The fabrication of shape memory alloy (SMA) based products requires the precise bending and high-temperature training of SMA wires to obtain desired two-dimensional (2D) and three-dimensional (3D) patterns. In the typical fabrication process, SMA wire is bent and fixed in a pre-built mold and is trained using a furnace. However, in the small batch production, the fabrication of a mold that can be put in a high-temperature oven is costly and requires a long time to fabricate. A novel SMA wire bending process using vat photopolymerization (VPP) is presented in this paper. A rotary wire extruding system was designed to control the feeding speed of the fed wire and the bending of the wire into the desired shape. The wire bending process was enabled by utilizing a VPP tool that was immersed in liquid resin to selectively cure the resin to firmly fix the extruded SMA wire on a substrate. An air bubble assisted separation process was developed to address the separation of the cured resin from the immersed VPP tool. After the bending of the SMA wire into the desired shape, the SMA wire was connected to an electric current to heat the wire to a high temperature required by the training process so the SMA wire can memorize the fabricated pattern. Finally, the photocured fixtures deposited by the VPP tool were dissolved by a chemical solution and the bent SMA wire was detached from the fixture that was ready to use. The developed numerically controlled wire bending process is flexible for designed patterns and can fabricate SMA wires into 2D/3D shapes without specific molds or tedious manual work. Several test cases were performed to demonstrate the effectiveness of the newly developed SMA wire bending process.

基于形状记忆合金（SMA）的产品的制造需要对SMA线材进行精确的弯曲和高温训练，以获得所需的二维（2D）和三维（3D）图案。在典型的制造过程中，将SMA导线弯曲并固定在预制模具中，然后使用熔炉对其进行培训。然而，在小批量生产中，可放入高温炉中的模具的制造成本高且制造时间长。本文提出了一种新颖的采用还原槽光聚合（VPP）的SMA线材弯曲工艺。设计了旋转线材挤出系统，以控制进给线材的进给速度和线材弯曲成所需形状的弯曲。通过利用浸入液态树脂中的VPP工具来选择性地固化树脂，以将挤出的SMA导线牢固地固定在基板上，从而可以进行导线弯曲过程。开发了气泡辅助分离工艺，以解决固化树脂与浸入式VPP工具的分离问题。将SMA线弯曲成所需形状后，将SMA线连接到电流以将线加热到训练过程所需的高温，以便SMA线可以记忆所制作的图案。最后，将VPP工具沉积的光固化固定装置用化学溶液溶解，然后将弯曲的SMA线从准备使用的固定装置上卸下。开发的数控线弯曲工艺可灵活地设计图案，并且可以将SMA线制成2D / 3D形状，而无需使用特定的模具或繁琐的手工工作。进行了几个测试案例，以证明新开发的SMA导线弯曲工艺的有效性。