Tool Structure Parameters Research Articles

Development and field application of a jetting and helical combination tool

Liquid loading occurs in gas wells after a period of production, and the vortex drainage gas recovery technology can alleviate this problem by removing liquid. To substantially enhance the efficiency of this technology, a novel tool combining jetting and helical mechanisms has been introduced. To validate its effectiveness, a laboratory system for detailed analysis of pressure drops by using various tools at multiple gas flow rates has been set up. The analysis approach encompasses both single-factor and orthogonal analyses of tool structure parameters to find out the optimal tool structural parameters under different operating conditions. Consequently, a correlation between the gas flow rates observed in controlled laboratory environments and those in actual gas wells has been established. The study indicates that the tool’s main structural parameters significantly impact pressure drops along the wellbore. Furthermore, it is evident that distinct well profiles require unique tool setups to minimize such pressure drop. Field tests of the optimized tool have shown notable enhancements: The average gas flow rate increased by 25.9%, reaching 5.39 × 104 m3/d (1.90 × 106 scf/d), while the average liquid flow rate increased by 20.1%, reaching 1.46 m3/d (9.18 bbl/d). These results highlight the superior drainage stimulation effect of the new jetting and helical combination tool, presenting novel insights and methodologies for enhancing gas recovery in liquid-loaded gas wells.

Numerical simulation of rock-breaking and influence laws of dynamic load parameters during axial-torsional coupled impact drilling with a single PDC cutter

Axial and torsional impact drilling technology is used to improve the drilling efficiency of hard rock formation in the deep underground. Still, the corresponding theory is not mature, and there are few correlative research reports on the rock-breaking mechanism of axial and torsional coupled impact drilling tools. Considering the influence of the impact hammer geometry and movement on the dynamic load parameters (i.e., wavelength, amplitude, frequency, and phase difference), a numerical model that includes a hard formation and single polycrystalline diamond compact cutter was established. The Riedel-Hiermaier-Thoma model, which considers the dynamic damage and strength behavior of rocks, was adopted to analyze the rock damage under axial and torsional impact loads. The numerical simulation results were verified by the experimental results. It was found that compared with conventional drilling, the penetration depths of axial, torsional, and axial-torsional coupled impact drilling increased by 31.3%, 5.6%, and 34.7%, respectively. Increasing the wavelength and amplitude of the axial impact stress wave improved the penetration depth. When the bit rotation speed remained unchanged, increasing the frequency in the axial and circumferential directions had little effect on the penetration depth. However, as the frequency increased, the cutting surface became increasingly smooth, which reduced the occurrence of bit vibration. When the phase difference between the axial and circumferential stress waves was 25%, the penetration depth significantly increased. In addition, the bit vibration problem can be effectively reduced. Finally, the adjustment of engineering and tool structure parameters is proposed to optimize the efficiency of the axial-torsional coupled impact drilling tool.

Analytical Model of Hole Diameter and Self-Guiding Machining Mechanism of BTA Deep Hole Drilling

The goal of this study was to explore the self-guided machining mechanism of boring and trepanning association (BTA) deep hole drilling and realize precise control of the machining quality. The motion analysis method was used to analyze the center motion trajectory of the drill during the entrance, and the self-guiding mechanism and hole-forming mechanism of BTA deep hole drilling were revealed. Considering the bending deformation of the drilling tube and the tool structure parameters, according to the elastic-plastic deformation theory and Hertzian contact theory, a novel analytical model of the extrusion contact between the guide pads and the hole wall of the BTA deep hole drilling was established for the theoretical prediction of the extrusion deformation and the machining hole diameter. Combined with the finite element method (FEM) simulation model, the variation law of the contact inclination angle, contact stress, and extrusion deformation of the guide pads and the hole wall with the drilling conditions were studied. The total extrusion deformation between the guide pad and the hole wall was between 10 and 50 μm. The maximum error between the FEM simulation results and the test results was 18.1%, and the maximum error between the analytical model results and the test results was 23.6%. The simulation and experimental results showed that the established extrusion contact model could accurately predict the extrusion deformation of the hole wall and the machining hole diameter.

Study on Processing Technology of Aluminium-based silicon carbide material for Shafting Installation

Abstract Aluminium-based silicon carbide (SiCp/Al) composites are widely used in spacecraft structures due to their excellent properties. Aiming at the high-precision machining requirements of thin-walled shell components installed in SiCp/Al shafting in aerospace field. The structural characteristics of thin-walled shell components are analysed. Combined with material characteristics and mechanical properties, a single clamping vertical horizontal conversion machining scheme is formulated. Match the right machine tools and PCD tools. Then the metal cutting process is simulated by AdvantEdge, and the tool structure parameters and cutting process parameters are optimized. Finally, the process route suitable for installing housing components is formulated, with dimension accuracy of H6, cylindricity of 0.003mm and coaxiality of 0.006mm, which solves the difficult problem of machining high-precision shaft mounting housing.

Numerical investigations on rock breaking mechanism and parameter influence of torsional percussive drilling with a single PDC cutter

Torsional percussive drilling tool was designed to reduce the risk of stick-slip and improve drilling efficiency, but there are few studies on the influence of torsional impact parameters, including amplitude, frequency, waveform, on the rate of penetration (ROP) while drilling the hard rock. The design of the torsional percussive drilling tool was proposed, and the mathematical model of torsion hammer movement was developed, the Riedel-Hiermaier-Thoma (RHT) rock dynamic material model was applied to analyze the rock-breaking process of the tool. A numerical model of hard rock cutting with a single polycrystalline diamond composite (PDC) bit cutter was established, the influences of amplitude, frequency, time parameters, and waveforms on the penetration depth of the PDC bit cutter were analyzed in the process of torsional percussive drilling. The results showed that the numerical simulation results were in good agreement with the indoor test results, which verified the correctness of the numerical simulation. Compared with conventional drilling, the penetration depth of torsional percussive drilling was increased by 20.0%, and the cutting debris particles were smaller, which was conducive to improving ROP and reducing stick-slip vibration of the bit. With the increase of the peak value of torsional percussive amplitude, the penetration depth of the cutter first increased and then decreased. When the ratio of torsional impact load to axial static load was 1.0, the penetration depth of the drilling cutter reached a maximum. When the torsional impact frequency was 40 Hz–100 Hz, the penetration depth decreased with the increase of the frequency, but the diameter of cuttings became smaller and smaller, which was conducive to cleaning the wellbore with drilling fluid. The latter has the highest rock-breaking efficiency compared with triangular, sine, and rectangular waves. Finally, suggestions are given on how to adjust these parameters by adjusting engineering parameters and tool structure parameters to optimize the efficiency of the torsional percussive drilling tool.

Dislocation Dynamics-Based Modeling and Simulations of Subsurface Damages Microstructure of Orthogonal Cutting of Titanium Alloy.

In this work, a novel method is put forward to quantitatively simulate the subsurface damages microstructural alteration of titanium alloy components subjected to microscale cutting. A trans-scale numerical framework is conducted with the purpose of revealing the underlying influence mechanism of tool structure parameters on subsurface dislocation configurations using a dislocation dynamics-based model, which considers both dislocation structural transformation and grain refining. Results showed that the developed framework not only captured the essential features of workpiece microstructure, but also predicted the subsurface damages layer states and their modifications. A series of defects were found in the material subsurface during the orthogonal cutting of titanium alloy, such as edge and screw dislocations, junctions, parallel slip lines, intersection dislocation bands, vacancy defects, and refinement grains. Particularly, in the process of micro-cutting, the depth of subsurface damages layer increased significantly with cutting length at the beginning, and then remained unchanged in the stable removal phase. Moreover, smaller edge radius and larger rake angle can greatly weaken the squeezing action and heat diffusion effect between the tool tip and workpiece, which further prevents the formation of subsurface defects and enhances finished surface quality. In addition, although increasing tool clearance angle could drastically lighten the thickness of subsurface damages layer, it is noteworthy that its performance would be decreased significantly when the clearance angle was greater than or equal to 5°. The micro-end-milling experiment was performed to validate the existing simulation results, and the results show very good agreement.

Transient cutting force model in turning large-pitch external thread

Transient cutting force is an important indicator to evaluate stability in the cutting process. When alternating turning large-pitch external thread using the tool’s left and right cutting edges, the cutting forces in the forming process of the left and right thread surfaces are different and in a state of instability. Through an experiment of turning external thread with pitch 16 mm, tool vibration characteristics involved in the forming process of left and right thread surfaces are achieved. We studied the transient cutting motion trajectory and cutting attitude of the tool’s left and right cutting edges, thereby establishing a transient cutting force model. The technology evaluation and design method of turning large-pitch external thread is proposed, and a technology verification experiment was completed. The results show that tool vibration has a different action mechanism on transient cutting force of left and right cutting edges. The differences in the dynamic change of the cutting force in the forming process of left and right thread surfaces are revealed by the transient cutting force model. This model is used to evaluate the turning process scheme, and the influence characteristics of the tool structure parameters and cutting parameters on the transient cutting force can be identified. Thus, the process scheme is obtained, which effectively improves the turning stability of left and right thread surfaces and the consistency of transient cutting force load.

Research on Cutting Force Model of Triangular Blade for Ultrasonic Assisted Cutting Honeycomb Composites

The triangular blade is a primary tool for ultrasonic assisted cutting honeycomb composites. The machining parameters optimization for cutting force minimization, it is proven important for a better surface quality, higher machining efficiency and lower tool wear to be obtained. Based on the analysis of the ultrasonic assisted cutting of honeycomb composites and the triangular blade movement law, the cutting force theoretical model was established. The relationship between the cutting force and the machining parameters was expressed explicitly. The experiments of blade cutting of honeycomb composites with ultrasonic and non- ultrasonic assistance were executed by the control variable method. The effects of the cutting depth, the blade inclined angle and the deflection angle on the cutting force were verified, which were reflected by the cutting force theoretical model. The theoretical foundation was provided for further optimizing other process parameters during ultrasonic assisted machining, such as both the acoustic and tool structure parameters.

Circular Milling Cutter Design and Finite Element Simulation for Machining Hardening Steel Mould

This paper aim at frequent alternating load, caused by milling large covering parts with hardened steel give rise to cutting chatter, increase surface size error in mould processing. Based on theory of helix spiral surface, design circular milling cutter with damping groove, and employ simulation of finite element to verify the efficient performance of chip breaker. Effectively reduce milling vibration problem caused by the mutation of cutting force, cutting temperature, provide theoretical model to the subsequent tool structure parameters and manufacture technology research.

Simulation-based solid carbide end mill design and geometry optimization

Designing a high-performance solid carbide end mill is difficult due to the complex relationship between end mill geometry and numerous or conflicting design goals. Earlier approaches of computer-aided solid end mill design are limited to only a few design aspects. This article presents a three-dimensional finite element method of milling process for solid carbide end mill design and optimization. The software was secondarily developed based on UG platform, integrating the parametric design with the development of the two-dimension drawing of solid carbide end mill. The three-dimension finite element simulation for milling Ti-6Al-4V alloy was performed and the geometrical parameters were optimized based on the objective of low cutting force and cutting temperature. As a result, a simulation-based design and optimization of geometrical parameters of tool structure and cutting edge is possible. The optimized results, for the geometrical parameters of tool structure and cutting edge when milling titanium alloy using a 20-mm diameter solid carbide end mill, is a 12-mm diameter of inner circle, four flutes, a 45 ° helix angle, and a 9 ° rake angle of the side cutting edge.