全電立式射出機射出系統之設計

A Study of the Design for the Injection System of A Fully Electric Vertical Injection Molding Machine

 

摘要

 

由於近來電子產業的快速成長,對製程設備的性能要求也相對提高,如IC等精密產品的生產機器除了必須滿足精密與穩定外,對生產速度與作業環境的污染率也非常重視,因此用以處理該類產品之塑膠封裝製程的射出成形機也需隨之改良。

本研究主要在探討完全電器驅動的立式射出機(Fully Electric Vertical Injection Molding Machine),首先使用3D繪圖軟體SolidWorks98,以模組化的設計程序,就一般30噸射出機的規格提出一個包含射出、計量與射座單元的馬達傳動機構設計,包含動力系統的分析與設計、伺服馬達容量大小的選定以及機械結構的有限元素應力應變分析與設計(使用SolidWorks外掛之FEM模組:COSMOS4.0)

設計過程中,各模組的零組件皆有功能上的描述、應力的分析、材料的選用以及組裝的說明,特別是感測元件(Load Cell,荷重元),本設計在這部分提出一個新式的組裝設計,使荷重元避免受到組裝軸承所施加的預壓以及滑座與導柱間的摩擦力而影響量測精度。

本研究第二階段是設計高速射出機,以市場上先進機種的性能規格以及射出機廠商相關的實務經驗做引導,對高速射出所面臨的問題與解決對策(分成材料、模具與機器三部分)進行研究,其中機器部分即是針對上一階段所提出的傳動機構,使用COSMOS分析做最佳化的低驅動慣量設計。同時作者亦提出一低驅動慣量的射出機構(柱塞式射出機構),可使射出機在達到高速與高響應性的性能時,其驅動單元的動力需求更為經濟,而且結構穩定性更佳。

此外,本研究特別強調產業界或學術界欲開發一個新產品時應做的準備工作,尤其是對國內外專利的完整探討,因此不僅能補足學術論文探討在具體性及實用性上的欠缺,更為可新產品開發時衍生的新技術預作專利申請的準備,達到智慧財產權的保護作用及提升附加價值。

 

ABSTRACT

 

     Due to the rapid growth of the electronic industry, the requirements for the functions and quality of the processing machines have been greatly raising up as well. Those precision products such as IC not only require the machines to be very accurate and steady, but also emphasize the production speed as well as the pollution of the working environment. Therefore, in order to satisfy those requirements, the injection molding machines which are used to pack those products have to make some improvements.

     It is an obvious trend that a fully electric-drive system is going to replace the conventional hydraulic-drive system. The reason is pretty clear that the motor-drive system would not cause the environment’s pollution, and the response speed as well as the controllability is better than that of the conventional hydraulic-drive. However, the fully electric-drive system has some inherent disadvantages at this current stage, for example, the output-force control of the motor is more complicated than that of the hydraulic system. Besides that, the measurement of the clamping force and the injecting force is the another problem needs to take care.

     This study is aimed to develop the injection system of a vertical-type fully electric injection-molding machine. A design of the motor-drive mechanism for a 30-ton injection-molding machine, which includes injection unit, measurement unit and screw-holding unit, is presented. The modularized design method is applied in this design with the 3D CAD software—SolidWorks 98. The new design has been verified by the stress analysis through the finite-element analysis software—COSMOS 4.0.

     All the machine elements of each module have the descriptions of their functions, stress analysis, material selection and the guidelines for assembling, Especially for the load cell, a new assembly design has been presented to decrease the error in accuracy caused by the pre-load and the friction force.

     This study has also developed the drive system and the structure for the high-speed fully electric molding machines according to the specifications of the current advanced molding machines as well as the practical design experience from the industry. This could include three major parts: material, mold and machine itself. For the machine part, an optimum drive mechanism with low inertia is designed through COSMOS. A plunger-type injection mechanism with high-speed and high-response is also presented. It has the advantages of economical drive unit and good stability of the structure. The results could provide the future research in this area as a reference.

     This study also emphasizes on the prepared work for the development of a new product for industry and academia, especially on the completed study of the related patents in the world. Not only it could fill the gap between the theory and the applicability, but also could prepare to file the patent application for the new technology during the development in order to protect the intellectual property as well as to increase the additional value of the product.