聚乳酸(polylactic acid，PLA)是目前被廣泛使用的生醫材料，其中包括手術縫線、心血管支架(stent)、組織工程支架(scaffolds)、和藥物傳輸裝置等。PLA其生物可降解性及製造來源已受到許多的關注，對今日醫療技術有著重要的地位。本研究開發一特殊環形轉印系統及製造方法製作PLA心血管支架，由於環形轉印中往往遇到脫模步驟時產生負拔模角問題，本研究將模具透過分為數塊以及將對單一結構經特殊設計而使各拔模角由負拔模角轉成正拔模角，成功解決了製程中脫模的問題。
本實驗更利用商用Computational fluid dynamics (CFD)，在有限體積法(Finite volume method, FVM)的基礎下模擬PLA材料於環型模具中模穴填充之行為，進而判斷模擬與實驗之差異程度，找出最佳化填充參數。最後利用特殊模具以環形轉印製作出之支架將與模擬做一交叉比對探討。
本研究以環形轉印系統成功轉印出直徑10 mm、厚度0.7 mm之心血管支架，由實驗結果得到在壓印時間60秒、轉印溫度110 oC及轉印壓力0.4 MPa具有最佳的填充率。此環形轉印製程相較於傳統雷射切割支架，不僅有效地降低了製程時間，對於目前心血管和非心血管的生物可降解支架在製程及量產上，具有一定的貢獻及突破。

Polylactide (PLA) is currently used in a number of biomedical tools, including sutures, stents, scaffolds, and drug delivery devices. PLA is a widely used polymer for biomedical devices which has received much attention for its biodegradability and origin in renewable resources.
This research developed a circular imprint system and the manufacturing method for PLA stent fabrication. A special designed circular mold and imprint system were employed to manufacture stent structure. The special designed circular mold was divided into several parts for the purpose of demolding easily. It makes draft angle from negative to positive when we carry out a circular imprint process. In addition, commercial computational fluid dynamics software based on the finite volume method (FVM) was used for simulating the material filling behavior and optimizing the imprint process. Finally, PLA stents were fabricated using the circular imprint process with the special design mold and the experimental results were compared with the simulation.
　The developed circular imprint system has successfully been used to fabricate PLA stents with dimensions of diameter 10 mm and thickness 0.7 mm. the results show the stent structures can be full filled with the process parameters of imprint time 60 sec, imprint temperature 110 oC and imprint pressure 0.4 MPa. This circular imprint process can efficaciously reduce the processing time comparing to laser cutting process which is used to fabricate biodegradable stents currently. This study contributes to the fabrication and mass production of biodegradable vascular and non-vascular polymer stents.

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