目前小腿義肢承筒主要由義肢師以手工製作，首先需使用石膏繃帶擷取患者殘肢形狀，以製作出殘肢石膏陽模，此過程繁複且耗時。接著還要進行複雜的石膏陽模外形修改，此步驟十分仰賴義肢師的經驗與技術。且承筒製作完成後原始的石膏陽模早已破壞無法保留。
本研究設計製作真空取模系統，以快速取得殘肢陽模。並參考逆向工程的概念，藉由三維掃描系統取得殘肢模型點資料，以提供承筒模型設計軟體進行編修，且掃描得到的殘肢形狀點資料可以保留。製作後的承筒檔案配合三維列印機(3D Printer, 3DP)製作承筒模型。期待藉由該取模流程改善傳統手工石膏陽模取模耗時、浪費材料等缺點，並有效提昇三維列印技術在小腿義肢承筒製作上之應用性，以協助義肢師製做品質穩定的小腿義肢承筒。
本研究發展之可開闔式真空取模系統，導入PTB(Patella-Tendon-Bearing)式承筒之概念應用於真空取模系統，先在患者殘肢之非耐壓區貼附襯墊以增加空間，減少與承筒接觸時的壓力，且依據殘肢狀況來評估襯墊的厚度、範圍及形狀。將貼附襯墊的殘肢置於陰模腔體中，闔上腔體並在外側提供預壓力，接著抽真空使腔體變硬後，開啟腔體即可輕易的取出患者殘肢，再次闔上並定位腔體，即可獲得殘肢陰模。再於此陰模注入矽砂粒，完成密封並抽真空以快速複製殘肢模型。
本研究以殘肢石膏模型進行取模測試，在掃描取得模型點資料後，以軟體輔助疊合數個相同石膏模型之點資料，驗證本研究工具取得模型點資料之一致性與穩定性。此外，徵求了二位小腿截肢患者參與，以本研究設計製作之真空取模工具取得患者殘肢形狀，並實際製作出義肢承筒供患者穿戴測試，患者主觀感覺並無不適之處，且由實驗結果顯示，製作出的承筒與殘肢的接觸壓力均小於患者可忍耐的疼痛壓力，可知本研究於取模前在非耐壓區貼附襯墊之步驟確實達到成效，且取得之殘肢模型形狀正確，輔以包含三維列印機的小腿義肢承筒製作流程，即可用基本手藝做出適合患者的義肢承筒。

Currently, a transtibial socket is manually fabricated by a prosthetist. First step is to capture the stump shape of the amputee by using plaster bandages to produce a plaster stump mold. A complex process to modify the shape of the plaster mold is then followed. This procedure heavily depends on the experiences and skills of the prosthetist and is time-consuming. The modified plaster mold is then used to making a transtibial socket. The original plaster mold should be removed and can’t be reserved after a socket is produced.
Based on the concept of reverse engineering and ‘dilatancy’, this research designed and manufactured a vacuum casting system to quickly duplicate the stump mold of an amputee. The casting system includes a detachable two-bag casting tool connected to a vacuum pump. Then combining some emerging technologies to develop a fabrication process of transtibial socket named CAD/3DP process, to ameliorate the shortcoming of the traditional process such as time-consuming and the requirement of plaster modification skills. This improvement can effectively enhance the application of 3D printing technology on the transtibial socket production, and to assist a prosthetist to fabricate stable quality of transtibial prosthetic sockets.
Two amputees participated the use of the vacuum casting system and the CAD/3DP process to produce transtibial sockets. The results of socket fits and contact pressures between stump and socket demonstrated that acceptable transtibial sockets can be fabricated by an inexperienced prosthetist.

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