氣體輔助射出成型控制系統之應用

Application of the Gas-Assisted Injection Molding Control System

蔡宗憲(Tsung-Hsien Tsai)

指導教授 ： 林百福

國立臺北科技大學/機電學院/車輛工程系所/碩士(2005年)

摘要

傳統射出成型機通常使用開迴路控制策略，來完成塑膠成品的成型。然而，此類的控制策略，不能滿足大尺寸或中空的複雜成型品，在成型時的要求。因此，在本研究中，發展閉迴路控制策略，來控制傳統射出成型機在射出成型時的充填及保壓階段。然後，在後充填行程的保壓階段，應用氣體輔助射出成型的高壓氣體，來完成塑膠產品的成型。將傳統射出成型機與氣體輔助射出成型系統合併，稱之為氣體輔助射出成型控制系統。此系統明顯的為非線性且不明確系統，其數學模式是難以正確建立出來，因此要設計以數學模式為基礎的控制器，來控制此系統是困難的。本研究中，提出不需要模式的智慧型控制策略：(1)傳統模糊控制器，(2)灰預測模糊控制器，及(3)修正型自組織模糊控制器，來控制氣體輔助射出成型控制系統，並評估對系統控制性能。經由實驗證實，在上升時間的反應及降低穩態誤差上，灰預測模糊控制器及修正型自組織模糊控制器，比起傳統模糊控制器有較佳的控制性能。

關鍵字

氣體輔助射出成型 ； 灰預測模糊控制器 ； 修正型自組織模糊控制器

並列摘要

Traditional injection molding machine (TIMM) generally employs an open-loop control strategy for performing injection molding of plastic products.However, such control strategy cannot satisfy for injection molding requirement in complicated geometric shape with large size or hollow plastic products.Therefore, this work developed a closed-loop control strategy to control the TIMM during the filling and holding phases of injection molding;then the high-pressure gas of the gas assisted injection molding system was applied in holding phase of the post-filling process for achieving injection molding of plastic products.
The TIMM incorporated the gas-assisted injection molding system that was called gas-assisted injection molding control system (GAIMCS).The GAIMCS is clearly a nonlinear with uncertain system; hence, designing a model-based controller to control it is difficult because its mathematical model is hard to establish accurately.This work proposes model-free intelligent control strategies: (1) traditional fuzzy controller (TFC), (2) grey prediction fuzzy controller (GPFC), and (3) new modifying self-organizing fuzzy controller (NMSOFC),to control the GAIMCS for evaluating control performance of the system. The GPFC and NMSOFC have better control performance in quickening the rise time and reducing the steady-state error than does TFC,as verified by experimental results.

並列關鍵字

gas-assisted injection molding ； grey prediction fuzzy controller ； new modifying self-organizing fuzzy controller

參考文獻

[1] R. Pantani, V. Speranza, A. Sorrention and G. Titomanlio, "Molecular orientation and strain in injection moulding of thermoplastics," Macromolecular Symposia, vol. 185, 2002, pp. 293-307.

[2] R. Pantani, V. Speranza, A. Sorrention and G. Titomanlio, "Molecular orientation in injection molding: experiments and analysis," Rheologica Acta, vol. 43, issue 2, 2004, pp. 109-118.

[3] X. Chen, Y.C. Lam and D.Q. Li, "Analysis of thermal residual stress in plastic injection molding," Journal of Materials Processing Technology, vol. 101, 2000, pp. 275-280.

[5] S. M. Chao, S. M. Wang, and S. C. Chen, "Dynamic modeling of a gas pressure control system for a gas-assisted injection molding process," Polymer Engineering and Science, vol. 40, no. 3, 2000, pp. 583-594.

[6] R. D. Chien, S. C. Chen, M. C. Lin, P. H. Lee and C. S. Chen, "Effect of gas channel design on the molding window of gas-assisted-injection-molded polystyrene parts," Journal of Applied Polymer Science, vol. 90, 2003, pp. 2979-2986.