制造技术与机床

Structure optimization of grinding rod based on VERICUT simulation

RONG Linsen, ZHU Xianglong, DONG Zhigang, KANG Renke, PAN Rui

2023, (3): 13-17. doi: 10.19287/j.mtmt.1005-2402.2023.03.001

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Abstract:
Aiming at the grinding rod with large length-diameter ratio used for machining a non-rotating cone cover, the machining simulation method is adopted to explore its maximum size without collision. Initial size of grinding rod is determined and 3D model is established. CATIA software is used to generate the machining track covering the inner surface of cover, and a special post-processor is developed to generate G code. The machining simulation is completed by VERICUT software. According to the simulation results, the structure of grinding rod is optimized, the diameter of collision place is reduced, and the diameter of non-collision place is increased. The length of grinding rod is 1 855 mm and the diameter of big end is 150 mm after optimization. The final simulation proves that the maximum size of grinding rod without collision is determined by simulation method.

Tool path optimization method for 5-axis flank milling based on deviation compensation of three-point offset cutter locations

CHEN Lizhi, ZHOU Lifeng, WANG Dong, MA Chi, YU Jianhua

2023, (3): 18-23. doi: 10.19287/j.mtmt.1005-2402.2023.03.002

[Abstract] FullText HTML PDF(1683KB)

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A cutter with straight generatrix is difficult to fit the curved surface accurately in five-axis flank milling of non-developable ruled surfaces, in order to solve this problem, a general three-point offset strategy is proposed for initial tool positioning, geometric deviation between the cutter and the design surface is then calculated along the tool axis, the desired distribution of points on the tool axis trajectory surface is obtained according to the concept of deviation compensation, and a tool axis trajectory surface model is constructed, furthermore, the SVD algorithm is utilized to solve the model, and the optimal solution is selected aimed at the minimum sum of all machining errors in absolute form. The simulation results showed that the proposed method has obvious advantage in machining accuracy over the heuristic-algorithm-based tool path optimization methods.

Study on formation mechanism and suppression of subsurface damage during nano-grinding of monocrystalline silicon

TIAN Hailan, HAN Tao, YAN Shaohua, YI Hongxing, YAN Haipeng

2023, (3): 24-30. doi: 10.19287/j.mtmt.1005-2402.2023.03.003

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The subsurface damage generated during nano-grinding of silicon wafers limits its service life. It is urgent to study the formation mechanism and suppression methods of subsurface damage during nano-grinding of monocrystalline silicon. In this study, a molecular dynamics simulation model of nano-grinding monocrystalline silicon was established to study the formation mechanism of subsurface damage. Then, the influence mechanism of grinding parameters on grinding force, grinding temperature and subsurface damage formation during grinding was studied. Finally, the damage suppression strategy of nano-grinding monocrystalline silicon was proposed. The results showed that the main subsurface damage formation mechanism was structural phase transformation and amorphousness during nano-grinding monocrystalline silicon. The original Si-I phase formed Si-II phase, Si-III phase, Si-IV phase, bct5-Si phase and amorphous phase under extrusion and shear. The increase of grinding depth led to the increase of grinding force and grinding temperature, while the increase of grinding speed led to the decrease of grinding force and the increase of grinding temperature. The increased grinding force was the main reason for the serious subsurface damage, and a certain degree of high temperature was beneficial to inhibit the subsurface damage of monocrystalline silicon. In nano-grinding of monocrystalline silicon, subsurface damage can be suppressed by reducing grinding depth and increasing grinding speed.

The influence of cutting parameters on the cutting performance of resin polyamide-66 material

ZHANG Jilin, SHEN Jiancheng, JIA Haishen, LIANG Zefen, ZHANG Defu

2023, (3): 31-38. doi: 10.19287/j.mtmt.1005-2402.2023.03.004

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In order to study the influence of cutting parameters on the cutting performance of resin polyamide-66 materials, the single factor and response surface method were used for experimental design and analysis. and roughness. The single factor study shows that when the cutting speed is increased, the cutting force gradually decreases, and the cutting temperature and roughness gradually increase; when the feed rate and the amount of back engagement are increased, the cutting force, cutting temperature and roughness all gradually increase. The quadratic regression model between cutting parameters and cutting force, cutting temperature and surface roughness was constructed by the response surface method, and the parameters of cutting speed, feed and back-cut amount and their interaction on the resin polyamide-66 were studied. The effect of cutting properties of materials. The results show that the quadratic regression model is significant, and its fitting accuracy is 98.89%, 99.09% and 96.00%, respectively. The predicted cutting speed is 90.02 m/min, the feed rate is 0.11 mm/r and the back-cut amount is 2.0 mm, the cutting force is the smallest, the cutting temperature is the lowest and the roughness is the smallest. Cutting tests were performed on the optimal cutting parameters and compared with the predicted results,cutting forces of 32.558 N and 31.762 N, cutting temperatures of 92.5℃ and 90.1℃, and roughness of 0.732 μm and 0.694 μm, respectively, with error rates of 2.44%, 2.59%, and 5.19% between the experimental and predicted values, respectively.

Research on digital twin standards system of CNC machine tool

XUE Ruijuan, HUANG Zuguang, WANG Jinjiang, TAO Fei, ZHANG Peisen, WU Yiran

2023, (3): 39-50. doi: 10.19287/j.mtmt.1005-2402.2023.03.005

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As a key enabling technology to promote the development of intelligent manufacturing, digital twin is drawing great attention on applying in the field of CNC machine tool. However, the lack of general and fundamental standards such as technical terms, reference architecture, key technology leads to problems of application in the field of CNC machine tool. Therefore, digital twin standards of CNC machine tool are urgently required. This study analyses the demand of digital twin standards of CNC machine tool. Based on the above research, combined with five-dimension on digital twin model and research on digital twin technology, this study constructs the framework of digital twin standard system of CNC machine tool, which contains fundamental standards such as general requirements, safety, test methods and key technology standards such as CNC machine tool configuration, data processing, connection and interaction. Discussion is done on the application and function of digital twin standards of CNC machine tool. Hope this work can not only give reference for researchers of digital twin standards and CNC machine tool standards, but also guide for digital twin application in the field of CNC machine tool.

Research and application of mold processing task and manufacturing resource service matching in cloud manufacturing environment

KUANG Chaopeng, TAO Jianhua, LI Tingtai, CHEN Bin, MA Yao, WANG Wei

2023, (3): 51-59. doi: 10.19287/j.mtmt.1005-2402.2023.03.006

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In view of the changing requirements of the processing tasks of traditional mold enterprises, more personalized mold processing tasks have been proposed. There is a lack of communication and cooperation between enterprises in different regions. Traditional mold enterprises only rely on their own processing resources, which is difficult to meet the needs of complex and changeable processing tasks. Introduction of cloud manufacturing model, classification and encoding rules of mold processing the task as well as the relationship between tasks, establishing the model of mold manufacturing enterprise order project using UML modeling technology, to formal description of mold processing task, determine the mold processing task constraint relations, and put forward the mold processing tasks and manufacturing resource service matching three models, And the gold, silver and copper manufacturing resources service retrieval algorithm, combined with the analytic hierarchy process, expert evaluation method and entropy weight coefficient method of subjective and objective comprehensive method to calculate the optimal index weight coefficient, the results obtained as the optimal service. The results show that it can effectively promote the cooperative work among enterprises, enrich the production and manufacturing mode of enterprises, effectively improve the utilization rate of idle processing resources, and reduce the production cost.

Manufacturing resource service allocation based on information axiom under mixed QoS

ZHANG Yuanshuo, WANG Youyuan

2023, (3): 60-64. doi: 10.19287/j.mtmt.1005-2402.2023.03.007

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In order to realize the effective allocation of manufacturing resources in cloud manufacturing environment, a manufacturing resource service allocation method based on information axiom under mixed QoS condition was proposed. Firstly, method distinguish the mixed QoS index, the information content of the index was calculated based on the information axiom, and the semantic phrase was transformed into fuzzy number by using fuzzy trigonometric number, building a mixed QoS index method to calculate the volume. According to the information of each QoS index and the corresponding weight, the comprehensive information of manufacturing resources was calculated and sorted to achieve the optimization of manufacturing resources allocation. Finally,the effectiveness of the method was verified by an example.

Workpiece recognition of assembly robot

ZHONG Peisi, FU Lin, LIU Mei, WANG Xiao, GUO Shihe

2023, (3): 65-70. doi: 10.19287/j.mtmt.1005-2402.2023.03.008

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To solve the problems of low assembly flexibility and poor workpiece recognition robustness of industrial robot, a workpiece recognition method based on machine vision is proposed for parts assembly. First, the feature points are extracted uniformly using the double-layer rotating filter with dimensional invariance and rotational invariance, then the feature point descriptors with orientation are generated by the rBRIEF algorithm, and then the Hamming distance and RANSAC algorithms are used for feature point matching and optimization to accurately identify the target artifacts. The proposed method is tested with workpiece images, and the results of workpiece recognition by the method and other three traditional methods under rotation and scaling transformation are compared and found to be more accurate and efficient in recognizing workpieces. Finally, the experimental platform of shaft-hole assembly based on machine vision is built to verify the feasibility of workpiece recognition.

A robot following pendant system based on visual recognition

XUE Jiaxing, LIU Xiaolin, XUE Yanjie

2023, (3): 71-75. doi: 10.19287/j.mtmt.1005-2402.2023.03.009

[Abstract] FullText HTML PDF(1402KB)

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Suspension chain transportation is an important link in the process of engine block casting transfer, Aiming at the problems of low production efficiency, high labor intensity, hidden safety risks and knock and tear caused by the artificial pendant in the existing process, a robot movable pendant system based on visual recognition was designed. The system uses visual recognition technology and robot tracking technology to realize the suspension chain in the motion of 300 kg heavy load cylinder automatically grab the pendant. The system has been put into use, operation is stable and reliable, the robot effectively replaces the manual, the production efficiency is increased by 10%, and the rejection rate due to the knock and bump of castings is reduced to below 0.4%, which has a good application prospect.

Design for intelligent detection and control system of CNC wireless probe based on least square methods

XUE Ming, WU Guangming, LIU Huiqiang

2023, (3): 76-84. doi: 10.19287/j.mtmt.1005-2402.2023.03.010

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A measurement error compensation model based on the least squares curve fitting interpolation method is studied aiming at various detection errors of the existing contact probe in order to improve the efficiency and quality of CNC on-machine detection. The algorithm calibrates the probe model and constructs the system measurement error compensation model through the least square method, and designs a set of CNC wireless probe intelligent detection and control system with high accuracy to achieve the dimensional accuracy and error compensation of on-machine measuring parts. The production results show that the system error compensation algorithm is feasible, effective and superior, which improves the production efficiency and quality, reduces the defective rate and production costs, and can be widely applied to size measurement and error compensation of CNC milling precision machining parts.

Current situation and development of key equipment and technology of new generation launch vehicle body system

LIU Dong

2023, (3): 85-93. doi: 10.19287/j.mtmt.1005-2402.2023.03.011

[Abstract] FullText HTML PDF(2641KB)

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Launch vehicles are the main means for a country to enter space, and its manufacturing level is crucial to the process of controlling space. As the main part of the launch vehicle, the structure of the rocket body is the key to rocket manufacturing. After decades of development, the rocket body manufacturing technology has gradually shifted from a manual operation-based model to a green and automated technology-based model. According to the manufacturing situation of the rocket body structure at home and abroad, this article gives a detailed introduction to the key technologies and equipment in the rocket body structure manufacturing process, including sheet metal forming, milling processing, drilling and riveting, welding and rocket body docking. The main process summarizes the domestic and foreign gaps and application difficulties of related technologies, and provides a reference for the development of my country's launch vehicle rocket body structure manufacturing level.

Design and research of "trinity" digital manufacturing experimental platform

LIU Jisheng, TAN Ziqiang, LI Wei, JIA Zhixin, FANG Pengcheng

2023, (3): 94-100. doi: 10.19287/j.mtmt.1005-2402.2023.03.012

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In order to adapt to the development requirements of digital transformation of education in mechanical design and manufacturing, the "Trinity" digital experiment platform was designed by using Internet technology, inverse design, five-axis CNC machining, virtual-real technology and modern mechanical design methods, and the digital design module, digital manufacturing module and digital inspection module were developed. Based on the "Trinity" experiment platform, the isentropic efficiency of complex impeller optimized design has increased by 0.7%, the flow rate has increased by 3.92%, and the machining quality and manufacturing efficiency have been improved, and the accuracy of five-axis CNC machine tools has been improved. The precision of the use of the five-axis CNC machine tools has been improved. The design and development of the "Trinity" digital manufacturing experimental platform provides a theoretical basis and construction solution for the digital transformation of education in enterprises and institutions of higher learning, and helps cultivate innovative and complex talents in the mechanical design and manufacturing industry.

Variable-domain double fuzzy active disturbance rejection control for electromagnetic linear actuators

LI Detong, GE Wenqing, TAN Cao, CHEN Jiewei, LU Yingtao, LI Xiaochen

2023, (3): 101-106. doi: 10.19287/j.mtmt.1005-2402.2023.03.013

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A variable-domain double fuzzy active disturbance rejection control method is proposed for the influence of internal parameter disturbances and external uncertainty disturbances on the control system of the electromagnetic linear actuator system. A dual closed-loop control with PI control for the inner current loop and variable-domain dual fuzzy self-rejecting control for the position loop is designed. Without changing the output domain division, the output of the primary fuzzy control is used as the scaling factor to flexibly adjust the output domain of the secondary fuzzy control, which makes the fuzzy control adaptive and improves the stability and anti-interference capability of the control system. The research results show that compared with the existing control methods, the proposed control method not only has better trajectory tracking capability and control accuracy, but also has good robustness to the internal and external uncertainty disturbances of the system.

Research on green path planning of AGV pickup and delivery with time window constraints

ZHENG Xiaojun, GAO Feng, GAO Jia, GUO Xingze

2023, (3): 107-114. doi: 10.19287/j.mtmt.1005-2402.2023.03.014

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Aiming at the green path planning problem of picking and delivering automated guided vehicles (AGVs) with time windows constraints in the context of flexible manufacturing workshops, minimizing the energy consumption and time deviation energy consumption of AGV collection and distribution process as the combined optimization goal, the AGV green vehicle path planning model is constructed. According to the characteristics of the research problem, a hybrid genetic algorithm with improved variable neighborhood search (GA-VNS) is proposed to solve it, a series of five neighborhood structures are designed to improve the algorithm's optimization ability. The feasibility of the proposed algorithm in this paper is verified by solving the test set of Solomon benchmark and comparing the solution with the internationally best-known optimal solutions. Further, take the AGV logistics transportation task in a certain production period of a flexible manufacturing workshop as an experimental case, the algorithm designed in this paper, GA, and VNS algorithm are adopted respectively. Through a detailed analysis of experimental results, the optimization and applicability of the model and algorithm proposed in this paper are verified. It provides a feasible solution for the workshop to achieve the development goal of energy saving and emission reduction.

Adaptive fuzzy sliding mode control of manipulator based on disturbance observer

LI Hu, LIU Hongbin

2023, (3): 115-120. doi: 10.19287/j.mtmt.1005-2402.2023.03.015

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There are some problems such as modeling error and external disturbance in trajectory tracking control of manipulator. In order to improve the accuracy and speed of trajectory tracking of manipulator, an adaptive fuzzy sliding mode control strategy based on disturbance observer is designed. Firstly, a novel reaching law is used to reduce the influence of chattering in the sliding mode control system of the manipulator. Secondly, a disturbance observer was used to estimate the modeling error and external interference of the manipulator, and the input torque of the manipulator was compensated according to the observed value of the disturbance observer. Finally, for the unobservable part, the unknown disturbances are estimated by the universal approximation principle in fuzzy system, which further improves the trajectory tracking performance of the manipulator. The simulation results show that the control strategy can not only overcome the influence of modeling errors and external disturbances, but also effectively weaken the chattering of the system, and ensure the accuracy and speed of the position tracking of each joint of the manipulator. It also shows that the control strategy is correct and effective.

Model predictive torque control of hot strip mill motor based on load torque observer

LIU Tao, FANG Yifang, WU Dayuan

2023, (3): 121-129. doi: 10.19287/j.mtmt.1005-2402.2023.03.016

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In the field of large hot strip mill drive, AC motor as a drive motor to replace DC motor is the inevitable development trend. With the advantages of low cost, small mass, easy operation, simple structure, reliable operation, easy maintenance, and the ability to be used in harsh environments such as flammable and explosive, AC asynchronous motors are widely favored in the main drive field of large hot strip mills. In this paper, we design a model predictive torque control system for a high power and low speed hot strip mill asynchronous drive motor, and design a load torque observer to do feedforward compensation for the speed external loop controller. The simulation results show that the control system can effectively control the asynchronous drive motor of the hot strip mill with fast response and high stability.

Design of hydraulic bulging process pressurization system for of automobile axle housing

WU Na, LIU Chao

2023, (3): 130-134. doi: 10.19287/j.mtmt.1005-2402.2023.03.017

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Hydraulic bulging is an advanced forming method for manufacturing tube shell parts. Based on the analysis of the hydraulic bulging process of the automobile axle housing, a two-stage supercharger system is designed to meet the working requirements of low-pressure rapid filling, hydraulic replenishment and boosting, high-pressure calibration and rapid pressure relief in the hydraulic bulging process. The pressure control path and the supercharger displacement path are determined. The control strategy based on the displacement control as the main and the pressure control as the auxiliary is given. The production test is carried out, and the pipe fittings with good formability are obtained.

Research on deep drawing process of aluminum alloy drawn box based on segment blank holder technique

ZHANG Hongsheng, QIN Siji, ZHANG Tingting

2023, (3): 135-140. doi: 10.19287/j.mtmt.1005-2402.2023.03.018

[Abstract] FullText HTML PDF(1681KB)

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A radial segmented blank holder technique for drawn box is proposed, which can realize independent loading of blank holder force along the different radial zones. Firstly, the wrinkling model on the flange is established by theoretical derivation. The wrinkles can be suppressed with a smaller blank holder force compared with the conventional blank holder method which preliminarily proves the theoretical feasibility of the new blank holder method. Then, the numerical forming simulations are carried out by using the finite element method. The results show that the radially segmented blank holder can effectively control the material flow, suppress wrinkling and improve the forming limit. Finally, the deep drawing experiment is carried out. With the same blank holder force of 5.9 kN, the drawn box under the action of the new blank holder method has better forming quality, which verifies that the radial segmented blank holder technique is feasible for sheet metal forming.

A clamping optimization method for aviation thin-walled parts with the aim of minimizing strain energy

MEN Xingchen, WANG Zhongqi, DU Zhaocai, LI Chao, CHANG Zhengping

2023, (3): 141-148. doi: 10.19287/j.mtmt.1005-2402.2023.03.019

[Abstract] FullText HTML PDF(1679KB)

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In the clamping process of thin-walled parts, different parameters such as positioning layout, clamping layout and clamping sequence lead to different degrees of deformation of thin-walled parts. Most of existing research by the method of node to the objective function is minimum deformation, deformation degree and ignores all directions of different regions of the stress distribution of the clamping effect, puts forward the minimum strain energy as the target air thin-walled clamping scheme optimization, the most hours, when the whole strain energy thin-walled deformation degree is small, the stress distribution is more uniform.Latin hypercube sampling and finite element software are used to generate sample data.A BP neural network prediction model is established to minimize the global strain energy, and the location of positioning elements is the decision variable. In the clamping process of thin-walled parts, positioning and clamping are interrelated processes. Based on the optimization of positioning layout, the nonlinear mapping relationship between clamping sequence, clamping position and overall strain energy is constructed. The established mapping relationship is iteratively optimized to determine the optimal clamping sequence and clamping position. The correctness and effectiveness of the proposed method are verified by an application example of a curved thin-walled piece.

The study of process test on drilling technology of titanium-steel composite tube plate based on replaceable drill tip

YANG Decun, JIANG Lei, SHUI Yan, DENG Yadi, XIANG Zhiyang, WEN Xiaoshan

2023, (3): 149-155. doi: 10.19287/j.mtmt.1005-2402.2023.03.020

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The end tube plate of the condenser of steam turbine is mostly made of titanium-steel composite tube plate. Due to the great difference in the machining properties of the two metals, the drilling efficiency of the tube hole is low. In this paper, the test of one-time drilling for tube plate with the replaceable drill tip is studied. Firstly, the drilling test of titanium-steel composite plate is designed. The data of diameter, roughness of hole and cutting force in the drilling process are measured, and the chip discharge and built-up edge of tool in the drilling process are analyzed. The adaptability of the drilling technology of the replaceable drill tip for the titanium-steel composite tube plate is summarized. The test results show that the replaceable drill tip has stability for diameter and good chip discharge, which has better ability of drilling hole for the rough machining of titanium-steel composite tube plate of steam turbine condenser.

Research on assembly process of part consumption based on 3D model

YU Zhangyong, WANG Liang, ZHENG Jinfeng

2023, (3): 156-162. doi: 10.19287/j.mtmt.1005-2402.2023.03.021

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Assembly-sets, consistency and integrality are highly required on assembly process of complex products, which needs to support visual assembly based on 3D Model in the case of BOM changes. By studying data relationship and changing process of multiple BOMs, a traceable static information model of BOM and a dynamic process model of BOM changing are established. A consumpable material distribution method from PBOM to MBOM based on path and part instance is proposed, and 3D coordinate dynamic operation is used to ensure the correctness of 3D model assembly and display. According to this method, the memory data structure is designed, and the system function is realized and verified, which proves that the method in this paper meets the practical application requirements.

Differential torque deviation collision detection method based on the dynamic model of industrial robot

ZHANG Zhenyu, ZHONG Peisi, ZHANG Chao, WANG Xiangwen, LIU Mei, SUN Yuyan

2023, (3): 163-172. doi: 10.19287/j.mtmt.1005-2402.2023.03.022

[Abstract] FullText HTML PDF(3292KB)

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Aiming at the problem of industrial robot collision detection, a differential torque deviation collision detection method based on the dynamic model of industrial robots is proposed. An adaptive genetic algorithm based on penalty function is used to calculate the optimal excitation trajectory in the identification of dynamic parameters. A single-layer neural network with an adaptive learning rate is used to identify the dynamic parameters of the robot, and the robot dynamic model is obtained. The torque deviation between the predicted torque and the actual torque is calculated by using the dynamic model, the sensor carried by the robot and the driving current signal.The backward first-order difference and backward second-order difference of the torque deviation are carried out to distinguish the industrial robot collision into intentional collision and unintentional collision, realize the robot collision detection, and trigger the corresponding collision avoidance mechanism to avoid equipment and personnel damage. Physical collision detection is verified with 6R industrial robots, and the experimental results show that the collision detection algorithm can effectively distinguish non-collision, unintentional collision and intentional collision, which improves the safety of collaborative operation of industrial robots.

Application of workpiece measurement function in Siemens 840D sl five-axis CNC machine tool

WANG Dashuang, HONG Rongjing

2023, (3): 173-178. doi: 10.19287/j.mtmt.1005-2402.2023.03.023

[Abstract] FullText HTML PDF(1362KB)

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Taking the Siemens 840D sl five-axis CNC machine tool as an example, this paper expounds in detail the five-axis function parameter configuration method, the 3D probe debugging and calibration method, and the accurate calculation of the five axis transformation geometric vector based on the space standard sphere and the Siemens five-axis calibration cycle (cycle9960). Through the vector calibration of the five axis machine tool rotation axis, axis and other motion systems, the workpiece measurement error of the five-axis CNC machine tool is effectively reduced. At the same time, the working principle and execution process of 840D sl five-axis coordinate conversion and Siemens measurement cycle are also deeply studied. Based on the motion change law of tool axis vector in the machining process of Siemens 840D sl five-axis machine tool, a workpiece measurement method suitable for universal five axis machine tool is adopted, so as to realize automatic measurement of workpiece coordinate in the process of machining, shorten the auxiliary time of part processing, and improve the processing efficiency and accuracy.

Research on accurate simulation technology of inspection process for manufacturing process

LIU Jing, WU Qiong, MA Fei

2023, (3): 179-183. doi: 10.19287/j.mtmt.1005-2402.2023.03.024

[Abstract] FullText HTML PDF(1483KB)

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The workpiece in the manufacturing process is the combination of theoretical shape and blank residue, the collision risk of measure is extremely high. To avoid risks in advance, an accurate simulation method of inspection process for manufacturing process is proposed. According to the similarity of NC machining process and CMM detection process in motion, the simulation environment of measuring machine based on VERICUT is constructed. The geometric state model of part processing is obtained by using the blank inheritance between simulation stations. and the accurate simulation of manufacturing process oriented inspection process is realized. The application shows that this method can effectively find the unreasonable problems of measurement trajectory and measurement parameters through computer virtual simulation, and avoid accidents and unnecessary losses caused by direct measurement of entities.

Fatigue damage detection of SLM alloy based on nonlinear ultrasonic

JIA Guanghui, YUAN Liukui, CHANG Hao, ZHANG Hao

2023, (3): 184-188. doi: 10.19287/j.mtmt.1005-2402.2023.03.025

[Abstract] FullText HTML PDF(1549KB)

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In order to improve the detection ability of fatigue damage of selective laser melting GH4169 nickel-based alloy for vehicle, an efficient detection method based on nonlinear ultrasound was designed. The fatigue damage state of the specimen was accurately judged according to the nonlinear coefficient of ultrasound, and the fatigue damage of the alloy was rapidly measured by the high-order harmonic detection technology. Results show that the second harmonic wave has a lower amplitude than the fundamental wave. The specimen after 20, 000 fatigue tests shows signals with a larger amplitude of change in comparison to the initial specimen. Equiaxed crystals are formed in the microstructure of the sample, and most of the columnar crystals show strong directivity. A large number of fatigue cracks appear in the periodic fatigue samples. With the increase of fatigue period, the variation of nonlinear ultrasonic test is enlarged, forming similar variation characteristics. Compared with the test point at the neck contraction, the ultrasonic nonlinear coefficient at the horn mouth has a positive correlation with the fatigue cycle, but it only increases slightly. This study has a good theoretical support value for improving the fatigue damage detection accuracy of laser fused samples.

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2023 No. 3

Journal DynamicsMore

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