以LOM為基礎的多種材料薄片快速原型製程之研究

Abstract

新世代之快速原型技術有全新名詞，稱為快速生產或快速製造。如何能快速製作具功能性元件，如嵌入件、組合件、及具有多種材質之原型，為目前快速原型技術的重要研究課題。一般大多數的快速原型系統侷限於製程加工或是材料的限制，難以製作具多材質之功能性元件，其中的薄片積層法製程，因薄片材料多樣性，可製作不同材質之元件，具發展潛力，但也因積層加工方式及廢料剝除問題無法達成。 為能製作具多種材質之功能性元件，擴展快速原型新領域，本文以薄片積層法的製程為基礎，發展了一套嶄新的多種材料之薄片積層法加工製程以先切後黏再切兩次切割的方式，順利自動去除廢料並提出多種材料積層製程規劃。新製程是以物件概念為依據，將加工層內每個2D輪廓圖形都轉化為物件，依據材質、層級、群組方式定義物件，進行物件積層加工，在此提出一套物件道次加工流程演算法則與簡化方式，可順利將切層內所有物件依序完成加工，應用於多種材質物件的積層製作。研究中利用製程中獨特的多重送料匣裝置，能將工件階梯狀誤差精度控制在定值下，提供數個不同厚度的薄片材料，進行可變層厚的加工，可減少薄片積層數量，增進製程的加工效率。此外研究中提出了特殊支撐結構之建構法則以及簡化方式，利用物件概念將水溶性材料或是臘材置入於空區域（廢料區），產生合宜的支撐結構，可有效解決廢料剝除的問題。 本研究以兩個不同案例進行模擬驗證，驗證得知，多種材料之薄片積層法加工製程不但可製作複雜的中空工件，也能應用於多種材質之元件製作。因此新式多種材料薄層積層法，不但可提升薄片積層製程的競爭能力，更能擴展整個快速原型製程應用的新領域。

The evolution of the new generation rapid prototyping (RP) technology has brought RP technology a new terminology named Rapid Production or Rapid Manufacturing. The efficient production of functional parts including RP part with insert, assembly part, and the multi-materials mock-up has been paid much attention in the current rapid prototyping technology. The inherent restrictions of the processes and materials are the main causes to refrain most of the rapid prototyping systems from making multi-materials functional parts. The Laminated Object Manufacturing (LOM), a kind of RP system, has great potential in this aspect since various materials are applicable to the process. On the other hand, the de-cubing problem of waste material of the process impedes its practical progress. In order to explore the new frontier of the RP technology in making multi-materials functional parts, a novel multi-materials LOM process is proposed in this study. In the proposed approach, two-stage cutting processes where a post cutting process following the normal cut-bond process are adopted to remove the waste material in-process such that manufacturing of multi-materials RP part can be accomplished. The object definition is the key concept in this new process. Each 2D contour in a layer is transformed as an object. Then the object manufacturing process is carried out according to the object definition of material, layer hierarchy, and related group. An algorithm together with its simplifying method is proposed to take all steps needed for different objects in one layer. A unique multi-material feeding mechanism is proposed in this study to achieve a reasonable tolerance of layer geometry. In addition, it can provide laminating materials with different thicknesses so that the number of the laminating layer can be reduced and the process efficiency can be significantly enhanced. More, a new forming methodology of the special supporting structure is also proposed by defining the blank area (waste-material area) as the object made of water-soluble material. Two case studies are investigated in the thesis. It is verified that not only the complex hollow part but also the multi-materials object is manufactured. The proposed new multi-materials laminated object manufacturing process is expected to make LOM more competitive besides opening up a new application field of RP technology.