A reliable process planning approach based on fuzzy comprehensive evaluation method incorporating historical machining data

2019 ◽  
Vol 234 (5) ◽  
pp. 900-909 ◽  
Author(s):  
Wenping Mou ◽  
Xin Gao
Keyword(s):  
Process Planning ◽  
Evaluation Method ◽  
Tool Path ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Machining Process ◽  
Prototype System ◽  
Machining Parameters ◽  
Entropy Weight ◽  
Structural Parts

The quality of process planning could directly affect product quality, machining efficiency and cost. In small batch production such as machining aircraft structural parts, human experience is dominant in the process planning of those parts with great variability. Inferior planning of the machining process directly leads to low efficiency and quality, which has serious impact on the lead time of aircraft structural parts. To address these problems, different from the existing process knowledge reuse method by estimating the geometric similarity, a more reliable process planning method based on fuzzy comprehensive evaluation via historical machining data is proposed in this article. As long as machining resources are determined, a feature-based historical machining data model can be built, and the similarities between new machining features and the features in the database are estimated accordingly. Machining strategy, which contains tool path strategy and machining parameters, can then be identified according to the evaluation results of the similar features based on entropy weight method. A prototype system is developed and successfully applied to the typical aircraft structural parts.

The Effect of Machining Toolpath on Surface Roughness and Dimensional Accuracy for High-Speed Micro Milling

2017 ◽  
Vol 261 ◽  
pp. 69-76
Author(s):  
Amin Dadgari ◽  
De Hong Huo ◽  
David Swailes
Keyword(s):  
Surface Roughness ◽  
Process Planning ◽  
Tool Path ◽  
Dimensional Accuracy ◽  
Machining Process ◽  
Micro Milling ◽  
Geometric Features ◽  
Machining Parameters ◽  
Machining Performance ◽  
Planning Stage

This paper investigates different machining toolpath strategies on machining efficiency and accuracy in the micro milling of linear and circular micro geometric features. Although micro milling includes many characteristics of the conventional machining process, detrimental size effect in downscaling of the process can lead to excessive tool wear and machining instability, which would, in turn, affects the geometrical accuracy and surface roughness. Most of the research in micro milling reported in literature focused on optimising specific machining parameters, such as feed rate and depth of cut, to achieve lower cutting force, better surface roughness, and higher material removal rate. However, there was little attention given to the suitability and effect of machining tool path strategies. In this research, a tool path optimisation method with respect to surface roughness and dimensional accuracy is proposed and tested experimentally. Various toolpath strategies, including lace(0°), lace(45°), lace(90°), concentric and waveform in producing linear and circular micro geometric features were compared and analysed. Experimental results show that the most common used strategies lace(0°) and concentric reported in the literature have provided the least satisfactory machining performance, while waveform toolpath provides the best balance of machining performance for both linear and circular geometries. Hence, at process planning stage it is critical to assign a suitable machining toolpath strategy to geometries accordingly. The paper concludes that an optimal choice of machining strategies in process planning is as important as balancing machining parameters to achieve desired machining performance.

Reliability Evaluation of Electromagnetic Flowmeter Based on Entropy Weight and Fuzzy Theory

2011 ◽  
Vol 383-390 ◽  
pp. 5321-5326
Author(s):  
Chun Yu Yu ◽  
Kai Li Zhang ◽  
De Zhong Ma ◽  
Zhen Zhou
Keyword(s):  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Electromagnetic Flowmeter ◽  
Qualitative Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Reliability Evaluation ◽  
Assessment Method ◽  
Entropy Weight ◽  
Evaluation Indexes ◽  
Mean Time

With regard to the problem that only single index has been used in assessment of reliability, a suitable comprehensive assessment method about reliability index of electromagnetic flowmeter was established, and Mean Time To First Failure(MTTFF), Mean Time Between Failure(MTBF) and equivalent failure rate(D) were selected as the standards of reliability evaluation for the electromagnetic flowmeter in this paper. Because many evaluation elements involved and failure information and evaluation indexes are fuzzy, fuzzy comprehensive evaluation based on entropy weight was introduced to quantify the qualitative evaluation indexes, and indexes weight were determined scientifically by using comprehensive evaluation obtained from combining a subjective expert’s evaluation weight with objective entropy weight. Two kinds of the domestically produced electromagnetic flowmeter were studied, the censored data obtained from the process of consumers’s use were analyzed, and fuzzy comprehensive evaluation method based on entropy weight was used to evaluate the indexes of reliability in two kinds of electromagnetic flowmeter comprehensively. The results show that the conclusion is consistent with the fact, the method can effectively solve the problem existed in current modeling, and evaluation of electromagnetic flowmeter reliability has great practical value in the application.

Entropy Weight Multi-Level Fuzzy Comprehensive Evaluation in Power Plant Security Based on Reliability Identification

2012 ◽  
Vol 482-484 ◽  
pp. 2390-2395
Author(s):  
De Qiang Li
Keyword(s):  
Power Plant ◽  
Evaluation System ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Evaluation Model ◽  
Fuzzy Comprehensive Evaluation ◽  
Security Evaluation ◽  
Fuzzy Evaluation ◽  
Entropy Weight ◽  
Multi Level

In the paper, we establish an evaluation system in the study of four aspects such as people, regulation, equipment and technology management, field management and engineering construction. We present an entropy weight multi-level fuzzy comprehensive evaluation model in power plant security on the basis of reliability identification. Firstly, it identifies the reliability of power plant security evaluation system. Secondly, it can meet the condition that the system is reliable. Then it obtains the indicator weight of all levels in the evaluation system by the entropy weight method. Finally, it carries out a comprehensive evaluation in power plant security by the multi-level fuzzy evaluation method.

Risk Assessment of Reservoir by Fuzzy Comprehensive Evaluation Method Based on Information Entropy

2013 ◽  
Vol 438-439 ◽  
pp. 1612-1618
Author(s):  
Yong Jia Song ◽  
Cong Cong Jin ◽  
Xian Cai Zhang ◽  
Jing Li
Keyword(s):  
Risk Assessment ◽  
Information Entropy ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Assessment Method ◽  
Assessment Model ◽  
Risk Level ◽  
Entropy Weight ◽  
Weighting Method

This paper proposes a new risk assessment model on account of the fuzziness and uncertainty of risk factors in the reservoir after earthquake. The paper adopts methods of information entropy and fuzzy mathematics to assess risk level of the model. After analyzing the statistical data of earthquake-damaged reservoirs, we present comprehensive weight composed of importance and improved entropy weight. Base on comprehensive weight, we can adopt membership function to establish single factor evaluation of the model. Moreover, we combine fuzzy weighting method to assess risk level of a reservoir after earthquake. The result shows that risk level of the reservoir is high-risk. The case study verifies the practicability and rationality of the risk assessment method. Therefore, the method could be applied in the emergency rescue and reinforcement for reservoir after earthquake.

Entropy Weight-Fuzzy Comprehensive Evaluation Method of the Safety Evaluation of Water Inrush

2013 ◽  
Vol 868 ◽  
pp. 300-305 ◽  
Author(s):  
Tian Jun Zhang ◽  
Jin Hu Ren ◽  
Sheng Hong Yu ◽  
Wei Cui
Keyword(s):  
Risk Assessment ◽  
Evaluation Method ◽  
Comprehensive Evaluation ◽  
Water Inrush ◽  
Safety Evaluation ◽  
Fuzzy Comprehensive Evaluation ◽  
Actual Situation ◽  
Entropy Weight ◽  
Fuzzy Comprehensive Evaluation Method ◽  
Comprehensive Evaluation Method

For the accuracy of the inrush risk assessment of the problem, put forward in the mine inrush risk assessment using the entropy weight fuzzy comprehensive evaluation method to determine the index weight, through the membership function in fuzzy comprehensive evaluation to quantify the qualitative description of these factors, evaluated the henan jiaozuo mine inrush risk. The results show that the mine water inrush risk grade is "great", the actual mine water inrush accidents have occurred, prediction results conform to the actual situation, and safety evaluation value based on the principle of maximum membership degree is more than analytic hierarchy - fuzzy comprehensive evaluation to get , 0.0696. Thus, the method in the mine inrush prediction can objectively and accurately reflect the actual situation of mine inrush.

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