本研究重點在於開發出以塑膠漿料為成型材料的快速原型系統。在光學平台方面使用的加工能量源為Nd:YAG固態雷射,雷射束射出到擴束鏡,把雷射束擴大打到X-Y掃描振鏡上,再由X-Y掃描振鏡的光學鏡片將雷射束重新聚焦,並且正確的找出雷射焦點能量最密集處,最後聚焦完的雷射束打到鋪層平台上。 材料方面是使用EOS快速原型系統的原廠尼龍粉末摻入適量的水溶性PVA及水,如此一來粉末材料也具有液態的特性,可以容易的鋪成薄層。實驗裡有進行漿料配方的調製,漿料必須好鋪層並且不影響燒結,之後對於燒結的試驗作出在不同瓦特數下,對坏料的燒結情形,導入總焦耳數的概念,來取得適當的燒結參數,並對於圖形內部線間距及疊層試驗做分析,可觀察對燒結層厚的影響,最後進一步找出適當的參數達到3D物件的製作成形。因為材料為塑膠漿料,所以在加工物件時,不需要製作支撐就可進行加工,最後物件的取得只需將加工完的塑膠漿料塊浸泡清水中,使塑膠漿料塊溶解即可取出塑膠物件,達到工件的製作。
The objective of this research is developing a plastic type rapid prototype system which can use plastic slurry material rather than conventional plastic powder to bring a thinner layer thickness during fabrication. In this developed system, Nd: YAG solid state laser is used to provide the energy source to sinter or to fuse the plastic material. The optical system were divided into three categories: 1. laser beam is penetrated into the 4x Beam Expander; 2. laser beam is expanded and projected into the X-Y scan head; 3. laser beam is focus via the f-theta lens followed by the X-Y scan head on the forming surface. The material used in this testing is plastic slurry which contents a fine nylon powder from EOS rapid prototype system, water soluble PVA, and water. The slurry material can pave a thin layer easily. The formula of the slurry has been studied. It should be good in paving and easy to be sintered. Furthermore, the processing parameters in terms of the laser power, scanning speed, and hatch spacing have been studied. Because the material used in this RP system is plastic slurry, it will not move during next layer paving. On the other hand, it acts like the support of the sold part and bring the advantage to build parts without supporting structures. After the building up process completed, soaking the completed parts into water, the green parts can be easy taken off from the working plate. The final 3D fabrication testing shows a good result of a 3D structure parts in a good structure definition which is very difficult to be fabricated in conventional RP system.