組織工程支架提供細胞生長的環境結構及組織成型後的外型，因此建構一個合適的支架結構與外型，對於組織培養相當重要。由於人體的器官或組織的構型非常複雜，可藉由電腦輔助設計或電腦斷層掃描影像重建來設計或重建支架的三維外型，並結合快速原型的切層理論與冷凍擠壓層積成型技術來建構複雜外型的組織工程用支架。 本研究目標在發展一套整合模型切層、加工路徑規劃以及四軸加工平台控制介面的軟體，以達成支架由設計到製作完成整合作業。本研究主要分為四個項目: 1.以減少支撐結構量進而縮短加工時間為目的的支架姿態最佳化。利用基因演算法來搜尋支架模型具最小軸對齊邊界方塊的方位，以符合製作平台可加工的區域；2.利用快速原型的切層理論建立支架模型輪廓，再根據切層輪廓的上下階層架構來建立支架模型的加工區域與支撐區域；3.依據支架內部多孔隙結構的要求，利用光柵掃瞄法規劃加工路徑方向，以求得加工路徑的點資料；4.經由串列通訊埠將加工路徑點資料傳輸至四軸加工平台，平台接收特定字串作動，以逐層堆積方式成型。 本研究以人體耳朵模型為例，由軟體分析其最佳建構位置、切層與規劃路徑點資料，並利用擠壓冷凍法製實作耳朵模型的切層路徑，以逐層堆疊方式製作複雜外型的組織工程用支架。 Three-dimensional scaffolds for tissue engineering provide growing structures and shapes for cells to grow into tissues. Therefore it is important to build suitable structures and appearances for cells to attach and grow. The shapes of scaffolds can be designed by applying computer-aided design or reconstructed from CT images. This research studies the procedure and path planning algorithm for building 3D scaffolds with complicate shapes. The algorithm integrates model slicing, determination of supporting areas, path planning of injection nozzles, and communication interface with a four-axis manufacturing platform. The goal is to develop a software program to integrate the processes from design to manufacturing. First, the orientation of the scaffold model is optimized by using genetic algorithm to reduce the manufacturing time and materials. Then, a slicing algorithm for rapid prototyping is applied to the model to generate the slices and their profile contours. The supporting area of each slicing layer is determined by minus the material area from the union of the profile contours of all slices above the current slicing layer. Finally, according to designed porous structure, the tool path points are determined by raster scanning. The coordinates of the tool path points are input to the manufacturing platform through a serial port so that the scaffold can be manufactured layer by layer. A human ear is used as an example for verifying the above algorithms. The 3D ear model is fabricated by using tooth paste. The video taken by the microscope mounted on the machine shows the algorithms developed are capable for optimizing the procedure to fabricate scaffolds for tissue engineering.
