Diagnosis of fault processing parameters based on qualities in injection molding
| Autor: | Bo-Shen Chen, 陳柏伸 |
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| Rok vydání: | 2016 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 104 In the injection molding processing, complex processing parameters need to be adjusted for expected qualities. Once the process is abnormal, it’s essential to spend a lot of time and human work in fault diagnosis. In this study, we focus on fault diagnosis of injection molding processing parameters for polylactide/glass fiber composites. The injection molding processing parameters include melt temperature, injection speed, packing pressure, packing time, and cooling time. The qualities include tensile strength, hardness, impact strength and flexure strength. In this thesis, we adjust the processing parameters to make the process conditions deviate from the optimal process condition, and the multivariate statistical control chart can be used to monitor downgrade qualities. The machine is operated at the optimal process conditions to generate normal samples and their four qualities data are chosen as historical data. With these historical data, the upper control limit(UCL) of optimal processing parameters can be found by using Hotelling’s T2, and is used to detect the fault T2 values with abnormal samples. Then, we obtain the residuals of qualities for abnormal samples by residual control chart, and choose them to be the feature values for the neural network in distinguishing fault processing parameters. On the other hand, we build a fault diagnosis table for single quality based on the relationship between the quality and significant processing parameters by using analysis of variance in Taguchi method. The results show that the proposed methods can diagnose fault processing parameters at a high rate. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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