body structure, along with an analysis of its structural characteristics and performance requirements. The study delves into the integration mode and working characteristics of the clamping mechanism and spin buckle mechanism for the integrated upper clamp body structure of the iron roughneck. Additionally, this paper conducts an in-depth theoretical study on the spin buckle mechanism. Firstly, it analyzes the actual working condition of the spin buckle roller from two perspectives, namely contact theory and rolling friction theory, determining the structural form of the spin buckle roller. Secondly, it investigates the relative displacement between the spin buckle mechanism and the drilling tool, proposing a design method for the floating device mounted on the spin buckle roller and establishing the kinematic equation of the spin buckle roller under the influence of the floating device. Furthermore, the kinematic equations of the spin buckle roller under the influence of the floating device are established. Finally, a dynamics simulation experiment is performed to simulate the working process of the spin buckle mechanism under actual working conditions, analyzing the dynamics and kinematics of the spin buckle mechanism and obtaining the relevant parameter curves of the spin buckle mechanism and drilling tools. Through data comparison and analysis, the correctness of the theoretical analysis results and the rationality of the performance and structure of the spin buckle mechanism are verified.
Riveting is an important interference-fit joining technology, which has been widely applied in aircraft assembly and many manufacturing fields. The rivet head flushness is an import industrial ...standard for the quality evaluation of a riveted joint. It would influence the aerodynamic performance of aircraft if not carefully controlled. In this paper, a finite element model (FEM) of automatic countersunk riveting is established and the formation of rivet head flushness is studied by the simulation results. Then, based on the coordinated motion of the riveting bar and the anvil tool, several compensation strategies are proposed to reduce the rivet head flushness and ensure the riveting quality, in which the riveting bar and anvil tool feed with the same speed (RASS) strategy is considered as the most efficient one. Finally, riveting experiments are conducted on a dual-machine-based automatic drilling and riveting system. The experimental results indicate that the simulation result is accurate, and the RASS compensation strategy is applicable and effective. This paper studies the formation mechanism and compensation method of the rivet head flushness for the countersunk rivet and provides scientific guidance for the riveting process optimization in engineering applications.
Unfavorable geological phenomena such as fault development and weak surrounding rocks are the common challenges encountered in tunnel excavation. However, the conventional rock mass classification ...method is complex, and the data obtained through disturbed rock samples cannot be used to dynamically and accurately class the surrounding rock in real time. In this study, discrete element method (DEM) is applied to simulate the rock-breaking process by pneumatic rock drill, and the drilling parameters of the surrounding rocks with different classes including drilling rate, vibration acceleration, and vibration frequency, are acquired during the excavation. The simulation results are verified through the data obtained by field tests in Luoping tunnel and Zilinshan tunnel of the Sandu Expressway in Guizhou province, China. Furthermore, a standard database for the dynamic classification of surrounding rocks is established. The numerical simulations reveal a good correlation between the average drilling rate, vibration acceleration, and vibration frequency of drill bit and the class of surrounding rock, and these factors can be used as dynamic evaluation indices for advanced geological prediction during tunnel construction. Overall, the results can serve as a useful reference for advanced geological prediction and dynamic classification of surrounding rocks during the construction of tunnels.
The oil and gas resources stored in deep strata are an important replacement field of the petroleum industry. Accelerating the exploration and development of deep oil and gas is of great significance ...to the security of energy strategy. Drilling is the primary link and necessary means of deep oil and gas exploration and development. Slow drilling speed is one of the key problems restricting the exploration and development of deep oil and gas. The research and development of down-hole equipment with an increasing ROP provides a technical means for increasing the ROP. However, the energy of existing down-hole equipment with an increasing ROP comes from the drilling circulation medium, and the ROP increase effect of such equipment is relatively obvious in shallow and middle formations. However, with the increase in well depth, energy in the circulation medium increasingly struggles to reach deeper formations, and the ROP increase effect is not good at the later stage of drilling. In the drilling process, drill string vibration is a frequently encountered complex situation, but it also contains sufficient energy, and the energy of drill string vibration will increase with an increase in the well depth, which can meet the energy demand of increasing the ROP in deep oil and gas exploration. This paper analyzes the characteristics of drill string vibration, and introduces six kinds of devices that take drill string vibration as energy and realize drill string vibration reduction, bottom-hole pressurization, and high-pressure pulse jet, providing a new idea for the development of deep down-hole speed-increasing devices.
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Dust is one of the main disasters in underground tunneling. This study developed and verified a novel dust suppression device, which was systematically tested in laboratory and field ...conditions. Based on the basic principle of the Coanda effect, with a small amount of compressed air as power supply, and through a uniform layout of circular hole for high-speed jet to drive the center air movement together thus forming the entrainment effect, the main structure of the new dust removal device was designed. The external dusty air is then drawn in and the dust is removed by water spray. According to laboratory experiments, the optimal structural parameters for the inlet inclination angle θ1, the outlet inclination angle θ2, and the number of the compressed drainage gas nozzle n were determined. It was found that when the inlet angle is 15° and the outlet angle is 5°, the Coanda effect is the most significant, and the suction rate of the dust removal device is the highest. With the increase of the number of gas orifices n, the suction rate firstly increased and then decreased. In addition, through numerical simulation, the optimal position of the spray nozzle is determined. In field tests, compared to that of the original dust removal device, the new device improved respirable dust and total dust suppression efficiencies by 30.5% and 11.5% (A: the motorman position), 56.2% and 24.5% (B: Behind the drilling machine), 69.4% and 21.6% (C: 20 m behind the drilling machine), respectively, thus the new technology effectively improves the atmosphere in the mechanized underground coal mines, creating a safer and healthier working environment.
The basic aim of this study is to develop empirical models for predicting performances of pilot hole drilling and reaming for raise boring operations using rock properties and pilot hole drilling ...operational parameters for classified raise inclinations vertical (90°) and inclined (70°) that could be used in feasibility and operational stages of a project. Field study includes collecting performance and operational parameters including rotational speeds, tricone bit and reamer head torques, weight on bit (pushing force), net reaming thrust (pulling) force, unit penetration rate, and field-specific energy. Totally 21 different rocks are sampled in eight different sites to define physical and mechanical properties. The empirical models developed by performing multi-variable regression analyses for the vertical and inclined reaming and pilot hole drilling data groups indicate that static elasticity modulus, dynamic elasticity modulus, uniaxial compressive strength, Brazilian tensile strength, and rock quality designation are the most important intact rock and rock mass properties affecting performances of the vertical and inclined reaming and pilot hole drilling. This study should be continued to develop more generalized and reliable prediction models, especially by adding different reamer head diameters and raise inclinations to the database as predictive parameters.
Purpose
Regarding the assembly of the fuselage panel, this paper aims to illustrate a design of pre-assembly tooling of the fuselage panel for the automatic drilling riveting machine. This new ...prototype of pre-assembly tooling can be used for different types and sizes of fuselage panels. Also, apply to the automated drilling and riveting machine of the fuselage panels.
Design/methodology/approach
Based on the different structures of the fuselage panel, the position of the preassembly tooling components, location of the clamp and position of the fuselage panel are determined. After that, the overall structure of the preassembly tooling is designed, including the movable frame and the cardboard. The cardboard positioning module and the clamping module formulate a detailed design scheme of preassembly tooling for the fuselage panel. The structure of the pre-assembled tooling is optimized by static analysis. The result of the overall design is optimized by using MATLAB and CATIA-V5 software, and the results meet the condition of the design requirements.
Findings
The traditional assembly process of the fuselage is to install the fuselage panel on the preassembly tooling for positioning the hole and then install it on the automated drilling and riveting tooling for secondary tooling. Secondary tooling can consume assembly errors of the fuselage panel. The new prototype of flexible tooling design for the fuselage panel not only avoids the secondary tooling error of the fuselage panel but also meets the preassembly of different types of fuselage panels.
Research limitations/implications
The further development of the flexible tooling design of the fuselage panel is to reduce the error of sliding tooling due to friction of the sliding components. Because if the assembly cycle is increased, the sliding parts will lose material due to corrosion. As a result, the repeated friction force is the root cause of the positioning error of sliding parts. Therefore, it is necessary to engage less corrosive material. Also, the lubricant may be used to reduce the corrosion in minimizing the positioning error of the sliding tool components. In addition, it is important to calculate the number of assembly cycles for efficient fuselage panel assembly.
Originality/value
According to the structure and assembly process characteristics of the fuselage panel, the fuselage panel preassembly tooling can optimize the assembly process of the fuselage panel and have certain practical application values.
Machine fault diagnosis (MFD) has gained an important enthusiasm since the unfolding of the pattern recognition techniques in the last three decades. It refers to all of the studies that aim to ...automatically detect the faults on the machines using various kinds of signals that they can generate. The present work proposes a MFD system for the drilling machines that is based on the sounds they produce. The first key contribution of this paper is to present a system specifically designed for the drills, by attempting not only to detect the faulty drills but also to detect whether the sounds were generated during the active or the idling stage of the whole machinery system, in order to provide a complete remote control. The second key contribution of the work is to represent the power spectrum of the sounds as images and apply some transformations on them in order to reveal, expose, and emphasize the health patterns that are hidden inside them. The created images, the so-called power spectrum density (PSD)-images, are then given to a deep convolutional autoencoder (DCAE) for a high-level feature extraction process. The final step of the scheme consists of adopting the proposed PSD-images + DCAE features as the final representation of the original sounds and utilize them as the inputs of a nonlinear classifier whose outputs will represent the final diagnosis decision. The results of the experiments demonstrate the high discrimination potential afforded by the proposed PSD-images + DCAE features. They were also tested on a noisy dataset and the results show their robustness against noises.
Engine nozzle orifices are broadly used in the automotive field, and their manufacture entails high drilling accuracy, consistency, and excellent machined surface quality. Electrochemical discharge ...drilling (ECDD) is an innovative compound machining technique, which can be used to machine small holes of difficult-to-cut materials. Electrical discharge machining (EDM) as well as electrochemical machining (ECM) can occur simultaneously in ECDD, owing to which it can obtain not only good surface quality but also high processing speed. However, the machining accuracy, taper, and surface quality achieved using ECDD do not satisfy the requirements of engine nozzle orifices, which are of a higher standard. For improving the machining accuracy and surface quality, a variable-parameter electrochemical discharge drilling (VPECDD) has been proposed. The machining process is divided into two consecutive stages, including perforation and shape modification, while different parameters are used in different stages. In this study, the finite element method was applied to study the mechanism of VPECDD, and comparative experiments were performed among EDM, ECDD, and VPECDD. The results indicate that VPECDD can achieve very high machining accuracy and consistency, obtain an inlet and outlet diameter difference at 0.002 mm, maintain an average hole taper at 0.0004°, and remove the recast layer completely. Finally, it is verified that VPECDD is suitable for machining microholes with high precision and no recast layer.
This service program is carried out in the context of lifting regional superior products, namely bamboo crafts from the villages of Brajan, Sendangagung, Minggir, Sleman. The main objectives of the ...research are improving the quality and quantity of products, increasing the level of comfort of facilities/facilities owned (production space, administration space and showroom), increasing marketing networks of partner small and medium enterprise (SME) products for the national level, and improving the function and role of cooperatives in the partner region. The method used is to formulate and carry out several activities that are solutions to problems faced by partners. The activity consists of two main activities, namely technology assistance in the form of production equipment (appropriate technology), construction of a showroom, website creation and enhancement of partners' capabilities by providing various training and mentoring. Technology equipment seconded to partners is drilling machines, sandpaper machines and drying ovens. While the training carried out was training in colouring and preserving bamboo products, training on the use of internet media as a marketing medium, administrative and bookkeeping training, and cooperative training. The results achieved were SME Prinx Mas production capacity increased 12.5%, revenue turnover increased 9.5%, assets increased 5.6%, and the addition of a workforce of 1 person in the production department. In addition, SME Pring Gedhe revenue turnover increased by 5% and assets increased by 7.8%.
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