制造技术与机床

The development and design of numerical control drilling machine for tire movable mould

LIU Xiaofei, ZHANG Yanjun, ZHANG Xiaofei, XIAN Xiaoling, ZHANG Jinsheng, ZHANG Heng

2022, (8): 9-13. doi: 10.19287/j.mtmt.1005-2402.2022.08.001

[Abstract] FullText HTML PDF(1427KB)

Abstract:
A tire mold needs to drill holes on its inner conical surface, and it is difficult to process with general drilling machine or drilling and milling machining center. In this paper, a numerical control drilling machine for this process is developed. In this machine tool, the workpiece is placed on the worktable, and the rotation of the worktable realizes the workpiece indexing. Relative to the worktable, the drilling head can move along 3 coordinates. The y-axis direction is parallel to the inner cone bus, and the y-axis direction can be adjusted within a certain range to adapt to workpieces with different inner cone. The 3-coordinate displacement of the drilling head is driven by the servo motor, driven by the ball screw and guided by the linear guide rail, so the displacement is accurate and the positioning accuracy is high. The worktable, base and other main parts are cast, with good precision retention and strong rigidity. The machine has the advantages of high machining precision and convenient operation. The process parameters need to be optimized to further improve the processing efficiency.

Mechanical dynamics modeling and analysis of the special machine for vertical inner cavity

LI Lingxiao, CHENG Qunlin, PING Hao, YUAN Zhendi, YE Lei

2022, (8): 14-20. doi: 10.19287/j.mtmt.1005-2402.2022.08.002

[Abstract] FullText HTML PDF(1917KB)

Abstract:
For the vertical four-axis inner cavity machining special machine,the mechanical dynamics modeling is carried out based on the dynamic sub-structure method. The dynamic stiffness characteristics of the ball screw pair and linear guide pair of the special motorized joint are solved. The natural mode of the whole machine is analyzed by the established dynamic mode, and the natural frequency is solved by the analytical method. The finite element mode of the machine is established by the finite element software, and the analysis results of the natural frequency, mode shape and harmonic response of the whole machine with the rigid contact of the joint and the dynamic stiffness are set. The results show that the established dynamic model with dynamic stiffness can effectively mirror the dynamic characteristics of the machine, and can be applied to the dynamic analysis of the machine and the research of the digital twin virtual prototype.

Research of optimization of complex runner surface milling paths for magazine based on MAX-PAC and Vericut

GUO Haobang, CAO Zheng, LEI Xuelin, HE Yun

2022, (8): 21-26. doi: 10.19287/j.mtmt.1005-2402.2022.08.003

[Abstract] FullText HTML PDF(2160KB)

Abstract:
For a magazine part with a deep runner, complex surface and prone to chatter and interference during machining. In order to improve the efficiency and quality of the milling process, a five-axis machining process and special tools were designed according to the structural characteristics of the magazine part. CNC path planning was completed using the 5-axis impeller part CNC machining software MAX-PAC, and was verified using Vericut. The test machining was completed on the machine and the results showed that the complex surfaces in the magazine were of good quality.

Research and analysis on the surface properties in cutting TC4

ZHANG Hao, LI Jinquan

2022, (8): 27-32. doi: 10.19287/j.mtmt.1005-2402.2022.08.004

[Abstract] FullText HTML PDF(2142KB)

Abstract:
Changes of surface material characteristics during the cutting process can easily cause surface fatigue damage. By cutting test of titanium alloy TC4, the influence law of feed rate on surface grain plastic deformation was studied, the TC4 cutting process was simulated using finite element simulation to obtain the cutting surface temperature and stress. Combined with experiment and simulationand, the connection between TC4 cutting surface grain change, cutting surface temperature and stress were explored. The results show that the plastic deformation degree of TC4 machined surface increases with the increase of feed rate, and the surface temperature and stress also increase with the increase of feed rate. Under the combination of surface temperature and stress, the surface grains appear elongated and torsional deformation, and the closer to the surface, the more obvious.

Research on cutting force model of forming spiral bevel gears

LUO Jing, KANG Xianqiang

2022, (8): 33-40. doi: 10.19287/j.mtmt.1005-2402.2022.08.005

[Abstract] FullText HTML PDF(2604KB)

Abstract:
Spiral bevel gear milling tooth cutting force is an important basis for the design of bevel gear machine tools, and also an important basis for milling tooth vibration control, tool wear status monitoring, and cutting parameter optimization. According to the cutting process of forming spiral bevel gear wheels, this paper firstly derives the instantaneous chip area according to the principle of gear cutting and the geometric theory of spiral bevel gears. Then, using the material constitutive equation and the oblique angle cutting theory to calculate the stress in the shear zone of the material, the instantaneous cutting force model for machining the spiral bevel gear wheel by the forming method is constructed. Finally, a calculation program is written using Matlab software, and the theoretical cutting force model is tested and verified, which proves that the model has a certain accuracy.

Analysis of drilling parameters on drilling quality of carbon fiber reinforced plastics

WANG Tianyu, JIN Chengzhe, SHAO Yongbo

2022, (8): 41-48. doi: 10.19287/j.mtmt.1005-2402.2022.08.006

[Abstract] FullText HTML PDF(2274KB)

Abstract:
Carbon fiber reinforced plastics (CFRP) have the characteristics of low interlayer strength and complex anisotropy, which are prone to machining damage. The selection of cutting parameters has a great influence on the quality of drilling. The finite element software was used to establish a machining simulation model for drilling T300 carbon fiber reinforced plastics, and different cutting parameters were selected for drilling simulation, and the chips and their formation reasons were analyzed. Orthogonal test method is selected for drilling processing test. The obtained damage test results such as burr, tearing, delamination damage and hole wall damage are compared with the simulation results to verify and analyze their causes. The results show that when drilling the T300 carbon fiber composite the tear defects at the exit of the hole are much larger than those at the entrance of the hole. That is, the quality of the entrance drilling is better than that of the exit drilling. The largest impact on the exit and the entrance tear value is the diameter of the drill bit, the cutting speed is the second, and the feed rate has the least effect. However, the diameter of the drill bit has the greatest influence on the hole size error, followed by the feed rate, and the cutting speed has the least effect.

Implementation of binocular vision algorithm for positioning and grasping of parallel robot

REN Jianhua, ZHANG Ningke, GAO Ruizhen

2022, (8): 49-56. doi: 10.19287/j.mtmt.1005-2402.2022.08.007

[Abstract] FullText HTML PDF(3122KB)

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In the automation industry, robot object grasping highly depends on machine vision for positioning analysis. Aiming at the problems of low positioning accuracy and poor effect of existing binocular vision robots, an improved SGBM stereo matching algorithm which can accurately locate in parallel robots is proposed. The gradient information is integrated into sad algorithm as the similarity measure function of cost calculation; Then the adaptive bilateral filtering is used as the cost aggregation, which makes up for the cumbersome defect of artificially setting parameters to find the optimal process. At the same time, the noise is removed and the matching accuracy is improved, so as to complete the reconstruction of 3D point cloud. Finally, the hand eye calibration algorithm is used to transfer the camera coordinate data to the robot coordinate system, and then guide the robot to complete the positioning and grasping of the workpiece. Experiments show that only when the workpiece is placed arbitrarily in the field of vision of the binocular camera, it can complete accurate grasping, and the average error rate is less than 5%. Compared with the traditional method, it has higher real-time and accuracy, and has a good application prospect in the automation industry.

A new method of piezoelectric inkjet ink drop recognition based on machine vision

LIU Qingtao, QIAN Man, LV Jingxiang, SONG Jiayao

2022, (8): 57-62. doi: 10.19287/j.mtmt.1005-2402.2022.08.008

[Abstract] FullText HTML PDF(2022KB)

Abstract:
In the field of 3D printed circuit board, the requirements for piezoelectric inkjet ink droplets are getting higher and higher. The traditional ink droplet observation method is not perfect and the accuracy is unstable. Therefore, this paper studies the identification and observation of piezoelectric inkjet ink droplets based on the non-contact principle of machine vision. Firstly, a telecentric machine vision measurement system is built to collect effective ink drop images. Then combined with sub-pixel edge extraction operator and least square method, an improved edge least square fitting method is designed and compared with regional least circumcircle method and edge least circumcircle method. The experimental results show that the ink droplet radius obtained by the method proposed in this paper has small error and high precision. The results obtained by calculating the radius of the edge are more accurate, and can be used to monitor the existence of satellite ink droplets. The research results have important guiding significance for improving the circuit inkjet effect.

Design of roller conveyor drive disk assembly system based on 3D vision

WU Jun, YUAN Haibing, XIA Lei

2022, (8): 63-68, 90. doi: 10.19287/j.mtmt.1005-2402.2022.08.009

[Abstract] FullText HTML PDF(2454KB)

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Aiming at the problem of high labor intensity and low work efficiency of manual assembly in the assembly process of roller line drive disc, an automatic assembly system based on 3D vision and robot is designed. The 3D point cloud image of the driver disk is obtained by Pro S Enhanced industrial camera, and the point cloud image is preprocessed by point cloud filtering, point cloud clustering segmentation and point cloud matching. The position and attitude of the drive disk are obtained with KUKA industrial robot. The experimental results show that the positioning error of the system is less than 0.5 mm and the assembly time is 12 s. Compared with the traditional manual assembly, the assembly beat is increased by 50%, and the production site runs stably and reliably to meet the production needs of enterprises.

Research on the current situation and development of motorized spindle technology based on patent analysis

ZHENG Yaqi, YAN Lei, PENG Ziping, XU Yichen, SONG Feifei

2022, (8): 69-73. doi: 10.19287/j.mtmt.1005-2402.2022.08.010

[Abstract] FullText HTML PDF(943KB)

Abstract:
At present, there is still a certain gap between China′s CNC machine tools and the world′s leading level, and some core technologies have not been fully mastered. In order to fully understand the research status and development trend of domestic motorized spindle technology in recent five years, from the perspective of patent analysis and based on various patent analysis platforms, the intellectual property rights between enterprises, universities and different types of patents are analyzed. The results show that domestic enterprises and colleges and universities apply for less intellectual property rights and low technological innovation in the machining center′s motorized spindle. In the follow-up research and development process, the research and development efforts should be strengthened to actively carry out the research and development of new goods, new technologies, and new processes, with an emphasis on the timeliness and significance of intellectual property.

Industry knowledge base construction based on knowledge graph

WANG Deqiang, WU Jun, GUAN Liwen

2022, (8): 74-80. doi: 10.19287/j.mtmt.1005-2402.2022.08.011

[Abstract] FullText HTML PDF(1764KB)

Abstract:
This paper firstly expounds the related concepts of machine learning and knowledge map, and their applications in the construction of knowledge base and the positions in the industry. Then introduces the common model of machine learning combined with the typical algorithm. To increase the relevance of industry knowledge in the knowledge base and reduce the redundancy, this paper introduces a new technology related industry knowledge map and its construction method, thus led to the study of the method of building knowledge base for industry, and combined with intelligent knowledge base shows the innovative application of knowledge map, using the knowledge map to provide technical support for the search and recommendation feature of the knowledge base, at the same time through knowledge map shown more visually for the domain knowledge. Finally, this paper further describe the role of machine learning and knowledge map play in industry knowledge.

Design and experimental study of a bidirectional support ultrasonic bearing

SU Jiang, TONG Jie, SHEN Yanhu

2022, (8): 81-84. doi: 10.19287/j.mtmt.1005-2402.2022.08.012

[Abstract] FullText HTML PDF(1207KB)

Abstract:
Ultrasonic bearing is a kind of non-contact bearing suitable for high speed and high precision, which has broad application prospects. A bidirectional support ultrasonic bearing is proposed. The suspension characteristics of the bearing are analyzed theoretically, and the influencing factors of suspension height are obtained. The prototype of bidirectional support ultrasonic suspension bearing is made, and the maximum speed and performance are tested. The experimental results show that the bidirectional support ultrasonic bearing has good antifriction performance, and its maximum speed can reach 9 364 r/min; When the shaft speed is reduced from 2 000 r/min to 200 r/min, the support time of ordinary ball bearing is 90 s, while that of bidirectional support ultrasonic bearing is 280 s.

Research on an adaptive thermal compensation structure of drilling and tapping center spindle-screw

YU Lianzhou, ZHOU Shousheng, WANG Na, LI Qi

2022, (8): 85-90. doi: 10.19287/j.mtmt.1005-2402.2022.08.013

[Abstract] FullText HTML PDF(1335KB)

Abstract:
Drilling and tapping center is a modern manufacturing in one of the most common machine tool in metal cutting, especially is widely applied in the 3C industry, on which the product of the cutting process, because of the high-speed spindle, tool change frequently, cause bearing and disc fever, passed to the main shaft by means of heat conduction and convection of other components, resulting in the thermal deformation of the spindle, affect the machining accuracy of machined parts. Drilling and tapping center Z axis screw usually adopt the upper fixed support, the bottom in the form of floating auxiliary support, through the research on the thermal elongation, this paper proposes a spindle - screw adaptive thermal compensation structure, to balance out due to the main shaft of the thermal deformation error caused by the problem of dimensional accuracy, and then improve the machining precision of the drilling and tapping center.

Improved butterfly optimization algorithm and its application in solving inverse kinematics problem of redundant manipulators

MENG Guangshuang, GAO Dedong

2022, (8): 91-96. doi: 10.19287/j.mtmt.1005-2402.2022.08.014

[Abstract] FullText HTML PDF(1354KB)

Abstract:
Aiming at the deficiency of butterfly optimization algorithm (BOA), an improved butterfly optimization algorithm (IBOA) was proposed and applied to the inverse kinematics of redundant manipulators. The IBOA algorithm integrates three strategies, namely dynamic transformation probability strategy, optimal neighborhood disturbance strategy and random inertia weight strategy, to improve the convergence speed and convergence accuracy of the algorithm, and overcomes the problems that BOA algorithm is easy to fall into local optimal and the late convergence accuracy is not high. The test results of the three benchmark functions show that IBOA is superior in solving accuracy, solving speed and computational stability. The application results of kinematic solution of redundant manipulator obtained by IBOA show that the manipulator has smaller pose error, less calculation time and better solution stability.

Research on dynamic parameters based on the interface of bolted joints

ZHAO Chuanqiang, WANG Zhengcheng

2022, (8): 97-103. doi: 10.19287/j.mtmt.1005-2402.2022.08.015

[Abstract] FullText HTML PDF(2175KB)

Abstract:
Bolt connection is widely used in the field of construction machinery. Because of the dynamic impact on the bolt interface, there are stiffness and damping at the joint, which makes the characteristic parameters of the bolt dynamic interface nonlinear and highly uncertain. In order to study the dynamic connection characteristics and parameters of bolt dynamic connection interface, an experimental device is designed, using the method of combining finite element analysis with experimental study, the normal tangent stiffness, Surface roughness, medium and damping coefficient of the dynamic connection interface of bolts are studied, the relationship between them is analyzed.

Damage analysis of diamond grinding based on controlling the grinding rake angle

PANG Fei, LEI Dajiang, WANG Wei

2022, (8): 104-108. doi: 10.19287/j.mtmt.1005-2402.2022.08.016

[Abstract] FullText HTML PDF(2533KB)

Abstract:
In order to solve the problem that subsurface damage of diamond material is difficult to detect, this paper is based on molecular dynamics theory and method. A three-dimensional simulation model of double grits grinding is established for analysis, and the influence of different grinding rake angle on grinding force and material damage is studied. The simulation analysis results show that grinding force can be reduced by increasing the grinding rake angle, and the influence of normal grinding force is more obvious. The average coefficient of friction of negative grinding rake angle is smaller, which makes it easier to achieve the removal of diamond atoms; The subsurface damage of the diamond material under negative grinding rake angle grinding is larger. The undulating change of subsurface damage can be reduced and the subsurface damage can be improved by increasing the grinding rake angle.

Micro-deformation of the hot bed of FDM printer and compensation printing method

WANG Chunxiang, PAN Yicheng, JI Kanghui, YIN Jinlin, WANG Qichao

2022, (8): 109-115. doi: 10.19287/j.mtmt.1005-2402.2022.08.017

[Abstract] FullText HTML PDF(2580KB)

Abstract:
The levelness and flatness of the hot bed platform in FDM type printers are important prerequisites to ensure the smooth printing of the molded parts. In view of the gradual deformation of the hot bed heating and the difficulty of obtaining a good first layer, ANSYS is used to perform thermal-mechanical indirect coupling of the hot bed platform. The deformation process was simulated by simulation. The BL touch contact sensor was used to collect 15 point data on the surface of the irregular hot bed in real time. The Lagrangian and bicubic interpolation algorithms were used to interpolate the curvature of the sampling points, and the generated mesh bed was triangular. Then, the thickness of 1mm is given and the slicing algorithm is used to form the compensation substrate code. On the dual-nozzle printer, nozzle 1 uses water-soluble PVA material to print the substrate in a supported form, and nozzle 2 prints the solid model. The experimental results show that this method has a simple principle and can remove the Compensation materials are convenient, and the printing model accuracy is improved, especially for the easily deformed hot bed of large FDM printers.

Optimization design and process improvement of horizontal machining center bed based on simulation

WANG Jianjun, ZHANG Xiaoye, ZHANG Wenshuai, YANG Hongjun, MU Longtao

2022, (8): 116-121. doi: 10.19287/j.mtmt.1005-2402.2022.08.018

[Abstract] FullText HTML PDF(2345KB)

Abstract:
In view of the problem that the guide rail is too distorted during the assembly of a horizontal machining center bed and the horizontal adjustment cannot reach the accuracy and needs to be repaired, this paper compares the torsional and flexural static stiffness of the bed and analyzes the stability of the processing technology support by using the simulation software, through which the weakness of the bed in the structural design and processing technology support is found and the improvement scheme is put forward. This study provides a reference structure and method for the structure and high quality manufacturing process design of the bed of the same type of machine tools. The quantitative value of torsional and flexural stiffness of the bed obtained in the research process can also provide a reference value for the finite element analysis of the same type of machine tools.

Research on forming process parameters optimization of TWB for automobile cover panel

JIANG Lei, LI Shiquan, WANG Long, WANG Dapeng, MA Peibing, ZHANG Xiongfei

2022, (8): 122-128. doi: 10.19287/j.mtmt.1005-2402.2022.08.019

[Abstract] FullText HTML PDF(2466KB)

Abstract:
Aiming at the problem that the forming margin of the TWB automotive cover panel was insufficient and the welding area was easy to crack, the front door inner panel of a certain model was used as the research object, and the method of combining the test method and finite element analysis was adopted, and the main process parameters causing the cracking on the welding seam area of the front door inner panel were quickly screened out based on the orthogonal test, and the influence of the main process parameters on the formability of the front door inner panel was analyzed. Based on the evaluation of the maximum thinning rate of the welding seam area, the effects of the blank holder force B.H.F., the friction coefficient μ, the height of the first piercing cutter H1, the height of the second piercing cutter H2, and the width of the thinner sheet W on the forming quality of the front door inner panel were studied in turn. Using the analysis of variance and range, the primary and secondary order of the influence of each process parameter on the maximum thinning rate of the welding seam area was obtained, and the value of the process parameters were: B.H.F.= 1 000 kN, μ = 0.13, W = 1 044 mm, H2=11 mm, H1=10 mm. The forming simulation of the front door inner panel was carried out by the optimal combination of process parameters, the die tryout verification was carried out on this basis, and the parts with good forming quality and high margin were obtained, the maximum thinning rate of the weld area was 19.1%, which met the quality judgment standards.

Research on topological modification method of internal gearing power honing based on multi-axis linkage

XIA Lian, JIANG Oupeng, TIAN Xiaoqing, HAN Jiang

2022, (8): 129-136. doi: 10.19287/j.mtmt.1005-2402.2022.08.020

[Abstract] FullText HTML PDF(1928KB)

Abstract:
As one of the commonly used gear finishing processes, the internal gearing power honing process requires a special diamond dressing wheel corresponding to the workpiece to be customized when the workpiece gear is reshaped, which makes the process less versatile and the processing cost is high. This paper proposes a topological modification method for internal gearing power honing, which realizes arbitrary topological modification of the tooth surface of workpiece gears with standard honing wheels. The mathematical model of topological modification tooth surface of internal gearing power honing is established, and the mapping relationship between the standard honing wheel and the workpiece gear is obtained, and the additional motion of the A-axis and X-axis of the machine tool motion during topology modification is expressed by a high-order polynomial together with the electronic gearbox, the effect of the variation of the motion parameters in the polynomial on the machining tooth surface is expressed by the sensitivity matrix, with the modified tooth surface as the goal, the sensitivity coefficient in the sensitivity matrix as the gradient, the dynamic programming algorithm is used to solve the motion parameters, and the modified workpiece tooth surface is obtained. The simulation results show that the method can realize the topological modification of the tooth surface through multi-axis linkage, the modification error is small, the cost is greatly reduced, and the method is universal.

Contact fatigue characteristics and life prediction model of carburized gear

KANG Heming, DENG Hailong, LI Mingkai, LI Yongping, CHEN Yu, YANG Pu, YU Huan

2022, (8): 137-141, 177. doi: 10.19287/j.mtmt.1005-2402.2022.08.021

[Abstract] FullText HTML PDF(2067KB)

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Considering the influence of heat treatment process on the contact fatigue life of carburized Cr-Ni gears, the contact fatigue life prediction model of carburized gears is constructed. The gear contact fatigue test is carried out by using the gear contact fatigue test machine, and the gear contact stress is calculated based on Hertz theory. The S-N curve is drawn according to the test results. Through the observation of tooth surface morphology and the comparison with the test data, it can be seen that the contact fatigue life of the gear before the pitting phenomenon is formed accounts for the main part, and the gear will fail rapidly after the pitting phenomenon occurs. Based on Paris formula, considering the local and overall hardness, residual stress, crack closure effect and crack length of gear, the contact fatigue life prediction model of gear is constructed. The model prediction results show that the model can accurately predict the gear contact fatigue life, which provides a new and reliable method for people to understand the gear contact fatigue characteristics and predict the gear contact fatigue life.

Detection method of bolt fatigue cracking based on vibration acoustics

LIU Yongchao

2022, (8): 142-148. doi: 10.19287/j.mtmt.1005-2402.2022.08.022

[Abstract] FullText HTML PDF(1845KB)

Abstract:
In this paper, a method to detect bolt crack defects using vibroacoustics technology is proposed. The feasibility of this method to identify bolt crack damage is demonstrated through percussion test, modal simulation and theoretical derivation. The test proves that the vibroacoustics method can effectively identify the location and depth of bolt crack defects. In addition, the minimum discernible defect depth of M30×200 mm bolt is 2 mm, and the defects located in 1/2 and 1/4 positions of bolts are most easily identified. Combined with the common fatigue fracture forms of bolts in engineering field, this method can effectively identify the fatigue cracking of bolts, which has certain engineering application significance. In addition, this paper proposes the research direction of the fusion of vibroacoustics technology and machine learning technology, providing intelligent research ideas for bolt damage detection.

Intelligent scheduling method of rollergrindingproduction line based on improved genetic algorithm

LU Yaoxun, WANG Liping, SUN Lirong, YANG Jinguang, WANG Dong, LI Xuekun

2022, (8): 149-155. doi: 10.19287/j.mtmt.1005-2402.2022.08.023

[Abstract] FullText HTML PDF(1707KB)

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Aiming at the scheduling problem of roller grinding production line with multiple workpieces, multiple processes, multiple grinding machines and multiple cranes, an improved genetic algorithm is proposed to realize efficient and intelligent scheduling under the constraints of “workpiece-equipment-crane” space-time coupling. The scheduling model of the roller grinding production line is established, and the genetic algorithm is improved from four aspects of coding, selection, crossover, and mutation, so as to generate feasible solutions and improve the ability to seek optimization and jump out of the local optimum.Crane decoding rules and series operators based on action decomposition are further designed to complete intelligent scheduling. Taking the maximum completion time as the performance index and comparing with other algorithms, the results show that the proposed intelligent scheduling method is obviously better.

Technical transformation of pin shaft heat treatment workshop based on process model

WANG Yajun

2022, (8): 156-160. doi: 10.19287/j.mtmt.1005-2402.2022.08.024

[Abstract] FullText HTML PDF(1607KB)

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Pin shaft is widely used in mining mechanical connection, and the heat treatment process plays an important role on its mechanical property. The existing heat treatment process has a low degree of automation and informatization, resulting in a large gap between the actual effect and the expected result, and does not adapt to the digital development trend. An approach to reform the heat treatment workshop is presented which is based on models of the key processes. The models, on one hand, are used to provide rapid-design guidance for the transformation scheme of the workshop. On the other hand, combined with the actual data obtained from the system operation, the models can be utilized as mechanism model for the subsequent upgrading of digital control (digital twin system).

Energy-efficient hybrid flow-shop scheduling considering job batching

ZHANG Zhongwei, MENG Ya, LI Yi, LI Yuansheng, HU Wenbo, HUI Yanbo

2022, (8): 161-170. doi: 10.19287/j.mtmt.1005-2402.2022.08.025

[Abstract] FullText HTML PDF(2967KB)

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Production scheduling is an effective measure to improve efficiency and reduce energy consumption (EC) in a hybrid flow shop. Taking the constraints of workpiece transport and tool change into account, a new energy-efficient hybrid flow-shop scheduling (EHFS) model with EC and makespan as the optimization objectives was established by combining tool blunt standard-based job equal batching method and “turn off/on” energy-saving strategy. Then, the non-dominated sorting genetic algorithm-II (NSGA-II) was employed to solve it. In a hybrid flow shop environment, the proposed EHFS model can make a trade-off between two optimization objectives, then rationally arrange processing batches for various types of jobs, select suitable machines to process each batch, and reasonably arrange the execution sequence of the relevant batch operations and the application of “turn off/on” energy-saving strategy on each machine simultaneously. Finally, the energy-saving effect of the proposed EHFS model and the effectiveness of its solution method were verified by the case study.

Calculation and evaluation method for accuracy characteristics of machine tool linear guide connection structure

ZHAO Hongan, WU Huimin

2022, (8): 171-177. doi: 10.19287/j.mtmt.1005-2402.2022.08.026

[Abstract] FullText HTML PDF(3139KB)

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The linear guide is an important connection structure of machine tools. There is no effective method to calculate and evaluate the overall accuracy of linear guide connection structure in the existing research. The equivalent model of the linear guide connection structure is proposed based on the finite element theory ,and the deformation characteristics of which are analyzed and calculated. With the homogeneous transformation matrix theory, the accuracy characteristic calculation and evaluation method of the linear guide connection structure is established. By the method, the performance calculation and accuracy analysis on the linear guides of a vertical machine tool are carried out. To evaluation the performance of the linear guide, The influence on the accuracy of load, slider position and initial error is analyzed, finally the feasibility of the model is demonstrated.

The stability analysis of control system of aerostatic worktable based on square box

ZHU Sida, LU Zhiwei, LIU Bo, ZHANG Junan

2022, (8): 178-184. doi: 10.19287/j.mtmt.1005-2402.2022.08.027

[Abstract] FullText HTML PDF(1715KB)

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In order to further study the matching stability of aerostatic guide rail support and linear motor drive, a two-dimensional aerostatic worktable based on square box was designed and developed. Taking square box as the mechanism design and assembly reference could effectively improve the bearing performance and motion accuracy of the two-dimensional aerostatic worktable. However, the stability of the control system of the whole aerostatic worktable was difference, due to the small friction damping and large load inertia. Therefore, the stability of the system needed to be analyzed and the improvement measures were proposed. In this essay, the mathematical model of the linear motor was established based on the aerostatic worktable, and the transfer function of the control system was derived. The Bode diagram was calculated and the stability margin was analyzed by Matlab, and an experimental platform was built for verification. The results showed that the phase margin of the current loop, the velocity loop and the position loop in the two axial directions of the aerostatic worktable were greater than 60° and the amplitude margin was greater than 10 dB, which met the requirements of the system stability margin and ensured the good stability of the control system. The experimental results were in good agreement with the simulation results, which verifies the stability of the control system of the aerostatic worktable.

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2022 No. 8

Journal DynamicsMore

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