制造技术与机床

Design of a test-rig for measuring the performance of different types of RV reducers

WANG Zihao, WANG Cheng, PAN Shilin

2022, (1): 9-13. doi: 10.19287/j.cnki.1005-2402.2022.01.001

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Abstract:
Traditional RV reducer test-rig can only complete the performance test of one type of RV reducer, which causes great waste. In order to overcome the above shortcoming, a design method of test-rig of RV reducer with replaceable types is proposed. Firstly, the composition of RV reducer test-rig is introduced and the theoretical analysis of test-rig design of RV reducer with replaceable types is completed. Secondly, the three-dimensional models of test-rig of RV reducer with replaceable types are established and the assembly and motion analysis of different RV reducer types on the test-rig are completed. Finally, the actual machining of components and parts, installation of test-rig of RV reducer with replaceable types and test measurement are completed, which verifies the feasibility of the proposed method.

Modeling and experimental research on mirror model of robotic processing equipment

NAN Xiaoxuan, WANG Jun, XIAO Ming, XI Wenming

2022, (1): 14-18. doi: 10.19287/j.cnki.1005-2402.2022.01.002

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Establishing a mirror model of processing equipment in the digital space is the basis for intelligent manufacturing. The mirror model and processing equipment constitute a digital twin, so as to realize the processing simulation, simulation and parameter optimization of the processing equipment in the digital space. The axis rotation method is used to obtain the axis and position of each axis of the physical robot, and the decoupling calibration of the geometric parameters and the zero position of the physical robot is realized. The coordinate transformation method is used to establish the kinematics equation of the physical robot and the Newton iteration method is used to obtain the inverse kinematics solution. In the digital space, the calibrated geometric parameters are used to establish a mirror model of the physical robot, and the tool path generation and post-processing modules are integrated. The experimental results show that the maximum processing error of the physical robot′s constant attitude is 0.28 mm, and the machining error range of the robot′s variable attitude is -0.83~+0.52 mm.

Research on 3D printing process of jewelry resin based on DLP

Maimaitireyimujiang TUER, Wurikaixi AIYITI

2022, (1): 19-23. doi: 10.19287/j.cnki.1005-2402.2022.01.003

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DLP (Digital Light Processing)is a kind of 3D printing technology which is building layer by layer by surface exposure. In the 3D printing process of DLP, when the thickness of the layer is determined, the printing accuracy of the part mainly depends on the exposure time and building direction. A test sample is designed to study the influence of single-layer exposure time and part building direction on the printing accuracy of different features in the process of printing jewelry resin materials by DLP process. The results show that, for the used jewelry casting resin, when the exposure time is small, the curing is not enough, which leads to larger size error. When the single-layer exposure time is set at 9.5 s, the printed feature accuracy is better; The printing error of features with the same size is different when the building direction is different. When the axis direction of square tube, circular tube, cone and semi cylinder and the height direction of inclined prism are the same as the slicing direction, the step effect can be avoided and the contour accuracy is higher.

Additive/subtractive flexible manufacturing and the structural composition of machining system

WANG Gonghai, FENG Peifeng

2022, (1): 24-28. doi: 10.19287/j.cnki.1005-2402.2022.01.004

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Abstract:
The idea of flexible manufacturing was introduced into additive/subtractive manufacturing, and the additive/subtractive flexible manufacturing process was formed. The connotation and processing range of the process were described, the process flow of additive/subtractive flexible manufacturing was established, the characteristics of each component process were discussed, and a variety of flexible processing methods in between the two processes of material deposition and material removal in additive/subtractive flexible manufacturing were emphatically expounded in detail.on this basis, The equipment structure and interrelation of the additive/subtractive flexible manufacturing system were established, and the general layout of the processing equipment was given.which lays a foundation forresearch of the process sequence planning and the detailed structure.

Design and analysis of magnetism installation based on Maxwell

ZHAO Changlong, LV Qiyin, WANG Xuxu, YANG Junbao, LI Ming

2022, (1): 29-33. doi: 10.19287/j.cnki.1005-2402.2022.01.005

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Abstract:
To realize the magnetization of hydrogel mixed with NdFeB powder, a new type of magnetic field generator based on Helmholtz coil is designed in this paper. The 3D model of the magnetic field system is drawn using the Maxwell software 3D module, and the Magnetostatic static magnetic field solver is used to analyze the influence of the added auxiliary coil distance on the field strength, and the optimized structure of the magnetic field generator is obtained; then compare the magnetic field generator and Helm The central magnetic field intensity and magnetic induction line distribution density of the Holtz coil verify the reliability of structural optimization. The results show that when the auxiliary coil distance is 70 mm, the central magnetic field strength is the largest; when the number of ampere turns is the same, the central magnetic field strength of the magnetic field generator is significantly higher than that of the Helmholtz coil, and the final optimized magnetic field generator′s central magnetic field strength can be reaching 1.37 T, the distribution of magnetic lines of induction is more uniform and denser. The simulation results can provide a reference for the structural design and working characteristics analysis of the magnetic field generating device and shorten the design cost and development cycle of the magnetic field generating device.

Application of TRIZ innovative method in the numerical control processing of plastic plates

CHEN Guohua, YAN Qing, ZHANG Lin, CHENG Zhongtai, YANG Xiaoping, ZHANG Haiyan

2022, (1): 34-37. doi: 10.19287/j.cnki.1005-2402.2022.01.006

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Aiming at the sticking problem of plastic plates in CNC machining, an innovative solution based on TRIZ theory is proposed. On the basis of analyzing the interaction, function, and causal chain of components such as spindle, tool, plastic plate, cutting, nozzle and compressed air in the CNC machining process, find the root cause of the sticking problem, and then use contradiction analysis and object-field model The analysis puts forward the solution of adding a fan on the main shaft and replacing the gas nozzle with a water mist nozzle. After application verification, this method effectively reduces the sticking phenomenon of plastic plates in processing and improves the processing efficiency.

Research on preventive maintenance method of motorized spindle based on performance measurement

ZHANG Risheng, LIU Weixin, YU Wei, HU Qiu

2022, (1): 38-44. doi: 10.19287/j.cnki.1005-2402.2022.01.007

[Abstract] FullText HTML PDF(17871KB)

Abstract:
Aiming at the problem of preventive maintenance of motorized spindle, firstly, the structure and common faults of motorized spindle are analyzed, and the fault prone parts and causes are obtained; Then, according to the fault prone parts of motorized spindle, the preventive maintenance system of motorized spindle is designed, the performance measurement scheme and evaluation standard of fault prone parts are designed, and the preventive maintenance method of motorized spindle is obtained; Finally, the preventive maintenance method is applied to a variety of precision CNC machine tool motorized spindle, and the effectiveness of the proposed preventive maintenance method is verified. The experimental results show that the proposed preventive maintenance method can effectively identify the early performance degradation of motorized spindle, and provide an effective basis for preventive maintenance and performance degradation trend monitoring.

A research based on the structure form of the front-end of high-speed spindle

ZHANG Haibo

2022, (1): 45-47. doi: 10.19287/j.cnki.1005-2402.2022.01.008

[Abstract] FullText HTML PDF(3554KB)

Abstract:
The spindle is the "heart" of machine tool. The performance of the spindle directly determines usage situation and behavior of machine tool, as a main functional component. The first "defender" of the spindle is the front-end seal structure. Large-flow cooling and machining dust can easily contaminate the spindle and bearings. Therefore, the design and selection of the front-end seal structure of the spindle should be seriously considered during the design of the spindle components. This paper focuses on how to select proper type of the spindle and its front-end seal structure, according to the structure and processing conditions of the machine tool.

Axis performance prediction of oscillating grinder based on crankshaft contour error analysis

FANG Xiaoyan, SHENG Xiaowei, SUN Yize

2022, (1): 48-52. doi: 10.19287/j.cnki.1005-2402.2022.01.009

[Abstract] FullText HTML PDF(5801KB)

Abstract:
Engine crankshaft production line requires high reliability and accuracy stability for the oscillating grinding machine. Based on the field contour error data of the crankshaft, the mapping relation between the contour error of the crankshaft and the axis position control error of the oscillating grinding machine can be obtained. There will be great significance for the axis performance predication and the reliability maintenance of the oscillating grinding machine. Firstly, a calculation method from the axis position control error of the oscillating grinder to the contour error of the crankshaft is presented. Secondly, the contour error analysis method based on variational mode decomposition (VMD) is proposed. Lastly, through the grinding experiments, the error data is acquired and measured to calculate and analyze the error data by using VMD method for obtaining the mapping relationship between the crankshaft contour error and the axis position control error. The conclusion shows the two IMF (intrinsic mode functions, IMF) components of the crankshaft contour error that are analyzed by VMD correspond to the contour error caused by X-axis and C-axis position control error respectively. Therefore, the proposed method can realize the axis performance prediction of the oscillating grinder.

New progress in reliability research of mechanical products-reliability theory of meta-action

ZHANG Genbao, RAN Yan, YU Hui, LI Li

2022, (1): 53-59. doi: 10.19287/j.cnki.1005-2402.2022.01.010

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Abstract:
The differences between mechanical products and electronic products are compared. The main problems of traditional reliability analysis methods of mechanical products are analyzed. The theoretical basis of meta-action reliability is given, and the theoretical system of meta-action reliability is introduced. The key technology of meta-action reliability theory is discussed. The practice shows that the meta-action method is very specific to carry out the reliability design and analysis of mechanical products, which is helpful to improve the reliability of mechanical products.

Research and optimization of the press-fitting process of valve guide and cylinder head of marine diesel engine

LIU Dongwei, BAO Junhua, HE Weidong

2022, (1): 60-64. doi: 10.19287/j.cnki.1005-2402.2022.01.011

[Abstract] FullText HTML PDF(4841KB)

Abstract:
Diesel engine cylinder head is one of the core components of marine diesel engine. The valve guide is the guiding device of the diesel engine valve. Accurate assembly can ensure that the valve can make straight reciprocating motion accurately. The valve guide and cylinder head generally adopt interference connection. Therefore, it is very important to ensure the assembly quality of the valve guide and the cylinder head. This paper mainly analyzed the press-fitting force and the stress and displacement changes caused by the valve guide and cylinder head assembly process under different interference conditions, and used the inner diameter of the valve guide of the contained part as the optimization parameter to optimize. Under the conditions of meeting actual working requirements, designed the optimal valve guide inner diameter size, and got the best fit size of the two interference fits, so as to provide the valve guide with the smallest pressing force, stress and the best interference pressing into the cylinder head, which provides a theoretical reference and guides actual production.

Research and improvement of the design scheme of the anti-stress cone cutting device for submarine cable based on TRIZ

DONG Hui, GAO Changqing, QU Aitao, ZHAO Yun, YANG Bo

2022, (1): 65-70. doi: 10.19287/j.cnki.1005-2402.2022.01.012

[Abstract] FullText HTML PDF(6742KB)

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Aiming at the low efficiency and poor quality of artificial cutting for anti-stress of submarine cable, a cutting device for the anti-stress cone of submarine cable is designed and a testing machine is made. Through the cutting experiment, it is found that the chip splashes everywhere, falls out of the device and sticks to the tool and gear, which affects the cutting accuracy. Aiming at this problem, using the method of substance-field analysis method in TRIZ, through analyzing the components of the system and establishing the functional model, the relationship between the key components is obtained. Through the reason analysis, the root cause of the problem is found. Through the substance-field analysis and the application of standard solutions, the idea of structure optimization is obtained, and a specific optimization scheme is proposed.Through the comparative experiments before and after optimization, the feasibility of the scheme is verified.

Research on H_∞ robust control of magnetic levitation system of electrically excitation linear synchronous motor

LAN Yipeng, ZHANG Minghui

2022, (1): 71-76. doi: 10.19287/j.cnki.1005-2402.2022.01.013

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In order to solve the nonlinearity of state variables, disturbance and parameter uncertainty of magnetically levitated linear synchronous motor, a H_∞ robust control method of magnetically levitated system was proposed. By electric excitation linear synchronous motor running mechanism of the magnetic levitation system, establish electric excitation linear synchronous motor suspension system of levitation force equation and the equation of motion, the state space model of suspension system is derived, in view of the nonlinear state space model, adopt the method of balance linearization for linearization, the system of disturbance rejection problem due to the design of the controller, By solving the positive definite solution of the Riccati inequality, the H_∞ robust controller of the suspension system is obtained.Finally, MATLAB/Simulink software is used for simulation research. Compared with the PI control, the results show that the H_∞ robust control method can make the electroexcited linear synchronous motor have good disturbance suppression ability.

Optimal design of column structure based on combined approximate model technology based on radial basis

WEI Fengtao, SHI Yunpeng, ZHANG Yangyang, LI Junyu, GAO Xinqin

2022, (1): 77-83. doi: 10.19287/j.cnki.1005-2402.2022.01.014

[Abstract] FullText HTML PDF(18828KB)

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In view of complex optimization problems in actual engineering, it is usually difficult to obtain the display function relationship expression between the optimization design variables and the optimization goals. This paper takes the column of the SZJY-14 machining center as the research object, and studies a technology based on a combined approximate model optimized design of the column structure.First of all, for the low prediction accuracy of the radial basis basis approximation model, a multi-strategy based radial basis approximation model technology is studied, and based on the improved radial basis basis approximation model technology, a combined approximation model technology is constructed; secondly, The finite element analysis software Abaqus was used to mesh the three-dimensional structure of the column, and the static and dynamic performance analysis was performed to determine the optimization target, and the sensitivity analysis method was used to determine the optimization design variables, and the combined approximate model technology was used to establish the column optimization model; finally, The improved backtracking search optimization algorithm is adopted to realize the optimization design of the column structure. The solution results show that compared with the original structure of the column, the optimized mass is reduced by 3.77%, the maximum deformation is reduced by 5.14%, and the first-order frequency is increased by 5.9%, achieving the expected effect.

Modeling and study on characteristic of high accuracy FTS system

ZHANG Min, WU Zhiqun, CHEN Dongsheng

2022, (1): 84-88. doi: 10.19287/j.cnki.1005-2402.2022.01.015

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Fast tool servo (FTS) is one of mechanical methods used in optical components with complex surfaces. In this paper, a FTS system which is drived by piezoelectric ceramic(PZT) and transferred by flexuer hinges is developed. The testing results show that the positioning errors are less than 4 nm, the repetitive positioning error is less than 4 nm, the max travel is 50 nm and the frequency response precedes 150 Hz at 20 μm; A good foundation for future use was built in optical components with complex surfaces.

Numerical simulation of wall thickness variation in single point incremental forming of TA1 sheet

HAO Yongxing, YANG Gongzheng, LIU Yahui, FAN Suxiang

2022, (1): 89-93. doi: 10.19287/j.cnki.1005-2402.2022.01.016

[Abstract] FullText HTML PDF(15598KB)

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Titanium and its alloys are increasingly used. At present, single point progressive forming technology has been applied to the forming of titanium and its alloys, but there is still a problem of excessive thinning of the wall thickness of the formed parts, which seriously affects the forming quality of the forming parts. In this paper, the influence of the process parameters such as tool head diameter, bottom edge length, original thickness and pitch on the average wall thickness reduction rate and the maximum wall thickness reduction rate of the forming parts are studied by using Abaqus finite element simulation software and the principle of single variable. The results show that the average wall thickness reduction rate increases with the increase of tool head diameter, and the maximum wall thickness reduction rate decreases; The average wall thickness reduction rate and the maximum wall thickness reduction rate increase with the increase of the bottom edge length; The original thickness of the plate increases, and the average wall thickness reduction rate and the maximum wall thickness reduction rate decrease; With the increase of pitch, the average wall thickness reduction rate decreases gradually, and the maximum wall thickness reduction rate increases gradually.

Research on control system of synchronous flexible punching device based on fuzzy PID algorithm

MU Tianchi, ZHANG Dongmin, ZHOU Weimin

2022, (1): 94-97. doi: 10.19287/j.cnki.1005-2402.2022.01.017

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Abstract:
The synchronous control system is a key part of the multilateral synchronous flexible stamping device. Its performance directly affects the quality of the product. The hydraulic synchronous system has established precise mathematics due to the influence of nonlinear friction, eccentric load, and time-varying operating parameters. It is very difficult to synchronize the system model. In response to this problem, the advantages of Simulink and AMESim simulation software are used to build a joint simulation platform for the synchronous control system, and a dual fuzzy control method with compensation factors is used to effectively solve this problem. Under the same working conditions, compared with traditional hydraulic control systems, the dual fuzzy PID control with compensation factor can better achieve the accuracy requirements of synchronous control, and the hydraulic control circuit can also achieve the purpose of energy saving and realize the three sides of the parts. The high precision of centering stamping can effectively reduce the generation of unqualified products and improve production efficiency.

Study on tribological properties of Ti6Al4V/WC-Co under different dry friction conditions

LIANG Xiong, DU Ping, GAO Dangxun, LI Shuangshou

2022, (1): 98-102. doi: 10.19287/j.cnki.1005-2402.2022.01.018

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The tribological properties of titanium alloy (Ti6Al4V) against cemented carbide (WC-Co) under dry sliding condition were studied by using Optimal SRV tribotester. The effects of load, temperature and sliding speed on the friction process were studied, and the wear mechanism was analyzed by characterizing the micro-morphology of the wear zone. The results show that the friction coefficient fluctuates violently under all experimental conditions, which indicated that serious stick-slip friction occurs, and the stick-slip phenomenon becomes more intense with the increase of load, temperature and sliding speed. In comparison, the effect of sliding speed on friction coefficient is more significant. Micro-morphology analysis shows that the wear form of titanium alloy is mainly adhesive wear, but accompanied by grooves caused by ploughing effect, while cemented carbide mainly shows a certain degree of adhesive wear because of its high hardness.

Effect of micro-sandblasting pretreatment on surface integrity of an AlCrN coatied tool

WU Zhenyu, ZHENG Guangming, GAI Shaolei, LI Fangliang, YANG Xianhai, CHENG Xiang

2022, (1): 103-106. doi: 10.19287/j.cnki.1005-2402.2022.01.019

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AlCrN coating is deposited on YG8 cemented carbide by physical vapor deposition after micro-sandblasting pretreatment of YG8. The effect of micro-sandblasting pretreatment parameters on the surface integrity (surface morphology, surface roughness, surface hardness and surface stress) is studied. The results show that the surface defects and the surface roughness Ra of the coated tool are reduced under the micro-sandblasting parameter of P=0.3 MPa and T=30 s, while the microhardness and surface residual stress of the coated tool are improved. And then the influence of micro-sandblasting pretreatment on the surface integrity of coated tools is explored. The micro-sandblasting process parameters are optimized. This work is helpful to promote the development of surface treatment technology of coated tools.

A coordination technique of precision holes in large truss structure

LIU Qiang, WANG Deting, YANG Hao, YAO Yachao, LI Jinlong

2022, (1): 107-111. doi: 10.19287/j.cnki.1005-2402.2022.01.020

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The engine frame of a launch vehicle is a large-diameter truss structure, which has the characteristics of weak stiffness and large welding deformation. As a transitional structure of connecting the engine and the rocket body to transmit thrust, its connecting hole on the upper and lower ends face has the coordination requirements of high precision and consistency. Aiming at this problem, a precision hole coordination scheme is proposed, which uses pre fitting and quadratic fitting method to coordinate the envelope problem of bottom hole, uses pin hole positioning to coordinate the secondary benchmark, and realizes the overall coordination of precision holes. At the same time, a prediction model of position degree based on BP neural network is proposed to predict the position degree of butt hole after machining.Through the actual processing verification, this method can realize the overall coordination of the 5-meter truss structure docking hole, and ensure the high precision requirements of the docking hole. Moreover, the algorithm can effectively predict and verify the test results of position degree, improve the inspection reliability, and provide a way of thinking for the overall coordination of aerospace large-scale product processing.

Discussion on application of simulation analysis method in gear hobbing

ZHANG Jianyu, WU Mingyang, MA Chunjie, WANG Xinyu, CHENG Yaonan

2022, (1): 112-118. doi: 10.19287/j.cnki.1005-2402.2022.01.021

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Because of its high productivity and versatility, gear hobbing has always been paid more attention in the gear manufacturing process. However, due to the complexity and particularity of the forming movement of gear hobbing, the simulation model and method should be established to assist the analysis of this process. In this paper, the CAD geometric simulation and finite element simulation research were discussed. From the aspects of chips, cutting force, cutting temperature and tool wear, the main research methods and results of scholars both at home and abroad were disscussed, the defects of the present study were analyzed, summarize and made a forecast, provide a certain reference for the research of hobbing process optimization, cutting tool life and workpiece surface quality improvement.

Mechanical and thermal coupling simulation analysis and dual-objective parameter optimization of TC11 titanium alloy

CONG Zheng, CAO Yan, HE Zhihao, CHU Zhiguo

2022, (1): 119-123. doi: 10.19287/j.cnki.1005-2402.2022.01.022

[Abstract] FullText HTML PDF(4970KB)

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Aiming at the difficult machining problem of a certain type of space disk parts made of TC11 titanium alloy, ABAQUS simulation software was used. Based on the actual cutting parameters, the cutting force, heat distribution law and the interaction of cutting parameters during the turning process were analyzed. First, a single factor experiment was used to explore the law of cutting force and heat distribution. Secondly, the orthogonal experiment method is used to study the cutting force and heat distribution law under the interaction, and to fit the multiple linear regression model of the cutting force and heat. Finally, the regression model is optimized with two goals. The experimental results show that the order of the effect of cutting amount on cutting force is: depth of cut>feed>cutting speed, and the order of influence on cutting temperature is feed>cutting speed>depth of cut. The regression model is highly fitting test, and the algorithm optimization can effectively optimize the cutting parameters and reduce the cutting force and cutting heat.

Experimental study of high-strength steel for high-speed milling AF1410

WANG Xi, HUANG Shutao, XU Lifu, ZHANG Yupu, YU Xiaolin

2022, (1): 124-129. doi: 10.19287/j.cnki.1005-2402.2022.01.023

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High-strength steel has excellent mechanical properties and wide application, but cutting is difficult, there are low processing efficiency, poor quality processing surface and other problems. In this paper, AF1410 high-strength steel as the research object, the application of high-speed milling machining methods, the use of coated carbide blades, the AF1410 high-strength steel high-speed milling experiments, research and analysis of tool wear, cutting force, cutting temperature and processed surface roughness changes in the conditions. The study found that CVD-coated tools combined with TiCN and Al₂O₃ can be adapted to long-term high-speed stable cutting of AF1410 high-strength steels, and that tool wear patterns are mainly normal wear on the flank surface; Radial force F_r is the largest, axial force F_z is second, and tangential force F_t is minimal during cutting, and as the cutting length increases, the radial force F_r and axial force F_z increase significantly and the tangential force F_t changes less; The chip temperature just cut out by the tool increases gradually, and the workpiece machined surface temperature increases less, and the roughness of the machined surface fluctuates less with the increase in cutting length.

Research on digitization technology of process documents based on regularization algorithm

SI Xingyao, LIAO Yinghua, XU Yun, JIANG Jie, YANG Ming

2022, (1): 130-134. doi: 10.19287/j.cnki.1005-2402.2022.01.024

[Abstract] FullText HTML PDF(4658KB)

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The process planning and data information of aeroengine blade are written and drawn by 2D CAD software. The generated DWG process files are difficult to manage easily and efficiently. In this paper, the management method of blade CAD process information digitization is proposed. Firstly, the relationship between blade drawing process specification and data information is analyzed. The least square method is used to locate the size of the drawing, and the key position is determined according to the coordinates to judge the type of blade process card; Then, the process information of the cells needed for recognition is judged, the text is sorted by using the regularization algorithm, and the special characters are recognized and processed to obtain the accurate blade process information data after adjustment. The practical results show that the method can quickly and stably identify the process information data in CAD process files, and provide the application reference of drawing management method for the factory to realize intelligent manufacturing digitization.

Research on error diagnosis of frame structure model based on a high precision convolution neural network

CAI Chaozhi, CHI Yaolei, GUO Lubin

2022, (1): 135-140. doi: 10.19287/j.cnki.1005-2402.2022.01.025

[Abstract] FullText HTML PDF(5797KB)

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Frame structure health detection and fault diagnosis is a very important scientific problem in mechanical engineering, civil engineering and other disciplines. In order to improve the accuracy of frame structure fault diagnosis under noise condition, this paper improves the existing TICNN (convolution neural networks with training interference) model, and obtains a new convolutional neural network model with strong anti-noise ability. In order to verify the superiority of the improved TICNN in anti-noise, the experimental results show that the improved TICNN has the best effect compared with TICNN, 1DCNN(dimensional convolution neural network) and WDCNN(first layer wide convolution kernel deep convolution Neural Network). On this basis, the fault diagnosis experiment of a four story steel structure model is carried out by using the improved TICNN and the two classification method. The results show that the improved TICNN can still get high diagnosis accuracy under noise conditions, which verifies the advantages of the improved TICNN.

Research on thermal error modeling of machine tool based on bayesian neural network

WANG Zihan, YANG Xiuzhi, DUAN Xianyin, JIANG Yuhui, WANG Xingdong

2022, (1): 141-145. doi: 10.19287/j.cnki.1005-2402.2022.01.026

[Abstract] FullText HTML PDF(13912KB)

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Thermal error seriously affects the machining accuracy of the machine tool. The thermal characteristic analysis of the key parts of the machine tool is an important link in the development of precision machine tool. Therefore, this paper studies the relationship between temperature rise and positioning error by measuring the thermal characteristics including the temperature and positioning error of special position of CNC machine tool, and proposes a thermal error modeling method based on Bayesian neural network. Using K-means clustering and correlation coefficient method to select temperature sensitive points can effectively suppress multicollinearity between temperature measurement points. The results show that the accuracy of machine tool can be improved by 88.015 9% by using bayesian neural network, which is 15.763 8% higher than BP neural network. Compared with BP neural network model, bayesian neural network has better prediction performance. Bayesian neural network model provides a new idea to reduce the influence of thermal error of machine tool.

Key technology of BPR6 screw rotor grinder and dynamic analysis of the machine tool

YU Ronghua

2022, (1): 146-151. doi: 10.19287/j.cnki.1005-2402.2022.01.027

[Abstract] FullText HTML PDF(18830KB)

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The precision machining of the screw compressor rotor is realized by a special CNC screw rotor grinder. At present, most of the machines are provided by western developed countries, with long delivery periods, high prices, and potential risks of restricting exports to our country. Under this background, Taizhou Beiping Machine Tool Co., Ltd. developed a BPR6 screw rotor grinder; this article discusses several features of the machine′s key technologies, and the solutions proposed for two shortcomings of foreign technology, and the third-party test results, the comparison of domestic and foreign technical indicators and user usage and evaluation are explained in detail. Finally, the modal analysis of the whole machine tool and its components is carried out. The frequencies of the whole machine tool and its components are obtained, in which the first-order frequency of the whole machine tool is 70.96 Hz.

An extraction model of critical to green quality characteristics in light industry equipment manufacturing stage

ZHENG Hui, ZHAO Naiying, GUO Tiantian, XING Meng

2022, (1): 152-157. doi: 10.19287/j.cnki.1005-2402.2022.01.028

[Abstract] FullText HTML PDF(17589KB)

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In order to enhance the sustainable competitiveness of light industry equipment manufacturing industry in the process of green development, based on the concept of critical to green quality characteristics (CTGQs), a CTGQs extraction model is established to identify the process parameters that have the greatest impact on the environment, The critical to green quality characteristics extraction of light industry equipment in manufacturing stage is realized. In order to eliminate the redundant data in the extraction process, the improved ReliefF algorithm is combined with adaptive particle swarm optimization (APSO) algorithm to improve the accuracy of CTGQs extraction. Finally, a beer fermentation tank is taken as an example to verify the effectiveness of the model.

Research on fault diagnosis method based on LMD and grey correlation degree

YANG Jingzong, SHI Chunchao, YANG Tianqing, LI Changfang

2022, (1): 158-164. doi: 10.19287/j.cnki.1005-2402.2022.01.029

[Abstract] FullText HTML PDF(18278KB)

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Aiming at the nonstationary characteristics of the fault vibration signal of high pressure diaphragm pump check valve, a fault diagnosis method based on local meandecomposition (LMD) and grey correlation theory is proposed. Firstly, LMD is used to decompose the vibration signals of the check valve of high pressure diaphragm pump under different operating conditions into multiple product functions. Then the cross-correlation coefficients of all product functions are calculated, and the product functions with high cross-correlation degree are selected to extract the corresponding feature vectors. Finally, the grey correlation theory is introduced to construct the fault diagnosis and identification model of one-way valve, and the results are compared with those obtained by empirical mode decomposition (EMD), mixed feature modeling and single feature modeling. The experimental results show that the proposed method can decompose the fault signal of one-way valve well, and effectively identify the fault signal of one-way valve under the condition of small samples.

Threaded hole detection method based on guided filtering and neural network algorithm

MA Xiaofeng, WANG Zhongren

2022, (1): 165-170. doi: 10.19287/j.cnki.1005-2402.2022.01.030

[Abstract] FullText HTML PDF(15615KB)

Abstract:
In order to solve the problems of tedious operation, poor accuracy and low efficiency in measuring the screw hole of crankshaft end face, a screw hole detection method based on guided filtering and neural network algorithm was proposed, taking the model YC4W75 crankshaft as an example. Firstly, real-time grabbed images were preprocessed using guided filtering and morphology to eliminate the effects of surface noise and mottle. The edge features of the internal thread path in the crankshaft end face were extracted. Then, combined with RANSAC algorithm, a neural network model was constructed using Pytorch to fit the extracted circle. The size of the internal thread path on the crankshaft end face and the distance between the centers of the circle were obtained. The test results show that the error of the small path of the internal thread is less than 0.070 mm, and the error of each thread hole and the center hole is less than 0.200 mm. The proposed method can meet the accuracy requirements of the industrial site due to high measurement accuracy and the operation simplicity. The automatic measurement of the position information of the threaded hole of the crankshaft end face is realized.

Accuracy detection and error compensation analysis of NC machine tools based on linear regression theory

YANG Xiuzhi, JIANG Yuhui, WANG Xingdong, WANG Zihan

2022, (1): 171-176. doi: 10.19287/j.cnki.1005-2402.2021.09.031

[Abstract] FullText HTML PDF(17631KB)

Abstract:
In order to improve the positioning accuracy of NC machine tool, the error source of machine tool precision should be analyzed and compensated. The principle of precision detection and compensation of numerical control machine tool based on linear regression theory with laser interferometer is discussed. The model of data detection is established. The characteristics of each error point are analyzed. The methods of one-time linear compensation and multistage linear compensation are determined and verified by comparison. Based on the analysis of a numerical control machine tool, the error compensation is realized according to the experimental data. Finally, the compensation effect of positioning accuracy is analyzed. The results show that the accuracy of X axis is increased from 4.853 1 ~35.025 0μm to -2.472 1 ~0.736 3 μm by linear compensation. The precision of Y-axis was improved from -14.425 0 ~-4.132 5μm to -2.481 2 ~0.752 9μm. The accuracy of Z-axis was improved from -4.128 0 ~17.227 1μm to -0.501 5~1.324 5μm. The precision of X axis was improved to -1.364 1 ~0.484 0μm by multi-stage linear compensation. The precision of Y-axis was improved to -1.364 1 ~0.551 0μm. The accuracy of Z-axis is improved to -0.412 0 ~0.495 2μm. Before compensation, according to the main characteristics of data distribution, the linear or segmented compensation for the system error of CNC machine tools has a good compensation effect.

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2022 No. 1

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