Research on self-maintenance strategy of CNC machine tools based on case-based reasoning

2021 ◽  
Author(s):  
Li Kangju ◽  
Sun Weitang ◽  
Liu Yefeng ◽  
Zhao Yuan
Keyword(s):  
Machine Tools ◽  
Cnc Machine Tools ◽  
Case Based Reasoning ◽  
Maintenance Strategy ◽  
Cnc Machine ◽  
Case Based

THE MODULAR CONFIGURATION SYSTEM BASED ON CASE-BASED REASONING

2012 ◽  
Vol 11 (02) ◽  
pp. 135-142
Author(s):  
CHANGCHUN LIU ◽  
ZHONGQI SHENG ◽  
LIKE WU ◽  
CHAOBIAO ZHANG
Keyword(s):  
Machine Tools ◽  
Modular Design ◽  
Numerical Control ◽  
Product Configuration ◽  
Cnc Machine Tools ◽  
Case Based Reasoning ◽  
Cnc Machine ◽  
Fuzzy Similarity ◽  
Configuration System ◽  
Case Based

Product configuration technology is the core of the modular design of computer numerical control (CNC) machine tools. Combined with modular design technology and case-based reasoning (CBR) technology, this paper proposed a modular configuration design method based on CBR for CNC machine tools. Using the fuzzy similarity priority ratio and gray correlation analysis algorithm, respectively, the calculation of case priority and the case evaluation are realized and the best match case of the user needs is selected. The module configuration system was developed using MATLAB/gui. By designing the example and analyzing the result, the configuration system is more rapid and accurate than conventional methods in the process to find the best match instance.

scholarly journals Group Maintenance Strategy of CNC Machine Tools Considering Three Kinds of Maintenance Dependence and Its Optimization

2021 ◽  
Author(s):  
Junkai Sun ◽  
Zezhou Sun ◽  
Chuanhai Chen ◽  
Chuliang Yan ◽  
Tongtong Jin ◽  
...  
Keyword(s):  
Machine Tools ◽  
Coupling Effect ◽  
Numerical Control ◽  
System Level ◽  
Cnc Machine Tools ◽  
Maintenance Cost ◽  
Maintenance Strategy ◽  
Cnc Machine ◽  
Stochastic Dependence ◽  
Failure Intensity

Abstract Unreasonable maintenance strategies will increase maintenance costs and reduce the efficiency of CNC (Computer Numerical Control) machine tools. Therefore, not only the degradation state of components but also their coupling effect should be considered to obtain a scientific and reasonable system-level maintenance strategy because of the dependence among different components of CNC machine tools. This study proposes a group maintenance strategy of CNC machine tools considering economic, structural, and stochastic dependence among critical components and optimizes the group maintenance strategy. The model of group maintenance of CNC machine tools is composed of four sub-models: sub-model of component degression, sub-model of group maintenance decisions, sub-model of imperfect maintenance, sub-model of maintenance cost. Utilizing the model of group maintenance of CNC machine tools, the time, objective, and measures of maintenance can be decided according to the degression state and failures. And then, the cost of each maintenance can be calculated. In the group maintenance model, economic dependence and structural dependence among components are quantified by cost, while stochastic dependence is quantified by failure intensity. On that basis, the Monte Carlo method is used to simulate the machine tool operation process and the long-term maintenance cost of CNC machine tools corresponding to a certain failure intensity threshold is calculated. Finally, Genetic Algorithm is used to optimize the failure intensity thresholds of preventive and group maintenance. A numerical example verifies the effectiveness of the proposed optimization method for group maintenance strategy.

scholarly journals Study of Machining of Gears with Regular and Modified Outline Using CNC Machine Tools

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2913
Author(s):  
Rafał Gołębski ◽  
Piotr Boral
Keyword(s):  
Machine Tools ◽  
Coordinate Measuring Machine ◽  
Optical Microscope ◽  
Numerical Control ◽  
Cnc Machine Tools ◽  
Cnc Milling ◽  
Cnc Machine ◽  
Cylindrical Gears ◽  
Measuring Machine ◽  
Five Axis

Classic methods of machining cylindrical gears, such as hobbing or circumferential chiseling, require the use of expensive special machine tools and dedicated tools, which makes production unprofitable, especially in small and medium series. Today, special attention is paid to the technology of making gears using universal CNC (computer numerical control) machine tools with standard cheap tools. On the basis of the presented mathematical model, a software was developed to generate a code that controls a machine tool for machining cylindrical gears with straight and modified tooth line using the multipass method. Made of steel 16MnCr5, gear wheels with a straight tooth line and with a longitudinally modified convex-convex tooth line were machined on a five-axis CNC milling machine DMG MORI CMX50U, using solid carbide milling cutters (cylindrical and ball end) for processing. The manufactured gears were inspected on a ZEISS coordinate measuring machine, using the software Gear Pro Involute. The conformity of the outline, the tooth line, and the gear pitch were assessed. The side surfaces of the teeth after machining according to the planned strategy were also assessed; the tests were carried out using the optical microscope Alicona Infinite Focus G5 and the contact profilographometer Taylor Hobson, Talysurf 120. The presented method is able to provide a very good quality of machined gears in relation to competing methods. The great advantage of this method is the use of a tool that is not geometrically related to the shape of the machined gear profile, which allows the production of cylindrical gears with a tooth and profile line other than the standard.

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