傳統單螺桿之電腦模擬及與障壁螺桿功能之比較

Abstract

電腦模擬為目前各工業先進國為了因應市場多樣化的需求,於電腦上進行 仿真分析,減少實測次數,節省產品開發所需之時間與資金。塑膠加工成型 中,螺桿負責塑膠原料的輸送、熔融、混練、計量等功能,設計(選擇)適當 之螺桿,有助提升產品品質、節約能源、降低不良率、增長機械壽命等多 方面之優點,為押出成型過程中最重要之元件。但目前國內押出業者不論 是在螺桿設計或操作條件,大多依傳統方式師徒授受、口耳相傳或採用試 誤法,憑經驗以尋求設計及加工條件,缺乏基本原理之研究與探討。本文係 利用電腦來模擬傳統單螺桿之特性,其內容包括改變加工條件(螺桿轉速、 套筒溫度等)及改變螺桿幾何形狀(溝深、螺旋角、壓縮比等)對固體床速 度、薄膜厚度、熔化速率、熔化量及熔融膠料平均溫度、壓力之影響;並 對傳統單螺桿與障壁螺間之差異加以比較。 For various market needs, industrialized countries recently began to simulate a screw process by CAD, which can decrease the number of tests and reduce the time and cost for developing a new screw. During plastic extrusion, a screw has the functions of feeding, melting, mixing, and weighing. A good screw can not only improve product's quality and reduce energy need, but also increase the durable life of an extruder, but local producers still design or operate it almost by traditional trial-and-error methods. In this study, CAD was utilized to simulate the characteristics conventional single screw. Processing parameters----rotation speed and chamber temperature ---- and the shape of a screw ---- ditch width, spiral angle, and compression ratio ---- were varied to indentify how those factors affected solid bed velocity, solid bed width, melt film thickness, melting rate, melting capacity, rage bulk temperature, and pressure buildup. Finally, the differences between single screw and barrier screws were found.